:root {
  --bg: #ffffff;
  --bg-soft: #f7f9fb;
  --text: #16202c;
  --text-soft: #5b6b7c;
  --border: #e4e9f0;
  --accent: #1f6feb;
  --accent-soft: #eaf1fe;
  --radius: 12px;
  --wrap: 880px;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  font-size: 16px;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

.wrap {
  width: 100%;
  max-width: var(--wrap);
  margin: 0 auto;
  padding: 0 24px;
}

/* ---------- 顶栏 ---------- */

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  background: rgba(255, 255, 255, 0.9);
  -webkit-backdrop-filter: saturate(180%) blur(12px);
  backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid var(--border);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 62px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--text);
  text-decoration: none;
  font-size: 15.5px;
  font-weight: 600;
  letter-spacing: -0.005em;
}

.brand-mark {
  width: 20px;
  height: 20px;
  border-radius: 6px;
  background: linear-gradient(135deg, #1f6feb 0%, #5b9bf5 100%);
  box-shadow: 0 1px 3px rgba(31, 111, 235, 0.35);
}

.site-nav {
  display: flex;
  gap: 26px;
}

.site-nav a {
  color: var(--text-soft);
  text-decoration: none;
  font-size: 14.5px;
  padding: 4px 0;
  border-bottom: 1.5px solid transparent;
  transition: color 0.18s ease, border-color 0.18s ease;
}

.site-nav a:hover {
  color: var(--accent);
  border-bottom-color: var(--accent);
}

/* ---------- 首屏 ---------- */

.hero {
  padding: 92px 0 76px;
  background: linear-gradient(180deg, #fbfcfe 0%, #ffffff 100%);
  border-bottom: 1px solid var(--border);
}

.eyebrow {
  margin: 0 0 14px;
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.16em;
  color: var(--accent);
}

.hero h1 {
  margin: 0 0 18px;
  font-size: clamp(30px, 4.6vw, 42px);
  line-height: 1.25;
  letter-spacing: -0.01em;
  font-weight: 650;
}

.lede {
  margin: 0;
  max-width: 620px;
  font-size: 17px;
  color: var(--text-soft);
}

.hero-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin: 30px 0 0;
  padding: 0;
  list-style: none;
}

.hero-tags li {
  padding: 5px 13px;
  border-radius: 999px;
  background: var(--accent-soft);
  color: #1858c4;
  font-size: 13.5px;
  line-height: 1.6;
}

/* ---------- 内容区块 ---------- */

.section {
  padding: 66px 0;
  scroll-margin-top: 78px;
}

.section-alt {
  background: var(--bg-soft);
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}

.section h2 {
  margin: 0 0 26px;
  font-size: 22px;
  font-weight: 620;
  letter-spacing: -0.005em;
}

.section h2::after {
  content: "";
  display: block;
  width: 30px;
  height: 3px;
  margin-top: 12px;
  border-radius: 2px;
  background: var(--accent);
}

.section p {
  margin: 0 0 16px;
  max-width: 680px;
  color: var(--text-soft);
}

.section p:last-child {
  margin-bottom: 0;
}

/* ---------- 卡片 ---------- */

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 16px;
}

.card {
  padding: 22px;
  background: #ffffff;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  transition: border-color 0.18s ease, box-shadow 0.18s ease, transform 0.18s ease;
}

.card:hover {
  border-color: #c9dbf8;
  box-shadow: 0 6px 18px rgba(23, 43, 77, 0.07);
  transform: translateY(-2px);
}

.card h3 {
  margin: 0 0 8px;
  font-size: 16px;
  font-weight: 620;
}

.card p {
  margin: 0;
  max-width: none;
  font-size: 14.5px;
  line-height: 1.7;
}

/* ---------- 联系 ---------- */

.email {
  display: inline-block;
  margin-top: 4px !important;
  padding: 9px 16px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: #ffffff;
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 14.5px;
  color: var(--text);
}

/* ---------- 页脚 ---------- */

.site-footer {
  padding: 40px 0 52px;
  background: var(--bg-soft);
  border-top: 1px solid var(--border);
  text-align: center;
}

.site-footer p {
  margin: 0 0 8px;
  font-size: 13.5px;
  color: var(--text-soft);
}

.site-footer p:last-child {
  margin-bottom: 0;
}

.site-footer .copyright {
  color: var(--text);
  font-weight: 500;
}

/* 备案信息：管局要求在页面底部显著位置展示，并链接到工信部备案官网首页 */
.site-footer .filings {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  align-items: center;
  gap: 6px 20px;
  margin-top: 14px;
  padding-top: 14px;
  border-top: 1px solid var(--border);
}

.site-footer .filing {
  font-size: 13.5px;
  color: var(--text-soft);
  text-decoration: none;
  transition: color 0.18s ease;
}

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

/* ---------- 响应式 ---------- */

@media (max-width: 640px) {
  .site-nav {
    display: none;
  }

  .hero {
    padding: 64px 0 54px;
  }

  .section {
    padding: 50px 0;
  }

  .wrap {
    padding: 0 20px;
  }
}