/* ===========================
   Book & Beyond — Web Hub
   Mobile-first · Dark Theme
   =========================== */

:root {
  /* Colors */
  --bg-primary: #0a0e17;
  --bg-secondary: #111827;
  --bg-card: #1a2234;
  --bg-card-hover: #212d45;
  --bg-glass: rgba(26, 34, 52, 0.85);
  
  --accent: #f59e0b;
  --accent-light: #fbbf24;
  --accent-glow: rgba(245, 158, 11, 0.15);
  --accent-gradient: linear-gradient(135deg, #f59e0b, #d97706);
  
  --green: #10b981;
  --green-bg: rgba(16, 185, 129, 0.1);
  --red: #ef4444;
  --red-bg: rgba(239, 68, 68, 0.1);
  --blue: #3b82f6;
  --purple: #8b5cf6;
  
  --text-primary: #f1f5f9;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  
  --border: rgba(255, 255, 255, 0.06);
  --border-light: rgba(255, 255, 255, 0.1);
  
  /* Sizing */
  --container-max: 960px;
  --nav-height: 64px;
  --radius: 16px;
  --radius-sm: 10px;
  --radius-xs: 6px;
  
  /* Transitions */
  --ease: cubic-bezier(0.4, 0, 0.2, 1);
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: var(--nav-height);
}

body {
  font-family: 'Be Vietnam Pro', -apple-system, BlinkMacSystemFont, sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

.container {
  width: 100%;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 20px;
}

/* ===========================
   Navbar
   =========================== */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--nav-height);
  background: rgba(10, 14, 23, 0.8);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border);
  z-index: 1000;
  transition: background 0.3s var(--ease);
}

.navbar.scrolled {
  background: rgba(10, 14, 23, 0.95);
}

.nav-container {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 20px;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-logo {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--text-primary);
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 8px;
}

.nav-logo span {
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.nav-logo-img {
  width: 28px;
  height: 28px;
  flex-shrink: 0;
}

.nav-toggle {
  display: flex;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
  z-index: 1001;
}

.nav-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--text-primary);
  border-radius: 2px;
  transition: all 0.3s var(--ease);
}

.nav-toggle.active span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle.active span:nth-child(2) { opacity: 0; }
.nav-toggle.active span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

.nav-links {
  position: fixed;
  top: 0;
  right: -100%;
  width: 280px;
  height: 100vh;
  background: var(--bg-secondary);
  padding: 80px 32px 32px;
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 4px;
  transition: right 0.3s var(--ease);
  border-left: 1px solid var(--border);
}

.nav-links.open { right: 0; }

.nav-links a {
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 1rem;
  font-weight: 500;
  padding: 12px 16px;
  border-radius: var(--radius-xs);
  transition: all 0.2s var(--ease);
  display: block;
}

.nav-links a:hover, .nav-links a.active {
  color: var(--accent);
  background: var(--accent-glow);
}

.nav-cta {
  background: var(--accent-gradient) !important;
  color: var(--bg-primary) !important;
  font-weight: 600 !important;
  text-align: center;
  margin-top: 12px;
  border-radius: var(--radius-sm) !important;
}

/* Desktop nav */
@media (min-width: 768px) {
  .nav-toggle { display: none; }
  
  .nav-links {
    position: static;
    width: auto;
    height: auto;
    background: none;
    padding: 0;
    flex-direction: row;
    gap: 2px;
    border: none;
  }
  
  .nav-links a {
    font-size: 0.85rem;
    padding: 8px 12px;
  }
  
  .nav-cta { margin-top: 0; }
}

/* ===========================
   Hero
   =========================== */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: calc(var(--nav-height) + 40px) 20px 60px;
  overflow: hidden;
}

.hero-bg {
  position: absolute;
  inset: 0;
  background: 
    radial-gradient(ellipse at 20% 50%, rgba(245, 158, 11, 0.08) 0%, transparent 60%),
    radial-gradient(ellipse at 80% 20%, rgba(139, 92, 246, 0.06) 0%, transparent 60%),
    radial-gradient(ellipse at 50% 100%, rgba(59, 130, 246, 0.05) 0%, transparent 50%);
  z-index: 0;
}

.hero-content {
  position: relative;
  z-index: 1;
  text-align: center;
  max-width: 680px;
}

.hero-badge {
  display: inline-block;
  background: var(--accent-glow);
  color: var(--accent);
  font-size: 0.85rem;
  font-weight: 600;
  padding: 6px 16px;
  border-radius: 40px;
  border: 1px solid rgba(245, 158, 11, 0.2);
  margin-bottom: 24px;
  animation: fadeInUp 0.6s var(--ease);
}

.hero-title {
  font-size: clamp(2.2rem, 6vw, 3.5rem);
  font-weight: 800;
  letter-spacing: -0.02em;
  line-height: 1.15;
  margin-bottom: 16px;
  background: linear-gradient(135deg, #f1f5f9 0%, #f59e0b 50%, #f1f5f9 100%);
  background-size: 200% auto;
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  animation: shimmer 3s linear infinite, fadeInUp 0.6s var(--ease) 0.1s both;
}

@keyframes shimmer {
  0% { background-position: 200% center; }
  100% { background-position: -200% center; }
}

.hero-slogan {
  font-size: 1.05rem;
  color: var(--text-secondary);
  margin-bottom: 40px;
  animation: fadeInUp 0.6s var(--ease) 0.2s both;
  font-style: italic;
}

/* Countdown */
.countdown-card {
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  border-radius: var(--radius);
  padding: 28px 24px;
  margin-bottom: 32px;
  animation: fadeInUp 0.6s var(--ease) 0.3s both;
}

.countdown-label {
  font-size: 0.85rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: 16px;
}

.countdown-timer {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
}

.countdown-unit { text-align: center; }

.countdown-number {
  display: block;
  font-size: clamp(2rem, 5vw, 3rem);
  font-weight: 800;
  color: var(--accent);
  line-height: 1;
  font-variant-numeric: tabular-nums;
}

.countdown-text {
  display: block;
  font-size: 0.7rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  margin-top: 4px;
}

.countdown-separator {
  font-size: 1.8rem;
  font-weight: 300;
  color: var(--text-muted);
  margin-top: -16px;
}

.countdown-info {
  display: flex;
  justify-content: center;
  gap: 24px;
  margin-top: 16px;
  font-size: 0.85rem;
  color: var(--text-secondary);
}

/* Buttons */
.hero-actions {
  display: flex;
  gap: 12px;
  justify-content: center;
  flex-wrap: wrap;
  animation: fadeInUp 0.6s var(--ease) 0.4s both;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: inherit;
  font-size: 0.95rem;
  font-weight: 600;
  padding: 14px 28px;
  border-radius: var(--radius-sm);
  text-decoration: none;
  cursor: pointer;
  border: none;
  transition: all 0.25s var(--ease);
}

.btn-primary {
  background: var(--accent-gradient);
  color: var(--bg-primary);
  box-shadow: 0 4px 20px rgba(245, 158, 11, 0.25);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 30px rgba(245, 158, 11, 0.35);
}

.btn-secondary {
  background: var(--bg-card);
  color: var(--text-primary);
  border: 1px solid var(--border-light);
}

.btn-secondary:hover {
  background: var(--bg-card-hover);
  border-color: var(--accent);
}

.btn-outline {
  background: transparent;
  color: var(--accent);
  border: 1px solid var(--accent);
}

.btn-outline:hover {
  background: var(--accent-glow);
}

.btn-sm { font-size: 0.85rem; padding: 10px 20px; }

/* ===========================
   Sections
   =========================== */
.section {
  padding: 80px 0;
  position: relative;
}

.section-alt {
  background: var(--bg-secondary);
}

.section-header {
  text-align: center;
  margin-bottom: 48px;
}

.section-icon {
  font-size: 2rem;
  display: block;
  margin-bottom: 12px;
}

.section-header h2 {
  font-size: 1.75rem;
  font-weight: 700;
  letter-spacing: -0.01em;
}

/* ===========================
   Current Book
   =========================== */
.book-card {
  display: flex;
  flex-direction: column;
  gap: 32px;
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  border-radius: var(--radius);
  padding: 28px;
  align-items: center;
}

@media (min-width: 640px) {
  .book-card { flex-direction: row; align-items: flex-start; }
}

.book-cover-wrapper { flex-shrink: 0; }

.book-cover {
  width: 180px;
  height: 260px;
  border-radius: 12px;
  background: var(--bg-card-hover);
  background-size: cover;
  background-position: center;
  box-shadow: 0 8px 30px rgba(0, 0, 0, 0.4);
  transition: transform 0.3s var(--ease);
}

.book-cover:hover { transform: scale(1.03) rotate(-1deg); }

.book-info {
  flex: 1;
  text-align: center;
}

@media (min-width: 640px) {
  .book-info { text-align: left; }
}

.book-title {
  font-size: 1.4rem;
  font-weight: 700;
  margin-bottom: 4px;
}

.book-author {
  color: var(--accent);
  font-weight: 500;
  margin-bottom: 4px;
}

.book-original {
  color: var(--text-muted);
  font-size: 0.85rem;
  font-style: italic;
  margin-bottom: 20px;
}

.book-progress {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 12px;
}

.progress-bar {
  flex: 1;
  height: 8px;
  background: rgba(255, 255, 255, 0.06);
  border-radius: 10px;
  overflow: hidden;
}

.progress-fill {
  height: 100%;
  background: var(--accent-gradient);
  border-radius: 10px;
  transition: width 1s var(--ease);
  width: 0;
}

.progress-text {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--accent);
  min-width: 40px;
}

.book-dates {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: 20px;
}

/* ===========================
   Schedule
   =========================== */
.schedule-grid {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.schedule-card {
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  border-radius: var(--radius);
  padding: 24px;
  transition: border-color 0.3s var(--ease);
}

.schedule-card.current {
  border-color: var(--accent);
  box-shadow: 0 0 30px rgba(245, 158, 11, 0.08);
}

.schedule-card.current::before {
  content: '📍 Tuần này';
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--bg-primary);
  background: var(--accent-gradient);
  padding: 3px 10px;
  border-radius: 20px;
  margin-bottom: 12px;
}

.schedule-card-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 16px;
  flex-wrap: wrap;
  gap: 8px;
}

.schedule-week {
  font-weight: 700;
  font-size: 1.05rem;
}

.schedule-date {
  font-size: 0.85rem;
  color: var(--text-muted);
}

.schedule-mc {
  font-size: 0.85rem;
  color: var(--accent);
  font-weight: 500;
  margin-bottom: 12px;
}

.schedule-sharers {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.sharer-item {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  background: rgba(255, 255, 255, 0.02);
  padding: 10px 14px;
  border-radius: var(--radius-xs);
  border-left: 3px solid var(--accent);
}

.sharer-index {
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--bg-primary);
  background: var(--accent-gradient);
  width: 24px;
  height: 24px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  margin-top: 1px;
}

.sharer-info { flex: 1; }

.sharer-name {
  font-weight: 600;
  font-size: 0.9rem;
}

.sharer-chapter {
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-top: 2px;
}

/* ===========================
   Leaderboard
   =========================== */
.leaderboard-table-wrapper {
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

.leaderboard-table {
  width: 100%;
  border-collapse: collapse;
  min-width: 500px;
}

.leaderboard-table th {
  text-align: left;
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-muted);
  padding: 12px 16px;
  border-bottom: 1px solid var(--border-light);
}

.leaderboard-table td {
  padding: 14px 16px;
  font-size: 0.9rem;
  border-bottom: 1px solid var(--border);
}

.leaderboard-table tr:hover td {
  background: var(--bg-card);
}

.rank-badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  border-radius: 50%;
  font-weight: 700;
  font-size: 0.85rem;
}

.rank-1 { background: linear-gradient(135deg, #fbbf24, #d97706); color: #0a0e17; }
.rank-2 { background: linear-gradient(135deg, #cbd5e1, #94a3b8); color: #0a0e17; }
.rank-3 { background: linear-gradient(135deg, #d97706, #92400e); color: #fff; }
.rank-other { background: var(--bg-card); color: var(--text-muted); }

.member-name {
  display: flex;
  align-items: center;
  gap: 8px;
  font-weight: 600;
}

.member-role {
  font-size: 0.7rem;
  color: var(--accent);
  background: var(--accent-glow);
  padding: 2px 8px;
  border-radius: 20px;
  font-weight: 500;
}

.points-cell {
  font-weight: 700;
  color: var(--accent);
}

.streak-cell {
  font-variant-numeric: tabular-nums;
}

/* ===========================
   Fund
   =========================== */
.fund-overview {
  display: grid;
  gap: 16px;
  margin-bottom: 32px;
}

@media (min-width: 640px) {
  .fund-overview { grid-template-columns: 1fr 1fr; }
}

.fund-balance-card {
  background: var(--bg-card);
  border: 1px solid var(--accent);
  border-radius: var(--radius);
  padding: 28px;
  text-align: center;
  box-shadow: 0 0 40px rgba(245, 158, 11, 0.06);
}

.fund-balance-label {
  font-size: 0.8rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: 8px;
}

.fund-balance-amount {
  font-size: 2rem;
  font-weight: 800;
  color: var(--accent);
  font-variant-numeric: tabular-nums;
}

.fund-stats {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.fund-stat {
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-sm);
  padding: 20px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.fund-stat-label {
  font-size: 0.85rem;
  color: var(--text-secondary);
}

.fund-stat-amount {
  font-weight: 700;
  font-size: 1.1rem;
  font-variant-numeric: tabular-nums;
}

.fund-stat.income .fund-stat-amount { color: var(--green); }
.fund-stat.expense .fund-stat-amount { color: var(--red); }

.fund-details h3 {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 16px;
  color: var(--text-secondary);
}

.fund-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.fund-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 14px 18px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-xs);
  gap: 12px;
}

.fund-item-desc {
  font-size: 0.9rem;
  flex: 1;
}

.fund-item-amount {
  font-weight: 700;
  font-size: 0.9rem;
  white-space: nowrap;
  font-variant-numeric: tabular-nums;
}

.fund-item-amount.positive { color: var(--green); }
.fund-item-amount.negative { color: var(--red); }

/* ===========================
   Library
   =========================== */
.library-grid {
  display: grid;
  gap: 16px;
}

@media (min-width: 640px) {
  .library-grid { grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); }
}

.library-card {
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  border-radius: var(--radius);
  padding: 24px;
  transition: transform 0.3s var(--ease), border-color 0.3s var(--ease);
}

.library-card:hover {
  transform: translateY(-3px);
  border-color: var(--accent);
}

.library-card-title {
  font-size: 1.1rem;
  font-weight: 700;
  margin-bottom: 4px;
}

.library-card-author {
  color: var(--accent);
  font-size: 0.85rem;
  margin-bottom: 8px;
}

.library-card-date {
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-bottom: 12px;
}

.library-card-rating {
  font-size: 1.1rem;
  margin-bottom: 12px;
}

.library-card-insight {
  font-size: 0.85rem;
  color: var(--text-secondary);
  font-style: italic;
  padding: 12px;
  background: rgba(245, 158, 11, 0.05);
  border-left: 3px solid var(--accent);
  border-radius: 0 var(--radius-xs) var(--radius-xs) 0;
}

/* ===========================
   Rules
   =========================== */
.rules-grid {
  display: flex;
  flex-direction: column;
  gap: 32px;
}

.rules-list {
  display: grid;
  gap: 10px;
}

.rule-item {
  display: flex;
  align-items: center;
  gap: 14px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 16px 20px;
  font-size: 0.95rem;
  transition: border-color 0.2s var(--ease);
}

.rule-item:hover { border-color: var(--accent); }

.rule-icon { font-size: 1.3rem; flex-shrink: 0; }

.rewards-penalties {
  display: grid;
  gap: 16px;
}

@media (min-width: 640px) {
  .rewards-penalties { grid-template-columns: 1fr 1fr; }
}

.rp-card {
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  border-radius: var(--radius);
  padding: 24px;
}

.rp-card h3 {
  font-size: 1.1rem;
  margin-bottom: 16px;
}

.penalties-card { border-color: rgba(239, 68, 68, 0.2); }
.rewards-card { border-color: rgba(16, 185, 129, 0.2); }

.rp-list { display: flex; flex-direction: column; gap: 10px; }

.rp-item {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 12px;
  font-size: 0.85rem;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--border);
}

.rp-item:last-child { border-bottom: none; padding-bottom: 0; }

.rp-item-desc { color: var(--text-secondary); flex: 1; }
.rp-item-value {
  font-weight: 600;
  white-space: nowrap;
  font-variant-numeric: tabular-nums;
}

.penalties-card .rp-item-value { color: var(--red); }
.rewards-card .rp-item-value { color: var(--green); }

/* ===========================
   Quick Links
   =========================== */
.links-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 12px;
}

@media (min-width: 640px) {
  .links-grid { grid-template-columns: repeat(3, 1fr); }
}

.link-card {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  gap: 8px;
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  border-radius: var(--radius);
  padding: 24px 16px;
  text-decoration: none;
  transition: all 0.3s var(--ease);
}

.link-card:hover {
  transform: translateY(-4px);
  border-color: var(--accent);
  box-shadow: 0 8px 30px rgba(245, 158, 11, 0.1);
}

.link-icon { font-size: 2rem; }

.link-title {
  font-weight: 600;
  color: var(--text-primary);
  font-size: 0.9rem;
}

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

/* ===========================
   Footer
   =========================== */
.footer {
  padding: 40px 20px;
  text-align: center;
  border-top: 1px solid var(--border);
  color: var(--text-muted);
  font-size: 0.85rem;
}

.footer-sub {
  margin-top: 4px;
  font-size: 0.75rem;
  color: var(--text-muted);
}

/* ===========================
   Animations
   =========================== */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.fade-in {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.6s var(--ease), transform 0.6s var(--ease);
}

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ===========================
   Empty / Loading States
   =========================== */
.empty-state {
  text-align: center;
  padding: 48px 24px;
  color: var(--text-muted);
}

.empty-state-icon {
  font-size: 2.5rem;
  margin-bottom: 12px;
  opacity: 0.5;
}

.empty-state-text {
  font-size: 0.95rem;
}

/* ===========================
   Mobile polish
   =========================== */
@media (max-width: 480px) {
  .hero { min-height: auto; padding-bottom: 40px; }
  .section { padding: 60px 0; }
  .countdown-info { flex-direction: column; gap: 4px; }
  .hero-actions { flex-direction: column; align-items: stretch; }
  .btn { justify-content: center; }
}