/* Modern EdTech Color System */
:root {
  --primary-blue: #2563EB;
  --dark-blue: #1E40AF;
  --soft-bg: #F1F5F9;
  --card-bg: #FFFFFF;
  --accent-green: #22C55E;
  --heading-text: #0F172A;
  --muted-text: #64748B;
  --light-border: #E2E8F0;
  --footer-dark: #0F172A;
  --footer-text: #CBD5E1;
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  background: var(--soft-bg);
  color: var(--heading-text);
}

header.navbar {
  background: linear-gradient(90deg, var(--dark-blue), var(--primary-blue));
  box-shadow: 0 4px 12px rgba(0,0,0,0.08);
}

header.navbar-brand {
  font-size: 1.5rem;
  font-weight: 600;
  color: #FFFFFF !important;
}

/* Test interface specific styles are in test_interface.html */

.option-image {
  max-width: 100px;
  margin-top: 0.5rem;
  border-radius: 0.375rem;
}

/* Math text rendering */
.math-text {
  font-family: 'Times New Roman', serif;
  font-style: italic;
}

/* Scrollbar styling */
::-webkit-scrollbar {
  width: 8px;
  height: 8px;
}

::-webkit-scrollbar-track {
  background: #f1f1f1;
}

::-webkit-scrollbar-thumb {
  background: #888;
  border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
  background: #555;
}

/* Navbar Styling */
.navbar {
  background: linear-gradient(90deg, var(--dark-blue), var(--primary-blue));
  box-shadow: 0 4px 12px rgba(0,0,0,0.08);
}
.navbar-brand, .navbar .navbar-brand {
  color: #FFFFFF !important;
}

/* Logo sizing — responsive scaling for all screen sizes */
.navbar-brand img,
.navbar-custom .navbar-brand img {
  width: clamp(80px, 33.33vw, 200px) !important;
  height: auto !important;
}

/* ── Mobile navbar: show only logo + profile avatar ── */
@media (max-width: 767.98px) {
  /* Hide everything except the avatar in the profile section */
  .navbar-custom .nav-link,
  .navbar-custom .btn-logout,
  .navbar-custom .btn-login {
    display: none !important;
  }
  /* Keep avatar visible and clickable */
  .navbar-custom .profile-avatar {
    display: flex !important;
  }
  /* Remove the fixed 25% brand width so logo doesn't over-allocate */
  .navbar-custom .navbar-brand {
    flex: 0 0 auto !important;
  }
  /* Hide desktop search bar inside navbar */
  .navbar-custom .navbar-search {
    display: none !important;
  }
}

/* ── Mobile bottom navigation bar ── */
.bottom-nav {
  display: none;
}

@media (max-width: 767.98px) {
  /* Show bottom nav on mobile */
  .bottom-nav {
    display: flex;
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    z-index: 9999 !important;
    background: #ffffff;
    border-top: 1px solid #e2e8f0;
    box-shadow: 0 -2px 12px rgba(0,0,0,0.10);
    height: 60px;
    align-items: stretch;
    pointer-events: auto !important;
  }
  .bottom-nav a {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    text-decoration: none;
    color: #64748b;
    font-size: 10px;
    font-weight: 500;
    gap: 3px;
    transition: color 0.2s;
    touch-action: manipulation;
    cursor: pointer;
    pointer-events: auto !important;
    -webkit-tap-highlight-color: rgba(37, 99, 235, 0.15);
  }
  .bottom-nav a i {
    font-size: 20px;
    pointer-events: none;
  }
  .bottom-nav a span {
    pointer-events: none;
  }
  .bottom-nav a.active,
  .bottom-nav a:hover {
    color: #2563eb;
  }
  /* Push page content above the bottom bar */
  body {
    padding-bottom: 60px !important;
  }
}

/* ── Global search overlay ── */
/* Always display:flex so it composes correctly;
   hide/show via visibility+opacity to avoid position:fixed bugs
   caused by backdrop-filter on some browsers */
.search-overlay {
  display: flex;
  flex-direction: column;
  visibility: hidden;
  opacity: 0;
  pointer-events: none;
  position: fixed;
  inset: 0;
  background: rgba(15, 31, 58, 0.82);
  z-index: 10001;
  padding: 20px 16px;
  align-items: flex-start;
  transition: opacity 0.18s ease, visibility 0.18s ease;
}
.search-overlay.active {
  visibility: visible;
  opacity: 1;
  pointer-events: auto;
}
.search-overlay-inner {
  background: #ffffff;
  border-radius: 16px;
  width: 100%;
  max-width: 540px;
  margin: 0 auto;
  box-shadow: 0 16px 48px rgba(0,0,0,0.25);
  overflow: hidden;
}
.search-overlay-input-wrap {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 14px 16px;
  border-bottom: 1px solid #e2e8f0;
}
.search-overlay-input-wrap .fa-search {
  color: #2563eb;
  font-size: 17px;
  flex-shrink: 0;
}
.search-overlay-input {
  flex: 1;
  border: none;
  outline: none;
  font-size: 16px;
  background: transparent;
  color: #0f172a;
}
.search-overlay-close {
  background: none;
  border: none;
  color: #64748b;
  font-size: 20px;
  cursor: pointer;
  padding: 0 2px;
  flex-shrink: 0;
  line-height: 1;
}
.search-suggestion-item {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 11px 16px;
  color: #1e293b !important;
  text-decoration: none !important;
  font-size: 14px;
  font-weight: 500;
  transition: background 0.12s, color 0.12s;
  border-bottom: 1px solid #f1f5f9;
  cursor: pointer;
}
.search-suggestion-item:last-child {
  border-bottom: none;
}
.search-suggestion-item:hover,
.search-suggestion-item:focus {
  background: #eff6ff;
  color: #2563eb !important;
}
.search-suggestion-item:hover i,
.search-suggestion-item:focus i {
  color: #2563eb;
}
.search-suggestion-item i {
  color: #94a3b8;
  font-size: 13px;
  flex-shrink: 0;
  width: 16px;
  text-align: center;
}
.search-no-results {
  padding: 18px 16px;
  color: #94a3b8;
  text-align: center;
  font-size: 13px;
}
/* bottom-nav search button — full reset to match anchor tabs */
.bottom-nav-btn {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  background: none !important;
  border: none !important;
  outline: none !important;
  box-shadow: none !important;
  -webkit-appearance: none;
  appearance: none;
  color: #64748b;
  font-size: 10px;
  font-weight: 500;
  line-height: 1;
  height: 100%;
  gap: 3px;
  transition: color 0.2s;
  touch-action: manipulation;
  cursor: pointer;
  -webkit-tap-highlight-color: rgba(37, 99, 235, 0.15);
  padding: 0;
  margin: 0;
}
.bottom-nav-btn i {
  font-size: 20px;
  pointer-events: none;
  display: block;
}
.bottom-nav-btn span {
  pointer-events: none;
  display: block;
}
.bottom-nav-btn:hover,
.bottom-nav-btn:active,
.bottom-nav-btn:focus {
  color: #2563eb;
  outline: none !important;
  box-shadow: none !important;
}

.navbar .btn-login {
  background-color: var(--accent-green);
  color: #FFFFFF;
  border: none;
  border-radius: 30px;
  transition: background 0.3s ease, color 0.3s ease;
}
.navbar .btn-login:hover {
  background-color: #16a34a;
}

.navbar .btn-register {
  background-color: #FFFFFF;
  color: var(--primary-blue);
  border: 1px solid var(--primary-blue);
  border-radius: 30px;
  transition: background 0.3s ease, color 0.3s ease, border 0.3s ease;
}
.navbar .btn-register:hover {
  background-color: var(--primary-blue);
  color: #FFFFFF;
}

/* Search Bar */
.search-input {
  background-color: #FFFFFF;
  border: 1px solid var(--light-border);
  border-radius: 30px;
  padding: 10px 20px;
  color: var(--heading-text);
  transition: border 0.3s ease, box-shadow 0.3s ease;
}
.search-input:focus {
  border-color: var(--primary-blue);
  outline: none;
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.15);
}
.search-input::placeholder {
  color: var(--muted-text);
}

/* Card Design */
.card, .series-card {
  background-color: var(--card-bg);
  border-radius: 16px;
  box-shadow: 0 10px 30px rgba(0,0,0,0.05);
  transition: all 0.3s ease;
  border: 1px solid var(--light-border);
  margin-bottom: 24px;
}
.card:hover, .series-card:hover {
  transform: translateY(-5px);
}
.card-header, .series-card-header {
  background-color: var(--primary-blue);
  color: #FFFFFF;
  font-weight: 600;
  border-top-left-radius: 16px;
  border-top-right-radius: 16px;
}
.card-text, .series-description, .text-muted {
  color: var(--muted-text) !important;
}

/* Primary Action Button */
.button-primary, .view-series-btn {
  background: linear-gradient(90deg, var(--primary-blue), var(--dark-blue));
  color: #FFFFFF;
  border-radius: 30px;
  padding: 12px 24px;
  border: none;
  font-weight: 600;
  transition: background 0.3s ease, transform 0.3s ease;
}
.button-primary:hover, .view-series-btn:hover {
  background: #1D4ED8;
  transform: translateY(-2px);
}

/* Footer Refinement */
.footer {
  background-color: var(--footer-dark);
  color: var(--footer-text);
  border-top: 4px solid var(--primary-blue);
  padding: 32px 0 16px 0;
}
.footer a {
  color: var(--footer-text);
  transition: color 0.3s ease;
}
.footer a:hover {
  color: var(--accent-green);
}
.footer .highlight {
  color: var(--accent-green);
  font-weight: 600;
}

/* Site-wide slim footer (policy links) */
.site-footer {
  background: #f8fafc;
  border-top: 1px solid #e2e8f0;
  font-size: 0.82rem;
  color: var(--muted-text);
  /* keep above mobile bottom-nav on small screens */
  padding-bottom: env(safe-area-inset-bottom, 0);
}
.site-footer-brand {
  font-weight: 600;
  color: #0f172a;
}
.site-footer-link {
  color: #4f46e5;
  text-decoration: none;
}
.site-footer-link:hover {
  text-decoration: underline;
}
.site-footer-sep {
  color: var(--muted-text);
}

/* Global Improvements */
.card, .series-card, .button-primary, .view-series-btn, .btn-login, .btn-register, .search-input {
  border-radius: 30px;
}

/* Consistent spacing */
.section {
  margin-bottom: 32px;
}

/* Responsive adjustments (keep existing structure) */
@media (max-width: 768px) {
  .card, .series-card {
    border-radius: 16px;
    margin-bottom: 16px;
  }
  .button-primary, .view-series-btn {
    padding: 10px 16px;
    font-size: 15px;
  }
}

/* ── Compact footer: 3 equal columns, links in 2 sub-columns ── */
.footer-custom {
  padding: 24px 0 12px !important;
  margin-top: 40px !important;
}
.footer-content {
  grid-template-columns: repeat(3, 1fr) !important;
  gap: 24px !important;
  margin-bottom: 16px !important;
  align-items: start !important;
}
/* Show Quick Links as a 2-column internal grid so they don't stack tall */
.footer-links {
  display: grid !important;
  grid-template-columns: auto auto !important;
  align-items: start !important;
  gap: 4px 20px !important;
}
/* Heading spans both link sub-columns */
.footer-links h6 {
  grid-column: 1 / -1 !important;
  margin-bottom: 4px !important;
}
.footer-contact {
  gap: 6px !important;
}
.footer-bottom {
  padding-top: 10px !important;
}
.footer-bottom p {
  margin: 2px 0 !important;
}
@media (max-width: 768px) {
  .footer-custom {
    padding: 20px 0 10px !important;
  }
  .footer-content {
    grid-template-columns: 1fr 1fr !important;
    gap: 16px !important;
  }
  .footer-logo-section {
    grid-column: 1 / -1 !important;
    text-align: center !important;
  }
}
@media (max-width: 480px) {
  .footer-content {
    grid-template-columns: 1fr !important;
  }
  .footer-links {
    grid-template-columns: auto auto !important;
  }
}