/* =============================================
   ReviseIQ — Main Stylesheet
   Green & White theme, fully responsive
   ============================================= */

/* --- RESET & BASE --- */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

:root {
  --green-50:  #f0fdf4;
  --green-100: #dcfce7;
  --green-200: #bbf7d0;
  --green-300: #86efac;
  --green-400: #4ade80;
  --green-500: #22c55e;
  --green-600: #16a34a;
  --green-700: #15803d;
  --green-800: #166534;
  --green-900: #14532d;

  --white: #ffffff;
  --gray-50:  #f9fafb;
  --gray-100: #f3f4f6;
  --gray-200: #e5e7eb;
  --gray-300: #d1d5db;
  --gray-400: #9ca3af;
  --gray-500: #6b7280;
  --gray-600: #4b5563;
  --gray-700: #374151;
  --gray-800: #1f2937;
  --gray-900: #111827;

  --font: 'Inter', system-ui, -apple-system, sans-serif;
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 20px;
  --radius-xl: 28px;
  --shadow-sm: 0 1px 3px rgba(0,0,0,.08), 0 1px 2px rgba(0,0,0,.06);
  --shadow-md: 0 4px 16px rgba(0,0,0,.10);
  --shadow-lg: 0 12px 40px rgba(0,0,0,.14);
  --transition: 0.22s ease;
}

html { scroll-behavior: smooth; }

body {
  font-family: var(--font);
  color: var(--gray-800);
  background: var(--white);
  line-height: 1.6;
  overflow-x: hidden;
}

a { text-decoration: none; color: inherit; }
ul { list-style: none; }
img { display: block; max-width: 100%; }

.container {
  width: 100%;
  max-width: 1160px;
  margin: 0 auto;
  padding: 0 24px;
}

/* =============================================
   NAVBAR
   ============================================= */
.navbar {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  background: rgba(255,255,255,0.9);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--gray-100);
  transition: box-shadow var(--transition);
}

.navbar.scrolled {
  box-shadow: var(--shadow-md);
}

.nav-container {
  max-width: 1160px;
  margin: 0 auto;
  padding: 0 24px;
  height: 60px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 8px;
  font-weight: 800;
  font-size: 1.25rem;
  color: var(--gray-900);
  flex-shrink: 0;
}

.logo-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  background: linear-gradient(135deg, var(--green-500), var(--green-700));
  color: white;
  border-radius: var(--radius-sm);
  font-size: 0.85rem;
  font-weight: 800;
  letter-spacing: -0.5px;
}

.logo-text { color: var(--green-700); }

.nav-links {
  display: flex;
  align-items: center;
  gap: 4px;
  margin-left: auto;
}

.nav-link {
  padding: 8px 14px;
  border-radius: var(--radius-sm);
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--gray-600);
  transition: color var(--transition), background var(--transition);
}

.nav-link:hover,
.nav-link.active {
  color: var(--green-700);
  background: var(--green-50);
}

.nav-link.nav-cta {
  background: var(--green-600);
  color: white;
  font-weight: 600;
  padding: 8px 18px;
  margin-left: 8px;
}

.nav-link.nav-cta:hover {
  background: var(--green-700);
  color: white;
}

.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: space-between;
  width: 28px;
  height: 20px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0;
}

.nav-toggle span {
  display: block;
  height: 2px;
  background: var(--gray-700);
  border-radius: 2px;
  transition: all var(--transition);
}

/* =============================================
   HERO
   ============================================= */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  padding: 100px 24px 80px;
  overflow: hidden;
  background: linear-gradient(160deg, var(--green-50) 0%, var(--white) 60%);
}

.hero-bg-shapes {
  position: absolute;
  inset: 0;
  pointer-events: none;
  overflow: hidden;
}

.shape {
  position: absolute;
  border-radius: 50%;
  opacity: 0.18;
}

.shape-1 {
  width: 600px; height: 600px;
  background: radial-gradient(circle, var(--green-400), transparent 70%);
  top: -200px; right: -150px;
}

.shape-2 {
  width: 400px; height: 400px;
  background: radial-gradient(circle, var(--green-300), transparent 70%);
  bottom: -100px; left: -100px;
}

.shape-3 {
  width: 250px; height: 250px;
  background: radial-gradient(circle, var(--green-500), transparent 70%);
  top: 40%; left: 40%;
  opacity: 0.08;
}

.hero-content {
  position: relative;
  z-index: 2;
  max-width: 580px;
  flex: 1;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: var(--green-100);
  color: var(--green-800);
  font-size: 0.82rem;
  font-weight: 600;
  padding: 5px 14px;
  border-radius: 100px;
  margin-bottom: 24px;
  border: 1px solid var(--green-200);
}

.hero-title {
  font-size: clamp(2.6rem, 6vw, 4rem);
  font-weight: 800;
  line-height: 1.1;
  color: var(--gray-900);
  letter-spacing: -1.5px;
  margin-bottom: 20px;
}

.highlight {
  color: var(--green-600);
  position: relative;
}

.hero-subtitle {
  font-size: 1.1rem;
  color: var(--gray-500);
  margin-bottom: 36px;
  max-width: 460px;
  line-height: 1.7;
}

.hero-actions {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  margin-bottom: 48px;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 14px 28px;
  border-radius: var(--radius-md);
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  border: 2px solid transparent;
  transition: all var(--transition);
}

.btn-primary {
  background: var(--green-600);
  color: white;
  box-shadow: 0 4px 20px rgba(22, 163, 74, 0.35);
}

.btn-primary:hover {
  background: var(--green-700);
  transform: translateY(-2px);
  box-shadow: 0 8px 28px rgba(22, 163, 74, 0.4);
}

.btn-secondary {
  background: white;
  color: var(--green-700);
  border-color: var(--green-200);
}

.btn-secondary:hover {
  background: var(--green-50);
  border-color: var(--green-400);
  transform: translateY(-2px);
}

.btn-white {
  background: white;
  color: var(--green-700);
  font-weight: 700;
}

.btn-white:hover {
  background: var(--green-50);
  transform: translateY(-2px);
}

/* Hero stats */
.hero-stats {
  display: flex;
  align-items: center;
  gap: 24px;
}

.stat { text-align: center; }

.stat-number {
  display: block;
  font-size: 1.6rem;
  font-weight: 800;
  color: var(--green-700);
  line-height: 1;
}

.stat-label {
  font-size: 0.8rem;
  color: var(--gray-500);
  font-weight: 500;
}

.stat-divider {
  width: 1px;
  height: 36px;
  background: var(--gray-200);
}

/* Floating cards */
.hero-visual {
  position: relative;
  flex: 1;
  min-height: 320px;
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 2;
}

.hero-card {
  position: absolute;
  display: flex;
  align-items: center;
  gap: 12px;
  background: white;
  border-radius: var(--radius-md);
  padding: 14px 20px;
  box-shadow: var(--shadow-lg);
  border: 1px solid var(--gray-100);
  animation: floatCard 4s ease-in-out infinite;
}

.card-float-1 { top: 0; left: 10%; animation-delay: 0s; }
.card-float-2 { top: 40%; right: 5%; animation-delay: 1.2s; }
.card-float-3 { bottom: 0; left: 20%; animation-delay: 2.4s; }

@keyframes floatCard {
  0%, 100% { transform: translateY(0px); }
  50% { transform: translateY(-12px); }
}

.mini-card-icon { font-size: 1.5rem; }

.mini-card-text {
  display: flex;
  flex-direction: column;
}

.mini-card-text strong {
  font-size: 0.9rem;
  color: var(--gray-900);
  font-weight: 600;
}

.mini-card-text span {
  font-size: 0.78rem;
  color: var(--gray-500);
}

/* =============================================
   SUBJECTS SECTION
   ============================================= */
.subjects {
  padding: 96px 0;
  background: var(--white);
}

.section-header {
  text-align: center;
  margin-bottom: 56px;
}

.section-title {
  font-size: clamp(1.8rem, 4vw, 2.4rem);
  font-weight: 800;
  color: var(--gray-900);
  letter-spacing: -0.8px;
  margin-bottom: 12px;
}

.section-sub {
  font-size: 1.05rem;
  color: var(--gray-500);
  max-width: 500px;
  margin: 0 auto;
}

.subject-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 20px;
}

.subject-card {
  position: relative;
  display: flex;
  flex-direction: column;
  background: var(--white);
  border: 2px solid var(--gray-100);
  border-radius: var(--radius-lg);
  padding: 28px 24px;
  cursor: pointer;
  transition: all var(--transition);
  overflow: hidden;
}

.subject-card::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, var(--green-50), transparent);
  opacity: 0;
  transition: opacity var(--transition);
}

.subject-card:hover {
  border-color: var(--green-300);
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}

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

.subject-card--featured {
  border-color: var(--green-300);
  background: linear-gradient(135deg, var(--green-50), var(--white));
}

.subject-card--featured::after {
  content: 'Popular';
  position: absolute;
  top: 14px; right: 14px;
  background: var(--green-600);
  color: white;
  font-size: 0.7rem;
  font-weight: 700;
  padding: 2px 8px;
  border-radius: 100px;
}

.subject-emoji {
  font-size: 2rem;
  margin-bottom: 12px;
  position: relative;
  z-index: 1;
}

.subject-card h3 {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--gray-900);
  margin-bottom: 4px;
  position: relative;
  z-index: 1;
}

.subject-card p {
  font-size: 0.82rem;
  color: var(--gray-500);
  margin-bottom: 14px;
  position: relative;
  z-index: 1;
}

.subject-meta { position: relative; z-index: 1; }

.tag {
  display: inline-block;
  font-size: 0.72rem;
  font-weight: 600;
  background: var(--green-100);
  color: var(--green-800);
  padding: 3px 10px;
  border-radius: 100px;
}

.subject-arrow {
  position: absolute;
  bottom: 20px; right: 20px;
  font-size: 1rem;
  color: var(--green-500);
  opacity: 0;
  transform: translateX(-6px);
  transition: all var(--transition);
  z-index: 1;
}

.subject-card:hover .subject-arrow {
  opacity: 1;
  transform: translateX(0);
}

/* =============================================
   FEATURES SECTION
   ============================================= */
.features {
  padding: 96px 0;
  background: var(--gray-50);
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 24px;
}

.feature-card {
  background: var(--white);
  border: 1px solid var(--gray-100);
  border-radius: var(--radius-lg);
  padding: 32px 28px;
  transition: all var(--transition);
}

.feature-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
  border-color: var(--green-200);
}

.feature-icon {
  font-size: 2rem;
  margin-bottom: 16px;
}

.feature-card h3 {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--gray-900);
  margin-bottom: 8px;
}

.feature-card p {
  font-size: 0.92rem;
  color: var(--gray-500);
  line-height: 1.65;
}

/* =============================================
   CTA BANNER
   ============================================= */
.cta-banner {
  padding: 80px 0;
  background: linear-gradient(135deg, var(--green-700), var(--green-500));
}

.cta-content {
  text-align: center;
  color: white;
}

.cta-content h2 {
  font-size: clamp(1.6rem, 3.5vw, 2.2rem);
  font-weight: 800;
  margin-bottom: 12px;
  letter-spacing: -0.5px;
}

.cta-content p {
  font-size: 1.05rem;
  opacity: 0.88;
  margin-bottom: 32px;
}

/* =============================================
   FOOTER
   ============================================= */
.footer {
  background: var(--gray-900);
  color: var(--gray-300);
  padding: 64px 0 0;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 48px;
  padding-bottom: 48px;
  border-bottom: 1px solid var(--gray-700);
}

.footer-brand .footer-logo {
  color: white;
  margin-bottom: 16px;
}

.footer-brand p {
  font-size: 0.88rem;
  line-height: 1.7;
  color: var(--gray-400);
  max-width: 280px;
}

.footer-col h4 {
  font-size: 0.85rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.8px;
  color: var(--white);
  margin-bottom: 16px;
}

.footer-col ul {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.footer-col a {
  font-size: 0.9rem;
  color: var(--gray-400);
  transition: color var(--transition);
}

.footer-col a:hover { color: var(--green-400); }

.footer-bottom {
  padding: 20px 0;
  text-align: center;
}

.footer-bottom p {
  font-size: 0.82rem;
  color: var(--gray-500);
}

/* =============================================
   RESPONSIVE
   ============================================= */
@media (max-width: 1024px) {
  .hero {
    flex-direction: column;
    text-align: center;
    min-height: auto;
    padding: 120px 24px 80px;
    gap: 60px;
  }

  .hero-content { max-width: 100%; }
  .hero-actions { justify-content: center; }
  .hero-stats { justify-content: center; }
  .hero-subtitle { margin: 0 auto 36px; }

  .hero-visual {
    width: 100%;
    min-height: 200px;
  }

  .hero-card {
    position: relative;
    animation: none;
    transform: none;
    display: inline-flex;
  }

  .card-float-1, .card-float-2, .card-float-3 {
    position: relative;
    top: auto; left: auto; right: auto; bottom: auto;
  }

  .hero-visual {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    justify-content: center;
  }

  .footer-grid {
    grid-template-columns: 1fr 1fr;
    gap: 32px;
  }

  .footer-brand { grid-column: 1 / -1; }
}

@media (max-width: 768px) {
  .nav-toggle {
    display: flex;
  }

  .nav-links {
    position: absolute;
    top: 68px;
    left: 0; right: 0;
    background: white;
    border-bottom: 1px solid var(--gray-100);
    flex-direction: column;
    align-items: stretch;
    padding: 16px 24px 24px;
    gap: 4px;
    box-shadow: var(--shadow-md);
    transform: translateY(-8px);
    opacity: 0;
    pointer-events: none;
    transition: all var(--transition);
  }

  .nav-links.open {
    transform: translateY(0);
    opacity: 1;
    pointer-events: all;
  }

  .nav-link.nav-cta {
    margin-left: 0;
    text-align: center;
    margin-top: 8px;
  }

  .subject-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 14px;
  }

  .subject-card { padding: 20px 18px; }

  .features-grid { grid-template-columns: 1fr; }

  .footer-grid {
    grid-template-columns: 1fr 1fr;
    gap: 24px;
  }
}

@media (max-width: 480px) {
  .hero-title { letter-spacing: -1px; }

  .hero-actions {
    flex-direction: column;
    align-items: stretch;
  }

  .btn { width: 100%; }

  .subject-grid {
    grid-template-columns: 1fr;
  }

  .footer-grid {
    grid-template-columns: 1fr;
  }
}

/* =============================================
   UTILITY — scroll fade-in
   ============================================= */
.fade-in {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.5s ease, transform 0.5s ease;
}

.fade-in.visible {
  opacity: 1;
  transform: none;
}

/* =============================================
   PAGE TRANSITIONS
   ============================================= */
@keyframes pageEnter {
  from { opacity: 0; transform: translateY(10px); }
  to   { opacity: 1; transform: translateY(0); }
}

body.page-ready {
  animation: pageEnter 0.35s ease forwards;
}

body.page-exit {
  opacity: 0;
  transform: translateY(-6px);
  transition: opacity 0.22s ease, transform 0.22s ease;
  pointer-events: none;
}

/* =============================================
   NAV AUTH (login / user name / logout)
   ============================================= */
.nav-auth {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-left: 8px;
  flex-shrink: 0;
}

.nav-user-name {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--green-700);
  white-space: nowrap;
}

.nav-logout-btn {
  padding: 6px 12px;
  background: none;
  border: 1.5px solid var(--gray-200);
  border-radius: var(--radius-sm);
  font-family: var(--font);
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--gray-500);
  cursor: pointer;
  transition: all var(--transition);
}

.nav-logout-btn:hover {
  border-color: #ef4444;
  color: #ef4444;
}

.nav-auth-login {
  font-size: 0.88rem;
  font-weight: 500;
  color: var(--gray-600);
  padding: 6px 10px;
  border-radius: var(--radius-sm);
  transition: color var(--transition), background var(--transition);
}

.nav-auth-login:hover {
  color: var(--green-700);
  background: var(--green-50);
}

.nav-auth-signup {
  display: inline-flex;
  align-items: center;
  padding: 7px 14px;
  background: var(--green-600);
  color: white;
  border-radius: var(--radius-sm);
  font-size: 0.85rem;
  font-weight: 600;
  transition: background var(--transition);
  white-space: nowrap;
}

.nav-auth-signup:hover { background: var(--green-700); color: white; }

/* =============================================
   ANNOUNCEMENT BANNER
   ============================================= */
.announcement-banner {
  background: linear-gradient(90deg, var(--green-700), var(--green-500));
  color: white;
  padding: 0;
  max-height: 80px;
  overflow: hidden;
  transition: opacity 0.3s ease, max-height 0.3s ease;
  position: relative;
  z-index: 99;
}

.announcement-inner {
  max-width: 1160px;
  margin: 0 auto;
  padding: 12px 24px;
  display: flex;
  align-items: center;
  gap: 12px;
}

.announcement-icon { font-size: 1.1rem; flex-shrink: 0; }

.announcement-text {
  flex: 1;
  font-size: 0.9rem;
  font-weight: 500;
  line-height: 1.45;
}

.announcement-close {
  background: none;
  border: 1.5px solid rgba(255,255,255,0.4);
  color: white;
  border-radius: 50%;
  width: 24px;
  height: 24px;
  font-size: 1rem;
  line-height: 1;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  transition: background var(--transition);
}

.announcement-close:hover { background: rgba(255,255,255,0.2); }

/* Dark mode overrides */
[data-theme="dark"] .nav-user-name { color: #4ade80; }
[data-theme="dark"] .nav-logout-btn { border-color: #334155; color: #94a3b8; }
[data-theme="dark"] .nav-logout-btn:hover { border-color: #f87171; color: #f87171; }
[data-theme="dark"] .nav-auth-login { color: #94a3b8; }
[data-theme="dark"] .nav-auth-login:hover { color: #4ade80; background: rgba(74,222,128,0.08); }

/* =============================================
   THEME TOGGLE BUTTON
   ============================================= */
.theme-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  background: none;
  border: 1.5px solid var(--gray-200);
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-size: 1.05rem;
  flex-shrink: 0;
  transition: background var(--transition), border-color var(--transition), transform var(--transition);
}

.theme-btn:hover {
  background: var(--green-50);
  border-color: var(--green-300);
  transform: scale(1.1);
}

/* Show/hide icons based on current theme */
.theme-icon-light { display: none; }
.theme-icon-dark  { display: block; line-height: 1; }

/* =============================================
   POMODORO TIMER SECTION
   ============================================= */
.pomodoro-section {
  padding: 72px 0;
  background: linear-gradient(135deg, var(--green-700) 0%, var(--green-500) 100%);
  position: relative;
  overflow: hidden;
}

.pomodoro-section::before {
  content: '';
  position: absolute;
  width: 500px; height: 500px;
  background: rgba(255,255,255,0.05);
  border-radius: 50%;
  top: -200px; right: -150px;
}

.pomodoro-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 48px;
}

.pomodoro-text { color: white; max-width: 420px; }

.pomodoro-text h2 {
  font-size: clamp(1.6rem, 3vw, 2.2rem);
  font-weight: 800;
  letter-spacing: -0.5px;
  margin-bottom: 10px;
}

.pomodoro-text p {
  font-size: 1rem;
  opacity: 0.88;
  line-height: 1.65;
  margin-bottom: 16px;
}

.pomodoro-tips {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

.pomodoro-tip {
  background: rgba(255,255,255,0.15);
  border: 1px solid rgba(255,255,255,0.2);
  color: white;
  font-size: 0.8rem;
  font-weight: 600;
  padding: 4px 12px;
  border-radius: 100px;
}

/* Timer widget */
.pomodoro-widget {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 20px;
  flex-shrink: 0;
}

.timer-ring-wrap {
  position: relative;
  width: 160px;
  height: 160px;
}

.timer-svg {
  width: 100%;
  height: 100%;
  transform: rotate(-90deg);
}

.timer-track {
  fill: none;
  stroke: rgba(255,255,255,0.2);
  stroke-width: 7;
}

.timer-fill {
  fill: none;
  stroke: white;
  stroke-width: 7;
  stroke-linecap: round;
  stroke-dasharray: 326.7;
  stroke-dashoffset: 0;
  transition: stroke-dashoffset 1s linear, stroke 0.4s ease;
}

.timer-fill.timer-urgent { stroke: #fcd34d; }
.timer-fill.timer-done   { stroke: #f87171; }

.timer-center {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  color: white;
}

.timer-time {
  font-size: 2rem;
  font-weight: 800;
  letter-spacing: -1px;
  line-height: 1;
  font-variant-numeric: tabular-nums;
}

.timer-label {
  font-size: 0.72rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.8px;
  opacity: 0.8;
  margin-top: 2px;
}

.timer-controls {
  display: flex;
  gap: 10px;
}

.timer-btn {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  padding: 9px 18px;
  border-radius: var(--radius-sm);
  font-family: var(--font);
  font-size: 0.88rem;
  font-weight: 700;
  cursor: pointer;
  border: none;
  transition: all 0.18s ease;
}

.timer-btn-start {
  background: white;
  color: var(--green-700);
}

.timer-btn-start:hover  { background: var(--green-50); transform: scale(1.04); }

.timer-btn-pause {
  background: rgba(255,255,255,0.2);
  color: white;
  border: 1.5px solid rgba(255,255,255,0.35);
}

.timer-btn-pause:hover { background: rgba(255,255,255,0.3); transform: scale(1.04); }

.timer-btn-reset {
  background: transparent;
  color: rgba(255,255,255,0.7);
  border: 1.5px solid rgba(255,255,255,0.25);
}

.timer-btn-reset:hover { color: white; border-color: rgba(255,255,255,0.5); }

@media (max-width: 900px) {
  .pomodoro-inner {
    flex-direction: column;
    text-align: center;
  }
  .pomodoro-tips { justify-content: center; }
}

/* =============================================
   ENHANCED BUTTON & CARD ANIMATIONS
   ============================================= */
.btn {
  position: relative;
  overflow: hidden;
}

.btn::after {
  content: '';
  position: absolute;
  inset: 0;
  background: rgba(255,255,255,0);
  transition: background 0.18s ease;
}

.btn:active::after { background: rgba(255,255,255,0.12); }
.btn:active         { transform: translateY(0) scale(0.98) !important; }

/* Ripple on subject cards */
.subject-card {
  transform: translateY(0);
  transition: transform 0.25s cubic-bezier(0.34, 1.56, 0.64, 1),
              box-shadow var(--transition),
              border-color var(--transition);
}

.subject-card:hover { transform: translateY(-6px) scale(1.01); }

.feature-card {
  transition: transform 0.25s cubic-bezier(0.34, 1.56, 0.64, 1),
              box-shadow var(--transition),
              border-color var(--transition);
}

/* =============================================
   PAGE HEADER BAND (shared inner pages)
   ============================================= */
.page-header-band {
  background: linear-gradient(135deg, var(--green-700), var(--green-500));
  padding: 56px 0 48px;
  color: white;
}

.page-title {
  font-size: clamp(1.8rem, 4vw, 2.6rem);
  font-weight: 800;
  letter-spacing: -0.8px;
  margin-bottom: 10px;
}

.page-subtitle {
  font-size: 1.05rem;
  opacity: 0.88;
  max-width: 560px;
  line-height: 1.6;
}

/* =============================================
   DARK MODE — Variables
   ============================================= */
[data-theme="dark"] {
  --white:    #1e293b;
  --gray-50:  #1e293b;
  --gray-100: #283548;
  --gray-200: #334155;
  --gray-300: #475569;
  --gray-400: #64748b;
  --gray-500: #94a3b8;
  --gray-600: #cbd5e1;
  --gray-700: #e2e8f0;
  --gray-800: #f1f5f9;
  --gray-900: #f8fafc;

  --shadow-sm: 0 1px 3px rgba(0,0,0,.3);
  --shadow-md: 0 4px 16px rgba(0,0,0,.45);
  --shadow-lg: 0 12px 40px rgba(0,0,0,.55);
}

/* =============================================
   DARK MODE — Base
   ============================================= */
[data-theme="dark"] body {
  background: #0f172a;
  color: #e2e8f0;
}

[data-theme="dark"] .theme-icon-light { display: block; }
[data-theme="dark"] .theme-icon-dark  { display: none; }

[data-theme="dark"] .theme-btn {
  border-color: #334155;
  color: #e2e8f0;
}

[data-theme="dark"] .theme-btn:hover {
  background: #283548;
  border-color: #4ade80;
}

/* =============================================
   DARK MODE — Navbar
   ============================================= */
[data-theme="dark"] .navbar {
  background: rgba(15, 23, 42, 0.92);
  border-bottom-color: #1e293b;
}

[data-theme="dark"] .nav-logo { color: #f1f5f9; }
[data-theme="dark"] .logo-text { color: #4ade80; }

[data-theme="dark"] .nav-link  { color: #94a3b8; }
[data-theme="dark"] .nav-link:hover,
[data-theme="dark"] .nav-link.active {
  color: #4ade80;
  background: rgba(74,222,128,0.1);
}

[data-theme="dark"] .nav-link.nav-cta { background: #16a34a; color: white; }
[data-theme="dark"] .nav-link.nav-cta:hover { background: #15803d; }

[data-theme="dark"] .nav-toggle span { background: #e2e8f0; }

[data-theme="dark"] .nav-links {
  background: #0f172a;
  border-bottom-color: #1e293b;
}

/* =============================================
   DARK MODE — Hero
   ============================================= */
[data-theme="dark"] .hero {
  background: linear-gradient(160deg, #0d2416 0%, #0f172a 60%);
}

[data-theme="dark"] .hero-card {
  background: #1e293b;
  border-color: #334155;
}

[data-theme="dark"] .mini-card-text strong { color: #f1f5f9; }
[data-theme="dark"] .mini-card-text span   { color: #94a3b8; }

[data-theme="dark"] .hero-badge {
  background: rgba(74,222,128,0.1);
  border-color: rgba(74,222,128,0.25);
  color: #4ade80;
}

[data-theme="dark"] .stat-divider { background: #334155; }

/* =============================================
   DARK MODE — Subjects & Features
   ============================================= */
[data-theme="dark"] .subjects { background: #0f172a; }

[data-theme="dark"] .subject-card {
  background: #1e293b;
  border-color: #334155;
}

[data-theme="dark"] .subject-card--featured {
  background: linear-gradient(135deg, #0d2416, #1e293b);
  border-color: #166534;
}

[data-theme="dark"] .subject-card::before {
  background: linear-gradient(135deg, rgba(74,222,128,0.08), transparent);
}

[data-theme="dark"] .subject-card:hover { border-color: #4ade80; }

[data-theme="dark"] .tag {
  background: rgba(74,222,128,0.1);
  color: #4ade80;
}

[data-theme="dark"] .features { background: #0a1120; }

[data-theme="dark"] .feature-card {
  background: #1e293b;
  border-color: #334155;
}

[data-theme="dark"] .feature-card:hover { border-color: #4ade80; }

/* =============================================
   DARK MODE — Buttons
   ============================================= */
[data-theme="dark"] .btn-secondary {
  background: #1e293b;
  color: #4ade80;
  border-color: #334155;
}

[data-theme="dark"] .btn-secondary:hover {
  background: #283548;
  border-color: #4ade80;
}

/* =============================================
   DARK MODE — Footer
   ============================================= */
[data-theme="dark"] .footer { background: #020617; }
[data-theme="dark"] .footer-col h4 { color: #f1f5f9; }

/* =============================================
   DARK MODE — Inner page shared
   ============================================= */
[data-theme="dark"] .page-main { background: #0f172a; }

/* =============================================
   DARK MODE — Quiz page
   ============================================= */
[data-theme="dark"] .setup-card,
[data-theme="dark"] .question-card,
[data-theme="dark"] .results-card,
[data-theme="dark"] .loading-card,
[data-theme="dark"] .error-card {
  background: #1e293b;
  border-color: #334155;
}

[data-theme="dark"] .select-wrap select,
[data-theme="dark"] .setup-field select {
  background: #283548;
  border-color: #334155;
  color: #e2e8f0;
}

[data-theme="dark"] .pill-toggle,
[data-theme="dark"] .level-pill-toggle {
  background: #0f172a;
}

[data-theme="dark"] .pill-btn,
[data-theme="dark"] .level-btn {
  color: #94a3b8;
}

[data-theme="dark"] .option-btn {
  background: #1e293b;
  border-color: #334155;
  color: #e2e8f0;
}

[data-theme="dark"] .option-btn:hover:not(:disabled) {
  background: rgba(74,222,128,0.08);
  border-color: #4ade80;
  color: #4ade80;
}

[data-theme="dark"] .option-letter { background: #283548; }

[data-theme="dark"] .option-btn.correct {
  background: rgba(74,222,128,0.1);
  border-color: #4ade80;
}

[data-theme="dark"] .option-btn.reveal {
  background: rgba(74,222,128,0.06);
  border-color: rgba(74,222,128,0.3);
}

[data-theme="dark"] .explanation-box.is-correct {
  background: rgba(74,222,128,0.08);
  border-color: rgba(74,222,128,0.25);
}

[data-theme="dark"] .explanation-box.is-correct strong,
[data-theme="dark"] .explanation-box.is-correct p { color: #4ade80; }

[data-theme="dark"] .explanation-box.is-wrong {
  background: rgba(248,113,113,0.08);
  border-color: rgba(248,113,113,0.25);
}

[data-theme="dark"] .review-item {
  background: #283548;
  border-color: #334155;
}

[data-theme="dark"] .review-item.review-correct {
  background: rgba(74,222,128,0.07);
  border-color: rgba(74,222,128,0.2);
}

[data-theme="dark"] .review-item.review-wrong {
  background: rgba(248,113,113,0.07);
  border-color: rgba(248,113,113,0.2);
}

[data-theme="dark"] .results-breakdown,
[data-theme="dark"] .review-list { background: transparent; }

[data-theme="dark"] .api-warning {
  background: rgba(251,146,60,0.1);
  border-color: rgba(251,146,60,0.25);
  color: #fb923c;
}

[data-theme="dark"] .api-warning code { background: rgba(251,146,60,0.15); }

/* =============================================
   DARK MODE — Trends page
   ============================================= */
[data-theme="dark"] .chart-card,
[data-theme="dark"] .sidebar-card {
  background: #1e293b;
  border-color: #334155;
}

[data-theme="dark"] .likely-item {
  background: #283548;
  border-color: #334155;
}

[data-theme="dark"] .likely-item:hover {
  background: #2d3f55;
  border-color: #4ade80;
}

[data-theme="dark"] .disclaimer-card {
  background: rgba(251,191,36,0.06);
  border-color: rgba(251,191,36,0.2);
}

[data-theme="dark"] .disclaimer-card p { color: #fbbf24; }

[data-theme="dark"] .mode-toggle { background: #0f172a; }
[data-theme="dark"] .mode-btn.active {
  background: #1e293b;
  border-color: #334155;
  color: #4ade80;
}

[data-theme="dark"] .glance-pill.pill-no {
  background: #283548;
  color: #64748b;
}

/* =============================================
   DARK MODE — Papers page
   ============================================= */
[data-theme="dark"] .selector-panel,
[data-theme="dark"] .filters-panel {
  background: #1e293b;
  border-color: #334155;
}

[data-theme="dark"] .pcard,
[data-theme="dark"] .paper-card {
  background: #1e293b;
  border-color: #334155;
}

[data-theme="dark"] .pcard:hover,
[data-theme="dark"] .paper-card:hover {
  border-color: #4ade80;
}

[data-theme="dark"] .empty-state {
  background: #1e293b;
  border-color: #334155;
}

[data-theme="dark"] .sort-row select,
[data-theme="dark"] .filter-group select {
  background: #283548;
  border-color: #334155;
  color: #e2e8f0;
}

[data-theme="dark"] .check-label { color: #e2e8f0; }

[data-theme="dark"] .paper-btn-secondary {
  background: #283548;
  color: #cbd5e1;
}

[data-theme="dark"] .paper-btn-secondary:hover { background: #334155; }

[data-theme="dark"] .covid-notice {
  background: rgba(251,146,60,0.08);
  border-color: rgba(251,146,60,0.2);
}

[data-theme="dark"] .covid-notice p { color: #fb923c; }

/* =============================================
   DARK MODE — Subject page
   ============================================= */
[data-theme="dark"] .quick-link-card {
  background: #1e293b;
  border-color: #334155;
}

[data-theme="dark"] .quick-link-card:hover { border-color: #4ade80; }
[data-theme="dark"] .quick-link-card strong { color: #f1f5f9; }
[data-theme="dark"] .quick-link-card span   { color: #94a3b8; }