/* ===================================
   核医学科普网站 - 全局样式
   =================================== */

/* 字体引入 */
@import url('https://fonts.googleapis.com/css2?family=Noto+Sans+SC:wght@300;400;500;700;900&display=swap');

/* CSS 变量 */
:root {
  --primary: #0ea5e9;
  --primary-dark: #0284c7;
  --primary-light: #e0f2fe;
  --secondary: #06b6d4;
  --accent: #6366f1;
  --success: #10b981;
  --warning: #f59e0b;
  --danger: #ef4444;

  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-muted: #94a3b8;

  --bg-white: #ffffff;
  --bg-light: #f8fafc;
  --bg-section: #f1f5f9;

  --border: #e2e8f0;
  --border-light: #f1f5f9;

  --shadow-sm: 0 1px 3px rgba(0,0,0,0.08), 0 1px 2px rgba(0,0,0,0.04);
  --shadow: 0 4px 16px rgba(0,0,0,0.08), 0 2px 8px rgba(0,0,0,0.04);
  --shadow-lg: 0 20px 40px rgba(0,0,0,0.1), 0 8px 20px rgba(0,0,0,0.06);
  --shadow-colored: 0 8px 24px rgba(14,165,233,0.2);

  --radius-sm: 8px;
  --radius: 16px;
  --radius-lg: 24px;
  --radius-xl: 32px;

  --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-fast: all 0.15s ease;

  --navbar-height: 70px;
  --max-width: 1200px;
}

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

html { scroll-behavior: smooth; font-size: 16px; }

body {
  font-family: 'Noto Sans SC', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  color: var(--text-primary);
  background: var(--bg-white);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

img { max-width: 100%; height: auto; display: block; }
a { color: inherit; text-decoration: none; }
ul { list-style: none; }
button { cursor: pointer; border: none; background: none; font-family: inherit; }

/* ===================================
   导航栏
   =================================== */
.navbar {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: var(--navbar-height);
  background: rgba(255,255,255,0.92);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border-light);
  z-index: 1000;
  transition: var(--transition);
}

.navbar.scrolled {
  box-shadow: var(--shadow);
  background: rgba(255,255,255,0.98);
}

.nav-container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: clamp(0.72rem, 1.8vw, 1rem);
  color: var(--primary-dark);
  line-height: 1.3;
}

.nav-logo .logo-icon {
  width: 38px; height: 38px;
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: 4px;
}

.nav-link {
  padding: 8px 16px;
  border-radius: var(--radius-sm);
  font-size: 0.92rem;
  font-weight: 500;
  color: var(--text-secondary);
  transition: var(--transition-fast);
  position: relative;
}

.nav-link:hover, .nav-link.active {
  color: var(--primary);
  background: var(--primary-light);
}

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  padding: 8px;
  border-radius: var(--radius-sm);
  transition: var(--transition-fast);
}

.nav-toggle:hover { background: var(--bg-section); }

.nav-toggle span {
  display: block;
  width: 22px; height: 2px;
  background: var(--text-primary);
  border-radius: 2px;
  transition: var(--transition);
}

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

/* ===================================
   页面主体偏移
   =================================== */
.page-content { padding-top: var(--navbar-height); }

/* ===================================
   通用区块样式
   =================================== */
.section {
  padding: 80px 24px;
}

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

.container {
  max-width: var(--max-width);
  margin: 0 auto;
}

.section-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: var(--primary-light);
  color: var(--primary-dark);
  font-size: 0.82rem;
  font-weight: 600;
  padding: 5px 14px;
  border-radius: 100px;
  margin-bottom: 16px;
  letter-spacing: 0.03em;
}

.section-title {
  font-size: clamp(1.6rem, 4vw, 2.4rem);
  font-weight: 700;
  color: var(--text-primary);
  line-height: 1.3;
  margin-bottom: 16px;
}

.section-subtitle {
  font-size: 1.05rem;
  color: var(--text-secondary);
  max-width: 560px;
  line-height: 1.8;
}

.section-header { margin-bottom: 52px; }
.section-header.center { text-align: center; }
.section-header.center .section-subtitle { margin: 0 auto; }

/* ===================================
   按钮
   =================================== */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 28px;
  border-radius: 100px;
  font-size: 0.95rem;
  font-weight: 600;
  transition: var(--transition);
  white-space: nowrap;
}

.btn-primary {
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  color: white;
  box-shadow: var(--shadow-colored);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 12px 32px rgba(14,165,233,0.35);
}

.btn-outline {
  background: transparent;
  color: var(--primary);
  border: 2px solid var(--primary);
}

.btn-outline:hover {
  background: var(--primary-light);
  transform: translateY(-2px);
}

.btn-white {
  background: white;
  color: var(--primary-dark);
  box-shadow: var(--shadow);
}

.btn-white:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

/* ===================================
   卡片
   =================================== */
.card {
  background: var(--bg-white);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--border-light);
  overflow: hidden;
  transition: var(--transition);
}

.card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-lg);
  border-color: var(--primary-light);
}

/* ===================================
   Hero 区域（首页）
   =================================== */
.hero {
  min-height: calc(100vh - var(--navbar-height));
  background: linear-gradient(160deg, #f0f9ff 0%, #e0f2fe 30%, #f8fafc 70%, #f0fdf4 100%);
  display: flex;
  align-items: center;
  padding: 60px 24px;
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: -200px; right: -200px;
  width: 600px; height: 600px;
  background: radial-gradient(circle, rgba(14,165,233,0.08) 0%, transparent 70%);
  border-radius: 50%;
}

.hero::after {
  content: '';
  position: absolute;
  bottom: -150px; left: -150px;
  width: 500px; height: 500px;
  background: radial-gradient(circle, rgba(6,182,212,0.06) 0%, transparent 70%);
  border-radius: 50%;
}

.hero-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  width: 100%;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: center;
  position: relative;
  z-index: 1;
}

.hero-tag {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: white;
  border: 1px solid var(--border);
  border-radius: 100px;
  padding: 6px 16px;
  font-size: 0.82rem;
  font-weight: 500;
  color: var(--text-secondary);
  margin-bottom: 24px;
  box-shadow: var(--shadow-sm);
}

.hero-tag .dot {
  width: 8px; height: 8px;
  background: var(--success);
  border-radius: 50%;
  animation: pulse 2s infinite;
}

@keyframes pulse {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.6; transform: scale(1.3); }
}

.hero-title {
  font-size: clamp(2rem, 5vw, 3.2rem);
  font-weight: 900;
  line-height: 1.2;
  margin-bottom: 20px;
  color: var(--text-primary);
}

.hero-title .highlight {
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-desc {
  font-size: 1.08rem;
  color: var(--text-secondary);
  line-height: 1.9;
  margin-bottom: 36px;
  max-width: 480px;
}

.hero-actions {
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
}

.hero-stats {
  display: flex;
  gap: 28px;
  margin-top: 44px;
  padding-top: 32px;
  border-top: 1px solid var(--border);
}

.stat-item { text-align: left; }

.stat-num {
  font-size: 1.6rem;
  font-weight: 800;
  color: var(--primary-dark);
  line-height: 1;
  margin-bottom: 4px;
}

.stat-label {
  font-size: 0.8rem;
  color: var(--text-muted);
  font-weight: 400;
}

/* Hero 插图区 */
.hero-visual {
  display: flex;
  justify-content: center;
  align-items: center;
}

.hero-illustration {
  width: 100%;
  max-width: 480px;
  position: relative;
}

/* ===================================
   SVG 卡通插图 - 通用
   =================================== */
.illustration-wrapper {
  position: relative;
  width: 100%;
  padding-bottom: 85%;
}

.illustration-wrapper svg {
  position: absolute;
  top: 0; left: 0;
  width: 100%; height: 100%;
}

/* 浮动动画 */
.float-anim {
  animation: floatAnim 4s ease-in-out infinite;
}

.float-anim-slow {
  animation: floatAnim 6s ease-in-out infinite reverse;
}

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

/* ===================================
   特性/栏目卡片区
   =================================== */
.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 24px;
}

.feature-card {
  padding: 32px 28px;
  border-radius: var(--radius-lg);
  background: var(--bg-white);
  border: 1px solid var(--border-light);
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
  position: relative;
  overflow: hidden;
}

.feature-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 4px;
  background: linear-gradient(90deg, var(--primary), var(--secondary));
  transform: scaleX(0);
  transform-origin: left;
  transition: var(--transition);
}

.feature-card:hover {
  transform: translateY(-8px);
  box-shadow: var(--shadow-lg);
  border-color: transparent;
}

.feature-card:hover::before { transform: scaleX(1); }

.feature-icon {
  width: 60px; height: 60px;
  border-radius: var(--radius);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.8rem;
  margin-bottom: 20px;
}

.feature-icon.blue { background: #e0f2fe; }
.feature-icon.cyan { background: #ecfeff; }
.feature-icon.purple { background: #ede9fe; }
.feature-icon.green { background: #d1fae5; }

.feature-title {
  font-size: 1.12rem;
  font-weight: 700;
  margin-bottom: 10px;
  color: var(--text-primary);
}

.feature-desc {
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.75;
  margin-bottom: 18px;
}

.feature-link {
  font-size: 0.88rem;
  font-weight: 600;
  color: var(--primary);
  display: inline-flex;
  align-items: center;
  gap: 4px;
  transition: var(--transition-fast);
}

.feature-link:hover { gap: 8px; }

/* ===================================
   文章卡片
   =================================== */
.articles-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 28px;
}

.article-card {
  border-radius: var(--radius-lg);
  background: var(--bg-white);
  border: 1px solid var(--border-light);
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
  overflow: hidden;
}

.article-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-lg);
}

.article-thumb {
  width: 100%;
  height: 180px;
  background: linear-gradient(135deg, var(--primary-light), #ecfeff);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 4rem;
  position: relative;
  overflow: hidden;
}

.article-thumb svg {
  width: 120px;
  height: 120px;
}

.article-body { padding: 24px; }

.article-tag {
  display: inline-block;
  background: var(--primary-light);
  color: var(--primary-dark);
  font-size: 0.75rem;
  font-weight: 600;
  padding: 3px 10px;
  border-radius: 100px;
  margin-bottom: 10px;
}

.article-title {
  font-size: 1.02rem;
  font-weight: 700;
  color: var(--text-primary);
  line-height: 1.5;
  margin-bottom: 8px;
}

.article-excerpt {
  font-size: 0.88rem;
  color: var(--text-secondary);
  line-height: 1.75;
  margin-bottom: 16px;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.article-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.8rem;
  color: var(--text-muted);
}

/* ===================================
   内页 Hero（非首页）
   =================================== */
.page-hero {
  background: linear-gradient(135deg, #0ea5e9 0%, #06b6d4 50%, #0284c7 100%);
  padding: 80px 24px;
  text-align: center;
  color: white;
  position: relative;
  overflow: hidden;
}

.page-hero::before {
  content: '';
  position: absolute;
  top: -100px; right: -100px;
  width: 400px; height: 400px;
  background: rgba(255,255,255,0.05);
  border-radius: 50%;
}

.page-hero::after {
  content: '';
  position: absolute;
  bottom: -80px; left: -80px;
  width: 320px; height: 320px;
  background: rgba(255,255,255,0.04);
  border-radius: 50%;
}

.page-hero-content { position: relative; z-index: 1; }

.page-hero-icon {
  font-size: 4rem;
  margin-bottom: 16px;
  display: block;
}

.page-hero h1 {
  font-size: clamp(1.8rem, 5vw, 2.8rem);
  font-weight: 800;
  margin-bottom: 14px;
}

.page-hero p {
  font-size: 1.08rem;
  opacity: 0.88;
  max-width: 540px;
  margin: 0 auto;
  line-height: 1.8;
}

/* ===================================
   内容详情区
   =================================== */
.content-section {
  padding: 72px 24px;
}

.content-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 64px;
  align-items: center;
  margin-bottom: 80px;
}

.content-grid.reverse { direction: rtl; }
.content-grid.reverse > * { direction: ltr; }

.content-text {}

.content-text h2 {
  font-size: clamp(1.4rem, 3vw, 1.9rem);
  font-weight: 700;
  margin-bottom: 16px;
  color: var(--text-primary);
}

.content-text p {
  font-size: 0.97rem;
  color: var(--text-secondary);
  line-height: 1.9;
  margin-bottom: 14px;
}

.content-text .highlight-box {
  background: var(--primary-light);
  border-left: 4px solid var(--primary);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  padding: 16px 20px;
  margin: 20px 0;
  font-size: 0.93rem;
  color: var(--primary-dark);
  line-height: 1.8;
}

.check-list { margin-top: 18px; }

.check-list li {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  margin-bottom: 10px;
  font-size: 0.93rem;
  color: var(--text-secondary);
  line-height: 1.7;
}

.check-list li::before {
  content: '✓';
  min-width: 22px; height: 22px;
  background: var(--success);
  color: white;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.75rem;
  font-weight: 700;
  margin-top: 2px;
}

/* ===================================
   信息卡片组（内页）
   =================================== */
.info-cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 20px;
  margin-top: 48px;
}

.info-card {
  background: var(--bg-white);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-lg);
  padding: 28px 24px;
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
}

.info-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow);
}

.info-card-icon {
  font-size: 2.4rem;
  margin-bottom: 14px;
}

.info-card h3 {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 8px;
  color: var(--text-primary);
}

.info-card p {
  font-size: 0.88rem;
  color: var(--text-secondary);
  line-height: 1.75;
}

/* ===================================
   FAQ 手风琴
   =================================== */
.faq-list { max-width: 800px; margin: 0 auto; }

.faq-item {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin-bottom: 12px;
  overflow: hidden;
  transition: var(--transition);
}

.faq-item.open {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(14,165,233,0.1);
}

.faq-question {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 20px 24px;
  font-size: 0.97rem;
  font-weight: 600;
  color: var(--text-primary);
  text-align: left;
  transition: var(--transition-fast);
  background: var(--bg-white);
}

.faq-question:hover { background: var(--bg-light); color: var(--primary); }
.faq-item.open .faq-question { color: var(--primary); background: var(--primary-light); }

.faq-icon {
  width: 28px; height: 28px;
  border-radius: 50%;
  background: var(--bg-section);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1rem;
  transition: var(--transition);
  flex-shrink: 0;
}

.faq-item.open .faq-icon {
  background: var(--primary);
  color: white;
  transform: rotate(45deg);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.4s ease, padding 0.3s ease;
  padding: 0 24px;
}

.faq-answer.open {
  max-height: 500px;
  padding: 0 24px 20px;
}

.faq-answer p {
  font-size: 0.93rem;
  color: var(--text-secondary);
  line-height: 1.9;
  border-top: 1px solid var(--border-light);
  padding-top: 16px;
}

/* ===================================
   安全指标区
   =================================== */
.safety-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 20px;
}

.safety-card {
  text-align: center;
  background: var(--bg-white);
  border-radius: var(--radius-lg);
  padding: 32px 20px;
  border: 1px solid var(--border-light);
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
}

.safety-card:hover { transform: translateY(-4px); box-shadow: var(--shadow); }

.safety-num {
  font-size: 2.2rem;
  font-weight: 900;
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  line-height: 1;
  margin-bottom: 6px;
}

.safety-unit {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-secondary);
  margin-bottom: 8px;
}

.safety-label {
  font-size: 0.84rem;
  color: var(--text-muted);
  line-height: 1.6;
}

/* ===================================
   面包屑
   =================================== */
.breadcrumb {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.84rem;
  color: var(--text-muted);
  padding: 16px 24px;
  max-width: var(--max-width);
  margin: 0 auto;
}

.breadcrumb a { color: var(--primary); transition: var(--transition-fast); }
.breadcrumb a:hover { color: var(--primary-dark); }
.breadcrumb span { color: var(--text-muted); }

/* ===================================
   CTA 区块
   =================================== */
.cta-section {
  background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 50%, var(--accent) 100%);
  padding: 80px 24px;
  text-align: center;
  color: white;
  position: relative;
  overflow: hidden;
}

.cta-section::before {
  content: '';
  position: absolute;
  inset: 0;
  background: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%23ffffff' fill-opacity='0.04'%3E%3Ccircle cx='30' cy='30' r='4'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
}

.cta-section .container { position: relative; }

.cta-section h2 {
  font-size: clamp(1.6rem, 4vw, 2.4rem);
  font-weight: 800;
  margin-bottom: 14px;
}

.cta-section p {
  font-size: 1.05rem;
  opacity: 0.88;
  max-width: 500px;
  margin: 0 auto 32px;
  line-height: 1.8;
}

.cta-buttons { display: flex; gap: 14px; justify-content: center; flex-wrap: wrap; }

/* ===================================
   页脚
   =================================== */
.footer {
  background: #0f172a;
  color: #94a3b8;
  padding: 60px 24px 32px;
}

.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
}

.footer-top {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 48px;
  padding-bottom: 40px;
  border-bottom: 1px solid #1e293b;
  margin-bottom: 32px;
}

.footer-brand .footer-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 1.1rem;
  color: white;
  margin-bottom: 14px;
}

.footer-logo-icon {
  width: 36px; height: 36px;
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1rem;
}

.footer-brand p {
  font-size: 0.88rem;
  line-height: 1.8;
  max-width: 280px;
}

.footer-col h4 {
  font-size: 0.9rem;
  font-weight: 700;
  color: white;
  margin-bottom: 16px;
}

.footer-col a {
  display: block;
  font-size: 0.85rem;
  margin-bottom: 10px;
  transition: var(--transition-fast);
}

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

.footer-bottom {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.82rem;
  flex-wrap: wrap;
  gap: 12px;
}

.footer-beian {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 20px;
  flex-wrap: wrap;
  margin-top: 12px;
  padding-top: 12px;
  border-top: 1px solid #1e293b;
}
.beian-icp, .beian-gongan {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  color: #94a3b8;
  font-size: 0.82rem;
  text-decoration: none;
  transition: color 0.2s;
}
.beian-icp:hover, .beian-gongan:hover {
  color: #cbd5e1;
}
.footer-disclaimer {
  font-size: 0.8rem;
  color: #475569;
  margin-top: 12px;
  line-height: 1.7;
  padding-top: 12px;
  border-top: 1px solid #1e293b;
}

/* ===================================
   滚动动画
   =================================== */
.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

.reveal-delay-1 { transition-delay: 0.1s; }
.reveal-delay-2 { transition-delay: 0.2s; }
.reveal-delay-3 { transition-delay: 0.3s; }
.reveal-delay-4 { transition-delay: 0.4s; }

/* ===================================
   Tag 标签色
   =================================== */
.tag { display: inline-flex; align-items: center; gap: 6px; padding: 4px 12px; border-radius: 100px; font-size: 0.78rem; font-weight: 600; }
.tag-blue { background: #e0f2fe; color: #0369a1; }
.tag-cyan { background: #ecfeff; color: #0e7490; }
.tag-purple { background: #ede9fe; color: #5b21b6; }
.tag-green { background: #d1fae5; color: #065f46; }
.tag-orange { background: #ffedd5; color: #9a3412; }

/* ===================================
   响应式
   =================================== */
@media (max-width: 768px) {
  :root { --navbar-height: 60px; }

  .nav-menu {
    position: fixed;
    top: var(--navbar-height);
    left: 0; right: 0;
    background: rgba(255,255,255,0.98);
    backdrop-filter: blur(16px);
    flex-direction: column;
    padding: 16px;
    gap: 4px;
    border-bottom: 1px solid var(--border);
    box-shadow: var(--shadow);
    transform: translateY(-100%);
    opacity: 0;
    pointer-events: none;
    transition: var(--transition);
  }

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

  .nav-link { width: 100%; padding: 12px 16px; }
  .nav-toggle { display: flex; }

  .hero-inner {
    grid-template-columns: 1fr;
    gap: 40px;
    text-align: center;
  }

  .hero-desc { margin: 0 auto 32px; }
  .hero-actions { justify-content: center; }
  .hero-stats { justify-content: center; }
  .hero-visual { order: -1; }
  .hero-illustration { max-width: 300px; margin: 0 auto; }

  .section { padding: 56px 20px; }

  .content-grid {
    grid-template-columns: 1fr;
    gap: 40px;
    margin-bottom: 56px;
  }

  .content-grid.reverse { direction: ltr; }

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

  .footer-bottom { flex-direction: column; text-align: center; }

  .cta-buttons { flex-direction: column; align-items: center; }
}

@media (max-width: 480px) {
  .hero-stats { flex-direction: column; gap: 16px; align-items: center; }
  .features-grid { grid-template-columns: 1fr; }
  .safety-grid { grid-template-columns: 1fr 1fr; }
}