/* ===== 全局重置 & 变量 ===== */
*, *::before, *::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root {
  --bg: #f4f7fc;
  --text: #1b2a3a;
  --primary: #0b1a2e;
  --accent: #f0b429;
  --glass: rgba(255,255,255,0.55);
  --shadow: 0 12px 30px rgba(0,0,0,0.06);
  --radius: 28px;
  --card-bg: #ffffff;
  --nav-bg: rgba(255,255,255,0.78);
  --footer-bg: #0b1a2e;
  --footer-text: #d0d9e6;
  --gradient-hero: linear-gradient(145deg, #0b1a2e 0%, #1f3450 100%);
  --gradient-card: linear-gradient(135deg, #0b1a2e, #1f3450);
  --transition-base: 0.25s ease;
  --transition-hover: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

body.dark {
  --bg: #0e141f;
  --text: #e8edf5;
  --card-bg: #1a2538;
  --glass: rgba(20,32,50,0.7);
  --nav-bg: rgba(14,20,31,0.88);
  --shadow: 0 12px 30px rgba(0,0,0,0.5);
  --gradient-hero: linear-gradient(145deg, #0a111f 0%, #152238 100%);
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: system-ui, -apple-system, 'Segoe UI', Roboto, 'Helvetica Neue', sans-serif;
  background: var(--bg);
  color: var(--text);
  transition: background var(--transition-base), color 0.2s;
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* ===== 通用容器 ===== */
.wrapper {
  max-width: 1400px;
  margin: 0 auto;
  padding: 0 28px;
}

/* ===== 毛玻璃效果 ===== */
.glass {
  background: var(--glass);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  border: 1px solid rgba(255,255,255,0.08);
}

/* ===== 头部导航 ===== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  padding: 12px 0;
  background: var(--nav-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid rgba(255,255,255,0.08);
  transition: background var(--transition-base);
}

.header-grid {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
}

.logo svg {
  height: 40px;
  width: auto;
  display: block;
  transition: transform 0.3s ease;
}

.logo:hover svg {
  transform: scale(1.03);
}

.nav-menu {
  display: flex;
  gap: 1.2rem;
  align-items: center;
  flex-wrap: wrap;
}

.nav-menu a {
  text-decoration: none;
  color: var(--text);
  font-weight: 500;
  padding: 6px 10px;
  border-radius: 40px;
  transition: all var(--transition-hover);
  font-size: 0.95rem;
  position: relative;
}

.nav-menu a::after {
  content: '';
  position: absolute;
  bottom: 2px;
  left: 50%;
  width: 0;
  height: 2px;
  background: var(--accent);
  transition: all 0.3s ease;
  transform: translateX(-50%);
  border-radius: 2px;
}

.nav-menu a:hover::after,
.nav-menu a.active::after {
  width: 60%;
}

.nav-menu a:hover,
.nav-menu a.active {
  background: var(--accent);
  color: #0b1a2e;
}

.dark-toggle {
  background: transparent;
  border: 1px solid var(--text);
  color: var(--text);
  border-radius: 40px;
  padding: 6px 14px;
  cursor: pointer;
  font-size: 0.9rem;
  font-weight: 500;
  transition: all var(--transition-hover);
}

.dark-toggle:hover {
  background: var(--accent);
  color: #0b1a2e;
  border-color: var(--accent);
  transform: scale(1.02);
}

.mobile-menu-btn {
  display: none;
  background: none;
  border: none;
  font-size: 1.8rem;
  color: var(--text);
  cursor: pointer;
  padding: 4px 8px;
  transition: transform 0.2s;
}

.mobile-menu-btn:hover {
  transform: scale(1.1);
}

@media (max-width: 900px) {
  .nav-menu {
    display: none;
    width: 100%;
    flex-direction: column;
    padding: 20px 0 10px;
    gap: 0.8rem;
    background: var(--nav-bg);
    backdrop-filter: blur(16px);
    border-radius: 0 0 var(--radius) var(--radius);
    margin-top: 8px;
  }
  .nav-menu.show {
    display: flex;
  }
  .mobile-menu-btn {
    display: block;
  }
}

/* ===== Hero 横幅 ===== */
.hero {
  padding: 50px 0 30px;
}

.hero-banner {
  background: var(--gradient-hero);
  border-radius: var(--radius);
  padding: 60px 40px;
  color: white;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  box-shadow: 0 20px 40px rgba(0,0,0,0.25);
  position: relative;
  overflow: hidden;
}

.hero-banner::before {
  content: '';
  position: absolute;
  top: -50%;
  right: -20%;
  width: 60%;
  height: 200%;
  background: radial-gradient(circle, rgba(240,180,41,0.08) 0%, transparent 70%);
  pointer-events: none;
}

.hero-text {
  max-width: 600px;
  position: relative;
  z-index: 1;
}

.hero-text h1 {
  font-size: 2.8rem;
  font-weight: 700;
  line-height: 1.2;
  margin-bottom: 20px;
  letter-spacing: -0.02em;
  background: linear-gradient(135deg, #fff 30%, var(--accent) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-text p {
  font-size: 1.2rem;
  opacity: 0.85;
  margin-bottom: 30px;
  line-height: 1.6;
}

.hero-cta {
  display: inline-block;
  background: var(--accent);
  color: #0b1a2e;
  padding: 14px 36px;
  border-radius: 60px;
  font-weight: 600;
  text-decoration: none;
  transition: all var(--transition-hover);
  position: relative;
  overflow: hidden;
}

.hero-cta::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(255,255,255,0.3), transparent);
  transition: left 0.5s;
}

.hero-cta:hover::before {
  left: 100%;
}

.hero-cta:hover {
  transform: scale(1.02);
  box-shadow: 0 8px 20px rgba(240,180,41,0.3);
}

.hero-visual svg {
  width: 280px;
  height: auto;
  filter: drop-shadow(0 0 20px rgba(240,180,41,0.2));
  animation: float 4s ease-in-out infinite;
}

@keyframes float {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-10px); }
}

@media (max-width: 700px) {
  .hero-text h1 {
    font-size: 2rem;
  }
  .hero-banner {
    padding: 40px 20px;
  }
  .hero-visual svg {
    width: 180px;
  }
}

/* ===== 通用区块 ===== */
section {
  padding: 50px 0;
}

.section-title {
  font-size: 2.2rem;
  font-weight: 600;
  margin-bottom: 30px;
  letter-spacing: -0.01em;
  border-left: 6px solid var(--accent);
  padding-left: 20px;
  position: relative;
}

.section-title::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 20px;
  width: 60px;
  height: 3px;
  background: var(--accent);
  border-radius: 3px;
}

/* ===== 卡片网格 ===== */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 28px;
}

.card {
  background: var(--card-bg);
  border-radius: var(--radius);
  padding: 24px;
  box-shadow: var(--shadow);
  transition: all var(--transition-hover);
  border: 1px solid rgba(255,255,255,0.05);
  position: relative;
  overflow: hidden;
}

.card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 4px;
  background: var(--accent);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.4s ease;
}

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

.card:hover {
  transform: translateY(-6px);
  box-shadow: 0 20px 40px rgba(0,0,0,0.08);
}

body.dark .card:hover {
  box-shadow: 0 20px 40px rgba(0,0,0,0.3);
}

.card-icon svg {
  width: 48px;
  height: 48px;
  margin-bottom: 12px;
  transition: transform 0.3s ease;
}

.card:hover .card-icon svg {
  transform: scale(1.1) rotate(-5deg);
}

.stat-number {
  font-size: 2.6rem;
  font-weight: 700;
  color: var(--accent);
  line-height: 1.2;
}

.badge {
  background: var(--accent);
  color: #0b1a2e;
  padding: 2px 14px;
  border-radius: 40px;
  font-weight: 500;
  font-size: 0.8rem;
  display: inline-block;
  transition: all 0.3s ease;
  cursor: default;
}

.badge:hover {
  transform: scale(1.05);
  box-shadow: 0 2px 10px rgba(240,180,41,0.3);
}

/* ===== 页脚 ===== */
.site-footer {
  background: var(--footer-bg);
  color: var(--footer-text);
  padding: 50px 0 30px;
  border-radius: var(--radius) var(--radius) 0 0;
  margin-top: 40px;
}

.footer-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(180px,1fr));
  gap: 30px;
}

.footer-grid a {
  color: #b0c4dd;
  text-decoration: none;
  display: block;
  margin: 6px 0;
  font-size: 0.9rem;
  transition: all 0.2s;
  position: relative;
  padding-left: 0;
}

.footer-grid a:hover {
  color: var(--accent);
  padding-left: 4px;
}

.copyright {
  border-top: 1px solid #273a50;
  margin-top: 40px;
  padding-top: 24px;
  text-align: center;
  font-size: 0.9rem;
}

/* ===== FAQ ===== */
.faq-item {
  background: var(--card-bg);
  border-radius: 20px;
  margin-bottom: 12px;
  padding: 18px 22px;
  cursor: pointer;
  transition: all var(--transition-hover);
  box-shadow: var(--shadow);
  border: 1px solid transparent;
}

.faq-item:hover {
  border-color: var(--accent);
  transform: translateX(4px);
}

.faq-question {
  font-weight: 600;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 1.05rem;
}

.faq-question span {
  font-size: 1.4rem;
  transition: transform 0.3s ease;
  color: var(--accent);
}

.faq-item.open .faq-question span {
  transform: rotate(45deg);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.4s ease, opacity 0.3s ease, margin 0.3s ease;
  margin-top: 0;
  opacity: 0;
  color: #4a5a6e;
  line-height: 1.6;
}

.faq-item.open .faq-answer {
  max-height: 240px;
  margin-top: 12px;
  opacity: 1;
}

body.dark .faq-answer {
  color: #b0c4dd;
}

/* ===== 返回顶部 ===== */
.back-top {
  position: fixed;
  bottom: 30px;
  right: 30px;
  background: var(--accent);
  color: #0b1a2e;
  border: none;
  border-radius: 60px;
  padding: 12px 18px;
  font-weight: 600;
  cursor: pointer;
  box-shadow: 0 6px 20px rgba(0,0,0,0.2);
  z-index: 200;
  transition: all var(--transition-hover);
  opacity: 0;
  transform: translateY(20px);
  pointer-events: none;
}

.back-top.show {
  opacity: 1;
  transform: translateY(0);
  pointer-events: auto;
}

.back-top:hover {
  transform: scale(1.05) translateY(-2px);
  box-shadow: 0 8px 25px rgba(240,180,41,0.4);
}

/* ===== 滚动动画 ===== */
.fade-up {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.6s ease-out, transform 0.6s ease-out;
}

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

/* ===== 卡片内链接 ===== */
.card a {
  color: var(--accent);
  text-decoration: none;
  font-weight: 500;
  transition: all 0.2s;
  display: inline-block;
}

.card a:hover {
  text-decoration: underline;
  transform: translateX(4px);
}

/* ===== 暗色模式微调 ===== */
body.dark .card {
  background: #1a2538;
  border-color: #2a3a50;
}

body.dark .site-header {
  background: rgba(14,20,31,0.9);
}

body.dark .badge {
  color: #0b1a2e;
}

body.dark .hero-cta {
  color: #0b1a2e;
}

/* ===== 响应式微调 ===== */
@media (max-width: 600px) {
  .wrapper {
    padding: 0 16px;
  }
  
  .section-title {
    font-size: 1.6rem;
    padding-left: 14px;
  }
  
  .card-grid {
    gap: 16px;
  }
  
  .card {
    padding: 18px;
  }
  
  .footer-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 20px;
  }
  
  .back-top {
    bottom: 16px;
    right: 16px;
    padding: 10px 14px;
    font-size: 0.85rem;
  }
}

/* ===== 图片/媒体自适应 ===== */
img, svg, video {
  max-width: 100%;
  height: auto;
  display: block;
}

/* ===== 焦点样式 ===== */
a:focus-visible,
button:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

/* ===== 打印样式 ===== */
@media print {
  .site-header,
  .back-top,
  .dark-toggle,
  .mobile-menu-btn {
    display: none;
  }
  
  body {
    background: white;
    color: black;
  }
  
  .card {
    box-shadow: none;
    border: 1px solid #ddd;
  }
}