/* ==========================================================================
   Cairo Education - Main Mobile-First Stylesheet
   ========================================================================== */

/* --- Container & Grid --- */
.cairo-container {
  width: 100%;
  max-width: 1200px;
  margin-left: auto;
  margin-right: auto;
  padding-left: 16px;
  padding-right: 16px;
}

@media (min-width: 768px) {
  .cairo-container {
    padding-left: 24px;
    padding-right: 24px;
  }
}

/* --- Header & Navigation --- */
.cairo-header {
  background: var(--cairo-surface);
  border-bottom: 1px solid var(--cairo-gray-light);
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: var(--cairo-shadow-sm);
}

.cairo-nav-wrapper {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 68px;
}

.cairo-brand {
  display: flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
}

.cairo-logo-badge {
  width: 42px;
  height: 42px;
  border-radius: var(--cairo-radius-full);
  background: linear-gradient(135deg, var(--cairo-primary), var(--cairo-secondary));
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-weight: 800;
  font-size: 20px;
  box-shadow: 0 2px 8px rgba(30, 58, 138, 0.3);
}

.cairo-brand-text h1 {
  font-size: 20px;
  font-weight: 800;
  color: var(--cairo-primary);
  line-height: 1.1;
}

.cairo-brand-text span {
  font-size: 11px;
  font-weight: 600;
  color: var(--cairo-secondary);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

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

@media (min-width: 992px) {
  .cairo-nav-menu {
    display: flex;
  }
}

.cairo-nav-link {
  color: var(--cairo-gray-dark);
  font-weight: 600;
  font-size: 15px;
  padding: 8px 12px;
  border-radius: var(--cairo-radius-sm);
  transition: all 0.2s ease;
}

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

.cairo-nav-actions {
  display: flex;
  align-items: center;
  gap: 12px;
}

/* --- Buttons --- */
.cairo-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  font-weight: 600;
  font-size: 14px;
  padding: 10px 20px;
  border-radius: var(--cairo-radius);
  border: none;
  cursor: pointer;
  transition: all 0.2s ease;
  text-decoration: none;
  text-align: center;
}

.cairo-btn-primary {
  background: var(--cairo-primary);
  color: #fff;
}
.cairo-btn-primary:hover {
  background: var(--cairo-primary-light);
  color: #fff;
  transform: translateY(-1px);
}

.cairo-btn-secondary {
  background: var(--cairo-secondary);
  color: #fff;
}
.cairo-btn-secondary:hover {
  background: var(--cairo-secondary-light);
  color: #fff;
}

.cairo-btn-outline {
  background: transparent;
  color: var(--cairo-primary);
  border: 1.5px solid var(--cairo-primary);
}
.cairo-btn-outline:hover {
  background: var(--cairo-primary-container);
}

.cairo-btn-sm {
  padding: 6px 14px;
  font-size: 13px;
  border-radius: var(--cairo-radius-sm);
}

.cairo-btn-lg {
  padding: 14px 28px;
  font-size: 16px;
  border-radius: var(--cairo-radius-lg);
}

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

.cairo-btn-full {
  width: 100%;
}

/* --- Mobile Bottom Navigation --- */
.cairo-mobile-nav {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  height: 62px;
  background: var(--cairo-surface);
  border-top: 1px solid var(--cairo-gray-light);
  display: flex;
  align-items: center;
  justify-content: space-around;
  z-index: 1000;
  box-shadow: 0 -2px 10px rgba(0, 0, 0, 0.05);
}

@media (min-width: 992px) {
  .cairo-mobile-nav {
    display: none;
  }
}

.cairo-mobile-nav-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 3px;
  color: var(--cairo-gray-medium);
  font-size: 11px;
  font-weight: 600;
  text-decoration: none;
  flex: 1;
}

.cairo-mobile-nav-item.active {
  color: var(--cairo-primary);
}

.cairo-mobile-nav-icon {
  font-size: 18px;
}

/* --- Hero Section --- */
.cairo-hero {
  background: linear-gradient(135deg, #1E3A8A 0%, #0F172A 100%);
  color: #fff;
  padding: 40px 0 60px;
  position: relative;
  overflow: hidden;
}

@media (min-width: 768px) {
  .cairo-hero {
    padding: 60px 0 90px;
  }
}

.cairo-hero-content {
  max-width: 650px;
}

.cairo-hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: rgba(255, 255, 255, 0.15);
  backdrop-filter: blur(8px);
  padding: 6px 14px;
  border-radius: var(--cairo-radius-full);
  font-size: 13px;
  font-weight: 600;
  color: #CCFBF1;
  margin-bottom: 18px;
}

.cairo-hero-title {
  font-size: 28px;
  font-weight: 800;
  line-height: 1.25;
  margin-bottom: 16px;
}

@media (min-width: 768px) {
  .cairo-hero-title {
    font-size: 42px;
  }
}

.cairo-hero-subtitle {
  font-size: 16px;
  color: #E2E8F0;
  line-height: 1.6;
  margin-bottom: 28px;
}

.cairo-hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

/* --- Stats Strip --- */
.cairo-stats-strip {
  background: var(--cairo-surface);
  border-radius: var(--cairo-radius-lg);
  box-shadow: var(--cairo-shadow);
  margin-top: -30px;
  padding: 24px;
  position: relative;
  z-index: 10;
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
}

@media (min-width: 768px) {
  .cairo-stats-strip {
    grid-template-columns: repeat(4, 1fr);
    padding: 28px;
  }
}

.cairo-stat-item {
  text-align: center;
}

.cairo-stat-number {
  font-size: 26px;
  font-weight: 800;
  color: var(--cairo-primary);
  line-height: 1.1;
}

.cairo-stat-label {
  font-size: 13px;
  color: var(--cairo-gray-medium);
  font-weight: 600;
  margin-top: 4px;
}

/* --- Section Titles --- */
.cairo-section {
  padding: 50px 0;
}

@media (min-width: 768px) {
  .cairo-section {
    padding: 70px 0;
  }
}

.cairo-section-header {
  text-align: center;
  max-width: 600px;
  margin: 0 auto 36px;
}

.cairo-section-badge {
  color: var(--cairo-secondary);
  font-weight: 700;
  font-size: 13px;
  text-transform: uppercase;
  letter-spacing: 1px;
}

.cairo-section-title {
  font-size: 26px;
  font-weight: 800;
  color: var(--cairo-dark);
  margin: 6px 0 10px;
}

@media (min-width: 768px) {
  .cairo-section-title {
    font-size: 32px;
  }
}

.cairo-section-desc {
  font-size: 15px;
  color: var(--cairo-gray-medium);
}

/* --- Course Cards Grid --- */
.cairo-course-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 20px;
}

@media (min-width: 640px) {
  .cairo-course-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 1024px) {
  .cairo-course-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

.cairo-course-card {
  background: var(--cairo-surface);
  border-radius: var(--cairo-radius-lg);
  overflow: hidden;
  box-shadow: var(--cairo-shadow);
  border: 1px solid var(--cairo-gray-light);
  display: flex;
  flex-direction: column;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.cairo-course-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--cairo-shadow-lg);
}

.cairo-card-thumb {
  position: relative;
  aspect-ratio: 16 / 9;
  background: linear-gradient(135deg, var(--cairo-primary), var(--cairo-secondary));
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  overflow: hidden;
}

.cairo-card-thumb img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.cairo-card-badge {
  position: absolute;
  top: 12px;
  left: 12px;
  background: rgba(15, 23, 42, 0.85);
  backdrop-filter: blur(4px);
  color: #fff;
  font-size: 11px;
  font-weight: 700;
  padding: 4px 10px;
  border-radius: var(--cairo-radius-full);
}

.cairo-card-body {
  padding: 18px;
  display: flex;
  flex-direction: column;
  flex: 1;
}

.cairo-card-category {
  font-size: 12px;
  font-weight: 700;
  color: var(--cairo-secondary);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  margin-bottom: 6px;
}

.cairo-card-title {
  font-size: 17px;
  font-weight: 700;
  color: var(--cairo-dark);
  line-height: 1.35;
  margin-bottom: 8px;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.cairo-card-instructor {
  font-size: 13px;
  color: var(--cairo-gray-medium);
  margin-bottom: 12px;
  display: flex;
  align-items: center;
  gap: 6px;
}

.cairo-card-meta {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 12px;
  color: var(--cairo-gray-dark);
  padding: 8px 0;
  border-top: 1px solid var(--cairo-gray-light);
  border-bottom: 1px solid var(--cairo-gray-light);
  margin-bottom: 14px;
}

.cairo-card-footer {
  margin-top: auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.cairo-price-group {
  display: flex;
  align-items: baseline;
  gap: 6px;
}

.cairo-price-current {
  font-size: 20px;
  font-weight: 800;
  color: var(--cairo-primary);
}

.cairo-price-original {
  font-size: 13px;
  color: var(--cairo-gray-medium);
  text-decoration: line-through;
}

/* --- Classroom Layout (Course -> Lesson -> Topic) --- */
.cairo-classroom-wrapper {
  display: grid;
  grid-template-columns: 1fr;
  min-height: calc(100vh - 68px);
}

@media (min-width: 992px) {
  .cairo-classroom-wrapper {
    grid-template-columns: 340px 1fr;
  }
}

.cairo-classroom-sidebar {
  background: var(--cairo-surface);
  border-right: 1px solid var(--cairo-gray-light);
  overflow-y: auto;
  max-height: calc(100vh - 68px);
}

.cairo-classroom-content {
  padding: 16px;
  background: var(--cairo-background);
  overflow-y: auto;
}

@media (min-width: 768px) {
  .cairo-classroom-content {
    padding: 24px;
  }
}

.cairo-player-container {
  position: relative;
  width: 100%;
  aspect-ratio: 16 / 9;
  background: #000;
  border-radius: var(--cairo-radius);
  overflow: hidden;
  box-shadow: var(--cairo-shadow-lg);
  margin-bottom: 20px;
}

.cairo-player-container iframe,
.cairo-player-container video {
  width: 100%;
  height: 100%;
  border: none;
}

/* Anti-Piracy Floating Watermark */
.cairo-watermark,
.cairo-watermark-overlay {
  position: absolute;
  top: 20%;
  left: 30%;
  color: rgba(255, 255, 255, 0.22);
  font-size: 11px;
  font-weight: 600;
  font-family: monospace;
  letter-spacing: 1px;
  pointer-events: none;
  user-select: none;
  z-index: 100;
  text-shadow: 0 1px 2px rgba(0, 0, 0, 0.6);
  transition: top 1.5s ease, left 1.5s ease;
}

/* Lesson Accordion */
.cairo-lesson-group {
  border-bottom: 1px solid var(--cairo-gray-light);
}

.cairo-lesson-header {
  padding: 14px 18px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  cursor: pointer;
  background: var(--cairo-surface);
  font-weight: 700;
  font-size: 14px;
}

.cairo-lesson-header:hover {
  background: var(--cairo-primary-container);
}

.cairo-topic-list {
  list-style: none;
  background: #FAFAFA;
}

.cairo-topic-item {
  padding: 10px 18px 10px 32px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 13px;
  cursor: pointer;
  border-top: 1px solid var(--cairo-gray-light);
  color: var(--cairo-gray-dark);
}

.cairo-topic-item:hover, .cairo-topic-item.active {
  background: var(--cairo-secondary-container);
  color: var(--cairo-secondary);
  font-weight: 600;
}

/* --- Student Dashboard & Profile --- */
.cairo-dashboard-tabs {
  display: flex;
  gap: 8px;
  border-bottom: 1px solid var(--cairo-gray-light);
  margin-bottom: 24px;
  overflow-x: auto;
  white-space: nowrap;
}

.cairo-tab-btn {
  padding: 12px 20px;
  font-weight: 600;
  font-size: 14px;
  color: var(--cairo-gray-medium);
  background: transparent;
  border: none;
  border-bottom: 3px solid transparent;
  cursor: pointer;
}

.cairo-tab-btn.active {
  color: var(--cairo-primary);
  border-bottom-color: var(--cairo-primary);
}

/* --- Footer --- */
.cairo-footer {
  background: var(--cairo-dark);
  color: #94A3B8;
  padding: 50px 0 20px;
  margin-top: auto;
}

.cairo-footer-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 30px;
  margin-bottom: 36px;
}

@media (min-width: 768px) {
  .cairo-footer-grid {
    grid-template-columns: 2fr repeat(3, 1fr);
  }
}

.cairo-footer-title {
  color: #fff;
  font-size: 16px;
  font-weight: 700;
  margin-bottom: 16px;
}

.cairo-footer-links {
  list-style: none;
}

.cairo-footer-links li {
  margin-bottom: 8px;
}

.cairo-footer-links a {
  color: #94A3B8;
  font-size: 14px;
}

.cairo-footer-links a:hover {
  color: #fff;
}

.cairo-footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  padding-top: 20px;
  text-align: center;
  font-size: 13px;
}

/* YouTube Anti-Branding Overscan & Top Mask */
.cairo-yt-wrapper {
  position: relative;
  width: 100%;
  aspect-ratio: 16 / 9;
  background: #000;
  overflow: hidden;
}

.cairo-yt-container {
  position: absolute;
  top: -65px;
  left: 0;
  width: 100%;
  height: calc(100% + 65px);
}

.cairo-yt-frame {
  width: 100%;
  height: 100%;
  border: none;
}

.cairo-yt-top-mask {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 52px;
  background: linear-gradient(to bottom, rgba(15, 23, 42, 0.95) 0%, rgba(15, 23, 42, 0.7) 60%, transparent 100%);
  z-index: 10;
  pointer-events: none;
  display: flex;
  align-items: center;
  padding: 0 16px;
}

.cairo-yt-topic-title {
  color: #f8fafc;
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.3px;
  text-shadow: 0 1px 3px rgba(0, 0, 0, 0.8);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  display: flex;
  align-items: center;
  gap: 8px;
}

.cairo-yt-topic-title i {
  color: #38bdf8;
}