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

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: system-ui, -apple-system, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  background: #f5f8fe;
  color: #1a2639;
  line-height: 1.6;
  transition: background 0.2s, color 0.2s;
  min-height: 100vh;
  overflow-x: hidden;
}

body.dark {
  background: #0b111f;
  color: #e6edf5;
}

a {
  color: inherit;
  text-decoration: none;
}

img,
svg {
  display: block;
  max-width: 100%;
  height: auto;
}

/* === 容器 === */
.container {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 24px;
}

/* === 毛玻璃效果 === */
.glass {
  background: rgba(255, 255, 255, 0.72);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid rgba(255, 255, 255, 0.25);
  box-shadow: 0 12px 28px -8px rgba(0, 20, 40, 0.12);
  border-radius: 32px;
}

.dark .glass {
  background: rgba(10, 16, 30, 0.7);
  border-color: rgba(255, 255, 255, 0.06);
  box-shadow: 0 12px 28px -8px rgba(0, 0, 0, 0.5);
}

/* === 卡片 === */
.card {
  background: #ffffff;
  border-radius: 28px;
  padding: 24px;
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.04);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.dark .card {
  background: #151e2e;
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.3);
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: 0 16px 32px rgba(0, 0, 0, 0.06);
}

.dark .card:hover {
  box-shadow: 0 16px 32px rgba(0, 0, 0, 0.5);
}

/* === 按钮 === */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: #0b1a2f;
  color: white;
  padding: 12px 28px;
  border-radius: 60px;
  font-weight: 600;
  transition: 0.2s ease;
  border: none;
  cursor: default;
  font-size: 1rem;
}

.dark .btn {
  background: #f0b429;
  color: #0b1a2f;
}

.btn:hover {
  background: #1f3450;
  transform: scale(1.02);
}

.dark .btn:hover {
  background: #f7c84d;
  transform: scale(1.02);
}

/* === 头部 === */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  width: 100%;
  padding: 12px 0;
  background: rgba(255, 255, 255, 0.6);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid rgba(0, 0, 0, 0.02);
  transition: background 0.3s, border-color 0.3s;
}

.dark .site-header {
  background: rgba(11, 17, 31, 0.7);
  border-color: rgba(255, 255, 255, 0.04);
}

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

.logo svg {
  width: 52px;
  height: 52px;
  transition: transform 0.2s;
}

.logo:hover svg {
  transform: rotate(-5deg) scale(1.05);
}

.nav {
  display: flex;
  gap: 20px;
  font-weight: 500;
}

.nav a {
  padding: 8px 0;
  border-bottom: 2px solid transparent;
  transition: 0.15s ease;
  position: relative;
}

.nav a::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 0;
  height: 2px;
  background: #f0b429;
  transition: width 0.25s ease;
}

.nav a:hover::after,
.nav a.active::after {
  width: 100%;
}

.nav a.active,
.nav a:hover {
  color: #0b1a2f;
}

.dark .nav a.active,
.dark .nav a:hover {
  color: #f0b429;
}

.hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 6px;
}

.hamburger span {
  width: 26px;
  height: 3px;
  background: #1a2639;
  border-radius: 4px;
  transition: 0.2s ease;
}

.dark .hamburger span {
  background: #e6edf5;
}

.dark-toggle {
  background: none;
  border: none;
  font-size: 24px;
  cursor: pointer;
  padding: 4px 8px;
  border-radius: 40px;
  transition: transform 0.2s;
}

.dark-toggle:hover {
  transform: rotate(15deg);
}

/* === 移动端导航 === */
@media (max-width: 900px) {
  .nav {
    display: none;
    flex-direction: column;
    background: white;
    position: absolute;
    top: 70px;
    left: 0;
    width: 100%;
    padding: 20px;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.05);
    border-radius: 0 0 28px 28px;
    gap: 8px;
  }

  .dark .nav {
    background: #0f1829;
  }

  .nav.open {
    display: flex;
  }

  .nav a {
    padding: 12px 16px;
    border-radius: 12px;
    border-bottom: none;
  }

  .nav a:hover,
  .nav a.active {
    background: rgba(240, 180, 41, 0.1);
  }

  .hamburger {
    display: flex;
  }
}

/* === Hero 区域 === */
.hero {
  padding: 80px 0 60px;
  background: linear-gradient(145deg, #e9f0fb 0%, #d6e2f5 100%);
  border-radius: 0 0 60px 60px;
  overflow: hidden;
  position: relative;
}

.hero::before {
  content: '';
  position: absolute;
  top: -50%;
  right: -20%;
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, rgba(240, 180, 41, 0.08), transparent 70%);
  border-radius: 50%;
  pointer-events: none;
}

.dark .hero {
  background: #0b1424;
}

.dark .hero::before {
  background: radial-gradient(circle, rgba(240, 180, 41, 0.05), transparent 70%);
}

.hero-grid {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 40px;
}

.hero-text {
  flex: 1 1 400px;
}

.hero-text h1 {
  font-size: 3.2rem;
  font-weight: 700;
  line-height: 1.2;
  letter-spacing: -0.02em;
}

.hero-text .highlight {
  color: #f0b429;
}

.hero-desc {
  font-size: 1.2rem;
  margin: 20px 0 28px;
  opacity: 0.8;
  max-width: 540px;
}

.hero-visual {
  flex: 1 1 300px;
  display: flex;
  justify-content: center;
}

.hero-visual svg {
  width: 100%;
  max-width: 380px;
  height: auto;
  filter: drop-shadow(0 20px 40px rgba(0, 0, 0, 0.1));
  animation: float 6s ease-in-out infinite;
}

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

.dark .hero-visual svg {
  filter: drop-shadow(0 20px 40px rgba(0, 0, 0, 0.4));
}

/* === 通用区块 === */
section {
  padding: 60px 0;
}

.section-title {
  font-size: 2.2rem;
  font-weight: 600;
  margin-bottom: 40px;
  letter-spacing: -0.01em;
  position: relative;
}

.section-title:after {
  content: '';
  display: block;
  width: 60px;
  height: 4px;
  background: #f0b429;
  margin-top: 10px;
  border-radius: 4px;
  transition: width 0.4s ease;
}

.section-title:hover:after {
  width: 100px;
}

/* === 网格 === */
.grid-2 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 32px;
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 28px;
}

.grid-4 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 24px;
}

/* === 统计数字 === */
.stat-number {
  font-size: 2.8rem;
  font-weight: 700;
  color: #0b1a2f;
}

.dark .stat-number {
  color: #f0b429;
}

/* === FAQ === */
.faq-item {
  border-bottom: 1px solid rgba(0, 0, 0, 0.05);
  padding: 18px 0;
  cursor: default;
  transition: background 0.2s;
}

.faq-item:hover {
  background: rgba(240, 180, 41, 0.03);
  border-radius: 8px;
  padding-left: 8px;
  padding-right: 8px;
}

.dark .faq-item {
  border-color: rgba(255, 255, 255, 0.05);
}

.dark .faq-item:hover {
  background: rgba(240, 180, 41, 0.05);
}

.faq-q {
  font-weight: 600;
  display: flex;
  justify-content: space-between;
  align-items: center;
  cursor: pointer;
  user-select: none;
}

.faq-q span {
  transition: transform 0.3s ease;
  font-size: 0.8rem;
}

.faq-item.open .faq-q span {
  transform: rotate(180deg);
}

.faq-a {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.35s ease, opacity 0.3s ease, margin 0.3s ease;
  opacity: 0;
}

.faq-item.open .faq-a {
  max-height: 260px;
  opacity: 1;
  margin-top: 12px;
}

/* === 页脚 === */
.footer {
  background: #0b1a2f;
  color: #cbd5e1;
  padding: 48px 0 24px;
  border-radius: 48px 48px 0 0;
  margin-top: 40px;
}

.dark .footer {
  background: #070c1a;
}

.footer a {
  color: #b0c4de;
  transition: color 0.2s;
}

.footer a:hover {
  color: #f0b429;
}

.footer-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 32px;
}

.footer h4 {
  color: #f0b429;
  margin-bottom: 12px;
}

/* === 滚动动画 === */
.scroll-fade {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.5s cubic-bezier(0.2, 0.9, 0.1, 1),
              transform 0.5s cubic-bezier(0.2, 0.9, 0.1, 1);
}

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

/* === 轮播 === */
.carousel {
  overflow: hidden;
  position: relative;
  border-radius: 28px;
}

.carousel-track {
  display: flex;
  transition: transform 0.5s ease;
}

.carousel-item {
  min-width: 100%;
  padding: 0 8px;
}

.carousel-btn {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  background: rgba(255, 255, 255, 0.5);
  border: none;
  font-size: 28px;
  padding: 8px 16px;
  border-radius: 40px;
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
  cursor: pointer;
  transition: background 0.2s, transform 0.2s;
  z-index: 2;
}

.carousel-btn:hover {
  background: rgba(255, 255, 255, 0.8);
  transform: translateY(-50%) scale(1.1);
}

.dark .carousel-btn {
  background: rgba(0, 0, 0, 0.4);
  color: white;
}

.dark .carousel-btn:hover {
  background: rgba(0, 0, 0, 0.6);
}

.carousel-btn.prev {
  left: 8px;
}

.carousel-btn.next {
  right: 8px;
}

/* === 返回顶部按钮 === */
.back-to-top {
  position: fixed;
  bottom: 30px;
  right: 30px;
  z-index: 200;
  border: none;
  background: #0b1a2f;
  color: white;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  font-size: 24px;
  cursor: pointer;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
  display: none;
  transition: background 0.2s, transform 0.2s, opacity 0.3s;
}

.back-to-top:hover {
  background: #1f3450;
  transform: translateY(-3px);
}

.dark .back-to-top {
  background: #f0b429;
  color: #0b1a2f;
}

.dark .back-to-top:hover {
  background: #f7c84d;
}

/* === 响应式微调 === */
@media (max-width: 640px) {
  .hero-text h1 {
    font-size: 2.4rem;
  }

  .section-title {
    font-size: 1.8rem;
  }

  .hero {
    padding: 60px 0 40px;
    border-radius: 0 0 40px 40px;
  }

  .hero-desc {
    font-size: 1rem;
  }

  .btn {
    padding: 10px 22px;
    font-size: 0.9rem;
  }

  .card {
    padding: 18px;
    border-radius: 20px;
  }

  .footer {
    border-radius: 32px 32px 0 0;
    padding: 32px 0 20px;
  }

  .footer-grid {
    gap: 24px;
  }

  .carousel-btn {
    font-size: 22px;
    padding: 6px 12px;
  }
}

@media (max-width: 480px) {
  .container {
    padding: 0 16px;
  }

  .grid-2,
  .grid-3,
  .grid-4 {
    gap: 20px;
  }

  .hero-text h1 {
    font-size: 2rem;
  }

  .section-title {
    font-size: 1.5rem;
    margin-bottom: 28px;
  }
}

/* === 暗色模式下的细节优化 === */
.dark .card h3 {
  color: #f0b429;
}

.dark .card p {
  color: #b8c7e0;
}

.dark .faq-q {
  color: #e6edf5;
}

.dark .faq-a {
  color: #b8c7e0;
}