/* 基础变量：颜色、内容宽度与字体可在此统一调整。 */
:root {
  --color-ink: #122b4b;
  --color-text: #53647a;
  --color-blue: #2368cc;
  --color-line: #e1e8f0;
  --color-soft: #f6f8fb;
  --color-white: #ffffff;
  --content-width: 1120px;
  --font-sans: "PingFang SC", "Microsoft YaHei", "Noto Sans CJK SC", system-ui, sans-serif;
}

* { box-sizing: border-box; }
body {
  margin: 0;
  color: var(--color-ink);
  background: var(--color-white);
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.8;
  -webkit-text-size-adjust: 100%;
}
a { color: inherit; text-decoration: none; }
svg { display: block; }
h1, h2, h3, p { margin: 0; }
a:focus-visible { outline: 3px solid var(--color-blue); outline-offset: 6px; border-radius: 3px; }
.container { width: min(var(--content-width), calc(100% - 80px)); margin-inline: auto; }
.sr-only, .skip-link:not(:focus) {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  overflow: hidden;
  clip-path: inset(50%);
  white-space: nowrap;
}
.skip-link:focus { position: absolute; z-index: 10; top: 12px; left: 20px; padding: 10px 18px; background: white; }

/* 顶部导航 */
.site-header { border-bottom: 1px solid #edf1f6; }
.header-inner { min-height: 88px; display: flex; align-items: center; justify-content: space-between; gap: 24px; }
.brand { font-size: 25px; font-weight: 750; letter-spacing: 1px; white-space: nowrap; }
.brand span { color: var(--color-blue); }
nav { display: flex; align-items: center; gap: 36px; }
nav a { display: inline-flex; align-items: center; min-height: 44px; font-size: 14px; color: var(--color-text); }
nav a:hover { color: var(--color-blue); }

/* 主视觉：纯 CSS 静态几何装饰，无图片或脚本依赖。 */
.hero { overflow: hidden; background: linear-gradient(112deg, #f7faff 0%, #f0f6fe 58%, #eaf3ff 100%); }
.hero-inner { min-height: 444px; display: flex; align-items: center; justify-content: space-between; gap: 24px; padding-block: 64px; }
.hero-copy { position: relative; z-index: 1; }
.eyebrow { display: flex; align-items: center; gap: 10px; margin-bottom: 22px; font-size: 13px; font-weight: 500; letter-spacing: 2px; color: #45658c; }
.eyebrow > span { width: 6px; height: 6px; border-radius: 50%; background: var(--color-blue); }
h1 { font-size: clamp(36px, 4.1vw, 54px); line-height: 1.4; font-weight: 700; letter-spacing: 1px; }
h1 > span { color: var(--color-blue); }
.hero-description { margin-top: 24px; font-size: 16px; line-height: 1.95; color: var(--color-text); }
.hero-art { position: relative; flex: 0 0 310px; height: 310px; margin-right: 32px; }
.orbit { position: absolute; border: 1px solid #c6dafa; border-radius: 36px; transform: rotate(-30deg); }
.orbit-outer { inset: 15px; }
.orbit-inner { inset: 46px; border-color: #b8d1f5; border-radius: 26px; }
.art-core { position: absolute; inset: 79px; display: flex; align-items: center; justify-content: center; gap: 10px; border: 1px solid #fff; border-radius: 24px; background: linear-gradient(140deg, #ffffffed, #d6e7ffb3); box-shadow: 0 18px 48px #396cb714; transform: rotate(-30deg); }
.art-core span { width: 17px; border-radius: 4px; background: linear-gradient(#74aaf0, #367bd7); }
.art-core span:nth-child(1) { height: 39px; }
.art-core span:nth-child(2) { height: 69px; }
.art-core span:nth-child(3) { height: 51px; }
.art-point { position: absolute; width: 10px; height: 10px; border: 3px solid #f2f7fe; border-radius: 50%; background: #6d9edb; box-sizing: content-box; }
.point-one { top: 33px; right: 61px; }
.point-two { left: 18px; bottom: 68px; }

/* 服务领域 */
.section { padding-block: 64px 68px; scroll-margin-top: 28px; }
.section-heading { display: flex; align-items: center; gap: 32px; margin-bottom: 28px; }
.section-label { margin-bottom: 6px; font-size: 12px; letter-spacing: 2px; font-weight: 500; color: #5a7190; }
h2 { font-size: 28px; font-weight: 650; line-height: 1.5; letter-spacing: 1px; }
.heading-line { height: 1px; flex: 1; background: var(--color-line); }
.service-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 24px; }
.service-card { padding: 28px 28px 30px; border: 1px solid var(--color-line); border-radius: 12px; background: linear-gradient(145deg, #fff 55%, #f9fbff); }
.card-top { display: flex; align-items: center; justify-content: space-between; margin-bottom: 24px; }
.service-icon { width: 34px; height: 34px; color: var(--color-blue); }
.card-number { font-size: 12px; letter-spacing: 1px; color: #6b7f99; font-variant-numeric: tabular-nums; }
.service-card h3 { margin-bottom: 10px; font-size: 19px; line-height: 1.6; font-weight: 600; }
.service-card p { font-size: 14px; line-height: 1.9; color: var(--color-text); }

/* 主体介绍与备案页脚 */
.about { background: var(--color-soft); border-top: 1px solid #edf1f6; }
.about-inner { display: grid; grid-template-columns: 1fr 3fr; gap: 48px; align-items: center; padding-block: 48px; }
.about-copy { padding-left: 40px; border-left: 1px solid #dce4ef; }
.about-copy h3 { margin-bottom: 10px; font-size: 18px; font-weight: 600; overflow-wrap: anywhere; }
.about-copy p { color: var(--color-text); font-size: 14px; }
.site-footer { background: var(--color-ink); color: #e0e8f4; }
.footer-inner { display: flex; flex-wrap: wrap; justify-content: space-between; align-items: center; gap: 8px 32px; min-height: 92px; padding-block: 24px; font-size: 13px; }
.footer-inner p { overflow-wrap: anywhere; }
.footer-inner a { display: inline-flex; align-items: center; gap: 8px; min-height: 44px; text-decoration: underline; text-decoration-color: #8c9fb9; text-underline-offset: 4px; }
.footer-inner a:hover { color: white; }
.footer-inner a:focus-visible { outline-color: #a8ceff; }
.footer-inner svg { width: 15px; height: 15px; flex-shrink: 0; }

/* 平板：保留清晰的文字空间。 */
@media (max-width: 980px) {
  .container { width: calc(100% - 48px); }
  .hero-art { flex-basis: 230px; height: 230px; margin-right: 10px; }
  .orbit-outer { inset: 8px; border-radius: 28px; }
  .orbit-inner { inset: 33px; border-radius: 20px; }
  .art-core { inset: 58px; gap: 8px; border-radius: 18px; }
  .art-core span { width: 13px; }
  .point-one { top: 20px; right: 40px; }
  .point-two { left: 8px; bottom: 48px; }
  .service-grid { gap: 16px; }
  .service-card { padding: 24px 20px; }
  .service-card h3 { font-size: 18px; }
  .about-inner { gap: 24px; }
  .about-copy { padding-left: 28px; }
}

/* 手机：单列卡片，主体与备案信息自然换行，装饰让位于内容。 */
@media (max-width: 680px) {
  .container { width: calc(100% - 40px); }
  .header-inner { min-height: 74px; gap: 16px; }
  .brand { font-size: 22px; letter-spacing: 0; }
  nav { gap: 20px; }
  nav a { font-size: 13px; }
  .hero-inner { min-height: 360px; padding-block: 52px; }
  .hero-art { display: none; }
  .eyebrow { font-size: 11px; letter-spacing: 1.5px; margin-bottom: 22px; }
  h1 { font-size: clamp(30px, 7.6vw, 44px); line-height: 1.5; letter-spacing: 0; }
  .hero-description { font-size: 14px; margin-top: 22px; }
  .desktop-break { display: none; }
  .section { padding-block: 40px; }
  .section-heading { gap: 24px; margin-bottom: 24px; }
  h2 { font-size: 24px; }
  .service-grid { grid-template-columns: 1fr; gap: 16px; }
  .service-card { padding: 24px; }
  .card-top { margin-bottom: 18px; }
  .service-card h3 { font-size: 19px; }
  .about-inner { grid-template-columns: 1fr; gap: 24px; padding-block: 36px; }
  .about-copy { border-left: 0; padding-left: 0; }
  .about-copy h3 { font-size: 17px; }
  .footer-inner { flex-direction: column; align-items: flex-start; gap: 4px; padding-block: 22px; font-size: 12px; }
}