/* Import premium fonts from Google Fonts */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&family=Outfit:wght@400;500;600;700;800&display=swap');

:root {
  --bg-primary: #06080c;
  --bg-secondary: #0b0e16;
  --bg-card: rgba(16, 22, 36, 0.65);
  --bg-input: rgba(11, 14, 23, 0.85);
  --border-color: rgba(255, 255, 255, 0.06);
  --border-hover: rgba(99, 102, 241, 0.45);
  
  --text-primary: #f3f4f6;
  --text-secondary: #9ca3af;
  --text-muted: #6b7280;
  
  --accent-color: #6366f1;
  --accent-gradient: linear-gradient(135deg, #6366f1 0%, #8b5cf6 50%, #d946ef 100%);
  --accent-glow: 0 0 25px rgba(99, 102, 241, 0.3);
  --card-glow: 0 10px 30px -10px rgba(0, 0, 0, 0.7);
  
  --font-display: 'Outfit', sans-serif;
  --font-body: 'Inter', sans-serif;
  
  --transition-smooth: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

body {
  background-color: var(--bg-primary);
  color: var(--text-primary);
  font-family: var(--font-body);
  line-height: 1.5;
  min-height: 100vh;
  overflow-x: hidden;
  background-image: 
    radial-gradient(circle at 12% 18%, rgba(99, 102, 241, 0.055) 0%, transparent 42%),
    radial-gradient(circle at 88% 82%, rgba(217, 70, 239, 0.055) 0%, transparent 42%);
  background-attachment: fixed;
}

/* Custom Scrollbar */
::-webkit-scrollbar {
  width: 8px;
}
::-webkit-scrollbar-track {
  background: var(--bg-primary);
}
::-webkit-scrollbar-thumb {
  background: var(--bg-secondary);
  border-radius: 4px;
  border: 1px solid var(--border-color);
}
::-webkit-scrollbar-thumb:hover {
  background: var(--accent-color);
}

/* Layout */
.app-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 2.5rem 1.5rem;
}

/* Header Section */
header {
  text-align: center;
  margin-bottom: 3.5rem;
}

.logo-area {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 2rem;
}

.logo {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 1.75rem;
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.logo svg {
  fill: var(--accent-color);
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.sync-btn {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  padding: 0.6rem 1.2rem;
  border-radius: 9999px;
  font-family: var(--font-body);
  font-weight: 500;
  font-size: 0.875rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  transition: var(--transition-smooth);
  backdrop-filter: blur(10px);
}

.sync-btn:hover:not(:disabled) {
  border-color: var(--border-hover);
  box-shadow: var(--accent-glow);
  transform: translateY(-1px);
}

.sync-btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.sync-btn svg.spin {
  animation: spin 1s linear infinite;
}

@keyframes spin {
  100% { transform: rotate(360deg); }
}

.hero-title {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 3.5rem;
  line-height: 1.1;
  margin-bottom: 1.25rem;
  letter-spacing: -0.03em;
  background: linear-gradient(135deg, #ffffff 30%, var(--text-secondary) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-subtitle {
  color: var(--text-secondary);
  font-size: 1.15rem;
  max-width: 650px;
  margin: 0 auto;
  font-weight: 300;
  line-height: 1.6;
}

/* Search Area */
.search-controls {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 24px;
  padding: 1.5rem;
  margin-bottom: 3rem;
  backdrop-filter: blur(12px);
  box-shadow: var(--card-glow);
}

.search-bar-row {
  display: grid;
  grid-template-columns: 1fr auto auto auto;
  gap: 1rem;
  margin-bottom: 1.25rem;
}

@media (max-width: 768px) {
  .logo-area {
    flex-direction: column;
    gap: 1.25rem;
    align-items: center;
    margin-bottom: 2.5rem;
  }
  .header-actions {
    flex-direction: column;
    align-items: center;
    gap: 1rem;
    width: 100%;
  }
  .search-bar-row {
    grid-template-columns: 1fr;
  }
}

.search-input-wrapper {
  position: relative;
  display: flex;
  align-items: center;
}

.search-input-wrapper svg {
  position: absolute;
  left: 1.25rem;
  color: var(--text-muted);
  pointer-events: none;
}

.search-input {
  width: 100%;
  background-color: var(--bg-input);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  font-family: var(--font-body);
  font-size: 1rem;
  padding: 0.85rem 1rem 0.85rem 3rem;
  border-radius: 14px;
  outline: none;
  transition: var(--transition-smooth);
}

.search-input:focus {
  border-color: var(--accent-color);
  box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.15);
}

.select-control {
  background-color: var(--bg-input);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  font-family: var(--font-body);
  font-size: 0.9rem;
  padding: 0.85rem 1.25rem;
  border-radius: 14px;
  outline: none;
  cursor: pointer;
  transition: var(--transition-smooth);
}

.select-control:focus {
  border-color: var(--accent-color);
}

/* Category Filter Pills */
.categories-pills {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
}

.pill {
  background: rgba(255, 255, 255, 0.02);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  padding: 0.5rem 1rem;
  border-radius: 9999px;
  font-size: 0.8rem;
  font-weight: 500;
  cursor: pointer;
  transition: var(--transition-smooth);
  display: flex;
  align-items: center;
  gap: 0.35rem;
}

.pill:hover {
  background: rgba(99, 102, 241, 0.08);
  color: var(--text-primary);
  border-color: var(--accent-color);
}

.pill.active {
  background: var(--accent-gradient);
  color: #fff;
  border-color: transparent;
  box-shadow: var(--accent-glow);
}

.pill-count {
  background: rgba(255, 255, 255, 0.15);
  color: inherit;
  padding: 0.05rem 0.4rem;
  border-radius: 9999px;
  font-size: 0.7rem;
  font-weight: 600;
}

/* Stats Row */
.stats-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1.5rem;
  color: var(--text-secondary);
  font-size: 0.875rem;
}

.stats-count {
  font-weight: 500;
}

/* Grid Container */
.lessons-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 1.5rem;
  margin-bottom: 3rem;
}

/* Lesson Card */
.lesson-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 20px;
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  min-height: 260px;
  transition: var(--transition-smooth);
  backdrop-filter: blur(10px);
  position: relative;
  overflow: hidden;
  box-shadow: var(--card-glow);
}

.lesson-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 4px;
  background: var(--accent-gradient);
  opacity: 0;
  transition: var(--transition-smooth);
}

.lesson-card:hover {
  transform: translateY(-5px);
  border-color: var(--border-hover);
  box-shadow: 0 15px 35px -15px rgba(99, 102, 241, 0.2);
}

.lesson-card:hover::before {
  opacity: 1;
}

.card-top {
  margin-bottom: 1.25rem;
}

.card-badges {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 0.75rem;
}

.badge-signup {
  background: rgba(139, 92, 246, 0.12);
  color: #c084fc;
  border: 1px solid rgba(139, 92, 246, 0.2);
  padding: 0.25rem 0.6rem;
  border-radius: 9999px;
  font-size: 0.75rem;
  font-weight: 600;
}

.badge-relevance {
  background: rgba(217, 70, 239, 0.12);
  color: #f472b6;
  border: 1px solid rgba(217, 70, 239, 0.2);
  padding: 0.25rem 0.6rem;
  border-radius: 9999px;
  font-size: 0.75rem;
  font-weight: 600;
}

.card-title {
  font-family: var(--font-display);
  font-size: 1.2rem;
  font-weight: 600;
  line-height: 1.35;
  margin-bottom: 0.5rem;
  color: var(--text-primary);
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
  text-overflow: ellipsis;
}

.card-authors {
  color: var(--text-secondary);
  font-size: 0.85rem;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  margin-bottom: 0.75rem;
}

/* Card Lesson Tags */
.card-tags {
  display: flex;
  gap: 0.35rem;
  flex-wrap: wrap;
  margin-bottom: 0.25rem;
}

.lesson-tag {
  font-size: 0.7rem;
  font-weight: 600;
  padding: 0.15rem 0.5rem;
  border-radius: 6px;
  cursor: pointer;
  transition: var(--transition-smooth);
}

.lesson-tag:hover {
  filter: brightness(1.2);
  transform: scale(1.02);
}

/* Specific Tag Colors */
.tag-ai {
  background: rgba(139, 92, 246, 0.1);
  color: #a78bfa;
  border: 1px solid rgba(139, 92, 246, 0.2);
}
.tag-product {
  background: rgba(59, 130, 246, 0.1);
  color: #60a5fa;
  border: 1px solid rgba(59, 130, 246, 0.2);
}
.tag-engineering {
  background: rgba(16, 185, 129, 0.1);
  color: #34d399;
  border: 1px solid rgba(16, 185, 129, 0.2);
}
.tag-design {
  background: rgba(245, 158, 11, 0.1);
  color: #fbbf24;
  border: 1px solid rgba(245, 158, 11, 0.2);
}
.tag-marketing {
  background: rgba(236, 72, 153, 0.1);
  color: #f472b6;
  border: 1px solid rgba(236, 72, 153, 0.2);
}
.tag-leadership {
  background: rgba(6, 182, 212, 0.1);
  color: #22d3ee;
  border: 1px solid rgba(6, 182, 212, 0.2);
}
.tag-founders {
  background: rgba(239, 68, 68, 0.1);
  color: #f87171;
  border: 1px solid rgba(239, 68, 68, 0.2);
}
.tag-general {
  background: rgba(107, 114, 128, 0.1);
  color: #9ca3af;
  border: 1px solid rgba(107, 114, 128, 0.2);
}

.card-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.04);
  padding-top: 1rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.card-info {
  display: flex;
  flex-direction: column;
  gap: 0.2rem;
  font-size: 0.75rem;
  color: var(--text-muted);
}

.info-item {
  display: flex;
  align-items: center;
  gap: 0.35rem;
}

.info-item svg {
  color: var(--text-muted);
  flex-shrink: 0;
}

.card-link {
  background: var(--accent-gradient);
  color: #fff;
  border: none;
  padding: 0.5rem 1rem;
  border-radius: 10px;
  font-size: 0.8rem;
  font-weight: 600;
  text-decoration: none;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 0.35rem;
  transition: var(--transition-smooth);
}

.card-link:hover {
  opacity: 0.9;
  transform: translateX(2px);
}

/* Status overlays */
.state-message {
  text-align: center;
  padding: 4rem 2rem;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 24px;
  backdrop-filter: blur(12px);
  grid-column: 1 / -1;
  max-width: 500px;
  margin: 0 auto;
}

.state-message svg {
  color: var(--accent-color);
  margin-bottom: 1rem;
}

.state-message h3 {
  font-family: var(--font-display);
  font-size: 1.5rem;
  margin-bottom: 0.5rem;
}

.state-message p {
  color: var(--text-secondary);
  margin-bottom: 1.5rem;
  font-size: 0.925rem;
}

.state-message button {
  background: var(--accent-gradient);
  color: #fff;
  border: none;
  padding: 0.75rem 1.75rem;
  border-radius: 12px;
  font-family: var(--font-body);
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition-smooth);
}

.state-message button:hover {
  box-shadow: var(--accent-glow);
  transform: translateY(-1px);
}

/* Sync Loader Overlay */
.sync-overlay {
  position: fixed;
  inset: 0;
  background: rgba(7, 9, 14, 0.85);
  backdrop-filter: blur(8px);
  z-index: 100;
  display: flex;
  justify-content: center;
  align-items: center;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.3s ease;
}

.sync-overlay.visible {
  opacity: 1;
  pointer-events: all;
}

.sync-spinner-box {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  padding: 2.5rem;
  border-radius: 28px;
  text-align: center;
  max-width: 320px;
  box-shadow: var(--card-glow);
}

.sync-spinner-box svg {
  color: var(--accent-color);
  animation: spin 1s linear infinite;
  margin-bottom: 1.25rem;
}

.sync-spinner-box h4 {
  font-family: var(--font-display);
  font-size: 1.25rem;
  margin-bottom: 0.5rem;
}

.sync-spinner-box p {
  color: var(--text-secondary);
  font-size: 0.85rem;
}

/* Detail Modal */
.modal-container {
  position: fixed;
  inset: 0;
  background: rgba(7, 9, 14, 0.75);
  backdrop-filter: blur(8px);
  z-index: 200;
  display: flex;
  justify-content: center;
  align-items: center;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.3s ease;
}

.modal-container.visible {
  opacity: 1;
  pointer-events: all;
}

.modal-content {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  width: 90%;
  max-width: 600px;
  border-radius: 28px;
  padding: 2.5rem;
  position: relative;
  box-shadow: var(--card-glow);
  transform: scale(0.95);
  transition: transform 0.3s ease;
}

.modal-container.visible .modal-content {
  transform: scale(1);
}

.modal-close {
  position: absolute;
  top: 1.5rem;
  right: 1.5rem;
  background: transparent;
  border: none;
  color: var(--text-secondary);
  cursor: pointer;
  transition: var(--transition-smooth);
}

.modal-close:hover {
  color: var(--text-primary);
  transform: rotate(90deg);
}

.modal-title {
  font-family: var(--font-display);
  font-size: 1.75rem;
  font-weight: 700;
  line-height: 1.25;
  margin-bottom: 1.25rem;
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.modal-tags {
  display: flex;
  gap: 0.5rem;
  margin-bottom: 1.5rem;
}

.modal-section-title {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 0.875rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-muted);
  margin-bottom: 0.75rem;
}

.modal-meta-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.25rem;
  margin-bottom: 2rem;
  border-bottom: 1px solid rgba(255, 255, 255, 0.05);
  padding-bottom: 1.5rem;
}

.modal-meta-item {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.modal-meta-item svg {
  color: var(--accent-color);
}

.modal-meta-text h5 {
  font-size: 0.75rem;
  color: var(--text-muted);
  font-weight: 500;
}

.modal-meta-text p {
  font-size: 0.9rem;
  color: var(--text-primary);
  font-weight: 600;
}

.modal-instructors-list {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  margin-bottom: 2.5rem;
}

.instructor-item {
  display: flex;
  align-items: center;
  gap: 1rem;
  background: rgba(255, 255, 255, 0.02);
  border: 1px solid var(--border-color);
  padding: 0.75rem 1rem;
  border-radius: 16px;
}

.instructor-img {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  object-fit: cover;
  border: 2px solid var(--border-color);
}

.instructor-name {
  font-weight: 600;
  font-size: 0.95rem;
}

.modal-action-row {
  display: flex;
  justify-content: flex-end;
}

.modal-action-btn {
  background: var(--accent-gradient);
  color: #fff;
  border: none;
  padding: 0.85rem 2rem;
  border-radius: 14px;
  font-family: var(--font-body);
  font-weight: 600;
  font-size: 0.95rem;
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  cursor: pointer;
  transition: var(--transition-smooth);
}

.modal-action-btn:hover {
  box-shadow: var(--accent-glow);
  transform: translateY(-1px);
}