@import url('https://fonts.googleapis.com/css2?family=Plus+Jakarta+Sans:wght@300;400;500;600;700;800&display=swap');

:root {
  /* Harmonious Color Palette */
  --bg-primary: #0b0f19;
  --bg-secondary: #131b2e;
  --bg-tertiary: #1e293b;
  
  --card-bg: rgba(30, 41, 59, 0.7);
  --card-border: rgba(255, 255, 255, 0.08);
  
  --accent-primary: #6366f1; /* Indigo */
  --accent-secondary: #a855f7; /* Purple */
  --accent-success: #10b981; /* Emerald */
  --accent-warning: #f59e0b; /* Amber */
  --accent-danger: #ef4444; /* Rose */
  
  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  
  --shadow-sm: 0 2px 8px -2px rgba(0, 0, 0, 0.5);
  --shadow-md: 0 4px 20px -4px rgba(0, 0, 0, 0.5);
  --shadow-lg: 0 12px 40px -8px rgba(0, 0, 0, 0.7);
  
  --border-radius-sm: 8px;
  --border-radius-md: 16px;
  --border-radius-lg: 24px;
  
  --transition-fast: 0.2s ease;
  --transition-normal: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 0.5s ease;
}

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

html, body {
  font-family: 'Plus Jakarta Sans', sans-serif;
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  overflow-x: hidden;
}

/* Custom Scrollbar */
::-webkit-scrollbar {
  width: 8px;
  height: 8px;
}
::-webkit-scrollbar-track {
  background: var(--bg-primary);
}
::-webkit-scrollbar-thumb {
  background: var(--bg-tertiary);
  border-radius: 4px;
}
::-webkit-scrollbar-thumb:hover {
  background: var(--accent-primary);
}

/* Global Layout Utilities */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

/* Navbar */
header {
  background: rgba(11, 15, 25, 0.8);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--card-border);
  position: sticky;
  top: 0;
  z-index: 100;
  padding: 16px 0;
}

.nav-container {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  font-weight: 800;
  font-size: 1.5rem;
  background: linear-gradient(135deg, var(--accent-primary), var(--accent-secondary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.logo-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background-color: var(--accent-secondary);
}

.nav-menu {
  display: flex;
  list-style: none;
  gap: 24px;
  align-items: center;
}

.nav-link {
  text-decoration: none;
  color: var(--text-secondary);
  font-weight: 500;
  transition: var(--transition-fast);
}

.nav-link:hover, .nav-link.active {
  color: var(--text-primary);
}

/* Glassmorphism Button */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 10px 20px;
  border-radius: var(--border-radius-sm);
  font-weight: 600;
  text-decoration: none;
  cursor: pointer;
  transition: var(--transition-normal);
  border: 1px solid transparent;
  font-size: 0.95rem;
}

.btn-primary {
  background: linear-gradient(135deg, var(--accent-primary), var(--accent-secondary));
  color: #fff;
  box-shadow: 0 4px 14px rgba(99, 102, 241, 0.4);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(99, 102, 241, 0.6);
}

.btn-secondary {
  background: rgba(255, 255, 255, 0.05);
  color: var(--text-primary);
  border: 1px solid var(--card-border);
}

.btn-secondary:hover {
  background: rgba(255, 255, 255, 0.1);
  transform: translateY(-2px);
}

.btn-danger {
  background: var(--accent-danger);
  color: #fff;
}

.btn-danger:hover {
  opacity: 0.9;
  transform: translateY(-2px);
}

.user-profile-nav {
  display: flex;
  align-items: center;
  gap: 12px;
}

.user-avatar {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background-color: var(--bg-tertiary);
  border: 2px solid var(--accent-primary);
  object-fit: cover;
}

/* Landing Page Hero */
.hero {
  padding: 80px 0;
  background: radial-gradient(circle at 80% 20%, rgba(99, 102, 241, 0.15), transparent 50%),
              radial-gradient(circle at 10% 80%, rgba(168, 85, 247, 0.15), transparent 50%);
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.2fr 0.8fr;
  gap: 40px;
  align-items: center;
}

.hero-title {
  font-size: 3.5rem;
  font-weight: 800;
  line-height: 1.15;
  margin-bottom: 24px;
}

.hero-title span {
  background: linear-gradient(135deg, var(--accent-primary), var(--accent-secondary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-subtitle {
  color: var(--text-secondary);
  font-size: 1.15rem;
  margin-bottom: 40px;
  max-width: 550px;
}

.hero-actions {
  display: flex;
  gap: 16px;
}

.hero-img-container {
  position: relative;
}

.hero-img {
  width: 100%;
  border-radius: var(--border-radius-md);
  box-shadow: var(--shadow-lg);
  border: 1px solid var(--card-border);
}

.hero-badge {
  position: absolute;
  bottom: -20px;
  left: -20px;
  background: rgba(30, 41, 59, 0.85);
  backdrop-filter: blur(16px);
  padding: 16px 24px;
  border-radius: var(--border-radius-md);
  border: 1px solid var(--card-border);
  box-shadow: var(--shadow-md);
  display: flex;
  align-items: center;
  gap: 12px;
}

.hero-badge-icon {
  font-size: 1.8rem;
}

.badge-text-primary {
  font-weight: 700;
  font-size: 1.1rem;
}

.badge-text-secondary {
  color: var(--text-secondary);
  font-size: 0.85rem;
}

/* Stat Cards */
.stats {
  padding: 60px 0;
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 24px;
}

.stat-card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--border-radius-md);
  padding: 30px;
  text-align: center;
  box-shadow: var(--shadow-sm);
  backdrop-filter: blur(16px);
}

.stat-val {
  font-size: 2.5rem;
  font-weight: 800;
  color: var(--accent-primary);
  margin-bottom: 8px;
}

.stat-label {
  color: var(--text-secondary);
  font-weight: 500;
}

/* Course Catalog Section */
.courses-sec {
  padding: 60px 0;
}

.sec-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-end;
  margin-bottom: 40px;
}

.sec-title {
  font-size: 2rem;
  font-weight: 700;
}

.filters-bar {
  display: flex;
  gap: 12px;
}

.filter-btn {
  padding: 8px 16px;
  border-radius: 20px;
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--card-border);
  color: var(--text-secondary);
  font-weight: 500;
  cursor: pointer;
  transition: var(--transition-fast);
}

.filter-btn:hover, .filter-btn.active {
  background: var(--accent-primary);
  color: #fff;
  border-color: var(--accent-primary);
}

.courses-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 30px;
}

/* Premium Course Card */
.course-card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--border-radius-md);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  transition: var(--transition-normal);
  display: flex;
  flex-direction: column;
  height: 100%;
  backdrop-filter: blur(16px);
}

.course-card:hover {
  transform: translateY(-8px);
  border-color: rgba(99, 102, 241, 0.3);
  box-shadow: var(--shadow-md), 0 0 25px rgba(99, 102, 241, 0.15);
}

.card-img-wrapper {
  position: relative;
  height: 180px;
  overflow: hidden;
}

.card-img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: var(--transition-slow);
}

.course-card:hover .card-img {
  transform: scale(1.05);
}

.card-badge {
  position: absolute;
  top: 16px;
  left: 16px;
  background: rgba(11, 15, 25, 0.7);
  backdrop-filter: blur(8px);
  padding: 4px 10px;
  border-radius: 4px;
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--text-primary);
  border: 1px solid var(--card-border);
}

.card-body {
  padding: 24px;
  display: flex;
  flex-direction: column;
  flex-grow: 1;
}

.card-title {
  font-size: 1.15rem;
  font-weight: 700;
  margin-bottom: 12px;
  line-height: 1.4;
  color: var(--text-primary);
}

.card-desc {
  color: var(--text-secondary);
  font-size: 0.9rem;
  margin-bottom: 20px;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
  height: 2.88rem; /* line-height 1.6 * 0.9rem * 2 lines = 2.88 */
}

.card-footer {
  margin-top: auto;
  border-top: 1px solid var(--card-border);
  padding-top: 16px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.card-instructor {
  font-size: 0.85rem;
  color: var(--text-muted);
}

.card-price {
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--accent-success);
}

.card-price.free {
  color: var(--accent-secondary);
}

/* Authentication Page */
.auth-page {
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 80vh;
  padding: 40px 24px;
}

.auth-card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--border-radius-md);
  padding: 40px;
  width: 100%;
  max-width: 450px;
  box-shadow: var(--shadow-lg);
  backdrop-filter: blur(16px);
}

.auth-tabs {
  display: flex;
  margin-bottom: 30px;
  border-bottom: 2px solid var(--bg-tertiary);
}

.auth-tab {
  flex: 1;
  padding: 12px;
  text-align: center;
  background: none;
  border: none;
  color: var(--text-secondary);
  font-weight: 600;
  font-size: 1.1rem;
  cursor: pointer;
  transition: var(--transition-fast);
  position: relative;
}

.auth-tab.active {
  color: var(--text-primary);
}

.auth-tab.active::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 100%;
  height: 2px;
  background-color: var(--accent-primary);
}

.form-group {
  margin-bottom: 20px;
}

.form-label {
  display: block;
  font-weight: 500;
  font-size: 0.9rem;
  margin-bottom: 8px;
  color: var(--text-secondary);
}

.form-input {
  width: 100%;
  padding: 12px 16px;
  background-color: var(--bg-secondary);
  border: 1px solid var(--card-border);
  border-radius: var(--border-radius-sm);
  color: var(--text-primary);
  font-family: inherit;
  font-size: 0.95rem;
  transition: var(--transition-fast);
}

.form-input:focus {
  outline: none;
  border-color: var(--accent-primary);
  box-shadow: 0 0 10px rgba(99, 102, 241, 0.25);
}

.auth-error {
  background: rgba(239, 68, 68, 0.1);
  border: 1px solid rgba(239, 68, 68, 0.2);
  color: var(--accent-danger);
  padding: 12px;
  border-radius: var(--border-radius-sm);
  font-size: 0.85rem;
  margin-bottom: 20px;
  display: none;
}

/* Dashboard */
.dashboard-grid {
  display: grid;
  grid-template-columns: 280px 1fr;
  gap: 30px;
  padding: 40px 0;
}

.sidebar-nav {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--border-radius-md);
  padding: 24px;
  backdrop-filter: blur(16px);
}

.sidebar-menu {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.sidebar-link {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 16px;
  color: var(--text-secondary);
  text-decoration: none;
  font-weight: 500;
  border-radius: var(--border-radius-sm);
  transition: var(--transition-fast);
}

.sidebar-link:hover, .sidebar-link.active {
  background: rgba(99, 102, 241, 0.1);
  color: var(--text-primary);
}

.sidebar-link.active {
  border-left: 3px solid var(--accent-primary);
}

.db-content {
  display: flex;
  flex-direction: column;
  gap: 30px;
}

.welcome-banner {
  background: linear-gradient(135deg, #1e1b4b, #311042);
  border: 1px solid var(--card-border);
  border-radius: var(--border-radius-md);
  padding: 30px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.welcome-info h1 {
  font-size: 1.8rem;
  margin-bottom: 8px;
}

.welcome-info p {
  color: var(--text-secondary);
}

/* Progress circle styling */
.progress-container {
  display: flex;
  gap: 20px;
  align-items: center;
}

.progress-circle {
  position: relative;
  width: 60px;
  height: 60px;
}

.progress-circle svg {
  width: 60px;
  height: 60px;
  transform: rotate(-90deg);
}

.progress-circle circle {
  width: 100%;
  height: 100%;
  fill: none;
  stroke-width: 6;
  stroke-linecap: round;
}

.progress-circle circle:first-child {
  stroke: var(--bg-tertiary);
}

.progress-circle circle:last-child {
  stroke: var(--accent-primary);
  stroke-dasharray: 170; /* 2 * PI * R (R=27) = 169.6 */
  stroke-dashoffset: 170;
  transition: stroke-dashoffset 0.8s ease;
}

.progress-val {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  font-size: 0.85rem;
  font-weight: 700;
}

/* Course Management for Instructors */
.instructor-panel {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--border-radius-md);
  padding: 30px;
}

.syllabus-builder {
  margin-top: 30px;
}

.section-builder-card {
  background: var(--bg-secondary);
  border: 1px solid var(--card-border);
  border-radius: var(--border-radius-sm);
  padding: 20px;
  margin-bottom: 20px;
}

.lecture-item {
  background: var(--bg-tertiary);
  padding: 10px 16px;
  margin: 10px 0;
  border-radius: 6px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

/* Course Landing View */
.course-hero {
  padding: 60px 0;
  background: radial-gradient(circle at right, rgba(99, 102, 241, 0.1), transparent);
  border-bottom: 1px solid var(--card-border);
}

.course-hero-grid {
  display: grid;
  grid-template-columns: 1.2fr 0.8fr;
  gap: 40px;
}

.course-meta {
  display: flex;
  gap: 16px;
  color: var(--text-secondary);
  font-size: 0.9rem;
  margin: 16px 0;
}

.syllabus-sec {
  padding: 40px 0;
}

.syllabus-section {
  border: 1px solid var(--card-border);
  border-radius: var(--border-radius-sm);
  background: var(--card-bg);
  margin-bottom: 16px;
  overflow: hidden;
}

.syllabus-section-header {
  padding: 16px 24px;
  background: rgba(255, 255, 255, 0.02);
  cursor: pointer;
  font-weight: 600;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.syllabus-section-lectures {
  padding: 16px 24px;
  display: flex;
  flex-direction: column;
  gap: 12px;
  border-top: 1px solid var(--card-border);
}

.syllabus-lecture {
  display: flex;
  align-items: center;
  gap: 12px;
  color: var(--text-secondary);
  text-decoration: none;
}

.syllabus-lecture-icon {
  color: var(--accent-primary);
  font-size: 1.1rem;
}

/* Checkout simulated page */
.checkout-box {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--border-radius-md);
  max-width: 550px;
  margin: 60px auto;
  padding: 40px;
  text-align: center;
}

.qr-code-img {
  width: 200px;
  height: 200px;
  margin: 30px auto;
  padding: 10px;
  background: #fff;
  border-radius: 8px;
}

.bank-info {
  background: var(--bg-secondary);
  border: 1px solid var(--card-border);
  padding: 16px;
  border-radius: 8px;
  text-align: left;
  margin: 20px 0;
}

.bank-row {
  display: flex;
  justify-content: space-between;
  margin-bottom: 8px;
}

/* Learning Platform Screen (Full screen layout concept) */
.learn-layout {
  display: grid;
  grid-template-columns: 1fr 350px;
  height: calc(100vh - 73px);
}

.player-panel {
  padding: 30px;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.video-container {
  width: 100%;
  aspect-ratio: 16/9;
  background-color: #000;
  border-radius: var(--border-radius-md);
  overflow: hidden;
  border: 1px solid var(--card-border);
  position: relative;
}

.video-player-tag {
  width: 100%;
  height: 100%;
}

.live-indicator {
  position: absolute;
  top: 20px;
  left: 20px;
  background-color: var(--accent-danger);
  color: #fff;
  padding: 4px 12px;
  border-radius: 4px;
  font-size: 0.8rem;
  font-weight: 700;
  animation: pulse 1.5s infinite;
  display: flex;
  align-items: center;
  gap: 6px;
  z-index: 10;
}

.live-indicator::before {
  content: '';
  display: inline-block;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background-color: #fff;
}

@keyframes pulse {
  0% { opacity: 0.6; }
  50% { opacity: 1; }
  100% { opacity: 0.6; }
}

.sidebar-playlist {
  border-left: 1px solid var(--card-border);
  background-color: var(--bg-secondary);
  overflow-y: auto;
  padding: 20px;
}

.playlist-sec-title {
  font-size: 0.85rem;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-bottom: 12px;
}

.playlist-item {
  padding: 12px;
  border-radius: var(--border-radius-sm);
  display: flex;
  align-items: center;
  gap: 12px;
  cursor: pointer;
  transition: var(--transition-fast);
  margin-bottom: 8px;
}

.playlist-item:hover, .playlist-item.active {
  background-color: var(--bg-tertiary);
}

.playlist-item.active {
  border-left: 3px solid var(--accent-primary);
}

.playlist-checkbox {
  width: 18px;
  height: 18px;
  border-radius: 4px;
  border: 2px solid var(--text-muted);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: var(--transition-fast);
}

.playlist-item.completed .playlist-checkbox {
  border-color: var(--accent-success);
  background-color: var(--accent-success);
}

.playlist-item.completed .playlist-checkbox::after {
  content: '✓';
  color: #fff;
  font-size: 0.7rem;
  font-weight: bold;
}

/* Livestream Layout */
.live-layout {
  display: grid;
  grid-template-columns: 1fr 380px;
  height: calc(100vh - 73px);
}

.live-player-area {
  padding: 30px;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.chat-panel {
  border-left: 1px solid var(--card-border);
  background-color: var(--bg-secondary);
  display: flex;
  flex-direction: column;
  height: 100%;
}

.chat-header {
  padding: 16px 20px;
  border-bottom: 1px solid var(--card-border);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.chat-body {
  flex-grow: 1;
  padding: 20px;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.chat-msg {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.chat-author {
  font-weight: 700;
  font-size: 0.85rem;
}

.chat-text {
  background: var(--bg-tertiary);
  padding: 10px 14px;
  border-radius: 8px;
  font-size: 0.9rem;
  color: var(--text-primary);
  display: inline-block;
  align-self: flex-start;
  max-width: 90%;
}

.chat-footer {
  padding: 16px 20px;
  border-top: 1px solid var(--card-border);
}

.chat-input-wrapper {
  display: flex;
  gap: 8px;
}

.chat-input {
  flex-grow: 1;
  background-color: var(--bg-tertiary);
}

/* Teacher Streaming Control Board */
.stream-ctrls {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--border-radius-md);
  padding: 20px;
  display: flex;
  gap: 16px;
  align-items: center;
  margin-top: 20px;
}

/* Toast Notification */
.toast {
  position: fixed;
  bottom: 24px;
  right: 24px;
  background: var(--bg-secondary);
  border: 1px solid var(--accent-primary);
  box-shadow: var(--shadow-lg);
  padding: 16px 24px;
  border-radius: var(--border-radius-sm);
  display: none;
  z-index: 1000;
  font-weight: 500;
  animation: slideIn 0.3s ease;
}

@keyframes slideIn {
  from { transform: translateY(20px); opacity: 0; }
  to { transform: translateY(0); opacity: 1; }
}

/* Footer */
footer {
  border-top: 1px solid var(--card-border);
  padding: 40px 0;
  text-align: center;
  color: var(--text-muted);
  font-size: 0.9rem;
}

/* Responsive adjustments */
@media (max-width: 992px) {
  .hero-grid, .course-hero-grid {
    grid-template-columns: 1fr;
  }
  .dashboard-grid, .learn-layout, .live-layout {
    grid-template-columns: 1fr;
  }
  .learn-layout, .live-layout {
    height: auto;
  }
  .sidebar-playlist, .chat-panel {
    border-left: none;
    border-top: 1px solid var(--card-border);
    height: 500px;
}

/* Pulsing glow badge for active livestreams */
.live-badge-glow {
  position: absolute;
  top: 12px;
  right: 12px;
  background: rgba(239, 68, 68, 0.95);
  color: #fff;
  padding: 6px 12px;
  border-radius: 20px;
  font-size: 0.75rem;
  font-weight: 800;
  box-shadow: 0 0 12px rgba(239, 68, 68, 0.75);
  animation: pulse-glow 1.5s infinite;
  z-index: 5;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  letter-spacing: 0.5px;
  border: 1px solid rgba(255, 255, 255, 0.25);
}

@keyframes pulse-glow {
  0% { transform: scale(0.96); box-shadow: 0 0 8px rgba(239, 68, 68, 0.6); }
  50% { transform: scale(1.05); box-shadow: 0 0 18px rgba(239, 68, 68, 0.9); }
  100% { transform: scale(0.96); box-shadow: 0 0 8px rgba(239, 68, 68, 0.6); }
}