/* ============================================
   AI赋能教育教学 - Design System
   Aesthetic: Scholarly Warmth — clean academic
   with subtle warmth, like a well-lit library
   ============================================ */

:root {
  --blue-50: #eff6ff; --blue-100: #dbeafe; --blue-200: #bfdbfe;
  --blue-300: #93c5fd; --blue-400: #60a5fa; --blue-500: #3b82f6;
  --blue-600: #2563eb; --blue-700: #1d4ed8; --blue-800: #1e40af;
  --amber-50: #fffbeb; --amber-100: #fef3c7; --amber-400: #fbbf24;
  --amber-500: #f59e0b; --amber-600: #d97706;
  --green-50: #f0fdf4; --green-500: #22c55e; --green-600: #16a34a;
  --red-50: #fef2f2; --red-500: #ef4444;
  --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-serif: 'Noto Serif SC', 'Songti SC', serif;
  --font-sans: -apple-system, 'PingFang SC', 'Microsoft YaHei', 'Helvetica Neue', sans-serif;
  --shadow-sm: 0 1px 2px rgba(0,0,0,.05);
  --shadow-md: 0 4px 6px -1px rgba(0,0,0,.07), 0 2px 4px -2px rgba(0,0,0,.05);
  --shadow-lg: 0 10px 15px -3px rgba(0,0,0,.08), 0 4px 6px -4px rgba(0,0,0,.04);
  --shadow-xl: 0 20px 25px -5px rgba(0,0,0,.08), 0 8px 10px -6px rgba(0,0,0,.04);
  --radius: 12px; --radius-sm: 8px; --radius-lg: 16px;
  --header-h: 64px;
  --transition: .25s cubic-bezier(.4,0,.2,1);
}

*, *::before, *::after { margin:0; padding:0; box-sizing:border-box; }

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-sans);
  color: var(--gray-800);
  background: var(--gray-50);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

/* Scrollbar */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--gray-300); border-radius: 3px; }

/* === HEADER === */
.site-header {
  position: fixed; top: 0; left: 0; right: 0; z-index: 1000;
  height: var(--header-h);
  background: rgba(255,255,255,.88);
  backdrop-filter: blur(20px) saturate(1.8);
  -webkit-backdrop-filter: blur(20px) saturate(1.8);
  border-bottom: 1px solid var(--gray-200);
  transition: box-shadow var(--transition);
}
.site-header.scrolled { box-shadow: var(--shadow-md); }
.header-inner {
  max-width: 1320px; margin: 0 auto; height: 100%;
  display: flex; align-items: center; justify-content: space-between;
  padding: 0 24px;
}
.logo {
  display: flex; align-items: center; gap: 10px;
  text-decoration: none; color: var(--gray-900);
}
.logo-icon {
  width: 38px; height: 38px; border-radius: 10px;
  background: linear-gradient(135deg, var(--blue-500), var(--blue-700));
  display: flex; align-items: center; justify-content: center;
  color: #fff; font-size: 18px; font-weight: 700;
  box-shadow: 0 2px 8px rgba(37,99,235,.35);
}
.logo-text {
  font-family: var(--font-serif);
  font-size: 18px; font-weight: 700;
  letter-spacing: .5px;
}
.logo-text span { color: var(--blue-600); }

.nav-links {
  display: flex; align-items: center; gap: 6px;
  list-style: none;
}
.nav-links a {
  display: flex; align-items: center; gap: 5px;
  padding: 8px 16px; border-radius: var(--radius-sm);
  text-decoration: none; color: var(--gray-600);
  font-size: 14.5px; font-weight: 500;
  transition: all var(--transition);
}
.nav-links a:hover, .nav-links a.active {
  color: var(--blue-600); background: var(--blue-50);
}

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

/* === BUTTONS === */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 6px;
  padding: 9px 20px; border-radius: var(--radius-sm);
  font-size: 14px; font-weight: 600; cursor: pointer;
  border: none; text-decoration: none;
  transition: all var(--transition);
  white-space: nowrap;
  font-family: var(--font-sans);
}
.btn-primary {
  background: linear-gradient(135deg, var(--blue-500), var(--blue-600));
  color: #fff;
  box-shadow: 0 2px 8px rgba(37,99,235,.3);
}
.btn-primary:hover {
  background: linear-gradient(135deg, var(--blue-600), var(--blue-700));
  box-shadow: 0 4px 12px rgba(37,99,235,.4);
  transform: translateY(-1px);
}
.btn-outline {
  background: #fff; color: var(--blue-600);
  border: 1.5px solid var(--blue-200);
}
.btn-outline:hover {
  background: var(--blue-50); border-color: var(--blue-400);
}
.btn-ghost {
  background: transparent; color: var(--gray-600);
}
.btn-ghost:hover { background: var(--gray-100); color: var(--gray-800); }
.btn-amber {
  background: linear-gradient(135deg, var(--amber-400), var(--amber-500));
  color: var(--gray-900);
  box-shadow: 0 2px 8px rgba(245,158,11,.3);
}
.btn-amber:hover {
  box-shadow: 0 4px 12px rgba(245,158,11,.45);
  transform: translateY(-1px);
}
.btn-green {
  background: linear-gradient(135deg, var(--green-500), var(--green-600));
  color: #fff; box-shadow: 0 2px 8px rgba(34,197,94,.3);
}
.btn-green:hover { transform: translateY(-1px); box-shadow: 0 4px 12px rgba(34,197,94,.45); }
.btn-sm { padding: 6px 14px; font-size: 13px; }
.btn-lg { padding: 13px 32px; font-size: 16px; border-radius: var(--radius); }
.btn-block { width: 100%; }
.btn:active { transform: translateY(0) scale(.98); }

/* === HERO === */
.hero {
  margin-top: var(--header-h);
  padding: 40px 24px 20px;
  background: linear-gradient(165deg, #f0f6ff 0%, #e8f0fe 30%, #fefce8 100%);
  position: relative; overflow: hidden;
  text-align: center;
}
.hero::before {
  content: ''; position: absolute; inset: 0;
  background: url("data:image/svg+xml,%3Csvg width='60' height='60' xmlns='http://www.w3.org/2000/svg'%3E%3Cpath d='M30 0v60M0 30h60' stroke='%233b82f6' stroke-width='.3' opacity='.08'/%3E%3C/svg%3E");
  pointer-events: none;
}
.hero-content { position: relative; max-width: 1300px; margin: 0 auto; }
.hero-badge {
  display: inline-flex; align-items: center; gap: 6px;
  padding: 6px 16px; border-radius: 50px;
  background: rgba(255,255,255,.8); border: 1px solid var(--blue-200);
  font-size: 13px; color: var(--blue-700); font-weight: 500;
  margin-bottom: 24px;
  backdrop-filter: blur(8px);
}
.hero-badge .dot {
  width: 7px; height: 7px; border-radius: 50%;
  background: var(--green-500);
  animation: pulse-dot 2s infinite;
}
@keyframes pulse-dot {
  0%,100% { opacity:1; } 50% { opacity:.4; }
}
.hero h1 {
  font-family: var(--font-serif);
  font-size: clamp(32px, 5vw, 48px);
  font-weight: 700; line-height: 1.3;
  color: var(--gray-900);
  margin-bottom: 20px;
}
.hero h1 .highlight {
  background: linear-gradient(135deg, var(--blue-600), var(--blue-400));
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  background-clip: text;
}
.hero-subtitle {
  font-size: clamp(15px, 2vw, 17px);
  color: var(--gray-600); line-height: 1.8;
  max-width: 620px; margin: 0 auto 36px;
}
.hero-actions { display: flex; gap: 14px; justify-content: center; flex-wrap: wrap; }

.hero-stats {
  display: flex; justify-content: center; gap: 48px;
  margin-top: 56px;
}
.hero-stat { text-align: center; }
.hero-stat-num {
  font-family: var(--font-serif);
  font-size: 32px; font-weight: 700; color: var(--blue-700);
}
.hero-stat-label {
  font-size: 13px; color: var(--gray-500); margin-top: 2px;
}

/* === SECTION === */
.section {
  padding: 64px 24px;
  max-width: 1320px; margin: 0 auto;
}
.section-header {
  text-align: center; margin-bottom: 48px;
}
.section-header h2 {
  font-family: var(--font-serif);
  font-size: 28px; font-weight: 700; color: var(--gray-900);
  margin-bottom: 10px;
}
.section-header p {
  font-size: 15px; color: var(--gray-500); max-width: 500px; margin: 0 auto;
}

/* === CATEGORY CHIPS === */
.category-bar {
  display: flex; gap: 10px; flex-wrap: wrap;
  justify-content: center; margin-bottom: 40px;
}
.chip {
  padding: 7px 18px; border-radius: 50px; font-size: 13.5px;
  font-weight: 500; cursor: pointer; border: 1.5px solid var(--gray-200);
  background: #fff; color: var(--gray-600);
  transition: all var(--transition);
}
.chip:hover { border-color: var(--blue-300); color: var(--blue-500); }
.chip.active {
  background: var(--blue-600); color: #fff;
  border-color: var(--blue-600);
  box-shadow: 0 2px 8px rgba(37,99,235,.25);
}

/* === PROGRAM CARDS GRID === */
.programs-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 24px;
}

.program-card {
  background: #fff; border-radius: var(--radius-lg);
  overflow: hidden; border: 1px solid var(--gray-200);
  transition: all .3s cubic-bezier(.4,0,.2,1);
  cursor: pointer; position: relative;
}
.program-card:hover {
  border-color: var(--blue-200);
  box-shadow: var(--shadow-xl);
  transform: translateY(-4px);
}
.card-cover {
  position: relative; padding-top: 58%; overflow: hidden;
  background: linear-gradient(135deg, var(--blue-100), var(--blue-50));
}
.card-cover-img {
  position: absolute; inset: 0;
  width: 100%; height: 100%; object-fit: cover;
}
.card-cover-placeholder {
  position: absolute; inset: 0;
  display: flex; align-items: center; justify-content: center;
  font-size: 48px;
  transition: transform .4s cubic-bezier(.4,0,.2,1);
}
.program-card:hover .card-cover-placeholder {
  transform: scale(1.15) rotate(-3deg);
}
.card-badges {
  position: absolute; top: 10px; left: 10px;
  display: flex; gap: 6px;
}
.card-badge {
  padding: 3px 10px; border-radius: 6px; font-size: 11px;
  font-weight: 600; backdrop-filter: blur(8px);
}
.card-badge-subject {
  background: rgba(37,99,235,.85); color: #fff;
}
.card-badge-grade {
  background: rgba(255,255,255,.9); color: var(--gray-700);
  border: 1px solid rgba(0,0,0,.06);
}
.card-badge-free {
  background: rgba(34,197,94,.9); color: #fff;
}
.card-price-tag {
  position: absolute; top: 10px; right: 10px;
  padding: 4px 12px; border-radius: 8px;
  font-size: 14px; font-weight: 700;
  background: rgba(255,255,255,.95); color: var(--amber-600);
  box-shadow: var(--shadow-sm);
  backdrop-filter: blur(6px);
}
.card-price-tag.free-price { color: var(--green-600); }
.card-body { padding: 16px 18px 18px; }
.card-title {
  font-size: 15.5px; font-weight: 600; color: var(--gray-900);
  margin-bottom: 6px; line-height: 1.4;
  display: -webkit-box; -webkit-line-clamp: 2;
  -webkit-box-orient: vertical; overflow: hidden;
}
.card-desc {
  font-size: 13px; color: var(--gray-500); line-height: 1.6;
  display: -webkit-box; -webkit-line-clamp: 2;
  -webkit-box-orient: vertical; overflow: hidden;
  margin-bottom: 12px;
}
.card-meta {
  display: flex; align-items: center; justify-content: space-between;
  font-size: 12px; color: var(--gray-400);
}
.card-author {
  display: flex; align-items: center; gap: 6px;
}
.card-avatar {
  width: 22px; height: 22px; border-radius: 50%;
  background: linear-gradient(135deg, var(--blue-400), var(--blue-600));
  display: flex; align-items: center; justify-content: center;
  color: #fff; font-size: 10px; font-weight: 600;
}
.card-stats {
  display: flex; gap: 10px;
}
.card-stats span { display: flex; align-items: center; gap: 3px; }
.card-rating { color: var(--amber-500); }
.cs {
  display: inline-block;
  width: 1em;
  text-align: center;
  overflow: hidden;
}
.chalf {
  position: relative;
  color: #d1d5db;
}
.chalf::before {
  content: '★';
  position: absolute;
  left: 0; top: 0;
  width: 1em;
  clip-path: inset(0 50% 0 0);
  color: var(--amber-500);
}

/* === BROWSE PAGE === */
.browse-layout {
  display: grid;
  grid-template-columns: 240px 1fr;
  gap: 32px;
  max-width: 1320px; margin: 0 auto;
  padding: calc(var(--header-h) + 24px) 24px 64px;
}

.filter-sidebar {
  position: sticky; top: calc(var(--header-h) + 24px);
  height: fit-content;
  background: #fff; border-radius: var(--radius-lg);
  border: 1px solid var(--gray-200);
  padding: 24px; overflow-y: auto;
  max-height: calc(100vh - var(--header-h) - 48px);
}
.filter-group { margin-bottom: 24px; }
.filter-group:last-child { margin-bottom: 0; }
.filter-group-title {
  font-size: 13px; font-weight: 700; color: var(--gray-800);
  text-transform: uppercase; letter-spacing: .5px;
  margin-bottom: 12px;
}
.filter-options { display: flex; flex-direction: column; gap: 4px; }
.filter-option {
  display: flex; align-items: center; gap: 8px;
  padding: 7px 10px; border-radius: var(--radius-sm);
  font-size: 13.5px; color: var(--gray-600); cursor: pointer;
  transition: all var(--transition);
  border: none; background: none; text-align: left;
  font-family: var(--font-sans); width: 100%;
}
.filter-option:hover { background: var(--gray-100); color: var(--gray-800); }
.filter-option.active { background: var(--blue-50); color: var(--blue-600); font-weight: 600; }
.filter-count {
  margin-left: auto; font-size: 11px; color: var(--gray-400);
  background: var(--gray-100); padding: 1px 7px; border-radius: 10px;
}

.browse-content { min-width: 0; }
.browse-topbar {
  display: flex; align-items: center; justify-content: space-between;
  margin-bottom: 24px; flex-wrap: wrap; gap: 12px;
}
.search-box {
  display: flex; align-items: center; gap: 8px;
  background: #fff; border: 1.5px solid var(--gray-200);
  border-radius: var(--radius); padding: 0 16px;
  flex: 1; max-width: 420px;
  transition: border-color var(--transition);
}
.search-box:focus-within { border-color: var(--blue-400); }
.search-box svg { color: var(--gray-400); flex-shrink: 0; }
.search-box input {
  flex: 1; border: none; outline: none; padding: 10px 0;
  font-size: 14px; color: var(--gray-800);
  font-family: var(--font-sans); background: transparent;
}
.search-box input::placeholder { color: var(--gray-400); }
.sort-select {
  padding: 9px 14px; border-radius: var(--radius-sm);
  border: 1.5px solid var(--gray-200); font-size: 13.5px;
  color: var(--gray-600); background: #fff; cursor: pointer;
  font-family: var(--font-sans);
}
.results-info { font-size: 13px; color: var(--gray-500); margin-bottom: 8px; }

/* === DETAIL PAGE / MODAL === */
.modal-overlay {
  position: fixed; inset: 0; z-index: 2000;
  background: rgba(0,0,0,.45); backdrop-filter: blur(4px);
  display: flex; align-items: center; justify-content: center;
  padding: 24px;
  opacity: 0; pointer-events: none;
  transition: opacity .3s ease;
}
.modal-overlay.show { opacity: 1; pointer-events: all; }
.modal {
  background: #fff; border-radius: var(--radius-lg);
  width: 100%; max-width: 860px;
  max-height: calc(100vh - 48px);
  overflow-y: auto; box-shadow: var(--shadow-xl);
  transform: translateY(20px) scale(.97);
  transition: transform .3s ease;
}
.modal-overlay.show .modal { transform: translateY(0) scale(1); }
.modal-close {
  position: sticky; top: 0; z-index: 10;
  display: flex; justify-content: flex-end; padding: 16px 20px 0;
}
.modal-close-btn {
  width: 36px; height: 36px; border-radius: 50%;
  border: none; background: var(--gray-100); cursor: pointer;
  display: flex; align-items: center; justify-content: center;
  font-size: 18px; color: var(--gray-500);
  transition: all var(--transition);
}
.modal-close-btn:hover { background: var(--gray-200); color: var(--gray-700); }
.detail-hero {
  display: grid; grid-template-columns: 1fr 1fr; gap: 32px;
  padding: 8px 32px 32px;
}
.detail-cover {
  border-radius: var(--radius); overflow: hidden;
  background: var(--gray-100); aspect-ratio: 16/10;
  display: flex; align-items: center; justify-content: center;
  font-size: 72px;
}
.detail-info { display: flex; flex-direction: column; }
.detail-title {
  font-family: var(--font-serif);
  font-size: 24px; font-weight: 700; color: var(--gray-900);
  margin-bottom: 8px;
}
.detail-tags { display: flex; gap: 6px; margin-bottom: 12px; flex-wrap: wrap; }
.detail-tag {
  padding: 3px 10px; border-radius: 6px; font-size: 12px;
  font-weight: 500; background: var(--blue-50); color: var(--blue-600);
}
.detail-desc {
  font-size: 14px; color: var(--gray-600); line-height: 1.8;
  margin-bottom: 16px; flex: 1;
}
.detail-price-row {
  display: flex; align-items: baseline; gap: 10px;
  margin-bottom: 20px;
}
.detail-price {
  font-size: 28px; font-weight: 700; color: var(--amber-600);
  font-family: var(--font-serif);
}
.detail-price.free { color: var(--green-600); }
.detail-trial-info {
  font-size: 13px; color: var(--gray-500);
  background: var(--amber-50); padding: 8px 14px;
  border-radius: var(--radius-sm); margin-bottom: 16px;
  border: 1px solid var(--amber-100);
}
.detail-trial-info strong { color: var(--amber-600); }
.detail-actions { display: flex; gap: 10px; }
.detail-author-row {
  padding: 20px 32px; border-top: 1px solid var(--gray-200);
  display: flex; align-items: center; gap: 12px;
}
.detail-author-avatar {
  width: 40px; height: 40px; border-radius: 50%;
  background: linear-gradient(135deg, var(--blue-400), var(--blue-600));
  display: flex; align-items: center; justify-content: center;
  color: #fff; font-weight: 700; font-size: 16px;
}
.detail-author-info { flex: 1; }
.detail-author-name { font-weight: 600; font-size: 14px; color: var(--gray-800); }
.detail-author-bio { font-size: 12px; color: var(--gray-500); }
.detail-reviews { padding: 0 32px 32px; }
.detail-reviews h3 {
  font-size: 16px; font-weight: 700; margin-bottom: 16px; color: var(--gray-800);
}
.review-item {
  padding: 14px 0; border-bottom: 1px solid var(--gray-100);
}
.review-header { display: flex; align-items: center; gap: 8px; margin-bottom: 6px; }
.review-name { font-weight: 600; font-size: 13px; color: var(--gray-700); }
.review-date { font-size: 12px; color: var(--gray-400); margin-left: auto; }
.review-stars { color: var(--amber-400); font-size: 12px; }
.review-text { font-size: 13.5px; color: var(--gray-600); line-height: 1.6; }

/* === VIEWER === */
.viewer-overlay {
  position: fixed; inset: 0; z-index: 3000;
  background: var(--gray-900); display: flex; flex-direction: column;
  opacity: 0; pointer-events: none; transition: opacity .3s;
}
.viewer-overlay.show { opacity: 1; pointer-events: all; }
.viewer-header {
  height: 52px; background: var(--gray-800);
  display: flex; align-items: center; padding: 0 20px;
  gap: 16px; flex-shrink: 0;
}
.viewer-title { color: #fff; font-size: 14px; font-weight: 600; flex: 1; }
.viewer-status {
  font-size: 12px; padding: 4px 12px; border-radius: 50px;
}
.viewer-status.trial { background: rgba(251,191,36,.2); color: var(--amber-400); }
.viewer-status.purchased { background: rgba(34,197,94,.2); color: var(--green-500); }
.viewer-close-btn {
  background: rgba(255,255,255,.1); border: none; color: #fff;
  width: 32px; height: 32px; border-radius: 8px;
  cursor: pointer; font-size: 16px;
  transition: background var(--transition);
}
.viewer-close-btn:hover { background: rgba(255,255,255,.2); }
.viewer-frame-wrap {
  flex: 1; position: relative; overflow: hidden;
}
.viewer-frame-wrap iframe {
  width: 100%; height: 100%; border: none;
}
.viewer-watermark {
  position: absolute; inset: 0; pointer-events: none;
  display: flex; flex-direction: column; align-items: center; justify-content: center;
  z-index: 10;
  /* 颜色自适应：用白色+差值混合，浅底显深色，深底显浅色 */
  color: #fff;
  mix-blend-mode: difference;
}
.viewer-watermark.trial-wm {
  gap: 10px;
  opacity: 0.13;
}
.viewer-watermark.trial-wm .wm-line {
  font-size: 42px; font-weight: 700;
  white-space: nowrap; user-select: none; letter-spacing: 3px;
}
.viewer-watermark.trial-wm .wm-url {
  font-size: 24px; font-weight: 500;
  white-space: nowrap; user-select: none; letter-spacing: 2px;
}
.viewer-watermark.member-wm {
  opacity: 0.35;
}
.viewer-watermark.member-wm .wm-corner {
  position: absolute; font-size: 26px;
  font-weight: 500; white-space: nowrap; user-select: none;
  padding: 10px 16px;
}
.viewer-watermark.member-wm .wm-tl { top: 6px; left: 12px; }
.viewer-watermark.member-wm .wm-br { bottom: 6px; right: 12px; }

/* === RESOURCE CENTER === */
.resource-type-tabs {
  display: flex; gap: 8px; flex-wrap: wrap; margin-bottom: 20px;
}
.resource-type-tab {
  padding: 8px 18px; border-radius: 50px; border: 1.5px solid var(--gray-200);
  background: #fff; color: var(--gray-600); font-size: 13.5px; font-weight: 500;
  cursor: pointer; transition: all var(--transition);
}
.resource-type-tab:hover { border-color: var(--blue-300); color: var(--blue-600); }
.resource-type-tab.active {
  background: var(--blue-600); color: #fff; border-color: var(--blue-600);
}
.resource-card {
  background: #fff; border-radius: var(--radius); border: 1px solid var(--gray-200);
  overflow: hidden; transition: all var(--transition); cursor: pointer;
}
.resource-card:hover {
  transform: translateY(-4px); box-shadow: var(--shadow-lg); border-color: var(--blue-200);
}
.resource-card-cover {
  height: 140px; display: flex; align-items: center; justify-content: center;
  font-size: 48px; position: relative;
}
.resource-card-cover .res-type-badge {
  position: absolute; top: 10px; left: 10px; padding: 3px 10px;
  border-radius: 50px; font-size: 11px; font-weight: 600; color: #fff;
}
.res-badge-courseware { background: #8b5cf6; }
.res-badge-video { background: #ef4444; }
.res-badge-document { background: #0ea5e9; }
.res-badge-image { background: #f59e0b; }
.res-badge-audio { background: #10b981; }
.resource-card-body { padding: 14px 16px; }
.resource-card-title {
  font-size: 14.5px; font-weight: 600; color: var(--gray-800);
  margin-bottom: 6px; line-height: 1.4;
  display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; overflow: hidden;
}
.resource-card-meta {
  display: flex; align-items: center; gap: 8px; flex-wrap: wrap;
  font-size: 12px; color: var(--gray-400); margin-bottom: 8px;
}
.resource-card-bottom {
  display: flex; align-items: center; justify-content: space-between;
  padding-top: 10px; border-top: 1px solid var(--gray-100);
}
.resource-card-price { font-weight: 700; color: var(--blue-600); font-size: 15px; }
.resource-card-price.free { color: var(--green-600); }
.resource-card-author { font-size: 12px; color: var(--gray-500); }
.resource-grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(250px, 1fr)); gap: 20px;
}
/* Resource viewer - image/doc/video with watermark */
.res-viewer-overlay {
  position: fixed; inset: 0; z-index: 3000;
  background: rgba(0,0,0,.92); display: flex; flex-direction: column;
  opacity: 0; pointer-events: none; transition: opacity .3s;
}
.res-viewer-overlay.show { opacity: 1; pointer-events: all; }
.res-viewer-content {
  flex: 1; display: flex; align-items: center; justify-content: center;
  position: relative; overflow: hidden; padding: 20px;
}
.res-viewer-content img, .res-viewer-content video {
  max-width: 90%; max-height: 80vh; border-radius: 8px; box-shadow: 0 8px 40px rgba(0,0,0,.5);
}
.res-viewer-content video { background: #000; }
.res-viewer-content .doc-preview {
  background: #fff; border-radius: 12px; padding: 48px; max-width: 800px; width: 90%;
  max-height: 80vh; overflow-y: auto; color: var(--gray-800); line-height: 1.8;
  box-shadow: 0 8px 40px rgba(0,0,0,.5);
}
.res-viewer-content .doc-preview h2 { font-size: 20px; margin-bottom: 16px; color: var(--gray-900); }
.res-viewer-content .doc-preview p { margin-bottom: 12px; font-size: 15px; }
.res-viewer-watermark-layer {
  position: absolute; inset: 0; pointer-events: none; z-index: 10;
  display: flex; flex-wrap: wrap; align-content: center; justify-content: center;
  gap: 80px; padding: 40px; transform: rotate(-25deg);
}
.res-viewer-watermark-layer span {
  font-size: 18px; color: rgba(255,255,255,.12); white-space: nowrap;
  font-weight: 700; user-select: none; letter-spacing: 2px;
}
.res-viewer-watermark-layer.dark-wm span { color: rgba(0,0,0,.08); }
/* Upload tabs for resource type */
.upload-type-selector {
  display: flex; gap: 10px; margin-bottom: 28px; flex-wrap: wrap;
}
.upload-type-btn {
  padding: 14px 24px; border-radius: var(--radius);
  border: 2px solid var(--gray-200); background: #fff;
  cursor: pointer; text-align: center; transition: all var(--transition);
  flex: 1; min-width: 140px;
}
.upload-type-btn:hover { border-color: var(--blue-300); }
.upload-type-btn.active { border-color: var(--blue-500); background: var(--blue-50); }
.upload-type-btn .utb-icon { font-size: 28px; margin-bottom: 6px; }
.upload-type-btn .utb-label { font-size: 13px; font-weight: 600; color: var(--gray-700); }
.upload-type-btn .utb-hint { font-size: 11px; color: var(--gray-400); margin-top: 2px; }

/* === AUTH MODAL === */
.auth-modal { max-width: 420px; }
.auth-modal .modal-body { padding: 32px; }
.auth-tabs {
  display: flex; margin-bottom: 28px;
  border-bottom: 2px solid var(--gray-100);
}
.auth-tab {
  flex: 1; padding: 12px; text-align: center;
  font-size: 15px; font-weight: 600;
  color: var(--gray-400); cursor: pointer;
  border-bottom: 2px solid transparent;
  margin-bottom: -2px; transition: all var(--transition);
  background: none; border-top: none; border-left: none; border-right: none;
  font-family: var(--font-sans);
}
.auth-tab.active { color: var(--blue-600); border-bottom-color: var(--blue-600); }
.form-group { margin-bottom: 18px; }
.form-label {
  display: block; font-size: 13px; font-weight: 600;
  color: var(--gray-700); margin-bottom: 6px;
}
.form-input {
  width: 100%; padding: 10px 14px; border-radius: var(--radius-sm);
  border: 1.5px solid var(--gray-200); font-size: 14px;
  font-family: var(--font-sans); color: var(--gray-800);
  transition: border-color var(--transition);
  outline: none; background: #fff;
}
.form-input:focus { border-color: var(--blue-400); }
.form-row {
  display: flex; gap: 10px;
}
.form-row .form-input { flex: 1; }
.form-row .btn { flex-shrink: 0; }
.form-hint { font-size: 12px; color: var(--gray-400); margin-top: 16px; text-align: center; }
.wechat-login {
  text-align: center; margin-top: 20px; padding-top: 20px;
  border-top: 1px solid var(--gray-100);
}
.wechat-login p { font-size: 13px; color: var(--gray-500); margin-bottom: 14px; }
.wechat-qr {
  width: 160px; height: 160px; margin: 0 auto;
  background: var(--gray-100); border-radius: var(--radius);
  display: flex; align-items: center; justify-content: center;
  font-size: 14px; color: var(--gray-400); border: 2px dashed var(--gray-300);
}

/* === PAYMENT MODAL === */
.payment-modal { max-width: 520px; }
.payment-body { padding: 32px; }
.payment-item {
  display: flex; align-items: center; gap: 14px;
  padding: 14px; background: var(--gray-50);
  border-radius: var(--radius-sm); margin-bottom: 20px;
}
.payment-item-icon {
  width: 48px; height: 48px; border-radius: 10px;
  display: flex; align-items: center; justify-content: center;
  font-size: 24px; background: var(--blue-100);
}
.payment-item-name { font-weight: 600; font-size: 15px; color: var(--gray-800); }
.payment-item-price {
  margin-left: auto; font-size: 20px; font-weight: 700; color: var(--amber-600);
}
.payment-methods { margin-bottom: 24px; }
.payment-methods h4 { font-size: 14px; font-weight: 600; margin-bottom: 12px; color: var(--gray-700); }
.payment-method-options { display: flex; gap: 12px; }
.payment-method-btn {
  flex: 1; padding: 14px; border-radius: var(--radius-sm);
  border: 2px solid var(--gray-200); background: #fff;
  cursor: pointer; text-align: center;
  transition: all var(--transition);
  font-family: var(--font-sans);
}
.payment-method-btn:hover, .payment-method-btn.selected {
  border-color: var(--blue-400);
}
.payment-method-btn .pm-icon { font-size: 28px; margin-bottom: 4px; }
.payment-method-btn .pm-name { font-size: 13px; font-weight: 600; color: var(--gray-700); }
.payment-qr-area {
  text-align: center; padding: 24px;
  background: var(--gray-50); border-radius: var(--radius);
  margin-bottom: 20px;
}
.payment-qr {
  width: 200px; height: 200px; margin: 0 auto 12px;
  background: #fff; border-radius: var(--radius-sm);
  display: flex; align-items: center; justify-content: center;
  border: 1px solid var(--gray-200);
  flex-direction: column; gap: 8px;
}
.payment-qr-hint { font-size: 13px; color: var(--gray-500); }
.payment-success-icon { font-size: 48px; margin-bottom: 8px; }

/* === COUPON CODE === */
.coupon-section {
  margin: 16px 0; padding: 14px 16px;
  background: linear-gradient(135deg, #fffbeb, #fef3c7);
  border: 1.5px dashed var(--amber-400); border-radius: var(--radius-sm);
}
.coupon-row {
  display: flex; gap: 8px; align-items: center;
}
.coupon-row input {
  flex: 1; padding: 9px 14px; border: 1.5px solid var(--gray-200);
  border-radius: var(--radius-sm); font-size: 14px; font-family: var(--font-sans);
  letter-spacing: 1px; text-transform: uppercase;
  transition: border-color var(--transition);
}
.coupon-row input:focus { outline: none; border-color: var(--amber-400); }
.coupon-row button {
  padding: 9px 18px; border-radius: var(--radius-sm); border: none;
  background: var(--amber-500); color: #fff; font-weight: 600; font-size: 13px;
  cursor: pointer; white-space: nowrap; font-family: var(--font-sans);
  transition: all var(--transition);
}
.coupon-row button:hover { background: var(--amber-600); }
.coupon-result {
  margin-top: 8px; font-size: 13px; font-weight: 600;
  display: none; align-items: center; gap: 6px;
}
.coupon-result.valid { display: flex; color: var(--green-600); }
.coupon-result.invalid { display: flex; color: var(--red-500); }
.price-original {
  text-decoration: line-through; color: var(--gray-400); font-size: 14px; font-weight: 400;
}

/* === ENTERPRISE FORM === */
.enterprise-modal { max-width: 560px; }
.enterprise-body { padding: 32px; }
.enterprise-body h2 {
  font-family: var(--font-serif); font-size: 20px;
  margin-bottom: 6px; text-align: center;
}
.enterprise-body .subtitle {
  font-size: 13px; color: var(--gray-400);
  text-align: center; margin-bottom: 24px;
}
.enterprise-badge {
  display: inline-flex; align-items: center; gap: 6px;
  padding: 6px 14px; border-radius: 50px; font-size: 12px; font-weight: 600;
  background: linear-gradient(135deg, var(--blue-50), #e0f2fe);
  color: var(--blue-700); margin: 0 auto 20px; width: fit-content;
}

/* === WECHAT QR LOGIN === */
.wechat-qr-main {
  text-align: center; padding: 8px 0 0;
}
.wechat-qr-box {
  width: 200px; height: 200px; margin: 16px auto;
  background: #fff; border: 1px solid var(--gray-200);
  border-radius: var(--radius); display: flex;
  align-items: center; justify-content: center;
  position: relative; overflow: hidden;
}
.wechat-qr-box::before {
  content: ''; position: absolute; inset: 0;
  background: repeating-linear-gradient(0deg, transparent, transparent 8px, rgba(0,0,0,.02) 8px, rgba(0,0,0,.02) 9px);
}
.qr-scan-line {
  position: absolute; top: 0; left: 0; right: 0; height: 3px;
  background: linear-gradient(90deg, transparent, #07c160, transparent);
  animation: qrScan 2.5s ease-in-out infinite;
}
@keyframes qrScan {
  0% { top: 0; opacity: 0; }
  10% { opacity: 1; }
  90% { opacity: 1; }
  100% { top: 100%; opacity: 0; }
}
.wechat-qr-hint { font-size: 13px; color: var(--gray-400); margin-top: 12px; }

/* === RICH EDITOR MOCK === */
.rich-editor-wrap {
  border: 1.5px solid var(--gray-200); border-radius: var(--radius-sm);
  overflow: hidden; transition: border-color var(--transition);
}
.rich-editor-wrap:focus-within { border-color: var(--blue-400); }
.rich-editor-toolbar {
  display: flex; gap: 2px; padding: 8px 10px; background: var(--gray-50);
  border-bottom: 1px solid var(--gray-200); flex-wrap: wrap;
}
.rich-editor-toolbar button {
  width: 32px; height: 32px; border: none; background: transparent;
  border-radius: 6px; cursor: pointer; font-size: 14px; color: var(--gray-600);
  display: flex; align-items: center; justify-content: center;
  transition: all var(--transition); font-family: var(--font-sans);
}
.rich-editor-toolbar button:hover { background: var(--gray-200); color: var(--gray-900); }
.rich-editor-toolbar .sep { width: 1px; background: var(--gray-200); margin: 4px 6px; }
.rich-editor-area {
  min-height: 180px; padding: 16px; font-size: 14px; line-height: 1.7;
  outline: none; color: var(--gray-800);
}
.rich-editor-area:empty::before {
  content: attr(data-placeholder); color: var(--gray-400);
}
.rich-editor-area img { max-width: 100%; border-radius: 8px; margin: 8px 0; }

/* === DUAL UPLOAD ZONE === */
.dual-upload {
  display: grid; grid-template-columns: 1fr 1fr; gap: 16px;
}
@media (max-width: 768px) {
  .dual-upload { grid-template-columns: 1fr; }
}
.dual-upload .upload-dropzone {
  padding: 28px 16px;
}
.dual-upload .upload-label {
  font-size: 13px; font-weight: 600; color: var(--gray-700);
  margin-bottom: 8px; display: flex; align-items: center; gap: 6px;
}
.dual-upload .upload-label .required { color: var(--red-500); }

/* === DOMAIN BLOCK === */
.domain-block-overlay {
  position: fixed; inset: 0; z-index: 99999;
  background: #111; display: flex; align-items: center;
  justify-content: center; flex-direction: column;
  color: #fff; text-align: center; padding: 40px;
}
.domain-block-overlay h1 { font-size: 28px; margin-bottom: 12px; color: #ef4444; }
.domain-block-overlay p { font-size: 15px; color: #9ca3af; max-width: 500px; }

/* === SSO ALERT === */
.sso-alert-overlay {
  position: fixed; inset: 0; z-index: 10000;
  background: rgba(0,0,0,.6); display: flex;
  align-items: center; justify-content: center;
  backdrop-filter: blur(8px);
}
.sso-alert-box {
  background: #fff; border-radius: var(--radius-lg); padding: 40px;
  max-width: 420px; text-align: center; box-shadow: var(--shadow-xl);
}
.sso-alert-box h3 { font-size: 18px; margin-bottom: 12px; color: var(--gray-900); }
.sso-alert-box p { font-size: 14px; color: var(--gray-500); margin-bottom: 24px; }

/* === MEMBERSHIP PAGE === */
.membership-hero {
  margin-top: var(--header-h);
  padding: 60px 24px;
  text-align: center;
  background: linear-gradient(165deg, #fef3c7 0%, #fef9ee 40%, #eff6ff 100%);
}
.membership-hero h1 {
  font-family: var(--font-serif); font-size: 36px;
  font-weight: 700; color: var(--gray-900); margin-bottom: 12px;
}
.membership-hero p { font-size: 16px; color: var(--gray-600); }
.membership-cards {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 24px; max-width: 900px; margin: 40px auto 0;
}
.membership-card {
  background: #fff; border-radius: var(--radius-lg);
  padding: 32px 28px; text-align: center;
  border: 2px solid var(--gray-200);
  transition: all var(--transition);
  position: relative;
}
.membership-card:hover {
  border-color: var(--blue-300);
  box-shadow: var(--shadow-lg);
}
.membership-card.popular {
  border-color: var(--blue-500);
  box-shadow: 0 8px 30px rgba(37,99,235,.15);
}
.membership-card.popular::before {
  content: '最受欢迎'; position: absolute; top: -12px;
  left: 50%; transform: translateX(-50%);
  background: var(--blue-600); color: #fff;
  padding: 4px 16px; border-radius: 50px;
  font-size: 12px; font-weight: 600;
}
.mc-name {
  font-size: 18px; font-weight: 700; color: var(--gray-700); margin-bottom: 6px;
}
.mc-price {
  font-family: var(--font-serif); font-size: 36px;
  font-weight: 700; color: var(--gray-900); margin-bottom: 4px;
}
.mc-price span { font-size: 14px; font-weight: 400; color: var(--gray-500); }
.mc-features {
  list-style: none; text-align: left; margin: 20px 0;
}
.mc-features li {
  padding: 6px 0; font-size: 13.5px; color: var(--gray-600);
  display: flex; align-items: center; gap: 8px;
}
.mc-features li::before { content: '✓'; color: var(--green-500); font-weight: 700; }

/* === UPLOAD PAGE === */
.upload-page {
  margin-top: var(--header-h);
  padding: 40px 24px 64px;
  max-width: 800px; margin-left: auto; margin-right: auto;
}
.upload-page h1 {
  font-family: var(--font-serif); font-size: 28px;
  font-weight: 700; margin-bottom: 8px;
}
.upload-page .page-desc {
  font-size: 14px; color: var(--gray-500); margin-bottom: 32px;
}
.upload-section {
  background: #fff; border-radius: var(--radius-lg);
  border: 1px solid var(--gray-200); padding: 28px;
  margin-bottom: 24px;
}
.upload-section h3 {
  font-size: 16px; font-weight: 700; margin-bottom: 16px;
  color: var(--gray-800);
}
.upload-dropzone {
  border: 2px dashed var(--gray-300); border-radius: var(--radius);
  padding: 48px 24px; text-align: center;
  cursor: pointer; transition: all var(--transition);
  background: var(--gray-50);
}
.upload-dropzone:hover {
  border-color: var(--blue-400); background: var(--blue-50);
}
.upload-dropzone-icon { font-size: 40px; margin-bottom: 12px; }
.upload-dropzone p { font-size: 14px; color: var(--gray-500); }
.upload-dropzone .hint { font-size: 12px; color: var(--gray-400); margin-top: 4px; }
.pricing-options { display: flex; gap: 12px; margin-bottom: 16px; }
.pricing-option {
  flex: 1; padding: 14px; border-radius: var(--radius-sm);
  border: 2px solid var(--gray-200); background: #fff;
  cursor: pointer; text-align: center; font-family: var(--font-sans);
  transition: all var(--transition);
}
.pricing-option.active { border-color: var(--blue-500); background: var(--blue-50); }
.pricing-option .po-label { font-size: 14px; font-weight: 600; color: var(--gray-700); }
.revenue-note {
  background: var(--amber-50); padding: 14px 18px;
  border-radius: var(--radius-sm); font-size: 13px;
  color: var(--gray-600); line-height: 1.7;
  border: 1px solid var(--amber-100);
}
.revenue-note strong { color: var(--amber-600); }

/* === USER DASHBOARD === */
.dashboard-page {
  margin-top: var(--header-h);
  padding: 32px 24px 64px;
  max-width: 1100px; margin-left: auto; margin-right: auto;
}
.dashboard-header {
  display: flex; align-items: center; gap: 20px;
  margin-bottom: 32px; padding-bottom: 24px;
  border-bottom: 1px solid var(--gray-200);
}
.dash-avatar {
  width: 64px; height: 64px; border-radius: 50%;
  background: linear-gradient(135deg, var(--blue-400), var(--blue-600));
  display: flex; align-items: center; justify-content: center;
  color: #fff; font-size: 24px; font-weight: 700;
}
.dash-user-info h2 { font-size: 20px; font-weight: 700; color: var(--gray-900); }
.dash-user-info p { font-size: 13px; color: var(--gray-500); }
.dash-stats {
  display: flex; gap: 24px; margin-left: auto;
}
.dash-stat {
  text-align: center; padding: 0 16px;
  border-right: 1px solid var(--gray-200);
}
.dash-stat:last-child { border: none; }
.dash-stat-num { font-size: 22px; font-weight: 700; color: var(--blue-600); }
.dash-stat-label { font-size: 12px; color: var(--gray-500); }
.dash-tabs {
  display: flex; gap: 4px; margin-bottom: 24px;
  border-bottom: 2px solid var(--gray-100); padding-bottom: 0;
}
.dash-tab {
  padding: 10px 20px; font-size: 14px; font-weight: 600;
  color: var(--gray-500); cursor: pointer;
  border-bottom: 2px solid transparent;
  margin-bottom: -2px; transition: all var(--transition);
  background: none; border-top: none; border-left: none; border-right: none;
  font-family: var(--font-sans);
}
.dash-tab.active { color: var(--blue-600); border-bottom-color: var(--blue-600); }
.dash-tab:hover { color: var(--gray-700); }

/* 横向可滚动的标签栏（管理后台用） */
.dash-tabs-scroll {
  overflow-x: auto;
  flex-wrap: nowrap;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: none;
}
.dash-tabs-scroll::-webkit-scrollbar { display: none; }
.dash-tabs-scroll .dash-tab {
  white-space: nowrap;
  padding: 10px 12px;
  font-size: 13px;
}
.dash-grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 20px;
}
.dash-empty {
  grid-column: 1 / -1; text-align: center;
  padding: 60px 24px; color: var(--gray-400);
}
.dash-empty-icon { font-size: 48px; margin-bottom: 12px; }
.earnings-card {
  background: linear-gradient(135deg, var(--blue-600), var(--blue-800));
  border-radius: var(--radius-lg); padding: 32px;
  color: #fff; margin-bottom: 24px;
}
.earnings-card h3 { font-size: 14px; opacity: .8; margin-bottom: 8px; }
.earnings-amount {
  font-size: 36px; font-weight: 700;
  font-family: var(--font-serif); margin-bottom: 16px;
}

/* === FEATURES SECTION === */
.features-grid {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 24px;
}
.feature-card {
  background: #fff; padding: 28px; border-radius: var(--radius-lg);
  border: 1px solid var(--gray-200);
  transition: all var(--transition);
}
.feature-card:hover {
  border-color: var(--blue-200);
  box-shadow: var(--shadow-md);
}
.feature-icon {
  width: 48px; height: 48px; border-radius: 12px;
  display: flex; align-items: center; justify-content: center;
  font-size: 22px; margin-bottom: 16px;
}
.feature-card h3 {
  font-size: 16px; font-weight: 700; color: var(--gray-800);
  margin-bottom: 8px;
}
.feature-card p { font-size: 13.5px; color: var(--gray-500); line-height: 1.7; }

/* === ANNOUNCEMENT BAR === */
.announce-section {
  max-width: 900px; margin: -10px auto 32px; padding: 0 20px;
}
.announce-inner {
  display: flex; align-items: center; gap: 14px;
  background: linear-gradient(135deg, #fffbeb 0%, #fef3c7 100%);
  border: 1.5px solid var(--amber-400);
  border-radius: 14px; padding: 16px 24px;
  box-shadow: 0 2px 12px rgba(251,191,36,.12);
  animation: announceGlow 3s ease-in-out infinite;
}
@keyframes announceGlow {
  0%, 100% { box-shadow: 0 2px 12px rgba(251,191,36,.12); }
  50% { box-shadow: 0 2px 20px rgba(251,191,36,.25); }
}
.announce-icon {
  font-size: 24px; flex-shrink: 0;
  animation: announceBounce 2s ease-in-out infinite;
}
@keyframes announceBounce {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-3px); }
}
.announce-text {
  font-size: 14px; color: var(--gray-700); font-weight: 500; line-height: 1.6;
}

/* === FOOTER === */
.site-footer {
  background: var(--gray-900); color: var(--gray-400);
  padding: 48px 24px 32px;
}
.footer-inner {
  max-width: 1320px; margin: 0 auto;
  display: grid; grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 40px;
}
.footer-brand p { font-size: 13px; line-height: 1.8; margin-top: 12px; }
.footer-col h4 {
  color: var(--gray-200); font-size: 14px; margin-bottom: 16px;
}
.footer-col a {
  display: block; padding: 4px 0; font-size: 13px;
  color: var(--gray-400); text-decoration: none;
  transition: color var(--transition);
}
.footer-col a:hover { color: var(--blue-400); }
.footer-bottom {
  max-width: 1320px; margin: 32px auto 0;
  padding-top: 24px; border-top: 1px solid var(--gray-800);
  display: flex; justify-content: space-between;
  font-size: 12px;
}

/* === ANIMATIONS === */
@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}
.animate-in {
  animation: fadeInUp .5s ease forwards;
  opacity: 0;
}

/* === TOAST === */
.toast-container {
  position: fixed; top: 80px; right: 24px; z-index: 5000;
  display: flex; flex-direction: column; gap: 8px;
}
.toast {
  padding: 12px 20px; border-radius: var(--radius-sm);
  background: #fff; box-shadow: var(--shadow-lg);
  font-size: 14px; color: var(--gray-700);
  border-left: 4px solid var(--blue-500);
  animation: slideIn .3s ease;
  display: flex; align-items: center; gap: 8px;
}
.toast.success { border-left-color: var(--green-500); }
.toast.error { border-left-color: var(--red-500); }
@keyframes slideIn {
  from { opacity: 0; transform: translateX(30px); }
  to { opacity: 1; transform: translateX(0); }
}

/* === RESPONSIVE === */
@media (max-width: 768px) {
  .hero { padding: 60px 18px 40px; }
  .hero h1 { font-size: 26px; }
  .hero-subtitle { font-size: 14px; }
  .hero-stats { gap: 16px; flex-wrap: wrap; }
  .hero-stat-num { font-size: 22px; }
  .browse-layout { grid-template-columns: 1fr; }
  .filter-sidebar { position: static; }
  .detail-hero { grid-template-columns: 1fr; }
  .footer-inner { grid-template-columns: 1fr 1fr; gap: 24px; }
  .dashboard-header { flex-direction: column; text-align: center; }
  .dash-stats { margin-left: 0; }
  .nav-links { display: none; }
  .membership-cards { grid-template-columns: 1fr; }
  .programs-grid { grid-template-columns: repeat(auto-fill, minmax(220px, 1fr)); gap: 16px; }
  .section { padding: 40px 16px; }
  .header-inner { padding: 0 16px; }
  .mobile-menu-btn { display: flex !important; }
  .mobile-nav { display: block !important; }
}

/* === MOBILE MENU === */
.mobile-menu-btn {
  display: none; width: 40px; height: 40px;
  align-items: center; justify-content: center;
  background: none; border: none; cursor: pointer;
  border-radius: var(--radius-sm); color: var(--gray-600);
  transition: background var(--transition);
}
.mobile-menu-btn:hover { background: var(--gray-100); }
.mobile-menu-btn svg { width: 22px; height: 22px; }
.mobile-nav {
  display: none; position: fixed;
  top: var(--header-h); left: 0; right: 0;
  background: #fff; border-bottom: 1px solid var(--gray-200);
  box-shadow: var(--shadow-lg);
  z-index: 999; padding: 12px 16px;
  transform: translateY(-10px); opacity: 0;
  pointer-events: none; transition: all .25s ease;
}
.mobile-nav.open {
  transform: translateY(0); opacity: 1; pointer-events: all;
}
.mobile-nav a {
  display: flex; align-items: center; gap: 10px;
  padding: 12px 14px; border-radius: var(--radius-sm);
  text-decoration: none; color: var(--gray-700);
  font-size: 15px; font-weight: 500;
  transition: background var(--transition);
}
.mobile-nav a:hover, .mobile-nav a.active {
  background: var(--blue-50); color: var(--blue-600);
}

/* === ENHANCED CARD COVERS === */
.card-cover[data-gradient="physics"] {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
}
.card-cover[data-gradient="chemistry"] {
  background: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
}
.card-cover[data-gradient="math"] {
  background: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
}
.card-cover[data-gradient="biology"] {
  background: linear-gradient(135deg, #43e97b 0%, #38f9d7 100%);
}
.card-cover[data-gradient="geography"] {
  background: linear-gradient(135deg, #fa709a 0%, #fee140 100%);
}
.card-cover[data-gradient="tool"] {
  background: linear-gradient(135deg, #a18cd1 0%, #fbc2eb 100%);
}

/* === SCROLL REVEAL === */
.reveal {
  opacity: 0; transform: translateY(30px);
  transition: opacity .6s ease, transform .6s ease;
}
.reveal.visible {
  opacity: 1; transform: translateY(0);
}

/* === NUMBER COUNTER ANIMATION === */
.counter-animate {
  display: inline-block;
  transition: all .3s ease;
}

/* === BACK TO TOP === */
.back-to-top {
  position: fixed; bottom: 32px; right: 32px;
  width: 44px; height: 44px; border-radius: 50%;
  background: var(--blue-600); color: #fff;
  border: none; cursor: pointer; font-size: 18px;
  box-shadow: 0 4px 14px rgba(37,99,235,.35);
  display: flex; align-items: center; justify-content: center;
  opacity: 0; transform: translateY(10px);
  pointer-events: none;
  transition: all .3s ease;
  z-index: 900;
}
.back-to-top.visible {
  opacity: 1; transform: translateY(0); pointer-events: all;
}
.back-to-top:hover {
  background: var(--blue-700); transform: translateY(-2px);
}

/* === SKELETON LOADING === */
.skeleton {
  background: linear-gradient(90deg, var(--gray-100) 25%, var(--gray-200) 50%, var(--gray-100) 75%);
  background-size: 200% 100%;
  animation: shimmer 1.5s infinite;
  border-radius: var(--radius-sm);
}
@keyframes shimmer {
  0% { background-position: 200% 0; }
  100% { background-position: -200% 0; }
}

/* === TOOLTIP === */
.tooltip-wrap { position: relative; }
.tooltip-wrap::after {
  content: attr(data-tip);
  position: absolute; bottom: calc(100% + 6px);
  left: 50%; transform: translateX(-50%) translateY(4px);
  padding: 5px 10px; border-radius: 6px;
  background: var(--gray-800); color: #fff;
  font-size: 12px; white-space: nowrap;
  opacity: 0; pointer-events: none;
  transition: all .2s ease;
}
.tooltip-wrap:hover::after {
  opacity: 1; transform: translateX(-50%) translateY(0);
}

/* === NOTIFICATION BADGE === */
.badge-dot {
  position: absolute; top: -2px; right: -2px;
  width: 8px; height: 8px; border-radius: 50%;
  background: var(--red-500); border: 2px solid #fff;
}
/* === AI CHAT BOX (Hero) === */
.ai-chat-box {
  width: 100%;
  max-width: 960px;
  margin: 24px auto;
  background: #1a1a2e;
  border-radius: 20px;
  overflow: hidden;
}
.ai-chat-box .ai-chat-iframe {
  width: 100%;
  height: 400px;
  border: none;
  display: block;
  transition: height 0.35s ease;
}
.ai-chat-header {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 16px 20px;
  border-bottom: 1px solid var(--gray-100);
}
.ai-chat-avatar {
  width: 40px; height: 40px;
  background: linear-gradient(135deg, #6366f1, #8b5cf6);
  border-radius: 12px;
  display: flex; align-items: center; justify-content: center;
  font-size: 20px;
}
.ai-chat-name { font-weight: 600; font-size: 15px; color: var(--gray-800); }
.ai-chat-subtitle { font-size: 12px; color: var(--gray-400); }
.ai-chat-messages {
  max-height: 280px;
  min-height: 80px;
  overflow-y: auto;
  padding: 16px 20px;
  display: flex;
  flex-direction: column;
  gap: 12px;
}
.ai-msg {
  max-width: 85%;
  padding: 10px 14px;
  border-radius: 14px;
  font-size: 14px;
  line-height: 1.6;
  word-break: break-word;
}
.ai-msg.user {
  align-self: flex-end;
  background: linear-gradient(135deg, var(--blue-500), #6366f1);
  color: white;
  border-bottom-right-radius: 4px;
}
.ai-msg.assistant {
  align-self: flex-start;
  background: var(--gray-50);
  color: var(--gray-700);
  border-bottom-left-radius: 4px;
  border: 1px solid var(--gray-100);
  text-align: left;
}
.ai-msg .program-cards {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-top: 10px;
}
.ai-msg .program-card {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 12px;
  background: white;
  border: 1px solid var(--gray-200);
  border-radius: 10px;
  cursor: pointer;
  transition: all 0.2s;
}
.ai-msg .program-card:hover {
  border-color: var(--blue-300);
  box-shadow: 0 2px 8px rgba(99,102,241,0.1);
}
.ai-msg .program-card-emoji { font-size: 28px; }
.ai-msg .program-card-info { flex: 1; }
.ai-msg .program-card-title { font-size: 13px; font-weight: 600; color: var(--gray-800); }
.ai-msg .program-card-meta { font-size: 11px; color: var(--gray-400); margin-top: 2px; }
.ai-msg .program-card-price { font-size: 13px; font-weight: 600; color: var(--blue-500); white-space: nowrap; }

.ai-chat-quick-actions {
  display: flex;
  gap: 8px;
  padding: 0 20px 12px;
  flex-wrap: wrap;
}
.ai-quick-btn {
  padding: 6px 14px;
  border-radius: 20px;
  border: 1px solid var(--gray-200);
  background: white;
  font-size: 13px;
  color: var(--gray-600);
  cursor: pointer;
  transition: all 0.2s;
  font-family: inherit;
}
.ai-quick-btn:hover {
  border-color: var(--blue-300);
  color: var(--blue-600);
  background: var(--blue-50);
}
.ai-chat-input-area {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 12px 16px;
  border-top: 1px solid var(--gray-100);
  background: var(--gray-50);
  border-radius: 0 0 20px 20px;
}
.ai-chat-textarea {
  width: 100%;
  min-height: 56px;
  max-height: 120px;
  padding: 12px 14px;
  border-radius: 12px;
  border: 1px solid var(--gray-200);
  font-size: 14px;
  font-family: inherit;
  outline: none;
  transition: border-color 0.2s;
  resize: none;
  line-height: 1.6;
  background: white;
}
.ai-chat-textarea:focus { border-color: var(--blue-400); }
.ai-chat-toolbar {
  display: flex;
  align-items: center;
  gap: 6px;
  flex-wrap: wrap;
}
.ai-chat-toolbar .ai-send-btn {
  margin-left: auto;
}
.ai-upload-btn {
  width: 36px; height: 36px;
  border-radius: 10px;
  border: 1px solid var(--gray-200);
  background: white;
  font-size: 18px;
  cursor: pointer;
  display: flex; align-items: center; justify-content: center;
  transition: all 0.2s;
  flex-shrink: 0;
}
.ai-upload-btn:hover { border-color: var(--blue-300); background: var(--blue-50); }
.ai-send-btn {
  padding: 8px 18px;
  border-radius: 12px;
  border: none;
  background: linear-gradient(135deg, var(--blue-500), #6366f1);
  color: white;
  font-size: 14px;
  font-weight: 500;
  cursor: pointer;
  font-family: inherit;
  transition: all 0.2s;
  flex-shrink: 0;
}
.ai-send-btn:hover { opacity: 0.9; box-shadow: 0 2px 8px rgba(99,102,241,0.3); }

.ai-typing {
  display: flex; gap: 4px; padding: 4px 0;
}
.ai-typing span {
  width: 6px; height: 6px;
  background: var(--gray-400);
  border-radius: 50%;
  animation: aiBounce 1.4s infinite;
}
.ai-typing span:nth-child(2) { animation-delay: 0.2s; }
.ai-typing span:nth-child(3) { animation-delay: 0.4s; }
@keyframes aiBounce {
  0%, 60%, 100% { transform: translateY(0); }
  30% { transform: translateY(-6px); }
}

/* === CATEGORY BAR COMPACT === */
.category-bar-compact {
  display: flex;
  gap: 8px;
  flex-wrap: nowrap;
  justify-content: center;
  margin-bottom: 24px;
  overflow: hidden;
}
.category-bar-compact.expanded {
  flex-wrap: wrap;
}
.category-bar-compact .chip {
  padding: 5px 14px;
  font-size: 12.5px;
  white-space: nowrap;
}
.category-more-btn {
  padding: 5px 14px;
  border-radius: 50px;
  font-size: 12.5px;
  font-weight: 500;
  cursor: pointer;
  border: 1.5px solid var(--blue-200);
  background: var(--blue-50);
  color: var(--blue-600);
  transition: all var(--transition);
  white-space: nowrap;
}
.category-more-btn:hover {
  background: var(--blue-100);
  border-color: var(--blue-400);
}
/* HTML Preview Panel */
.preview-overlay {
  display: none;
  position: fixed;
  top: 0; right: 0;
  width: 55%;
  height: 100vh;
  background: white;
  box-shadow: -4px 0 30px rgba(0,0,0,0.15);
  z-index: 9999;
  flex-direction: column;
  animation: slideInRight 0.3s ease;
}
.preview-overlay.active { display: flex; }
/* 图小灵全屏预览：覆盖整个浏览器窗口 */
.preview-overlay.tuxiaoling-fullscreen {
  width: 100% !important;
  left: 0 !important;
}
@keyframes adminCardIn {
  from { opacity: 0; transform: translateY(30px) scale(0.96); }
  to { opacity: 1; transform: translateY(0) scale(1); }
}

@keyframes slideInRight {
  from { transform: translateX(100%); }
  to { transform: translateX(0); }
}
.preview-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 20px;
  border-bottom: 1px solid var(--gray-200);
  background: var(--gray-50);
  flex-shrink: 0;
}
.preview-header-title {
  font-size: 14px;
  font-weight: 600;
  color: var(--gray-700);
}
.preview-header-actions {
  display: flex;
  gap: 8px;
  align-items: center;
}
.preview-header-actions button {
  padding: 5px 14px;
  border-radius: 8px;
  border: 1px solid var(--gray-200);
  background: white;
  font-size: 12px;
  cursor: pointer;
  font-family: inherit;
  color: var(--gray-600);
  transition: all 0.2s;
}
.preview-header-actions button:hover {
  border-color: var(--blue-300);
  color: var(--blue-600);
}
.preview-iframe {
  flex: 1;
  width: 100%;
  border: none;
  background: white;
}
@media (max-width: 768px) {
  .preview-overlay { width: 100%; }
}

/* ⭐ 评分系统 */
.star-rating {
  display: inline-flex;
  align-items: center;
  gap: 2px;
  font-size: 20px;
  cursor: pointer;
  user-select: none;
}
.star-rating .star {
  position: relative;
  color: #d1d5db;
  transition: color .15s, transform .15s;
}
.star-rating .star.active {
  color: #f59e0b;
}
.star-rating .star.half {
  position: relative;
  color: #d1d5db;
}
.star-rating .star.half::before {
  content: '★';
  position: absolute;
  left: 0; top: 0;
  clip-path: inset(0 50% 0 0);
  color: #f59e0b;
}
.star-rating .star.hover {
  color: #fbbf24;
}
.star-rating .star.hover-half {
  position: relative;
  color: #d1d5db;
}
.star-rating .star.hover-half::before {
  content: '★';
  position: absolute;
  left: 0; top: 0;
  clip-path: inset(0 50% 0 0);
  color: #fbbf24;
}
.star-rating .star:hover {
  transform: scale(1.2);
}
.star-rating-readonly {
  cursor: default;
}
.star-rating-readonly .star:hover {
  transform: none;
}
.detail-rating-section {
  padding: 12px 32px 16px;
  background: var(--gray-50);
  border-bottom: 1px solid var(--gray-200);
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.rating-summary {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 13px;
  color: var(--gray-500);
}
.rating-summary .avg-score {
  font-weight: 600;
  font-size: 14px;
  color: var(--gray-600);
}
.rating-summary .rating-number {
  font-weight: 700;
  font-size: 16px;
  color: var(--gray-800);
  margin-left: -2px;
}
.rating-my-score {
  font-size: 12px;
  color: var(--blue-500);
  margin-left: 8px;
}
.my-rating-section {
  display: flex;
  align-items: center;
  gap: 6px;
}
.my-rating-label {
  font-size: 13px;
  color: var(--gray-500);
  white-space: nowrap;
}