@charset "UTF-8";
:root {
  --primary-color: #8b5cf6;
  --primary-dark: #7c3aed;
  --primary-light: #a78bfa;
  --secondary-color: #6c757d;
  --secondary-dark: #545b62;
  --secondary-light: #868e96;
  --success-color: #10b981;
  --danger-color: #ef4444;
  --warning-color: #f59e0b;
  --info-color: #06b6d4;
  --text-color: #333333;
  --text-light: #666666;
  --text-lighter: #999999;
  --bg-color: #ffffff;
  --bg-light: #f8f9fa;
  --bg-dark: #212529;
  --border-color: #dee2e6;
  --border-light: #e9ecef;
  --font-family-base: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
  --font-family-heading: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
  --font-family-code: "Courier New", monospace;
  --font-size-base: 16px;
  --font-size-sm: 14px;
  --font-size-lg: 18px;
  --font-size-xl: 20px;
  --font-weight-light: 300;
  --font-weight-normal: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;
  --line-height-base: 1.6;
  --line-height-sm: 1.4;
  --line-height-lg: 1.8;
  --spacing-xs: 4px;
  --spacing-sm: 8px;
  --spacing-md: 16px;
  --spacing-lg: 24px;
  --spacing-xl: 32px;
  --spacing-xxl: 48px;
  --spacing-3xl: 64px;
  --spacing-4xl: 96px;
  --spacing-5xl: 128px;
  --spacing-6xl: 192px;
  --container-max-width: 1200px;
  --container-padding: 20px;
  --border-radius-sm: 4px;
  --border-radius-md: 8px;
  --border-radius-lg: 12px;
  --border-radius-xl: 16px;
  --border-radius-round: 50%;
  --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.1);
  --shadow-md: 0 4px 8px rgba(0, 0, 0, 0.12);
  --shadow-lg: 0 8px 16px rgba(0, 0, 0, 0.15);
  --shadow-xl: 0 12px 24px rgba(0, 0, 0, 0.18);
  --transition-base: all 0.3s ease;
  --transition-fast: all 0.15s ease;
  --transition-slow: all 0.5s ease;
  --breakpoint-xs: 480px;
  --breakpoint-sm: 768px;
  --breakpoint-md: 992px;
  --breakpoint-lg: 1200px;
  --breakpoint-xl: 1400px;
  --z-index-dropdown: 1000;
  --z-index-sticky: 1020;
  --z-index-fixed: 1030;
  --z-index-modal-backdrop: 1040;
  --z-index-modal: 1050;
  --z-index-popover: 1060;
  --z-index-tooltip: 1070;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  font-size: var(--font-size-base);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-family-base);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-normal);
  line-height: var(--line-height-base);
  color: var(--text-color);
  background-color: var(--bg-color);
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-family-heading);
  font-weight: var(--font-weight-bold);
  line-height: 1.2;
  margin-bottom: var(--spacing-md);
  color: var(--text-color);
}

h1 {
  font-size: 2.5rem;
}

h2 {
  font-size: 2rem;
}

h3 {
  font-size: 1.75rem;
}

h4 {
  font-size: 1.5rem;
}

h5 {
  font-size: 1.25rem;
}

h6 {
  font-size: 1rem;
}

p {
  margin-bottom: var(--spacing-md);
}

a {
  color: var(--primary-color);
  text-decoration: none;
  transition: var(--transition-base);
}
a:hover {
  color: var(--primary-dark);
}

ul, ol {
  margin-bottom: var(--spacing-md);
  padding-left: var(--spacing-lg);
}

li {
  margin-bottom: var(--spacing-sm);
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

button {
  cursor: pointer;
  border: none;
  outline: none;
  background: none;
  font-family: inherit;
}

.container {
  max-width: var(--container-max-width);
  margin: 0 auto;
  padding: 0 var(--container-padding);
}

.text-center {
  text-align: center;
}

.text-left {
  text-align: left;
}

.text-right {
  text-align: right;
}

.mt-sm {
  margin-top: var(--spacing-sm);
}

.mt-md {
  margin-top: var(--spacing-md);
}

.mt-lg {
  margin-top: var(--spacing-lg);
}

.mt-xl {
  margin-top: var(--spacing-xl);
}

.mb-sm {
  margin-bottom: var(--spacing-sm);
}

.mb-md {
  margin-bottom: var(--spacing-md);
}

.mb-lg {
  margin-bottom: var(--spacing-lg);
}

.mb-xl {
  margin-bottom: var(--spacing-xl);
}

.pt-sm {
  padding-top: var(--spacing-sm);
}

.pt-md {
  padding-top: var(--spacing-md);
}

.pt-lg {
  padding-top: var(--spacing-lg);
}

.pt-xl {
  padding-top: var(--spacing-xl);
}

.pb-sm {
  padding-bottom: var(--spacing-sm);
}

.pb-md {
  padding-bottom: var(--spacing-md);
}

.pb-lg {
  padding-bottom: var(--spacing-lg);
}

.pb-xl {
  padding-bottom: var(--spacing-xl);
}

.course-track {
  margin-bottom: var(--spacing-xl);
}
.course-track__header {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-md);
  padding: var(--spacing-md);
  background-color: var(--bg-light);
  border-radius: var(--border-radius-md);
  cursor: pointer;
  transition: var(--transition-base);
}
.course-track__header:hover {
  background-color: #e9ecef;
  transform: translateX(5px);
}
.course-track__icon {
  font-size: 24px;
}
.course-track__title {
  flex: 1;
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-semibold);
  margin: 0;
}
.course-track__progress {
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-bold);
  color: var(--primary-color);
}

.course-list {
  list-style: none;
  padding: 0;
  margin: 0;
  padding-left: var(--spacing-md);
}

.course-item {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-sm) var(--spacing-md);
  margin-bottom: var(--spacing-xs);
  border-radius: var(--border-radius-md);
  cursor: pointer;
  transition: var(--transition-base);
  position: relative;
}
.course-item:hover {
  background-color: var(--bg-light);
}
.course-item__status {
  width: 20px;
  height: 20px;
  border: 2px solid var(--border-color);
  border-radius: var(--border-radius-round);
  flex-shrink: 0;
  position: relative;
}
.course-item__name {
  flex: 1;
  font-size: var(--font-size-sm);
  color: var(--text-light);
}
.course-item.completed .course-item__status {
  background-color: var(--success-color);
  border-color: var(--success-color);
}
.course-item.completed .course-item__status::after {
  content: "✓";
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  color: var(--bg-color);
  font-size: 12px;
  font-weight: bold;
}
.course-item.completed .course-item__name {
  color: var(--text-color);
  font-weight: var(--font-weight-medium);
}
.course-item.active {
  background-color: rgba(139, 92, 246, 0.1);
}
.course-item.active .course-item__status {
  border-color: var(--primary-color);
  border-width: 3px;
  animation: pulse 2s infinite;
}
.course-item.active .course-item__name {
  color: var(--primary-color);
  font-weight: var(--font-weight-semibold);
}
.course-item.locked .course-item__status {
  background-color: var(--bg-light);
}
.course-item.locked .course-item__status::after {
  content: "🔒";
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  font-size: 10px;
}
.course-item.locked .course-item__name {
  color: var(--text-lighter);
}
.course-item.locked:hover {
  background-color: transparent;
  cursor: not-allowed;
}

@keyframes pulse {
  0%, 100% {
    box-shadow: 0 0 0 0 rgba(139, 92, 246, 0.7);
  }
  50% {
    box-shadow: 0 0 0 6px rgba(139, 92, 246, 0);
  }
}
.app-layout {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  padding-top: 70px;
}

.main-content {
  flex: 1;
  width: 100%;
  max-width: 100%;
  padding: var(--spacing-xl);
  background-color: var(--bg-light);
  min-height: 100vh;
  margin-left: 0;
  opacity: 0;
  transition: none;
}
@media (max-width: 992px) {
  .main-content {
    padding: var(--spacing-lg);
  }
}

#character {
  position: fixed;
  top: calc(100dvh - 128px);
  cursor: pointer;
  z-index: 100;
}
#character.fade-in {
  animation: fadeIn 0.5s ease-in-out forwards;
}
#character.fade-out {
  animation: fadeOut 0.5s ease-in-out forwards;
}
#character.hidden {
  display: none;
}
#character #health {
  position: absolute;
  bottom: 80px;
  left: 40px;
  height: 4px;
  width: 50px;
  background-color: #d1d5db;
  border-radius: 2px;
  overflow: hidden;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.2);
}
#character #health div {
  width: 100%;
  height: 100%;
  background-color: #dc2626;
  transition: width 0.3s ease;
}
#character #character-info {
  position: absolute;
  bottom: 90px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  align-items: center;
  gap: 4px;
  background: rgba(0, 0, 0, 0.75);
  color: #fbbf24;
  padding: 3px 10px;
  border-radius: 8px;
  font-size: 12px;
  font-weight: 600;
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.3);
  white-space: nowrap;
  opacity: 0;
  transition: opacity 0.3s ease;
}
#character #character-info #title-text {
  color: white;
  font-weight: normal;
}
#character #sprite {
  cursor: pointer;
  background-size: auto;
}

#donate {
  position: fixed;
  top: 0;
  right: 0;
  width: 100%;
  height: 100%;
  display: none;
  justify-content: center;
  align-items: center;
  background-color: rgba(0, 0, 0, 0.6);
  backdrop-filter: blur(4px);
  z-index: 999;
  user-select: none;
  cursor: pointer;
}
#donate.flex {
  display: flex;
}
#donate.hidden {
  display: none;
}
#donate.fade-in {
  animation: fadeIn 0.5s ease-in-out forwards;
}
#donate.fade-out {
  animation: fadeOut 0.5s ease-in-out forwards;
}
#donate > div {
  padding: 2.5rem;
  background-color: white;
  width: 100%;
  border-radius: 12px;
  max-width: 28rem;
  margin: 0 auto;
  box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
}
#donate > div.scale-in-bottom {
  animation: scaleInBottom 0.5s cubic-bezier(0.25, 0.46, 0.45, 0.94) both;
}
#donate > div.scale-out-center {
  animation: scaleOutCenter 0.5s cubic-bezier(0.55, 0.085, 0.68, 0.53) both;
}
#donate > div .flex.items-center.justify-center {
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 900;
  margin: 0 0.75rem 0.75rem;
}
#donate > div .flex.items-center.justify-center svg {
  height: 2.5rem;
  width: 2.5rem;
  margin-right: 0.75rem;
  color: #dc2626;
}
#donate > div .flex.items-center.justify-center svg.animate-ping {
  position: absolute;
  animation: ping 1s cubic-bezier(0, 0, 0.2, 1) infinite;
}
#donate > div .flex.flex-col {
  display: flex;
  flex-direction: column;
  justify-content: center;
  width: 100%;
}
#donate > div .flex.flex-col p {
  text-align: center;
  color: #000;
  font-size: 1rem;
  line-height: 1.5;
  margin: 0;
}
#donate > div .flex.flex-col .qr-donate {
  margin-top: 1rem;
}
#donate > div .flex.flex-col .qr-donate img {
  border-radius: 8px;
}

@keyframes fadeIn {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}
@keyframes fadeOut {
  from {
    opacity: 1;
  }
  to {
    opacity: 0;
  }
}
@keyframes scaleInBottom {
  0% {
    transform: scale(0);
    transform-origin: 50% 100%;
    opacity: 1;
  }
  100% {
    transform: scale(1);
    transform-origin: 50% 100%;
    opacity: 1;
  }
}
@keyframes scaleOutCenter {
  0% {
    transform: scale(1);
    opacity: 1;
  }
  100% {
    transform: scale(0);
    opacity: 1;
  }
}
@keyframes ping {
  75%, 100% {
    transform: scale(2);
    opacity: 0;
  }
}
.section-content table,
.section__content table {
  width: 100%;
  border-collapse: collapse;
  margin: var(--spacing-lg) 0;
  background-color: var(--bg-color);
  border-radius: var(--border-radius-md);
  overflow: hidden;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
}
.section-content table thead,
.section__content table thead {
  background-color: var(--primary-color);
  color: white;
}
.section-content table thead tr th,
.section__content table thead tr th {
  padding: var(--spacing-md);
  text-align: left;
  font-weight: var(--font-weight-semibold);
  font-size: var(--font-size-base);
}
.section-content table tbody tr,
.section__content table tbody tr {
  border-bottom: 1px solid var(--border-color);
  transition: background-color 0.2s ease;
}
.section-content table tbody tr:hover,
.section__content table tbody tr:hover {
  background-color: rgba(139, 92, 246, 0.05);
}
.section-content table tbody tr:last-child,
.section__content table tbody tr:last-child {
  border-bottom: none;
}
.section-content table tbody tr td,
.section__content table tbody tr td {
  padding: var(--spacing-md);
  font-size: var(--font-size-sm);
  color: var(--text-color);
}
.section-content table tbody tr td:first-child,
.section__content table tbody tr td:first-child {
  font-weight: var(--font-weight-medium);
}

.btn {
  background-color: var(--primary-color);
  color: #fff;
  padding: var(--spacing-sm) var(--spacing-lg);
  border-radius: var(--border-radius-md);
  transition: var(--transition-base);
  display: inline-block;
  font-weight: var(--font-weight-medium);
}
.btn:hover {
  filter: brightness(0.9);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}
.btn:active {
  transform: translateY(0);
}
.btn {
  text-align: center;
  border: none;
  cursor: pointer;
  font-size: var(--font-size-base);
}
.btn--primary {
  background-color: var(--primary-color);
  color: #fff;
  padding: var(--spacing-sm) var(--spacing-lg);
  border-radius: var(--border-radius-md);
  transition: var(--transition-base);
  display: inline-block;
  font-weight: var(--font-weight-medium);
}
.btn--primary:hover {
  filter: brightness(0.9);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}
.btn--primary:active {
  transform: translateY(0);
}
.btn--secondary {
  background-color: var(--secondary-color);
  color: #fff;
  padding: var(--spacing-sm) var(--spacing-lg);
  border-radius: var(--border-radius-md);
  transition: var(--transition-base);
  display: inline-block;
  font-weight: var(--font-weight-medium);
}
.btn--secondary:hover {
  filter: brightness(0.9);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}
.btn--secondary:active {
  transform: translateY(0);
}
.btn--success {
  background-color: var(--success-color);
  color: #fff;
  padding: var(--spacing-sm) var(--spacing-lg);
  border-radius: var(--border-radius-md);
  transition: var(--transition-base);
  display: inline-block;
  font-weight: var(--font-weight-medium);
}
.btn--success:hover {
  filter: brightness(0.9);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}
.btn--success:active {
  transform: translateY(0);
}
.btn--danger {
  background-color: var(--danger-color);
  color: #fff;
  padding: var(--spacing-sm) var(--spacing-lg);
  border-radius: var(--border-radius-md);
  transition: var(--transition-base);
  display: inline-block;
  font-weight: var(--font-weight-medium);
}
.btn--danger:hover {
  filter: brightness(0.9);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}
.btn--danger:active {
  transform: translateY(0);
}
.btn--warning {
  background-color: var(--warning-color);
  color: var(--text-color);
  padding: var(--spacing-sm) var(--spacing-lg);
  border-radius: var(--border-radius-md);
  transition: var(--transition-base);
  display: inline-block;
  font-weight: var(--font-weight-medium);
}
.btn--warning:hover {
  filter: brightness(0.9);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}
.btn--warning:active {
  transform: translateY(0);
}
.btn--info {
  background-color: var(--info-color);
  color: #fff;
  padding: var(--spacing-sm) var(--spacing-lg);
  border-radius: var(--border-radius-md);
  transition: var(--transition-base);
  display: inline-block;
  font-weight: var(--font-weight-medium);
}
.btn--info:hover {
  filter: brightness(0.9);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}
.btn--info:active {
  transform: translateY(0);
}
.btn--outline-primary {
  background-color: transparent;
  color: var(--primary-color);
  border: 2px solid var(--primary-color);
}
.btn--outline-primary:hover {
  background-color: var(--primary-color);
  color: var(--bg-color);
}
.btn--block {
  display: block;
  width: 100%;
}
.btn--sm {
  padding: var(--spacing-xs) var(--spacing-md);
  font-size: var(--font-size-sm);
}
.btn--lg {
  padding: var(--spacing-md) var(--spacing-xl);
  font-size: var(--font-size-lg);
}
.btn:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}
.btn:disabled:hover {
  transform: none;
  box-shadow: none;
}
.btn.completed {
  background-color: var(--success-color);
  border-color: var(--success-color);
}
.btn.completed:hover {
  filter: brightness(0.9);
}
.btn-back-to-list {
  background: linear-gradient(135deg, #6366f1 0%, #4f46e5 100%);
}
.btn-back-to-list:hover {
  background: linear-gradient(135deg, #4f46e5 0%, #4338ca 100%);
}

.skill-tree {
  max-width: 1400px;
  margin: 0 auto;
}
.skill-tree__header {
  text-align: center;
  margin-bottom: var(--spacing-xxl);
}
.skill-tree__title {
  font-size: 2.5rem;
  background: linear-gradient(135deg, var(--primary-color), #764ba2);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: var(--spacing-lg);
}
@media (max-width: 992px) {
  .skill-tree__title {
    font-size: 2rem;
  }
}
.skill-tree__stats {
  display: flex;
  justify-content: center;
  gap: var(--spacing-xl);
  flex-wrap: wrap;
}
.skill-tree__content {
  position: relative;
  padding: var(--spacing-xl) 0;
}
.skill-tree__svg {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: 1;
  overflow: visible;
}

.stat-item {
  text-align: center;
  padding: var(--spacing-md) var(--spacing-lg);
  background-color: var(--bg-color);
  border-radius: var(--border-radius-lg);
  box-shadow: var(--shadow-sm);
}
.stat-item__value {
  display: block;
  font-size: 2rem;
  font-weight: var(--font-weight-bold);
  color: var(--primary-color);
  margin-bottom: var(--spacing-xs);
}
.stat-item__label {
  display: block;
  font-size: var(--font-size-sm);
  color: var(--text-light);
}

.skill-level {
  position: relative;
  margin-bottom: var(--spacing-4xl);
  z-index: 1;
}

.skill-row {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: var(--spacing-xl);
  flex-wrap: wrap;
  margin-bottom: var(--spacing-lg);
}
.skill-row--branching {
  gap: var(--spacing-xxl);
}

.skill-node {
  position: relative;
  width: 280px;
  background-color: var(--bg-color);
  border-radius: var(--border-radius-lg);
  padding: var(--spacing-lg);
  box-shadow: var(--shadow-md);
  cursor: pointer;
  transition: all 0.3s ease;
  border: 3px solid transparent;
  z-index: 10;
}
@media (max-width: 768px) {
  .skill-node {
    width: 100%;
    max-width: 280px;
  }
}
.skill-node:hover {
  transform: translateY(-8px) scale(1.02);
  box-shadow: var(--shadow-xl);
}
.skill-node__icon {
  position: absolute;
  top: -25px;
  left: 50%;
  transform: translateX(-50%);
  width: 50px;
  height: 50px;
  background: linear-gradient(135deg, var(--primary-color), var(--primary-light));
  border-radius: var(--border-radius-round);
  display: flex;
  justify-content: center;
  align-items: center;
  font-size: 24px;
  box-shadow: var(--shadow-md);
  border: 3px solid var(--bg-color);
}
.skill-node__icon i {
  color: #ffffff;
  font-size: 22px;
}
.skill-node__content {
  margin-top: var(--spacing-md);
}
.skill-node__title {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-bold);
  margin-bottom: var(--spacing-xs);
  text-align: center;
}
.skill-node__description {
  font-size: var(--font-size-sm);
  color: var(--text-light);
  text-align: center;
  margin-bottom: var(--spacing-md);
}
.skill-node__progress .progress-bar {
  height: 8px;
  background-color: var(--bg-light);
  border-radius: var(--border-radius-lg);
  overflow: hidden;
  margin-bottom: var(--spacing-xs);
}
.skill-node__progress .progress-bar__fill {
  height: 100%;
  background: linear-gradient(90deg, var(--primary-color), var(--primary-light));
  transition: width 0.5s ease;
}
.skill-node__progress .progress-text {
  font-size: var(--font-size-sm);
  color: var(--text-light);
  text-align: center;
  display: block;
}
.skill-node__badge {
  position: absolute;
  top: var(--spacing-sm);
  right: var(--spacing-sm);
  width: 30px;
  height: 30px;
  border-radius: var(--border-radius-round);
  display: flex;
  justify-content: center;
  align-items: center;
  font-size: 16px;
  font-weight: bold;
  display: none;
}
.skill-node__badge i {
  font-size: 14px;
}
.skill-node.completed {
  border-color: var(--success-color);
  background: linear-gradient(135deg, rgba(16, 185, 129, 0.05), rgba(16, 185, 129, 0.1));
}
.skill-node.completed .skill-node__icon {
  background: linear-gradient(135deg, var(--success-color), #059669);
}
.skill-node.completed .skill-node__title {
  color: var(--success-color);
}
.skill-node.completed .skill-node__badge {
  background-color: var(--success-color);
  color: var(--bg-color);
  display: flex;
}
.skill-node.completed:hover {
  border-color: #059669;
  box-shadow: 0 8px 24px rgba(16, 185, 129, 0.3);
}
.skill-node.completed .progress-bar__fill {
  background: linear-gradient(90deg, var(--success-color), #059669);
}
.skill-node.active {
  border-color: var(--primary-color);
  background: linear-gradient(135deg, rgba(139, 92, 246, 0.05), rgba(139, 92, 246, 0.1));
  animation: glow 2s infinite;
}
.skill-node.active .skill-node__icon {
  animation: pulse-icon 2s infinite;
}
.skill-node.active .skill-node__title {
  color: var(--primary-color);
}
.skill-node.active .skill-node__badge {
  background-color: var(--warning-color);
  color: var(--bg-dark);
  animation: spin 2s linear infinite;
  display: flex;
}
.skill-node.active:hover {
  border-color: #6d28d9;
  box-shadow: 0 8px 24px rgba(139, 92, 246, 0.4);
}
.skill-node.locked {
  opacity: 0.6;
  cursor: not-allowed;
  background-color: var(--bg-light);
  border-color: var(--border-light);
}
.skill-node.locked .skill-node__icon {
  background: linear-gradient(135deg, var(--secondary-color), #495057);
}
.skill-node.locked .skill-node__title {
  color: var(--text-lighter);
}
.skill-node.locked .skill-node__description {
  color: var(--text-lighter);
}
.skill-node.locked .skill-node__badge {
  background-color: var(--secondary-color);
  display: flex;
}
.skill-node.locked .progress-bar__fill {
  background: var(--secondary-color);
}
.skill-node.locked:hover {
  transform: none;
  box-shadow: var(--shadow-md);
}

.skill-connection {
  stroke: var(--border-color);
  stroke-width: 3;
  fill: none;
  stroke-linecap: round;
  stroke-linejoin: round;
  opacity: 0.85;
  transition: all 0.3s ease;
}
.skill-connection.completed {
  stroke: var(--success-color);
  stroke-width: 4;
  opacity: 1;
}
.skill-connection.completed:hover {
  stroke-width: 5;
  filter: drop-shadow(0 0 6px rgba(40, 167, 69, 0.5));
}
.skill-connection.active {
  stroke: var(--primary-color);
  stroke-width: 4;
  stroke-dasharray: 10 5;
  opacity: 1;
  animation: dash 25s linear infinite;
}
.skill-connection.active:hover {
  stroke-width: 5;
  filter: drop-shadow(0 0 6px rgba(0, 102, 255, 0.5));
}
.skill-connection.locked {
  stroke: #94a3b8;
  stroke-width: 3;
  stroke-dasharray: 8, 4;
  opacity: 0.6;
}
.skill-connection.locked:hover {
  stroke-width: 4;
  opacity: 0.8;
}

@keyframes glow {
  0%, 100% {
    box-shadow: 0 4px 8px rgba(139, 92, 246, 0.2), 0 0 20px rgba(139, 92, 246, 0.1);
  }
  50% {
    box-shadow: 0 8px 16px rgba(139, 92, 246, 0.4), 0 0 40px rgba(139, 92, 246, 0.2);
  }
}
@keyframes pulse-icon {
  0%, 100% {
    transform: translateX(-50%) scale(1);
  }
  50% {
    transform: translateX(-50%) scale(1.1);
  }
}
@keyframes spin {
  from {
    transform: rotate(0deg);
  }
  to {
    transform: rotate(360deg);
  }
}
@keyframes dash {
  to {
    stroke-dashoffset: -20;
  }
}
.skill-tooltip {
  position: absolute;
  bottom: 100%;
  left: 50%;
  transform: translateX(-50%);
  background-color: var(--bg-dark);
  color: var(--bg-color);
  padding: var(--spacing-sm) var(--spacing-md);
  border-radius: var(--border-radius-md);
  font-size: var(--font-size-sm);
  white-space: nowrap;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.3s ease;
  margin-bottom: var(--spacing-lg);
  z-index: 1000;
}
.skill-tooltip::after {
  content: "";
  position: absolute;
  top: 100%;
  left: 50%;
  transform: translateX(-50%);
  border: 6px solid transparent;
  border-top-color: var(--bg-dark);
}
.skill-node:hover .skill-tooltip {
  opacity: 1;
}

@media (max-width: 992px) {
  .skill-tree__content {
    padding: var(--spacing-lg) 0;
  }
  .skill-level {
    margin-bottom: var(--spacing-xl);
  }
  .skill-row {
    gap: var(--spacing-lg);
  }
  .skill-row--branching {
    gap: var(--spacing-lg);
  }
  .skill-node {
    width: 100%;
    max-width: 300px;
  }
}
.responsive-warning {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
  z-index: 9999;
  justify-content: center;
  align-items: center;
  padding: var(--spacing-xl);
}
@media (max-width: 1023px) {
  .responsive-warning {
    display: flex;
  }
}
.responsive-warning__content {
  text-align: center;
  color: #ffffff;
  max-width: 500px;
  animation: fadeInUp 0.5s ease;
}
.responsive-warning__icon {
  font-size: 80px;
  margin-bottom: var(--spacing-xl);
  opacity: 0.9;
}
.responsive-warning__icon i {
  color: #ffffff;
}
.responsive-warning__title {
  font-size: 2rem;
  font-weight: var(--font-weight-bold);
  margin-bottom: var(--spacing-lg);
  color: #ffffff;
}
.responsive-warning__message {
  font-size: var(--font-size-lg);
  line-height: var(--line-height-lg);
  margin-bottom: var(--spacing-xl);
  opacity: 0.95;
}
.responsive-warning__size {
  font-size: var(--font-size-base);
  padding: var(--spacing-md) var(--spacing-lg);
  background-color: rgba(255, 255, 255, 0.1);
  border-radius: var(--border-radius-lg);
  backdrop-filter: blur(10px);
}
.responsive-warning__size span {
  font-weight: var(--font-weight-bold);
  color: var(--warning-color);
}

@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}
.modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.6);
  backdrop-filter: blur(4px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 10000;
  opacity: 0;
  visibility: hidden;
  transition: all 0.3s ease;
}
.modal-overlay.show {
  opacity: 1;
  visibility: visible;
}

.modal {
  background: white;
  border-radius: 24px;
  padding: 0;
  max-width: 480px;
  width: 90%;
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
  transform: scale(0.8) translateY(-20px);
  opacity: 0;
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}
.modal.show {
  transform: scale(1) translateY(0);
  opacity: 1;
}

.modal-content {
  padding: 2.5rem;
  text-align: center;
}

.modal-title {
  font-size: 1.75rem;
  font-weight: 800;
  color: #0f172a;
  margin-bottom: 1rem;
  line-height: 1.3;
}

.modal-message {
  font-size: 1.05rem;
  color: #64748b;
  line-height: 1.6;
  margin-bottom: 2rem;
}

.modal-buttons {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
}

.modal-btn {
  padding: 0.875rem 2rem;
  border-radius: 12px;
  font-size: 1rem;
  font-weight: 700;
  cursor: pointer;
  transition: all 0.3s ease;
  border: none;
  min-width: 120px;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}
.modal-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.15);
}
.modal-btn:active {
  transform: translateY(0);
}
.modal-btn--primary {
  background: linear-gradient(135deg, #3b82f6 0%, #2563eb 100%);
  color: white;
}
.modal-btn--primary:hover {
  background: linear-gradient(135deg, #2563eb 0%, #1d4ed8 100%);
}
.modal-btn--secondary {
  background: white;
  color: #64748b;
  border: 2px solid #e2e8f0;
}
.modal-btn--secondary:hover {
  background: #f8fafc;
  border-color: #cbd5e1;
}
.modal-btn--success {
  background: linear-gradient(135deg, #10b981 0%, #059669 100%);
  color: white;
}
.modal-btn--success:hover {
  background: linear-gradient(135deg, #059669 0%, #047857 100%);
}
.modal-btn--danger {
  background: linear-gradient(135deg, #ef4444 0%, #dc2626 100%);
  color: white;
}
.modal-btn--danger:hover {
  background: linear-gradient(135deg, #dc2626 0%, #b91c1c 100%);
}

.toast-container {
  position: fixed;
  top: 20px;
  left: 50%;
  transform: translateX(-50%);
  z-index: 10001;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.75rem;
  pointer-events: none;
  width: 100%;
  max-width: 600px;
  padding: 0 1rem;
}

.toast {
  background: white;
  padding: 1rem 1.5rem;
  border-radius: 16px;
  box-shadow: 0 10px 40px rgba(0, 0, 0, 0.15);
  display: flex;
  align-items: center;
  gap: 0.75rem;
  min-width: 300px;
  max-width: 100%;
  transform: translateY(-100px);
  opacity: 0;
  transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
  border-left: 4px solid;
  pointer-events: auto;
}
.toast.show {
  transform: translateY(0);
  opacity: 1;
}
.toast i {
  font-size: 1.5rem;
  flex-shrink: 0;
}
.toast span {
  color: #0f172a;
  font-weight: 600;
  font-size: 0.95rem;
  line-height: 1.5;
}
.toast--success {
  border-color: #10b981;
  background: linear-gradient(135deg, #ffffff 0%, #f0fdf4 100%);
}
.toast--success i {
  color: #10b981;
}
.toast--error {
  border-color: #ef4444;
  background: linear-gradient(135deg, #ffffff 0%, #fef2f2 100%);
}
.toast--error i {
  color: #ef4444;
}
.toast--warning {
  border-color: #f59e0b;
  background: linear-gradient(135deg, #ffffff 0%, #fffbeb 100%);
}
.toast--warning i {
  color: #f59e0b;
}
.toast--info {
  border-color: #3b82f6;
  background: linear-gradient(135deg, #ffffff 0%, #eff6ff 100%);
}
.toast--info i {
  color: #3b82f6;
}

@media (max-width: 768px) {
  .modal {
    width: 95%;
    max-width: 400px;
  }
  .modal-content {
    padding: 2rem 1.5rem;
  }
  .modal-title {
    font-size: 1.5rem;
  }
  .modal-message {
    font-size: 1rem;
  }
  .modal-buttons {
    flex-direction: column;
  }
  .modal-btn {
    width: 100%;
  }
  .toast {
    min-width: unset;
    width: 100%;
  }
}
@media (max-width: 480px) {
  .toast-container {
    top: 10px;
    padding: 0 0.75rem;
  }
  .toast {
    padding: 0.875rem 1.25rem;
    font-size: 0.9rem;
  }
  .toast i {
    font-size: 1.25rem;
  }
}
.code-block {
  margin: 1.5rem 0;
  border-radius: 8px;
  overflow: hidden;
  background: #1e1e1e;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
  border: 1px solid #333;
}
.code-block .code-block {
  margin: 0;
}
.code-block__header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0.75rem 1rem;
  background: #2d2d2d;
  border-bottom: 1px solid #333;
}
.code-block__language {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.875rem;
  font-weight: 600;
  color: #888;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}
.code-block__language i {
  font-size: 1rem;
}
.code-block__language span {
  line-height: 1;
}
.code-block__copy {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.5rem 0.75rem;
  background: transparent;
  border: 1px solid #555;
  border-radius: 4px;
  color: #aaa;
  font-size: 0.875rem;
  cursor: pointer;
  transition: all 0.2s ease;
}
.code-block__copy:hover {
  background: #3a3a3a;
  border-color: #666;
  color: #fff;
}
.code-block__copy:active {
  transform: scale(0.95);
}
.code-block__copy--success {
  background: #28a745 !important;
  border-color: #28a745 !important;
  color: #fff !important;
}
.code-block__copy--success:hover {
  background: #218838 !important;
  border-color: #218838 !important;
}
.code-block__copy i {
  font-size: 0.875rem;
}
.code-block__copy-text {
  font-weight: 500;
}
.code-block__content {
  max-height: 500px;
  overflow: auto;
  background: #1e1e1e;
}
.code-block__content::-webkit-scrollbar {
  width: 8px;
  height: 8px;
}
.code-block__content::-webkit-scrollbar-track {
  background: #2d2d2d;
}
.code-block__content::-webkit-scrollbar-thumb {
  background: #555;
  border-radius: 4px;
}
.code-block__content::-webkit-scrollbar-thumb:hover {
  background: #666;
}
.code-block__content {
  scrollbar-width: thin;
  scrollbar-color: #555 #2d2d2d;
}
.code-block__pre {
  margin: 0 !important;
  padding: 1.25rem;
  background: transparent;
  overflow-x: auto;
}
.code-block__pre code {
  font-family: "Courier New", Courier, monospace;
  font-size: 0.9rem;
  line-height: 1.6;
  color: #d4d4d4;
  background: transparent;
  padding: 0;
  white-space: pre;
  word-wrap: normal;
  display: block;
}

@media (max-width: 768px) {
  .code-block {
    margin: 1rem 0;
    border-radius: 6px;
  }
  .code-block__header {
    padding: 0.625rem 0.875rem;
  }
  .code-block__language {
    font-size: 0.8125rem;
  }
  .code-block__copy {
    padding: 0.375rem 0.625rem;
    font-size: 0.8125rem;
    gap: 0.375rem;
  }
  .code-block__copy i {
    font-size: 0.8125rem;
  }
  .code-block__copy-text {
    display: none;
  }
  .code-block__content {
    max-height: 400px;
  }
  .code-block__pre {
    padding: 1rem;
  }
  .code-block__pre code {
    font-size: 0.8125rem;
    line-height: 1.5;
  }
}
.dark-mode .code-block {
  background: #0d1117;
  border-color: #30363d;
}
.dark-mode .code-block__header {
  background: #161b22;
  border-bottom-color: #30363d;
}
.dark-mode .code-block__copy {
  border-color: #30363d;
  color: #8b949e;
}
.dark-mode .code-block__copy:hover {
  background: #21262d;
  border-color: #444c56;
  color: #c9d1d9;
}
.dark-mode .code-block__content {
  background: #0d1117;
}
.dark-mode .code-block__content::-webkit-scrollbar-track {
  background: #161b22;
}
.dark-mode .code-block__content::-webkit-scrollbar-thumb {
  background: #30363d;
}
.dark-mode .code-block__content::-webkit-scrollbar-thumb:hover {
  background: #444c56;
}
.dark-mode .code-block__content {
  scrollbar-color: #30363d #161b22;
}
.dark-mode .code-block__pre code {
  color: #c9d1d9;
}

.light-mode .code-block {
  background: #f6f8fa;
  border-color: #d0d7de;
}
.light-mode .code-block__header {
  background: #fff;
  border-bottom-color: #d0d7de;
}
.light-mode .code-block__language {
  color: #57606a;
}
.light-mode .code-block__copy {
  border-color: #d0d7de;
  color: #24292f;
}
.light-mode .code-block__copy:hover {
  background: #f3f4f6;
  border-color: #afb8c1;
}
.light-mode .code-block__content {
  background: #f6f8fa;
}
.light-mode .code-block__content::-webkit-scrollbar-track {
  background: #fff;
}
.light-mode .code-block__content::-webkit-scrollbar-thumb {
  background: #d0d7de;
}
.light-mode .code-block__content::-webkit-scrollbar-thumb:hover {
  background: #afb8c1;
}
.light-mode .code-block__content {
  scrollbar-color: #d0d7de #fff;
}
.light-mode .code-block__pre code {
  color: #24292f;
}

.code-block .keyword {
  color: #569cd6;
  font-weight: 500;
}
.code-block .string {
  color: #ce9178;
}
.code-block .comment {
  color: #6a9955;
  font-style: italic;
}
.code-block .number {
  color: #b5cea8;
}
.code-block .function {
  color: #dcdcaa;
}
.code-block .tag {
  color: #569cd6;
}
.code-block .attr-name {
  color: #9cdcfe;
}
.code-block .attr-value {
  color: #ce9178;
}
.code-block .selector {
  color: #d7ba7d;
}
.code-block .property {
  color: #9cdcfe;
}
.code-block .value {
  color: #ce9178;
}
.code-block .variable {
  color: #9cdcfe;
}

.light-mode .code-block .keyword {
  color: #0000ff;
}
.light-mode .code-block .string {
  color: #a31515;
}
.light-mode .code-block .comment {
  color: #008000;
}
.light-mode .code-block .number {
  color: #098658;
}
.light-mode .code-block .function {
  color: #795e26;
}
.light-mode .code-block .tag {
  color: #800000;
}
.light-mode .code-block .attr-name {
  color: #ff0000;
}
.light-mode .code-block .attr-value {
  color: #0000ff;
}
.light-mode .code-block .selector {
  color: #800000;
}
.light-mode .code-block .property {
  color: #ff0000;
}
.light-mode .code-block .value {
  color: #0451a5;
}
.light-mode .code-block .variable {
  color: #001080;
}

.hero {
  padding: var(--spacing-xxl) 0;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: var(--bg-color);
}
.hero .container {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--spacing-xxl);
  align-items: center;
}
@media (max-width: 992px) {
  .hero .container {
    grid-template-columns: 1fr;
    gap: var(--spacing-lg);
  }
}
@media (max-width: 992px) {
  .hero__content {
    text-align: center;
  }
}
.hero__title {
  font-size: 3rem;
  margin-bottom: var(--spacing-lg);
  color: var(--bg-color);
}
@media (max-width: 992px) {
  .hero__title {
    font-size: 2rem;
  }
}
.hero__subtitle {
  font-size: var(--font-size-lg);
  margin-bottom: var(--spacing-xl);
  opacity: 0.9;
  line-height: var(--line-height-lg);
}
.hero__actions {
  display: flex;
  gap: var(--spacing-md);
}
@media (max-width: 992px) {
  .hero__actions {
    justify-content: center;
    flex-wrap: wrap;
  }
}
@media (max-width: 992px) {
  .hero__image {
    display: none;
  }
}
.hero__image img {
  width: 100%;
  height: auto;
}

.home-header {
  margin: 0 auto var(--spacing-xxl);
  max-width: 680px;
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--spacing-xs);
}
.home-header__avatar {
  width: 100px;
  height: 100px;
  border-radius: var(--border-radius-round);
  display: grid;
  place-items: center;
  padding: 14px;
  position: relative;
}
.home-header__logo-3d {
  width: 100%;
  height: 100%;
  perspective: 800px;
  display: grid;
  place-items: center;
}
.home-header__logo-3d .home-header__logo-img {
  width: 100%;
  height: 100%;
  object-fit: contain;
  border-radius: var(--border-radius-round);
  transform-style: preserve-3d;
  animation: logo-rotate-3d 6s linear infinite;
  box-shadow: 0 12px 24px rgba(0, 0, 0, 0.08);
}
.home-header__social {
  margin: 0;
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-bold);
  color: #14151a;
  letter-spacing: 0.2px;
}
.home-header__label {
  color: #101318;
  opacity: 0.9;
}
.home-header__handle {
  color: #8b5cf6;
  text-decoration: none;
  margin-left: 6px;
  transition: var(--transition-base);
}
.home-header__handle:hover {
  color: #7c3aed;
  text-shadow: 0 2px 12px rgba(139, 92, 246, 0.55);
}

@keyframes logo-rotate-3d {
  0% {
    transform: rotateY(0deg) rotateX(0deg);
  }
  25% {
    transform: rotateY(90deg) rotateX(5deg);
  }
  50% {
    transform: rotateY(180deg) rotateX(0deg);
  }
  75% {
    transform: rotateY(270deg) rotateX(-5deg);
  }
  100% {
    transform: rotateY(360deg) rotateX(0deg);
  }
}
.features {
  padding: var(--spacing-xxl) 0;
}
.features__grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: var(--spacing-xl);
}

.feature-card {
  background-color: var(--bg-color);
  border-radius: var(--border-radius-lg);
  box-shadow: var(--shadow-sm);
  padding: var(--spacing-lg);
  transition: var(--transition-base);
}
.feature-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-4px);
}
.feature-card {
  text-align: center;
}
.feature-card__icon {
  width: 60px;
  height: 60px;
  display: flex;
  justify-content: center;
  align-items: center;
  background: linear-gradient(135deg, var(--primary-color), var(--primary-light));
  color: var(--bg-color);
  border-radius: var(--border-radius-round);
  margin: 0 auto var(--spacing-lg);
  font-size: 24px;
}
.feature-card__title {
  font-size: var(--font-size-xl);
  margin-bottom: var(--spacing-md);
}
.feature-card__text {
  color: var(--text-light);
}

.courses {
  padding: var(--spacing-xxl) 0;
  background-color: var(--bg-light);
}
.courses__grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: var(--spacing-xl);
}

.course-card {
  background-color: var(--bg-color);
  border-radius: var(--border-radius-lg);
  box-shadow: var(--shadow-sm);
  padding: var(--spacing-lg);
  transition: var(--transition-base);
}
.course-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-4px);
}
.course-card {
  overflow: hidden;
  padding: 0;
}
.course-card__image {
  position: relative;
}
.course-card__image::before {
  content: "";
  display: block;
  padding-top: 56.25%;
}
.course-card__image > * {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
}
.course-card__image {
  overflow: hidden;
}
.course-card__image img {
  object-fit: cover;
  transition: var(--transition-base);
}
.course-card:hover .course-card__image img {
  transform: scale(1.1);
}
.course-card__content {
  padding: var(--spacing-lg);
}
.course-card__title {
  font-size: var(--font-size-xl);
  margin-bottom: var(--spacing-sm);
}
.course-card__description {
  color: var(--text-light);
  margin-bottom: var(--spacing-md);
}
.course-card__meta {
  display: flex;
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-lg);
  font-size: var(--font-size-sm);
  color: var(--text-lighter);
}

.section-title {
  font-size: 2.5rem;
  text-align: center;
  margin-bottom: var(--spacing-xxl);
}
@media (max-width: 992px) {
  .section-title {
    font-size: 2rem;
  }
}

.lessons-container {
  max-width: 1400px;
  width: 100%;
  margin: 0 auto;
  padding: 3rem 2rem;
}

.back-button {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.75rem 1.5rem;
  background: white;
  border: 2px solid var(--border-color);
  border-radius: 12px;
  color: var(--text-primary);
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
  text-decoration: none;
  margin-bottom: 2rem;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
}
.back-button i {
  font-size: 1.1rem;
  transition: transform 0.3s ease;
}
.back-button:hover {
  background: var(--primary-color);
  color: white;
  border-color: var(--primary-color);
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(0, 102, 255, 0.2);
}
.back-button:hover i {
  transform: translateX(-4px);
}

.breadcrumb {
  display: none;
}

.skill-header {
  display: flex;
  align-items: center;
  gap: 2.5rem;
  padding: 3rem;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  border-radius: 20px;
  box-shadow: 0 10px 30px rgba(102, 126, 234, 0.4);
  margin-bottom: 3rem;
  position: relative;
  overflow: hidden;
}
.skill-header::before {
  content: "";
  position: absolute;
  top: -50%;
  right: -10%;
  width: 400px;
  height: 400px;
  background: radial-gradient(circle, rgba(255, 255, 255, 0.15) 0%, transparent 70%);
  border-radius: 50%;
}
.skill-header::after {
  content: "";
  position: absolute;
  bottom: -30%;
  left: -5%;
  width: 300px;
  height: 300px;
  background: radial-gradient(circle, rgba(255, 255, 255, 0.1) 0%, transparent 70%);
  border-radius: 50%;
}
.skill-header__icon {
  width: 100px;
  height: 100px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.25);
  backdrop-filter: blur(10px);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  box-shadow: 0 8px 20px rgba(0, 0, 0, 0.15);
  position: relative;
  z-index: 1;
  border: 3px solid rgba(255, 255, 255, 0.3);
}
.skill-header__icon i {
  font-size: 3rem;
  color: white;
  filter: drop-shadow(0 2px 4px rgba(0, 0, 0, 0.2));
}
.skill-header__content {
  flex: 1;
  position: relative;
  z-index: 1;
}
.skill-header__top {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  margin-bottom: 0.75rem;
}
.skill-header__back {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.5rem 1rem;
  background: rgba(255, 255, 255, 0.2);
  backdrop-filter: blur(10px);
  border-radius: 10px;
  color: white;
  font-size: 0.9rem;
  font-weight: 600;
  text-decoration: none;
  transition: all 0.3s ease;
  border: 2px solid rgba(255, 255, 255, 0.3);
}
.skill-header__back i {
  font-size: 0.9rem;
  transition: transform 0.3s ease;
}
.skill-header__back:hover {
  background: rgba(255, 255, 255, 0.3);
  border-color: rgba(255, 255, 255, 0.5);
  color: white !important;
  transform: translateX(-4px);
}
.skill-header__back:hover i {
  transform: translateX(-3px);
}
.skill-header__complete-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.6rem 1.2rem;
  background: linear-gradient(135deg, #fbbf24 0%, #f59e0b 100%);
  border-radius: 10px;
  color: white;
  font-size: 0.95rem;
  font-weight: 700;
  text-decoration: none;
  transition: all 0.3s ease;
  border: 2px solid rgba(255, 255, 255, 0.4);
  cursor: pointer;
  margin-left: auto;
  box-shadow: 0 4px 12px rgba(251, 191, 36, 0.3);
}
.skill-header__complete-btn i {
  font-size: 1.1rem;
}
.skill-header__complete-btn:hover {
  background: linear-gradient(135deg, #f59e0b 0%, #d97706 100%);
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(251, 191, 36, 0.5);
}
.skill-header__complete-btn:active {
  transform: translateY(0);
}
.skill-header__complete-btn.completed {
  background: linear-gradient(135deg, #10b981 0%, #059669 100%);
  box-shadow: 0 4px 12px rgba(16, 185, 129, 0.3);
}
.skill-header__complete-btn.completed:hover {
  background: linear-gradient(135deg, #059669 0%, #047857 100%);
  box-shadow: 0 6px 20px rgba(16, 185, 129, 0.5);
}
.skill-header__title {
  font-size: 2.5rem;
  font-weight: 800;
  color: white;
  margin-bottom: 0;
  text-shadow: 0 2px 10px rgba(0, 0, 0, 0.2);
  letter-spacing: -0.5px;
}
.skill-header__description {
  color: rgba(255, 255, 255, 0.95);
  margin-bottom: 2rem;
  font-size: 1.15rem;
  line-height: 1.6;
}
.skill-header__progress .progress-stats {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  margin-bottom: 1rem;
}
.skill-header__progress .progress-stats .stats-left {
  display: flex;
  align-items: center;
  gap: 1.5rem;
}
.skill-header__progress .progress-stats .stat-item {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  color: white;
  font-size: 0.95rem;
  font-weight: 600;
  background: rgba(255, 255, 255, 0.15);
  padding: 0.5rem 1rem;
  border-radius: 20px;
  backdrop-filter: blur(10px);
}
.skill-header__progress .progress-stats .stat-item i {
  font-size: 1.1rem;
}
.skill-header__progress .progress-stats .stat-item--total {
  background: transparent;
  border: none;
  box-shadow: none;
  padding: 0;
}
.skill-header__progress .progress-stats .progress-percentage {
  font-size: 2rem;
  font-weight: 800;
  color: white;
  text-shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
  letter-spacing: -1px;
}
.skill-header__progress .progress-bar-container {
  position: relative;
  height: 16px;
  background: rgba(255, 255, 255, 0.25);
  border-radius: 12px;
  overflow: hidden;
  box-shadow: inset 0 2px 6px rgba(0, 0, 0, 0.15);
}
.skill-header__progress .progress-bar-container .progress-bar__fill {
  height: 100%;
  background: linear-gradient(90deg, #4ade80 0%, #22c55e 50%, #16a34a 100%);
  border-radius: 12px;
  transition: width 0.8s cubic-bezier(0.4, 0, 0.2, 1);
  box-shadow: 0 0 20px rgba(74, 222, 128, 0.6);
  position: relative;
  overflow: hidden;
}
.skill-header__progress .progress-bar-container .progress-bar__fill::after {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.4), transparent);
  animation: shimmer 2s infinite;
}

@keyframes shimmer {
  0% {
    transform: translateX(-100%);
    opacity: 0;
  }
  50% {
    opacity: 1;
  }
  100% {
    transform: translateX(100%);
    opacity: 0;
  }
}
.lessons-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(340px, 1fr));
  gap: 2rem;
}

.lesson-card {
  background: white;
  border-radius: 20px;
  padding: 2rem;
  cursor: pointer;
  transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
  position: relative;
  border: 3px solid;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
  min-height: 280px;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  text-decoration: none;
}
.lesson-card::before {
  content: "";
  position: absolute;
  top: -50%;
  right: -50%;
  width: 200%;
  height: 200%;
  background: radial-gradient(circle, rgba(255, 255, 255, 0.1) 0%, transparent 70%);
  opacity: 0;
  transition: opacity 0.4s ease;
}
.lesson-card:hover::before {
  opacity: 1;
}
.lesson-card:hover {
  transform: translateY(-6px) scale(1.02);
  box-shadow: 0 12px 32px rgba(0, 0, 0, 0.15);
}
.lesson-card__header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1.5rem;
  position: relative;
  z-index: 2;
}
.lesson-card__number {
  font-size: 0.9rem;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 1px;
  padding: 0.5rem 1.1rem;
  border-radius: 25px;
  background: rgba(0, 0, 0, 0.05);
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.06);
}
.lesson-card__number::before {
  content: "BÀI";
  font-size: 0.7rem;
  opacity: 0.7;
}
.lesson-card__status-badge {
  position: absolute;
  top: 2rem;
  right: 2rem;
  width: 64px;
  height: 64px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2rem;
  box-shadow: 0 6px 20px rgba(0, 0, 0, 0.15);
  transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
  z-index: 3;
  border: 3px solid rgba(255, 255, 255, 0.8);
}
.lesson-card__status-badge i {
  filter: drop-shadow(0 2px 4px rgba(0, 0, 0, 0.2));
}
.lesson-card__title {
  font-size: 1.6rem;
  font-weight: 800;
  color: var(--text-primary);
  margin-bottom: 0.85rem;
  line-height: 1.3;
  padding-right: 80px;
  position: relative;
  z-index: 2;
  letter-spacing: -0.3px;
}
.lesson-card__description {
  color: var(--text-secondary);
  font-size: 1rem;
  margin-bottom: auto;
  line-height: 1.7;
  flex: 1;
  position: relative;
  z-index: 2;
}
.lesson-card__meta {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  padding-top: 1.5rem;
  margin-top: 1.5rem;
  border-top: 2px solid;
  font-size: 0.95rem;
  font-weight: 700;
  position: relative;
  z-index: 2;
}
.lesson-card__meta i {
  font-size: 1.1rem;
}
.lesson-card--locked {
  border-color: #d1d5db;
  background: linear-gradient(135deg, #fafafa 0%, #f3f4f6 100%);
  opacity: 0.75;
  cursor: not-allowed;
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.05);
}
.lesson-card--locked::after {
  content: "🔒 Chưa khả dụng";
  position: absolute;
  bottom: 1.75rem;
  right: 2rem;
  padding: 0.4rem 1rem;
  background: linear-gradient(135deg, #e5e7eb 0%, #d1d5db 100%);
  color: #6b7280;
  font-size: 0.75rem;
  font-weight: 700;
  border-radius: 20px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  z-index: 4;
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.1);
}
.lesson-card--locked .lesson-card__number {
  background: linear-gradient(135deg, #e5e7eb 0%, #d1d5db 100%);
  color: #9ca3af;
  border: 2px solid #d1d5db;
  box-shadow: none;
}
.lesson-card--locked .lesson-card__status-badge {
  background: linear-gradient(135deg, #e5e7eb 0%, #d1d5db 100%);
  color: #9ca3af;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
  border-color: #f3f4f6;
}
.lesson-card--locked .lesson-card__title {
  color: #9ca3af;
}
.lesson-card--locked .lesson-card__description {
  color: #d1d5db;
}
.lesson-card--locked .lesson-card__meta {
  border-color: #e5e7eb;
  color: #9ca3af;
}
.lesson-card--locked .lesson-card__meta i {
  color: #d1d5db;
}
.lesson-card--locked:hover {
  transform: none;
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.05);
}
.lesson-card--locked:hover::before {
  opacity: 0;
}
.lesson-card--in-progress {
  border-color: #60a5fa;
  background: linear-gradient(135deg, #ffffff 0%, #eff6ff 100%);
  box-shadow: 0 6px 24px rgba(96, 165, 250, 0.35);
  animation: cardPulse 3s ease-in-out infinite;
}
.lesson-card--in-progress::after {
  content: "⏳ Đang học";
  position: absolute;
  bottom: 1.75rem;
  right: 2rem;
  padding: 0.5rem 1.2rem;
  background: linear-gradient(135deg, #3b82f6 0%, #2563eb 100%);
  color: white;
  font-size: 0.8rem;
  font-weight: 800;
  border-radius: 25px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  z-index: 4;
  box-shadow: 0 4px 16px rgba(59, 130, 246, 0.4);
  animation: pulseGlow 2s ease-in-out infinite;
}
.lesson-card--in-progress .lesson-card__number {
  background: linear-gradient(135deg, #dbeafe 0%, #bfdbfe 100%);
  color: #1e3a8a;
  border: 2px solid #3b82f6;
  box-shadow: 0 2px 8px rgba(59, 130, 246, 0.3);
}
.lesson-card--in-progress .lesson-card__status-badge {
  background: linear-gradient(135deg, #60a5fa 0%, #3b82f6 100%);
  color: white;
  animation: rotateAndPulse 3s ease-in-out infinite;
  box-shadow: 0 6px 24px rgba(59, 130, 246, 0.5);
  border-color: rgba(255, 255, 255, 0.9);
}
.lesson-card--in-progress .lesson-card__title {
  color: #1e3a8a;
}
.lesson-card--in-progress .lesson-card__description {
  color: #1e40af;
}
.lesson-card--in-progress .lesson-card__meta {
  border-color: #bfdbfe;
  color: #1e3a8a;
  font-weight: 800;
}
.lesson-card--in-progress .lesson-card__meta i {
  color: #3b82f6;
  animation: iconBounce 2s ease-in-out infinite;
}
.lesson-card--in-progress:hover {
  border-color: #3b82f6;
  box-shadow: 0 12px 40px rgba(59, 130, 246, 0.5);
  transform: translateY(-8px) scale(1.03);
}
.lesson-card--completed {
  border-color: #34d399;
  background: linear-gradient(135deg, #ffffff 0%, #ecfdf5 100%);
  box-shadow: 0 6px 24px rgba(52, 211, 153, 0.35);
}
.lesson-card--completed::after {
  content: "✓ Hoàn thành";
  position: absolute;
  bottom: 1.75rem;
  right: 2rem;
  padding: 0.5rem 1.2rem;
  background: linear-gradient(135deg, #10b981 0%, #059669 100%);
  color: white;
  font-size: 0.8rem;
  font-weight: 800;
  border-radius: 25px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  z-index: 4;
  box-shadow: 0 4px 16px rgba(16, 185, 129, 0.4);
}
.lesson-card--completed .lesson-card__number {
  background: linear-gradient(135deg, #d1fae5 0%, #a7f3d0 100%);
  color: #064e3b;
  border: 2px solid #10b981;
  box-shadow: 0 2px 8px rgba(16, 185, 129, 0.3);
}
.lesson-card--completed .lesson-card__status-badge {
  background: linear-gradient(135deg, #34d399 0%, #10b981 100%);
  color: white;
  box-shadow: 0 6px 24px rgba(16, 185, 129, 0.5);
  border-color: rgba(255, 255, 255, 0.9);
}
.lesson-card--completed .lesson-card__title {
  color: #064e3b;
}
.lesson-card--completed .lesson-card__description {
  color: #065f46;
}
.lesson-card--completed .lesson-card__meta {
  border-color: #a7f3d0;
  color: #064e3b;
  font-weight: 800;
}
.lesson-card--completed .lesson-card__meta i {
  color: #10b981;
}
.lesson-card--completed:hover {
  border-color: #10b981;
  box-shadow: 0 12px 40px rgba(16, 185, 129, 0.5);
  transform: translateY(-8px) scale(1.03);
}

@keyframes cardPulse {
  0%, 100% {
    box-shadow: 0 6px 24px rgba(96, 165, 250, 0.35);
  }
  50% {
    box-shadow: 0 8px 32px rgba(96, 165, 250, 0.5);
  }
}
@keyframes pulseGlow {
  0%, 100% {
    box-shadow: 0 4px 16px rgba(59, 130, 246, 0.4);
    transform: scale(1);
  }
  50% {
    box-shadow: 0 6px 24px rgba(59, 130, 246, 0.6);
    transform: scale(1.05);
  }
}
@keyframes rotateAndPulse {
  0%, 100% {
    transform: rotate(0deg) scale(1);
  }
  25% {
    transform: rotate(-5deg) scale(1.05);
  }
  75% {
    transform: rotate(5deg) scale(1.05);
  }
}
@keyframes iconBounce {
  0%, 100% {
    transform: translateY(0);
  }
  50% {
    transform: translateY(-3px);
  }
}
@keyframes successPulse {
  0%, 100% {
    box-shadow: 0 6px 24px rgba(16, 185, 129, 0.5);
    transform: scale(1);
  }
  50% {
    box-shadow: 0 8px 32px rgba(16, 185, 129, 0.7);
    transform: scale(1.05);
  }
}
@keyframes checkmarkScale {
  0%, 100% {
    transform: scale(1);
  }
  50% {
    transform: scale(1.15);
  }
}
@keyframes pulseStatus {
  0%, 100% {
    opacity: 1;
  }
  50% {
    opacity: 0.85;
  }
}
@keyframes bounceIcon {
  0%, 100% {
    transform: scale(1);
  }
  50% {
    transform: scale(1.1);
  }
}
.btn--mark-done-small {
  padding: 0.5rem 0.75rem;
  font-size: 0.85rem;
  border-radius: 6px;
  border: none;
  background: var(--bg-secondary);
  color: white;
  cursor: pointer;
  transition: all 0.3s ease;
  display: flex;
  align-items: center;
  gap: 0.3rem;
}
.btn--mark-done-small:hover {
  background: var(--success-color);
  transform: scale(1.05);
}
.btn--mark-done-small.completed {
  background: var(--success-color);
  pointer-events: none;
}
.btn--mark-done-small i {
  font-size: 0.8rem;
}

.btn--view {
  padding: 0.5rem 1rem;
  font-size: 0.85rem;
  border-radius: 6px;
  border: none;
  background: var(--primary-color);
  color: white;
  cursor: pointer;
  transition: all 0.3s ease;
}
.btn--view:hover {
  background: var(--primary-dark);
  transform: scale(1.05);
}
.btn--view i {
  margin-left: 0.3rem;
}

@media (max-width: 768px) {
  .lessons-container {
    padding: 2rem 1rem;
  }
  .back-button {
    padding: 0.6rem 1.2rem;
    font-size: 0.9rem;
  }
  .back-button span {
    display: none;
  }
  .back-button i {
    margin: 0;
    font-size: 1.2rem;
  }
  .skill-header {
    flex-direction: column;
    align-items: center;
    text-align: center;
    padding: 2rem 1.5rem;
    gap: 1.5rem;
  }
  .skill-header::before, .skill-header::after {
    display: none;
  }
  .skill-header__icon {
    width: 80px;
    height: 80px;
  }
  .skill-header__icon i {
    font-size: 2.5rem;
  }
  .skill-header__content {
    width: 100%;
  }
  .skill-header__title {
    font-size: 2rem;
  }
  .skill-header__description {
    font-size: 1rem;
    margin-bottom: 1.5rem;
  }
  .skill-header__progress .progress-stats {
    flex-direction: column;
    gap: 1rem;
    margin-bottom: 1rem;
  }
  .skill-header__progress .progress-stats .stats-left {
    width: 100%;
    justify-content: center;
    gap: 1rem;
  }
  .skill-header__progress .progress-stats .stat-item {
    font-size: 0.85rem;
    padding: 0.4rem 0.8rem;
  }
  .skill-header__progress .progress-stats .progress-percentage {
    font-size: 1.75rem;
  }
  .skill-header__progress .progress-bar-container {
    height: 14px;
  }
  .lessons-grid {
    grid-template-columns: 1fr;
    gap: 1.5rem;
  }
  .lesson-card {
    padding: 1.75rem;
    min-height: 260px;
  }
  .lesson-card::after {
    bottom: 0.75rem;
    right: 0.75rem;
    font-size: 0.7rem;
    padding: 0.4rem 0.9rem;
  }
  .lesson-card__header {
    margin-bottom: 1.25rem;
  }
  .lesson-card__number {
    font-size: 0.8rem;
    padding: 0.45rem 0.95rem;
  }
  .lesson-card__number::before {
    font-size: 0.65rem;
  }
  .lesson-card__status-badge {
    width: 56px;
    height: 56px;
    font-size: 1.6rem;
    top: 1.5rem;
    right: 1.5rem;
  }
  .lesson-card__title {
    font-size: 1.35rem;
    padding-right: 70px;
  }
  .lesson-card__description {
    font-size: 0.95rem;
  }
  .lesson-card__meta {
    padding-top: 1.25rem;
    margin-top: 1.25rem;
    font-size: 0.9rem;
  }
  .lesson-card__meta i {
    font-size: 1rem;
  }
}
@media (max-width: 480px) {
  .lessons-container {
    padding: 1.5rem 0.75rem;
  }
  .skill-header {
    padding: 1.5rem 1rem;
  }
  .skill-header__title {
    font-size: 1.75rem;
  }
  .skill-header__progress .progress-stats .stat-item {
    font-size: 0.8rem;
    padding: 0.35rem 0.7rem;
  }
  .skill-header__progress .progress-stats .progress-percentage {
    font-size: 1.5rem;
  }
  .lesson-card {
    padding: 1.5rem;
    min-height: 240px;
  }
  .lesson-card::after {
    bottom: 0.5rem;
    right: 0.5rem;
    font-size: 0.65rem;
    padding: 0.35rem 0.8rem;
  }
  .lesson-card__header {
    margin-bottom: 1rem;
  }
  .lesson-card__number {
    font-size: 0.75rem;
    padding: 0.4rem 0.85rem;
  }
  .lesson-card__number::before {
    font-size: 0.6rem;
  }
  .lesson-card__status-badge {
    width: 50px;
    height: 50px;
    font-size: 1.4rem;
    top: 1.25rem;
    right: 1.25rem;
  }
  .lesson-card__title {
    font-size: 1.2rem;
    padding-right: 60px;
  }
  .lesson-card__description {
    font-size: 0.9rem;
  }
  .lesson-card__meta {
    padding-top: 1rem;
    margin-top: 1rem;
    font-size: 0.85rem;
  }
  .lesson-card__meta i {
    font-size: 0.95rem;
  }
}
@keyframes sparkle {
  0%, 100% {
    transform: rotate(0deg) scale(1);
    opacity: 1;
  }
  50% {
    transform: rotate(180deg) scale(1.2);
    opacity: 0.8;
  }
}
.locked-skill-message {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 4rem 2rem;
  text-align: center;
  min-height: 400px;
  background: white;
  border-radius: 20px;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
  margin: 2rem 0;
}
.locked-skill-message__icon {
  width: 120px;
  height: 120px;
  border-radius: 50%;
  background: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 2rem;
  animation: pulse 2s ease-in-out infinite;
}
.locked-skill-message__icon i {
  font-size: 4rem;
  color: white;
  filter: drop-shadow(0 2px 8px rgba(0, 0, 0, 0.2));
}
.locked-skill-message h2 {
  font-size: 2.5rem;
  color: var(--text-primary);
  margin-bottom: 1rem;
  font-weight: 700;
}
.locked-skill-message p {
  font-size: 1.15rem;
  color: var(--text-secondary);
  margin-bottom: 2rem;
  max-width: 600px;
}
.locked-skill-message .btn {
  margin-top: 1rem;
  color: white;
}

@keyframes pulse {
  0%, 100% {
    transform: scale(1);
  }
  50% {
    transform: scale(1.05);
  }
}
.lesson-detail-container {
  max-width: 1200px;
  width: 100%;
  margin: 0 auto;
  padding: 3rem 2rem;
  position: relative;
}

.back-button {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.75rem 1.5rem;
  background: transparent;
  border: 2px solid var(--border-color);
  border-radius: 10px;
  color: var(--text-primary);
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
  text-decoration: none;
  box-shadow: none;
  white-space: nowrap;
  margin-bottom: 0;
}
.back-button i {
  font-size: 1rem;
  transition: transform 0.3s ease;
}
.back-button:hover {
  background: var(--bg-light);
  color: var(--primary-color);
  border-color: var(--primary-color);
  transform: translateX(-4px);
  box-shadow: 0 2px 8px rgba(0, 102, 255, 0.1);
}
.back-button:hover i {
  transform: translateX(-2px);
}
@media (max-width: 768px) {
  .back-button {
    width: 100%;
    justify-content: center;
  }
}

.lesson-nav {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
  padding: 1.5rem;
  background: white;
  border-radius: 12px;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
  margin-bottom: 2rem;
}
.lesson-nav--bottom {
  margin-top: 3rem;
  margin-bottom: 0;
}
.lesson-nav__top-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
}
@media (max-width: 768px) {
  .lesson-nav__top-row {
    flex-direction: column;
    align-items: stretch;
  }
}
.lesson-nav__controls {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  flex: 1;
}
@media (max-width: 768px) {
  .lesson-nav__controls {
    flex-direction: column;
    align-items: stretch;
  }
}
.lesson-nav__nav-buttons {
  display: flex;
  gap: 1rem;
  align-items: center;
}
@media (max-width: 768px) {
  .lesson-nav__nav-buttons {
    width: 100%;
    justify-content: space-between;
  }
}
.lesson-nav .btn--nav {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.75rem 1.5rem;
  background: white;
  border: 2px solid var(--border-color);
  border-radius: 8px;
  color: var(--text-primary);
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
}
.lesson-nav .btn--nav:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}
.lesson-nav .btn--nav:disabled:hover {
  background: white;
  border-color: var(--border-color);
  color: var(--text-primary);
  transform: none;
}
.lesson-nav .btn--nav:not(:disabled):hover {
  background: var(--primary-color);
  border-color: var(--primary-color);
  color: white;
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(0, 102, 255, 0.2);
}
.lesson-nav .btn--mark-done, .lesson-nav .btn--mark-done-bottom {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.85rem 2rem;
  background: linear-gradient(135deg, #fbbf24 0%, #f59e0b 100%);
  border-radius: 10px;
  color: white;
  font-size: 0.95rem;
  font-weight: 700;
  text-decoration: none;
  transition: all 0.3s ease;
  border: 2px solid rgba(255, 255, 255, 0.4);
  cursor: pointer;
  margin-left: auto;
  box-shadow: 0 4px 12px rgba(251, 191, 36, 0.3);
}
.lesson-nav .btn--mark-done i, .lesson-nav .btn--mark-done-bottom i {
  font-size: 1.1rem;
}
.lesson-nav .btn--mark-done:hover, .lesson-nav .btn--mark-done-bottom:hover {
  background: linear-gradient(135deg, #f59e0b 0%, #d97706 100%);
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(251, 191, 36, 0.5);
}
.lesson-nav .btn--mark-done.completed, .lesson-nav .btn--mark-done-bottom.completed {
  background: linear-gradient(135deg, #10b981 0%, #059669 100%);
  box-shadow: 0 4px 12px rgba(16, 185, 129, 0.3);
}
.lesson-nav .btn--mark-done.completed:hover, .lesson-nav .btn--mark-done-bottom.completed:hover {
  background: linear-gradient(135deg, #059669 0%, #047857 100%);
  box-shadow: 0 6px 20px rgba(16, 185, 129, 0.5);
}

.toc-dots {
  position: fixed;
  right: 3rem;
  top: 50%;
  transform: translateY(-50%);
  display: flex;
  flex-direction: column;
  gap: 1rem;
  z-index: 100;
  background: white;
  padding: 1rem 0.75rem;
  border-radius: 24px;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
}
.toc-dots__item {
  position: relative;
  cursor: pointer;
  transition: all 0.3s ease;
}
.toc-dots__item-dot {
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: #cbd5e1;
  transition: all 0.3s ease;
  border: 2px solid #cbd5e1;
}
.toc-dots__item-label {
  position: absolute;
  right: 30px;
  top: 50%;
  transform: translateY(-50%);
  background: var(--text-primary);
  color: white;
  padding: 0.5rem 1rem;
  border-radius: 8px;
  font-size: 0.85rem;
  font-weight: 600;
  white-space: nowrap;
  opacity: 0;
  visibility: hidden;
  transition: all 0.3s ease;
  pointer-events: none;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
}
.toc-dots__item-label::after {
  content: "";
  position: absolute;
  right: -6px;
  top: 50%;
  transform: translateY(-50%);
  width: 0;
  height: 0;
  border-left: 6px solid var(--text-primary);
  border-top: 6px solid transparent;
  border-bottom: 6px solid transparent;
}
.toc-dots__item:hover .toc-dots__item-label {
  opacity: 1;
  visibility: visible;
  right: 35px;
  background: var(--primary-color);
}
.toc-dots__item:hover .toc-dots__item-dot {
  background: var(--primary-color);
  border-color: var(--primary-color);
  transform: scale(1.3);
}
.toc-dots__item.active .toc-dots__item-dot {
  background: var(--primary-color);
  border-color: var(--primary-color);
  transform: scale(1.5);
  box-shadow: 0 0 0 4px rgba(59, 130, 246, 0.2);
}
.toc-dots__item.active .toc-dots__item-label {
  background: var(--primary-color);
}
.toc-dots__item.active .toc-dots__item-label::after {
  border-left-color: var(--primary-color);
}

.lesson-content {
  background: white;
  border-radius: 16px;
  padding: 3rem;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
  margin-bottom: 2rem;
}

.locked-lesson-message {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 4rem 2rem;
  text-align: center;
  min-height: 400px;
  background: white;
  border-radius: 20px;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
  margin: 2rem 0;
}
.locked-lesson-message__icon {
  width: 120px;
  height: 120px;
  border-radius: 50%;
  background: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 2rem;
  animation: pulse 2s ease-in-out infinite;
}
.locked-lesson-message__icon i {
  font-size: 4rem;
  color: white;
  filter: drop-shadow(0 2px 8px rgba(0, 0, 0, 0.2));
}
.locked-lesson-message h2 {
  font-size: 2.5rem;
  color: var(--text-primary);
  margin-bottom: 1rem;
  font-weight: 700;
}
.locked-lesson-message p {
  font-size: 1.15rem;
  color: var(--text-secondary);
  margin-bottom: 2rem;
  max-width: 600px;
}
.locked-lesson-message .btn {
  margin-top: 1rem;
  color: white;
}

.lesson-article {
  max-width: 800px;
  margin: 0 auto;
}
.lesson-article .section {
  margin-bottom: 4rem;
  scroll-margin-top: 2rem;
}
.lesson-article .section:last-child {
  margin-bottom: 0;
}
.lesson-article .section__header {
  display: flex;
  align-items: center;
  gap: 1rem;
  margin-bottom: 2rem;
  padding-bottom: 1rem;
  border-bottom: 3px solid var(--primary-color);
}
.lesson-article .section__icon {
  width: 48px;
  height: 48px;
  border-radius: 12px;
  background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-size: 1.5rem;
  flex-shrink: 0;
}
.lesson-article .section__title {
  font-size: 1.75rem;
  font-weight: 700;
  color: var(--text-primary);
  margin: 0;
}
.lesson-article .section__content {
  font-size: 1.05rem;
  line-height: 1.8;
  color: var(--text-secondary);
  margin-bottom: 2rem;
}
.lesson-article .section__content h3 {
  font-size: 1.35rem;
  font-weight: 600;
  color: var(--text-primary);
  margin: 2rem 0 1rem;
}
.lesson-article .section__content h4 {
  font-size: 1.2rem;
  font-weight: 600;
  color: var(--text-primary);
  margin: 1.5rem 0 0.75rem;
}
.lesson-article .section__content p {
  margin-bottom: 1rem;
}
.lesson-article .section__content ul, .lesson-article .section__content ol {
  margin: 1rem 0;
  padding-left: 2rem;
}
.lesson-article .section__content ul li, .lesson-article .section__content ol li {
  margin-bottom: 0.5rem;
}
.lesson-article .section__content code {
  background: #f3f4f6;
  padding: 0.2rem 0.4rem;
  border-radius: 4px;
  font-family: "Courier New", monospace;
  font-size: 0.9em;
  color: #e11d48;
}
.lesson-article .section__content pre {
  background: #1e293b;
  color: #e2e8f0;
  padding: 1.5rem;
  border-radius: 8px;
  overflow-x: auto;
  margin: 1.5rem 0;
}
.lesson-article .section__content pre code {
  background: none;
  color: inherit;
  padding: 0;
}
.lesson-article .exercise-section {
  background: linear-gradient(135deg, #fef3c7 0%, #fde68a 100%);
  border-left: 4px solid #f59e0b;
  padding: 2rem;
  border-radius: 12px;
  margin-bottom: 2rem;
}
.lesson-article .exercise-section__header {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 1.5rem;
}
.lesson-article .exercise-section__header i {
  font-size: 1.5rem;
  color: #f59e0b;
}
.lesson-article .exercise-section__header h3 {
  font-size: 1.35rem;
  font-weight: 700;
  color: #92400e;
  margin: 0;
}
.lesson-article .exercise-section__header h4 {
  font-size: 1.1rem;
  font-weight: 600;
  color: #92400e;
  margin: 0;
}
.lesson-article .exercise-section__content {
  color: #78350f;
  line-height: 1.7;
}
.lesson-article .exercise-section__content h3 {
  font-size: 1.35rem;
  font-weight: 700;
  color: #92400e;
  margin: 18px 0 10px;
}
.lesson-article .exercise-section__content h4 {
  font-size: 1.1rem;
  font-weight: 600;
  color: #92400e;
  margin: 18px 0 10px;
}
.lesson-article .exercise-section__content ol {
  padding-left: 1.5rem;
}
.lesson-article .exercise-section__content ol li {
  margin-bottom: 0.75rem;
  font-weight: 500;
}
.lesson-article .quiz-section {
  background: linear-gradient(135deg, #e0e7ff 0%, #c7d2fe 100%);
  border-left: 4px solid #6366f1;
  padding: 2rem;
  border-radius: 12px;
  margin-bottom: 2rem;
}
.lesson-article .quiz-section__header {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 1.5rem;
}
.lesson-article .quiz-section__header i {
  font-size: 1.5rem;
  color: #6366f1;
}
.lesson-article .quiz-section__header h3 {
  font-size: 1.35rem;
  font-weight: 700;
  color: #3730a3;
  margin: 0;
}
.lesson-article .quiz-section__header h4 {
  font-size: 1.1rem;
  font-weight: 600;
  color: #3730a3;
  margin: 0;
}
.lesson-article .quiz-section__question {
  margin-bottom: 2rem;
}
.lesson-article .quiz-section__question:last-child {
  margin-bottom: 0;
}
.lesson-article .quiz-section__question-text {
  font-weight: 600;
  color: #3730a3;
  margin-bottom: 1rem;
  font-size: 1.05rem;
}
.lesson-article .quiz-section__question-options {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}
.lesson-article .quiz-section__question-option {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 1rem;
  background: white;
  border: 2px solid #c7d2fe;
  border-radius: 8px;
  cursor: pointer;
  transition: all 0.3s ease;
}
.lesson-article .quiz-section__question-option input[type=radio] {
  width: 20px;
  height: 20px;
  cursor: pointer;
  accent-color: #6366f1;
}
.lesson-article .quiz-section__question-option label {
  flex: 1;
  cursor: pointer;
  color: #3730a3;
  font-weight: 500;
}
.lesson-article .quiz-section__question-option:hover {
  border-color: #6366f1;
  background: #f5f3ff;
}
.lesson-article .quiz-section__question-option.correct {
  border-color: #22c55e;
  background: #f0fdf4;
}
.lesson-article .quiz-section__question-option.correct label {
  color: #166534;
}
.lesson-article .quiz-section__question-option.incorrect {
  border-color: #ef4444;
  background: #fef2f2;
}
.lesson-article .quiz-section__question-option.incorrect label {
  color: #991b1b;
}
.lesson-article .quiz-section__submit {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.75rem 2rem;
  background: linear-gradient(135deg, #6366f1 0%, #4f46e5 100%);
  border: none;
  border-radius: 8px;
  color: white;
  font-weight: 700;
  cursor: pointer;
  transition: all 0.3s ease;
  margin-top: 1.5rem;
}
.lesson-article .quiz-section__submit:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(99, 102, 241, 0.4);
}
.lesson-article .quiz-section__result {
  margin-top: 1rem;
  padding: 1rem;
  border-radius: 8px;
  font-weight: 600;
  text-align: center;
  display: none;
}
.lesson-article .quiz-section__result.show {
  display: block;
}
.lesson-article .quiz-section__result--success {
  background: #d1fae5;
  color: #065f46;
  border: 2px solid #6ee7b7;
}
.lesson-article .quiz-section__result--error {
  background: #fee2e2;
  color: #991b1b;
  border: 2px solid #fca5a5;
}

@media (max-width: 1023px) {
  .toc-dots {
    display: none;
  }
}
@media (max-width: 768px) {
  .lesson-detail-container {
    padding: 2rem 1rem;
  }
  .back-button {
    padding: 0.6rem 1.2rem;
    font-size: 0.9rem;
  }
  .back-button span {
    display: none;
  }
  .back-button i {
    margin: 0;
    font-size: 1.2rem;
  }
  .lesson-nav {
    flex-direction: column;
    gap: 0.75rem;
  }
  .lesson-nav .btn--nav,
  .lesson-nav .btn--mark-done,
  .lesson-nav .btn--mark-done-bottom {
    width: 100%;
    justify-content: center;
  }
  .lesson-content {
    padding: 2rem 1.5rem;
  }
  .lesson-article .section__header {
    flex-direction: column;
    align-items: flex-start;
  }
  .lesson-article .section__title {
    font-size: 1.5rem;
  }
  .lesson-article .section__content {
    font-size: 1rem;
  }
  .lesson-article .exercise-section,
  .lesson-article .quiz-section {
    padding: 1.5rem;
  }
}
@media (max-width: 480px) {
  .lesson-detail-container {
    padding: 1.5rem 0.75rem;
  }
  .lesson-content {
    padding: 1.5rem 1rem;
    border-radius: 12px;
  }
  .lesson-article .section {
    margin-bottom: 3rem;
  }
  .lesson-article .section__icon {
    width: 40px;
    height: 40px;
    font-size: 1.25rem;
  }
  .lesson-article .section__title {
    font-size: 1.25rem;
  }
}