/* ===== 基础 ===== */
:root {
  --primary: #1a3a6b;
  --primary-dark: #12294d;
  --accent: #c9a45c;
  --bg-light: #f6f8fb;
  --text: #333a45;
  --text-light: #6b7280;
  --font-serif: "Noto Serif SC", "Songti SC", "SimSun", serif;
  --font-sans: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
}

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

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-sans);
  color: var(--text);
  line-height: 1.8;
  -webkit-font-smoothing: antialiased;
}

.container { max-width: 1080px; margin: 0 auto; padding: 0 24px; }
.container.narrow { max-width: 800px; }

/* ===== 顶部导航 ===== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid rgba(26, 58, 107, 0.08);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
}

.brand-mark {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: 8px;
  background: var(--primary);
  color: var(--accent);
  font-family: var(--font-serif);
  font-size: 20px;
}

.brand-name {
  font-family: var(--font-serif);
  font-size: 20px;
  font-weight: 700;
  color: var(--primary);
  letter-spacing: 2px;
}

.site-nav a {
  margin-left: 32px;
  text-decoration: none;
  color: var(--text);
  font-size: 15px;
  transition: color 0.2s;
}

.site-nav a:hover { color: var(--primary); }

.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 40px;
  height: 40px;
  padding: 8px;
  border: none;
  background: none;
  cursor: pointer;
}

.nav-toggle span {
  display: block;
  height: 2px;
  background: var(--primary);
  border-radius: 2px;
  transition: transform 0.25s, opacity 0.25s;
}

.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); }

/* ===== 首屏 Banner ===== */
.hero {
  display: flex;
  align-items: center;
  min-height: 480px;
  padding: 96px 0;
  background:
    linear-gradient(135deg, rgba(18, 41, 77, 0.92), rgba(26, 58, 107, 0.85)),
    radial-gradient(circle at 80% 20%, rgba(201, 164, 92, 0.25), transparent 55%);
  background-color: var(--primary-dark);
  text-align: center;
}

.hero-eyebrow {
  color: var(--accent);
  font-size: 15px;
  letter-spacing: 4px;
  margin-bottom: 20px;
}

.hero-title {
  font-family: var(--font-serif);
  color: #fff;
  font-size: clamp(26px, 4.5vw, 44px);
  font-weight: 700;
  letter-spacing: 3px;
  line-height: 1.4;
}

.hero-subtitle {
  margin-top: 20px;
  color: rgba(255, 255, 255, 0.85);
  font-size: clamp(15px, 2vw, 19px);
  letter-spacing: 6px;
}

/* ===== 通用板块 ===== */
.section { padding: 88px 0; }
.section-light { background: var(--bg-light); }

.section-title {
  font-family: var(--font-serif);
  text-align: center;
  font-size: 30px;
  color: var(--primary);
  letter-spacing: 4px;
}

.title-underline {
  width: 48px;
  height: 3px;
  margin: 16px auto 40px;
  background: var(--accent);
  border-radius: 2px;
}

.section-text {
  margin-bottom: 16px;
  font-size: 16px;
  text-align: justify;
}

/* ===== 业务卡片 ===== */
.card-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}

.card {
  padding: 36px 24px;
  background: #fff;
  border: 1px solid rgba(26, 58, 107, 0.08);
  border-radius: 12px;
  text-align: center;
  transition: transform 0.25s, box-shadow 0.25s;
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: 0 12px 28px rgba(26, 58, 107, 0.12);
}

.card-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 56px;
  height: 56px;
  margin: 0 auto 20px;
  border-radius: 50%;
  background: rgba(26, 58, 107, 0.08);
  color: var(--primary);
  font-family: var(--font-serif);
  font-size: 24px;
}

.card-title {
  font-size: 18px;
  color: var(--primary);
  margin-bottom: 12px;
  letter-spacing: 1px;
}

.card-text {
  font-size: 14px;
  color: var(--text-light);
  text-align: justify;
}

/* ===== 页脚 ===== */
.site-footer {
  padding: 32px 0;
  background: var(--primary-dark);
  color: rgba(255, 255, 255, 0.7);
  text-align: center;
  font-size: 14px;
}

.site-footer .beian { margin-top: 8px; }

.site-footer a {
  color: rgba(255, 255, 255, 0.7);
  text-decoration: none;
}

.site-footer a:hover { color: var(--accent); }

/* ===== 响应式 ===== */
@media (max-width: 900px) {
  .card-grid { grid-template-columns: repeat(2, 1fr); }
  .section { padding: 64px 0; }
}

@media (max-width: 600px) {
  .nav-toggle { display: flex; }

  .site-nav {
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    display: none;
    flex-direction: column;
    background: #fff;
    border-bottom: 1px solid rgba(26, 58, 107, 0.1);
    box-shadow: 0 8px 20px rgba(26, 58, 107, 0.1);
  }

  .site-nav.active { display: flex; }

  .site-nav a {
    margin: 0;
    padding: 14px 24px;
    border-top: 1px solid rgba(26, 58, 107, 0.06);
  }

  .card-grid { grid-template-columns: 1fr; }
  .hero { min-height: 400px; padding: 72px 0; }
}