:root {
  --bg: #f5f6fb;
  --card: #ffffff;
  --text: #1a1d29;
  --muted: #6b7280;
  --primary: #4f46e5;
  --primary-dark: #4338ca;
  --accent: #7c3aed;
  --border: #e5e7eb;
  --star: #f59e0b;
  --radius: 16px;
  --shadow: 0 4px 20px rgba(79, 70, 229, .08);
}
* { box-sizing: border-box; margin: 0; padding: 0; }
html, body { height: 100%; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}
a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }
button { font-family: inherit; cursor: pointer; }

/* ---------- 导航栏 ---------- */
.nav {
  position: sticky; top: 0; z-index: 50;
  background: rgba(255,255,255,.9);
  backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid var(--border);
}
.nav-inner {
  max-width: 1100px; margin: 0 auto;
  display: flex; align-items: center; justify-content: space-between;
  padding: 12px 20px;
}
.logo {
  display: flex; align-items: center;
}
.logo a { display: flex; align-items: center; }
.nav-actions { display: flex; align-items: center; gap: 12px; }
.nav-user {
  font-size: 13px; color: var(--muted);
  display: flex; align-items: center; gap: 8px;
}
.btn {
  display: inline-flex; align-items: center; justify-content: center;
  padding: 9px 18px; border: none; border-radius: 10px;
  font-size: 14px; font-weight: 600;
  transition: all .15s ease;
}
.btn-primary {
  background: linear-gradient(135deg, var(--primary), var(--accent));
  color: #fff;
}
.btn-primary:hover { transform: translateY(-1px); box-shadow: 0 6px 16px rgba(79,70,229,.3); }
.btn-outline {
  background: #fff; color: var(--primary);
  border: 1px solid var(--border);
}
.btn-outline:hover { border-color: var(--primary); }
.btn-block { width: 100%; padding: 12px; font-size: 15px; }

/* ---------- 容器 ---------- */
.container { max-width: 1100px; margin: 0 auto; padding: 0 20px; }

/* ---------- Hero ---------- */
.hero {
  background: linear-gradient(135deg, var(--primary) 0%, var(--accent) 100%);
  color: #fff;
  padding: 56px 20px 72px;
  text-align: center;
}
.hero h1 { font-size: 34px; font-weight: 800; letter-spacing: 1px; }
.hero p { margin-top: 12px; opacity: .9; font-size: 16px; }

/* ---------- 应用卡片网格 ---------- */
.apps-wrap { margin-top: -36px; padding-bottom: 64px; }
.app-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 18px;
}
.app-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 22px;
  display: flex; flex-direction: column; gap: 12px;
  transition: transform .15s ease, box-shadow .15s ease;
  text-decoration: none; color: inherit;
}
.app-card:hover { transform: translateY(-3px); box-shadow: var(--shadow); }
.app-icon {
  width: 52px; height: 52px; border-radius: 14px;
  display: flex; align-items: center; justify-content: center;
  font-size: 24px;
  background: linear-gradient(135deg, #eef2ff, #e0e7ff);
  color: var(--primary);
  font-weight: 800;
}
.app-card h3 { font-size: 18px; }
.app-desc { color: var(--muted); font-size: 14px; flex: 1; }
.app-meta {
  display: flex; align-items: center; justify-content: space-between;
  font-size: 13px; color: var(--muted);
}
.stars { color: var(--star); letter-spacing: 1px; }
.price-tag {
  background: #ecfdf5; color: #059669;
  padding: 3px 10px; border-radius: 999px; font-size: 12px; font-weight: 600;
}
.price-tag.paid { background: #fef3c7; color: #d97706; }
.empty { text-align: center; color: var(--muted); padding: 64px 0; }

/* ---------- 应用详情 ---------- */
.detail { padding: 28px 0 64px; }
.detail-header {
  background: var(--card); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 28px;
  display: flex; gap: 24px; flex-wrap: wrap; align-items: flex-start;
}
.detail-header .app-icon { width: 72px; height: 72px; font-size: 32px; flex-shrink: 0; }
.detail-info { flex: 1; min-width: 220px; }
.detail-info h1 { font-size: 26px; margin-bottom: 8px; }
.detail-info .app-desc { font-size: 15px; margin-bottom: 14px; }
.detail-actions { display: flex; gap: 12px; flex-wrap: wrap; }
.detail-stats {
  display: flex; gap: 24px; margin-top: 14px;
  font-size: 14px; color: var(--muted);
}
.detail-stats b { color: var(--text); font-size: 16px; }

.section { margin-top: 28px; }
.section h2 { font-size: 18px; margin-bottom: 14px; }
.intro-frame {
  background: var(--card); border: 1px solid var(--border);
  border-radius: var(--radius); overflow: hidden;
}
.intro-frame iframe {
  width: 100%; min-height: 420px; border: none; display: block;
}

/* ---------- 评价 ---------- */
.review-form {
  background: var(--card); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 20px; margin-bottom: 20px;
}
.rating-input { display: flex; gap: 4px; font-size: 28px; cursor: pointer; user-select: none; }
.rating-input .star { color: #d1d5db; transition: color .1s; }
.rating-input .star.active { color: var(--star); }
.review-form textarea {
  width: 100%; margin-top: 12px; padding: 12px;
  border: 1px solid var(--border); border-radius: 10px;
  font-family: inherit; font-size: 14px; resize: vertical; min-height: 80px;
}
.review-list { display: flex; flex-direction: column; gap: 14px; }
.review-item {
  background: var(--card); border: 1px solid var(--border);
  border-radius: 12px; padding: 16px;
}
.review-head { display: flex; justify-content: space-between; margin-bottom: 6px; }
.review-user { font-weight: 600; font-size: 14px; }
.review-date { color: var(--muted); font-size: 12px; }
.review-content { color: #374151; font-size: 14px; }

/* ---------- 登录 ---------- */
.auth-wrap {
  min-height: calc(100vh - 60px);
  display: flex; align-items: center; justify-content: center;
  padding: 32px 20px;
}
.auth-card {
  background: var(--card); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 32px;
  width: 100%; max-width: 400px;
  box-shadow: var(--shadow);
}
.auth-card h1 { text-align: center; margin-bottom: 8px; }
.auth-card .sub { text-align: center; color: var(--muted); margin-bottom: 24px; }
.tabs { display: flex; background: #f3f4f6; border-radius: 10px; padding: 4px; margin-bottom: 20px; }
.tabs button {
  flex: 1; padding: 10px; border: none; background: transparent;
  border-radius: 8px; font-weight: 600; color: var(--muted);
}
.tabs button.active { background: #fff; color: var(--primary); box-shadow: 0 1px 3px rgba(0,0,0,.1); }
.form-row { margin-bottom: 16px; }
.form-row label { display: block; font-size: 13px; color: var(--muted); margin-bottom: 6px; }
.form-row input {
  width: 100%; padding: 11px 14px;
  border: 1px solid var(--border); border-radius: 10px;
  font-size: 14px; font-family: inherit;
}
.form-row input:focus { outline: none; border-color: var(--primary); }

.toast {
  position: fixed; top: 70px; left: 50%; transform: translateX(-50%);
  background: #1f2937; color: #fff; padding: 10px 18px; border-radius: 10px;
  font-size: 14px; z-index: 100; opacity: 0; transition: opacity .2s;
}
.toast.show { opacity: 1; }

.footer { text-align: center; color: var(--muted); font-size: 13px; padding: 0 0 40px; line-height: 1.8; }
.footer .beian { display: inline-block; margin-top: 4px; color: var(--muted); text-decoration: none; }
.footer .beian:hover { color: var(--accent, #4f46e5); text-decoration: underline; }

/* ---------- 响应式 ---------- */
@media (max-width: 640px) {
  .hero { padding: 40px 16px 60px; }
  .hero h1 { font-size: 26px; }
  .hero p { font-size: 14px; }
  .detail-header { padding: 20px; }
  .detail-info h1 { font-size: 22px; }
  .app-grid { grid-template-columns: 1fr; }
  .intro-frame iframe { min-height: 360px; }
  .auth-card { padding: 24px 20px; }
}

/* ==========================================================================
   SEO / 应用介绍页（新增，不影响原有首页与详情页样式）
   ========================================================================== */
.btn-sm { padding: 7px 14px; font-size: 13px; }

.seo-section { margin-top: 48px; }
.seo-section h2 { font-size: 22px; margin-bottom: 14px; }
.seo-section p { color: #374151; font-size: 15px; margin-bottom: 12px; }
.seo-section .note { color: var(--muted); font-size: 13px; }

.app-link-list { list-style: none; display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 12px; }
.app-link-list li {
  background: var(--card); border: 1px solid var(--border); border-radius: 12px;
  padding: 14px 16px; font-size: 14px; color: var(--muted);
}
.app-link-list li a { color: var(--primary); font-size: 15px; }
.app-link-list li span { display: block; margin-top: 4px; }

.bullet-list, .step-list, .scene-list { padding-left: 22px; color: #374151; font-size: 15px; }
.bullet-list li, .step-list li, .scene-list li { margin-bottom: 10px; }
.scene-list { list-style: none; padding-left: 0; }
.scene-list li {
  background: var(--card); border: 1px solid var(--border); border-radius: 12px;
  padding: 14px 16px;
}

.faq-item {
  background: var(--card); border: 1px solid var(--border); border-radius: 12px;
  padding: 16px 18px; margin-bottom: 12px;
}
.faq-item h3 { font-size: 16px; margin-bottom: 8px; }
.faq-item p { font-size: 14px; color: #4b5563; margin: 0; }

.footer-links { display: flex; flex-wrap: wrap; justify-content: center; gap: 8px 16px; margin: 10px 0 6px; }
.footer-links a { color: var(--muted); font-size: 13px; }
.footer-links a:hover { color: var(--primary); }

/* 介绍页骨架 */
.seo-topbar {
  position: sticky; top: 0; z-index: 50;
  background: rgba(255,255,255,.92);
  backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid var(--border);
}
.seo-topbar-inner {
  max-width: 1000px; margin: 0 auto; padding: 12px 20px;
  display: flex; align-items: center; justify-content: space-between; gap: 16px;
}
.seo-brand { font-weight: 800; font-size: 16px; color: var(--primary); }
.seo-brand span { font-weight: 500; font-size: 13px; color: var(--muted); margin-left: 6px; }
.seo-topnav { display: flex; align-items: center; gap: 16px; font-size: 14px; color: var(--muted); }
.seo-topnav a:hover { color: var(--primary); }

.seo-wrap { max-width: 1000px; margin: 0 auto; padding: 20px 20px 48px; }
.breadcrumb { font-size: 13px; color: var(--muted); display: flex; flex-wrap: wrap; gap: 6px; margin-bottom: 16px; }
.breadcrumb a { color: var(--muted); }
.breadcrumb a:hover { color: var(--primary); }

.app-hero {
  background: var(--card); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 28px; box-shadow: var(--shadow);
}
.app-icon-lg { width: 64px; height: 64px; font-size: 28px; margin-bottom: 16px; }
.app-hero h1 { font-size: 26px; line-height: 1.4; margin-bottom: 12px; }
.app-hero .lead { font-size: 16px; color: #374151; margin-bottom: 18px; }
.app-hero-actions { display: flex; flex-wrap: wrap; gap: 12px; margin-bottom: 18px; }
.fact-list {
  list-style: none; display: grid; grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 8px 24px; padding-top: 16px; border-top: 1px solid var(--border);
  font-size: 14px; color: var(--muted);
}
.fact-list strong { color: var(--text); }

.seo-block { margin-top: 36px; }
.seo-block h2 { font-size: 21px; margin-bottom: 12px; }
.seo-block p { color: #374151; font-size: 15px; margin-bottom: 10px; }
.seo-block > ul, .seo-block > ol { color: #374151; font-size: 15px; }

.feature-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 16px; margin-top: 14px; }
.feature-card {
  background: var(--card); border: 1px solid var(--border); border-radius: 14px; padding: 18px;
}
.feature-card h3 { font-size: 16px; margin-bottom: 8px; }
.feature-card p { font-size: 14px; color: #4b5563; margin-bottom: 10px; }
.feature-card ul { padding-left: 18px; font-size: 13px; color: var(--muted); }
.feature-card li { margin-bottom: 4px; }

.related { border-top: 1px solid var(--border); padding-top: 24px; }
.related-links { list-style: none; display: flex; flex-wrap: wrap; gap: 10px; }
.related-links a {
  display: inline-block; background: #fff; border: 1px solid var(--border);
  border-radius: 999px; padding: 7px 14px; font-size: 13px; color: var(--primary);
}
.related-links a:hover { border-color: var(--primary); }

.disclaimer {
  margin-top: 28px; padding: 14px 16px; border-radius: 12px;
  background: #fffbeb; border: 1px solid #fde68a;
  font-size: 13px; color: #92400e;
}
.intro-more { margin-top: 12px; font-size: 14px; }
.intro-more a { color: var(--primary); }

@media (max-width: 720px) {
  .app-link-list, .feature-grid, .fact-list { grid-template-columns: 1fr; }
  .app-hero { padding: 20px; }
  .app-hero h1 { font-size: 22px; }
  .seo-topnav { gap: 10px; }
  .seo-topnav a:not(.btn) { display: none; }
}