/* ====================================================================
   BIONUL EDTECH PLATFORM - COMPLETE PREMIUM COMPONENTS
   Matched to Reference Design for Home & Courses Pages
   ==================================================================== */

/* ====================================================================
   1. APP HEADER & TOP BARS
   ==================================================================== */

.app-header {
  position: sticky;
  top: 0;
  z-index: 40;
  height: var(--header-height);
  background-color: #FFFFFF;
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 16px;
}

.brand-logo {
  display: flex;
  align-items: center;
  gap: 8px;
  text-decoration: none;
  line-height: 1;
}

.brand-logo-img {
  height: 38px;
  width: auto;
  max-width: 160px;
  object-fit: contain;
  display: block;
}

.brand-logo-icon {
  width: 34px;
  height: 34px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--primary);
}

.brand-logo-icon svg {
  width: 30px;
  height: 30px;
  fill: var(--primary);
}

/* ====================================================================
   GLOBAL CARD & BADGE UTILITIES
   ==================================================================== */
.card {
  background-color: var(--surface-card, #FFFFFF);
  border: 1px solid var(--border-color, #EAEBF2);
  border-radius: var(--radius-lg, 16px);
  padding: 18px;
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-fast);
}

.card-hover:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
  border-color: var(--primary-border, #DCD6FE);
}

.badge {
  display: inline-flex;
  align-items: center;
  padding: 3px 8px;
  border-radius: var(--radius-xs, 6px);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.02em;
  text-transform: uppercase;
}

.badge-purple {
  background-color: var(--pastel-purple, #F3F0FF);
  color: var(--pastel-purple-icon, #5B3DF5);
}

.badge-outline {
  background-color: transparent;
  color: var(--text-muted, #64748B);
  border: 1px solid var(--border-color, #EAEBF2);
}

/* ====================================================================
   PREMIUM DEVELOPER CREDIT BADGE
   ==================================================================== */
.dev-credit-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 16px;
  border-radius: var(--radius-full, 9999px);
  background: linear-gradient(135deg, rgba(91, 61, 245, 0.08) 0%, rgba(147, 51, 234, 0.12) 100%);
  border: 1px solid rgba(91, 61, 245, 0.22);
  color: var(--primary, #5B3DF5);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  box-shadow: 0 2px 8px rgba(91, 61, 245, 0.08);
  transition: all var(--transition-fast);
}

.dev-credit-badge:hover {
  background: linear-gradient(135deg, rgba(91, 61, 245, 0.14) 0%, rgba(147, 51, 234, 0.18) 100%);
  transform: translateY(-1px);
  box-shadow: 0 4px 12px rgba(91, 61, 245, 0.16);
}

.dev-credit-badge strong {
  font-weight: 900;
  color: var(--text-heading, #0F172A);
  letter-spacing: 0.06em;
}

.dev-badge-icon {
  display: flex;
  align-items: center;
  justify-content: center;
}

.dev-badge-icon svg {
  width: 14px;
  height: 14px;
  fill: var(--primary, #5B3DF5);
}

.header-user-actions {
  display: flex;
  align-items: center;
  gap: 10px;
}

.icon-circle-btn {
  width: 38px;
  height: 38px;
  border-radius: 50%;
  background-color: var(--surface-subtle);
  border: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-heading);
  position: relative;
  transition: all var(--transition-fast);
  text-decoration: none;
}

.icon-circle-btn:hover {
  background-color: var(--primary-light);
  color: var(--primary);
}

.notification-badge-dot {
  position: absolute;
  top: -2px;
  right: -2px;
  background-color: #EF4444;
  color: #FFFFFF;
  font-size: 0.62rem;
  font-weight: 800;
  min-width: 16px;
  height: 16px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  border: 2px solid #FFFFFF;
  padding: 0 2px;
}

.user-avatar-btn {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  overflow: hidden;
  border: 2px solid var(--primary-light);
  display: block;
  flex-shrink: 0;
}

.user-avatar-btn img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

/* ====================================================================
   2. SEARCH BAR WITH FILTER ICON
   ==================================================================== */

.search-bar-wrapper {
  position: relative;
  display: flex;
  align-items: center;
  width: 100%;
  margin-bottom: 16px;
}

.search-input-field {
  width: 100%;
  height: 48px;
  padding: 0 46px 0 44px;
  background-color: #FFFFFF;
  border: 1.5px solid var(--border-color);
  border-radius: var(--radius-md);
  color: var(--text-heading);
  font-size: 0.92rem;
  font-family: inherit;
  transition: all var(--transition-fast);
  box-shadow: var(--shadow-sm);
}

.search-input-field:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3.5px rgba(91, 61, 245, 0.12);
  background-color: #FFFFFF;
}

.search-icon-left {
  position: absolute;
  left: 14px;
  top: 50%;
  transform: translateY(-50%);
  width: 20px;
  height: 20px;
  color: var(--text-light);
  pointer-events: none;
}

.search-filter-btn {
  position: absolute;
  right: 12px;
  top: 50%;
  transform: translateY(-50%);
  width: 28px;
  height: 28px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-muted);
  background: none;
  border: none;
  cursor: pointer;
  border-radius: var(--radius-xs);
  transition: color var(--transition-fast);
}

.search-filter-btn:hover {
  color: var(--primary);
}

/* ====================================================================
   3. HORIZONTALLY SCROLLABLE CATEGORY PILLS
   ==================================================================== */

.category-pills-scroll {
  display: flex;
  align-items: center;
  gap: 8px;
  overflow-x: auto;
  padding-bottom: 6px;
  margin-bottom: 22px;
  scrollbar-width: none; /* Firefox */
  -webkit-overflow-scrolling: touch;
}

.category-pills-scroll::-webkit-scrollbar {
  display: none; /* Chrome/Safari */
}

.category-pill {
  padding: 8px 18px;
  border-radius: var(--radius-full);
  font-size: 0.85rem;
  font-weight: 700;
  white-space: nowrap;
  background-color: #FFFFFF;
  color: var(--text-body);
  border: 1.5px solid var(--border-color);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.category-pill:hover {
  border-color: var(--primary-border);
  color: var(--primary);
}

.category-pill.active {
  background-color: var(--primary);
  color: #FFFFFF;
  border-color: var(--primary);
  box-shadow: 0 4px 12px rgba(91, 61, 245, 0.3);
}

/* ====================================================================
   4. FEATURED COURSE HERO CARD (With 3D Science Graphic)
   ==================================================================== */

.featured-course-card {
  background: var(--hero-card-gradient);
  border-radius: var(--radius-xl);
  padding: 22px 20px;
  color: #FFFFFF;
  box-shadow: var(--shadow-hero);
  position: relative;
  overflow: hidden;
  margin-bottom: 26px;
  display: grid;
  grid-template-columns: 1fr auto;
  align-items: center;
  gap: 12px;
}

.featured-tag {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  font-size: 0.75rem;
  font-weight: 700;
  color: rgba(255, 255, 255, 0.9);
  margin-bottom: 8px;
}

.featured-title {
  font-size: 1.45rem;
  font-weight: 800;
  color: #FFFFFF;
  line-height: 1.22;
  margin-bottom: 6px;
}

.featured-desc {
  font-size: 0.82rem;
  color: rgba(255, 255, 255, 0.85);
  margin-bottom: 18px;
  line-height: 1.45;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.featured-cta-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 9px 18px;
  background-color: #FFFFFF;
  color: var(--primary);
  border-radius: var(--radius-full);
  font-size: 0.85rem;
  font-weight: 800;
  text-decoration: none;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
  transition: transform var(--transition-fast);
}

.featured-cta-btn:hover {
  transform: translateY(-1px);
}

.featured-science-art {
  width: 110px;
  height: 110px;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
}

/* ====================================================================
   5. MOBILE-FIRST FULL-WIDTH COURSE CARDS (1 Card Per Row)
   ==================================================================== */

.course-list-container {
  display: flex;
  flex-direction: column;
  gap: 14px;
  margin-bottom: 24px;
}

.mobile-course-card {
  background-color: var(--surface-card);
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-color);
  box-shadow: var(--shadow-sm);
  padding: 14px;
  display: flex;
  gap: 14px;
  align-items: stretch;
  text-decoration: none;
  color: inherit;
  transition: all var(--transition-fast);
}

.mobile-course-card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
  border-color: var(--primary-border);
}

.mobile-course-thumb {
  width: 100px;
  min-width: 100px;
  border-radius: var(--radius-md);
  overflow: hidden;
  background-color: #0F172A;
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
}

.mobile-course-thumb img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.mobile-course-info {
  flex: 1;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  min-width: 0; /* Prevents overflow */
}

.mobile-course-badge {
  font-size: 0.7rem;
  font-weight: 800;
  color: var(--primary);
  letter-spacing: 0.04em;
  text-transform: uppercase;
  margin-bottom: 3px;
}

.mobile-course-title {
  font-size: 1rem;
  font-weight: 800;
  color: var(--text-heading);
  line-height: 1.3;
  margin-bottom: 4px;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.mobile-course-teacher {
  display: flex;
  align-items: center;
  gap: 5px;
  font-size: 0.78rem;
  color: var(--text-muted);
  font-weight: 500;
  margin-bottom: 6px;
}

.teacher-micro-avatar {
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background-color: var(--primary-light);
  color: var(--primary);
  font-size: 0.6rem;
  font-weight: 800;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.mobile-course-meta-row {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.78rem;
  color: var(--text-muted);
  font-weight: 600;
  margin-bottom: 8px;
}

.rating-star {
  color: #F59E0B;
  font-weight: 800;
}

.mobile-course-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 6px;
  border-top: 1px solid var(--border-subtle);
  margin-top: auto;
}

.mobile-course-price {
  font-size: 1.15rem;
  font-weight: 800;
  color: var(--text-heading);
}

.mobile-course-enrolled {
  font-size: 0.8rem;
  font-weight: 800;
  color: var(--pastel-green-icon);
}

.mobile-view-btn {
  padding: 6px 14px;
  border-radius: var(--radius-sm);
  background-color: #FFFFFF;
  color: var(--primary);
  border: 1.5px solid var(--primary-border);
  font-size: 0.8rem;
  font-weight: 700;
  text-decoration: none;
  transition: all var(--transition-fast);
}

.mobile-view-btn:hover {
  background-color: var(--primary);
  color: #FFFFFF;
}

/* ====================================================================
   6. COURSE DETAILS PAGE (Matched to Right Screen of Screenshot)
   ==================================================================== */

.course-detail-header-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 0 16px 0;
  margin-bottom: 8px;
}

.back-circle-btn {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background-color: #FFFFFF;
  border: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-heading);
  text-decoration: none;
}

.course-detail-title-top {
  font-size: 1.05rem;
  font-weight: 800;
  color: var(--text-heading);
}

.course-media-hero {
  position: relative;
  width: 100%;
  border-radius: var(--radius-lg);
  overflow: hidden;
  background-color: #0F172A;
  box-shadow: var(--shadow-md);
  margin-bottom: 18px;
}

.course-media-hero img {
  width: 100%;
  height: auto;
  display: block;
}

.media-play-overlay-btn {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 52px;
  height: 52px;
  border-radius: 50%;
  background-color: rgba(255, 255, 255, 0.95);
  color: var(--primary);
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.25);
  border: none;
  cursor: pointer;
}

.media-play-overlay-btn svg {
  width: 22px;
  height: 22px;
  fill: currentColor;
  margin-left: 3px;
}

.detail-features-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
  margin: 20px 0;
}

.detail-feature-card {
  background-color: #FFFFFF;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 12px;
  display: flex;
  align-items: center;
  gap: 10px;
  box-shadow: var(--shadow-sm);
}

.detail-feature-icon {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.detail-feature-title {
  font-size: 0.82rem;
  font-weight: 800;
  color: var(--text-heading);
  line-height: 1.2;
}

.detail-feature-sub {
  font-size: 0.68rem;
  color: var(--text-muted);
}

.chapter-item-row {
  background-color: #FFFFFF;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 14px 16px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 8px;
  transition: all var(--transition-fast);
}

.chapter-item-row:hover {
  border-color: var(--primary-border);
  background-color: var(--primary-light);
}

.chapter-left-info {
  display: flex;
  align-items: center;
  gap: 12px;
}

.chapter-play-icon {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background-color: var(--primary-light);
  color: var(--primary);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.chapter-name-text {
  font-size: 0.9rem;
  font-weight: 700;
  color: var(--text-heading);
}

.chapter-duration-text {
  font-size: 0.75rem;
  color: var(--text-muted);
}

/* ====================================================================
   7. SKELETON LOADERS & EMPTY STATES
   ==================================================================== */

.course-card-skeleton {
  background-color: #FFFFFF;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-color);
  padding: 14px;
  display: flex;
  gap: 14px;
  margin-bottom: 12px;
}

.skeleton-thumb {
  width: 100px;
  height: 90px;
  border-radius: var(--radius-md);
}

.skeleton-lines {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 8px;
  justify-content: center;
}

/* ====================================================================
   7.1 PREMIUM EMPTY STATE CARDS
   ==================================================================== */
.empty-state-card {
  background-color: var(--surface-card, #FFFFFF);
  border: 1px solid var(--border-color, #EAEBF2);
  border-radius: var(--radius-xl, 18px);
  padding: 24px 20px;
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow-sm);
  margin-bottom: 8px;
}

.empty-state-icon-box {
  width: 52px;
  height: 52px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 12px;
}

.empty-state-icon-box svg {
  width: 24px;
  height: 24px;
}

.empty-state-icon-box.purple {
  background-color: var(--pastel-purple, #F3F0FF);
  color: var(--pastel-purple-icon, #5B3DF5);
}

.empty-state-icon-box.red {
  background-color: var(--pastel-red, #FFF1F2);
  color: var(--pastel-red-icon, #F43F5E);
}

.empty-state-icon-box.yellow {
  background-color: var(--pastel-yellow, #FEF8E7);
  color: var(--pastel-yellow-icon, #F59E0B);
}

.empty-state-icon-box.green {
  background-color: var(--pastel-green, #EBFBF5);
  color: var(--pastel-green-icon, #10B981);
}

.empty-state-title {
  font-size: 0.98rem;
  font-weight: 800;
  color: var(--text-heading, #0F172A);
  margin-bottom: 4px;
  letter-spacing: -0.01em;
}

.empty-state-desc {
  font-size: 0.82rem;
  color: var(--text-muted, #64748B);
  line-height: 1.45;
  max-width: 290px;
  margin-bottom: 14px;
}

.empty-state-desc:last-child {
  margin-bottom: 0;
}

.empty-state-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 18px;
  border-radius: var(--radius-full, 9999px);
  background-color: var(--primary-light, #F1EEFF);
  color: var(--primary, #5B3DF5);
  font-size: 0.82rem;
  font-weight: 700;
  text-decoration: none;
  border: 1px solid rgba(91, 61, 245, 0.15);
  transition: all var(--transition-fast);
}

.empty-state-btn:hover {
  background-color: var(--primary, #5B3DF5);
  color: #FFFFFF;
}

.empty-state-btn svg {
  width: 14px;
  height: 14px;
  fill: currentColor;
}

/* Generic fallback aliases for .empty-state */
.empty-state {
  background-color: var(--surface-card, #FFFFFF);
  border: 1px solid var(--border-color, #EAEBF2);
  border-radius: var(--radius-xl, 18px);
  padding: 28px 20px;
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow-sm);
  margin: 12px 0;
  width: 100%;
}

.empty-icon,
.empty-state-icon {
  width: 52px;
  height: 52px;
  border-radius: 50%;
  background-color: var(--pastel-purple, #F3F0FF);
  color: var(--pastel-purple-icon, #5B3DF5);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 12px;
}

.empty-icon svg,
.empty-state-icon svg {
  width: 24px;
  height: 24px;
  max-width: 24px;
  max-height: 24px;
  fill: currentColor;
}

.empty-title {
  font-size: 1rem;
  font-weight: 800;
  color: var(--text-heading, #0F172A);
  margin-bottom: 6px;
  letter-spacing: -0.01em;
}

.empty-desc {
  font-size: 0.82rem;
  color: var(--text-muted, #64748B);
  line-height: 1.5;
  max-width: 320px;
  margin-bottom: 16px;
}

/* ====================================================================
   8. GLOBAL MODAL DIALOGS & OVERLAYS
   ==================================================================== */

.modal-backdrop {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  background-color: rgba(15, 23, 42, 0.65);
  backdrop-filter: blur(6px);
  -webkit-backdrop-filter: blur(6px);
  z-index: 9999;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
  transition: opacity 0.25s ease, visibility 0.25s ease;
}

.modal-backdrop.show {
  opacity: 1;
  visibility: visible;
  pointer-events: auto;
}

.modal-content {
  background: #FFFFFF;
  border-radius: var(--radius-xl, 20px);
  width: 100%;
  max-width: 420px;
  box-shadow: var(--shadow-lg, 0 20px 40px rgba(0, 0, 0, 0.18));
  border: 1px solid var(--border-color);
  transform: translateY(20px) scale(0.96);
  transition: transform 0.25s cubic-bezier(0.16, 1, 0.3, 1);
  overflow: hidden;
  box-sizing: border-box;
}

.modal-backdrop.show .modal-content {
  transform: translateY(0) scale(1);
}