:root {
  --about-ink: #07101f;
  --about-copy: #343c49;
  --about-gold: #dfa94d;
  --about-gold-light: #efc966;
  --about-blue: #081a3d;
  --about-line: #e8eaed;
  --about-header-height: 76px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; background: #fff; color: var(--about-ink); font-family: "PingFang SC", "Microsoft YaHei", Arial, sans-serif; line-height: 1.65; letter-spacing: 0; -webkit-font-smoothing: antialiased; }
body.menu-open { overflow: hidden; }
a { color: inherit; text-decoration: none; -webkit-tap-highlight-color: transparent; }
button { font: inherit; cursor: pointer; -webkit-tap-highlight-color: transparent; }
img { display: block; max-width: 100%; }
.skip-link { position: fixed; z-index: 1000; left: 12px; top: -60px; padding: 8px 14px; background: #fff; }
.skip-link:focus { top: 12px; }

.about-header { position: fixed; z-index: 100; inset: 0 0 auto; height: var(--about-header-height); background: rgba(255,255,255,.98); box-shadow: 0 1px 0 rgba(7,16,31,.07); }
.about-header-inner { width: min(calc(100% - 64px), 1360px); height: 100%; margin: auto; display: flex; align-items: center; }
.about-brand { display: inline-flex; align-items: center; gap: 14px; flex: 0 0 auto; }
.about-brand > img { width: 46px; height: 46px; object-fit: contain; }
.about-brand > span { display: flex; flex-direction: column; line-height: 1; }
.about-brand strong { font-size: 24px; font-weight: 750; }
.about-brand small { margin-top: 7px; color: #6d7370; font-size: 9px; }
.about-main-nav { margin: 0 34px 0 auto; display: flex; gap: clamp(20px, 2.4vw, 42px); align-self: stretch; }
.about-main-nav a { position: relative; min-width: max-content; padding: 24px 0 22px; color: #4c5564; font-size: 17px; font-weight: 650; line-height: 30px; }
.about-main-nav a::after { content: ""; position: absolute; inset: auto 18% 9px; height: 3px; border-radius: 3px; background: var(--about-gold); transform: scaleX(0); transition: transform .2s ease; }
.about-main-nav a:hover, .about-main-nav a.active { color: var(--about-gold); }
.about-main-nav a:hover::after, .about-main-nav a.active::after { transform: scaleX(1); }
.about-phone { display: inline-flex; align-items: center; gap: 8px; font-size: 20px; line-height: 1; }
.about-phone span { color: var(--about-gold); font-size: 22px; }
.about-menu-toggle { display: none; width: 34px; height: 34px; padding: 6px; border: 0; background: transparent; }
.about-menu-toggle span { display: block; width: 21px; height: 2px; margin: 4px 0; border-radius: 2px; background: currentColor; transition: transform .2s ease, opacity .2s ease; }

.about-hero { position: relative; min-height: 620px; margin-top: var(--about-header-height); overflow: hidden; color: #fff; background: #081b43 url('https://files.beihuantu.cn/1780973201015.jpg') center 42% / cover no-repeat; }
.about-hero-shade { position: absolute; inset: 0; background: linear-gradient(180deg, rgba(15,24,62,.7), rgba(1,27,68,.91)); }
.about-hero-inner { position: relative; z-index: 1; width: min(calc(100% - 64px), 1120px); margin: auto; padding: 42px 0 38px; }
.about-hero-logo { width: 122px; height: 69px; margin: 0 auto; object-fit: contain; filter: brightness(0) saturate(100%) invert(78%) sepia(47%) saturate(748%) hue-rotate(354deg) brightness(99%); }
.about-hero h1 { margin: 22px 0 42px; text-align: center; font-size: clamp(28px, 3.1vw, 48px); font-weight: 550; line-height: 1.35; }
.about-promises { display: grid; grid-template-columns: 1fr 1fr; gap: 28px; }
.about-promises article { position: relative; min-height: 154px; padding: 35px 28px 22px; border: 1px solid rgba(255,255,255,.2); border-radius: 22px; background: rgba(85,104,155,.36); backdrop-filter: blur(9px); }
.about-promises h2 { position: absolute; left: 0; top: -24px; margin: 0; padding: 7px 18px; border-radius: 14px; background: #020b1c; color: var(--about-gold-light); font-size: 22px; font-weight: 550; }
.about-promises article > div { height: 100%; display: grid; grid-template-columns: 1fr 1fr; align-content: center; gap: 12px 32px; }
.about-promises span { position: relative; padding-left: 18px; font-size: 21px; }
.about-promises span::before { content: "·"; position: absolute; left: 0; }
.about-stats { margin-top: 46px; display: grid; grid-template-columns: repeat(4, 1fr); text-align: center; }
.about-stats div { position: relative; display: flex; flex-direction: column; }
.about-stats div:not(:last-child)::after { content: ""; position: absolute; right: 0; top: 8px; width: 1px; height: 64px; background: rgba(255,255,255,.18); }
.about-stats strong { font-size: 34px; font-weight: 600; line-height: 1.2; }
.about-stats strong small { font-size: 16px; font-weight: 500; }
.about-stats span { margin-top: 5px; color: rgba(255,255,255,.82); font-size: 17px; }

.about-body { position: relative; z-index: 2; width: min(100%, 1180px); margin: -18px auto 0; padding: 28px 52px 110px; border-radius: 28px 28px 0 0; background: #fff; }
.about-tabs { position: sticky; z-index: 20; top: calc(var(--about-header-height) + 8px); display: grid; grid-template-columns: repeat(3, 1fr); gap: 8px; padding: 8px; border-radius: 16px; background: rgba(247,248,248,.96); backdrop-filter: blur(10px); }
.about-tabs a { height: 62px; display: grid; place-items: center; border-radius: 12px; color: #5b6371; font-size: 23px; font-weight: 550; cursor: pointer; user-select: none; }
.about-tabs a:hover:not(.active) { color: #020b1c; background: rgba(2,11,28,.05); }
.about-tabs a.active { background: #020b1c; color: var(--about-gold-light); }
.about-section { padding: 90px 0 10px; scroll-margin-top: 150px; }
.about-eyebrow { margin: 0 0 10px; color: var(--about-gold); font-size: 12px; font-weight: 700; }
.about-section > h2 { margin: 0 0 28px; font-size: clamp(28px, 3vw, 42px); line-height: 1.4; }
.about-positioning > h2 span { margin-right: 14px; color: var(--about-gold-light); font: 700 64px/0.4 Georgia, serif; vertical-align: -20px; }
.about-copy { color: var(--about-copy); font-size: 18px; line-height: 1.9; }
.about-copy p { margin: 0 0 24px; }
.about-value-grid { margin-top: 48px; display: grid; grid-template-columns: repeat(3, 1fr); gap: 18px; }
.about-value-grid article { min-height: 150px; padding: 28px; border: 1px solid var(--about-line); border-radius: 8px; background: #fafbfc; }
.about-value-grid strong, .about-value-grid span { display: block; }
.about-value-grid strong { color: var(--about-ink); font-size: 22px; }
.about-value-grid span { margin-top: 9px; color: #66707c; font-size: 14px; }
.about-qualifications { border-top: 1px solid var(--about-line); }
.qualification-layout { display: grid; grid-template-columns: 260px 1fr; gap: 54px; align-items: center; padding: 42px; border-radius: 8px; background: #f6f8fb; }
.qualification-icon { height: 220px; display: grid; place-items: center; border-radius: 8px; background: #fff; }
.qualification-icon img { width: 104px; height: 104px; opacity: .78; }
.qualification-copy h3 { margin: 0 0 12px; font-size: 24px; }
.qualification-copy > p { margin: 0 0 26px; color: #66707c; }
.qualification-copy dl { margin: 0; }
.qualification-copy dl div { padding: 10px 0; display: grid; grid-template-columns: 90px 1fr; border-top: 1px solid #e2e6eb; }
.qualification-copy dt { color: #77808c; }
.qualification-copy dd { margin: 0; }
.about-story { border-top: 1px solid var(--about-line); }
.story-list { display: grid; gap: 16px; }
.story-list article { padding: 26px 28px; display: grid; grid-template-columns: 62px 1fr; gap: 24px; border: 1px solid var(--about-line); border-radius: 8px; }
.story-list b { width: 52px; height: 52px; display: grid; place-items: center; border-radius: 6px; background: var(--about-blue); color: var(--about-gold-light); font-size: 18px; }
.story-list h3 { margin: 0 0 5px; font-size: 21px; }
.story-list p { margin: 0; color: #66707c; }
.about-api-copy > :first-child { margin-top: 0; }
.about-api-copy > :last-child { margin-bottom: 0; }
.about-api-copy h3, .about-api-copy h4 { margin: 24px 0 10px; }
.about-api-copy ul, .about-api-copy ol { padding-left: 24px; }
.about-api-gallery { margin-top: 20px; display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 14px; }
.about-api-gallery img { width: 100%; max-height: 420px; border-radius: 8px; object-fit: cover; }
.about-api-timeline { margin-top: 22px; padding: 20px 0 0 22px; border-top: 1px solid #e2e6eb; border-left: 3px solid var(--about-gold); }
.about-api-timeline h4 { margin: 0 0 8px; font-size: 18px; }
.about-footer { padding: 30px max(24px, calc((100vw - 1180px) / 2)); display: flex; gap: 24px; color: rgba(255,255,255,.65); background: #07101f; font-size: 12px; }
.about-footer a { margin-right: auto; color: #fff; font-size: 14px; }

@media (max-width: 1100px) and (min-width: 761px) {
  .about-header-inner { width: calc(100% - 36px); }
  .about-brand > img { width: 38px; height: 38px; }
  .about-brand strong { font-size: 18px; }
  .about-main-nav { margin-right: 18px; gap: 12px; }
  .about-main-nav a { font-size: 13px; }
  .about-phone { gap: 5px; font-size: 14px; }
}

@media (max-width: 760px) {
  :root { --about-header-height: 46px; }
  .about-header-inner { width: 100%; padding: 0 13px; }
  .about-brand { gap: 8px; }
  .about-brand > img { width: 25px; height: 25px; }
  .about-brand strong { font-size: 13px; }
  .about-brand small { display: none; }
  .about-phone { margin-left: auto; gap: 5px; font-size: 12px; }
  .about-phone span { font-size: 14px; }
  .about-menu-toggle { display: block; margin-left: 7px; }
  .about-menu-toggle[aria-expanded="true"] span:nth-child(1) { transform: translateY(6px) rotate(45deg); }
  .about-menu-toggle[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
  .about-menu-toggle[aria-expanded="true"] span:nth-child(3) { transform: translateY(-6px) rotate(-45deg); }
  .about-main-nav { position: fixed; inset: var(--about-header-height) 0 auto; max-height: 0; margin: 0; overflow: hidden; background: #fff; display: flex; flex-direction: column; gap: 0; transition: max-height .25s ease; }
  .about-main-nav.open { max-height: 280px; border-top: 1px solid var(--about-line); box-shadow: 0 12px 26px rgba(0,0,0,.12); }
  .about-main-nav a { padding: 11px 18px; border-bottom: 1px solid var(--about-line); font-size: 13px; line-height: 26px; }
  .about-main-nav a::after { display: none; }

  .about-hero { min-height: 430px; }
  .about-hero-inner { width: 100%; padding: 17px 16px 30px; }
  .about-hero-logo { width: 88px; height: 49px; }
  .about-hero h1 { margin: 15px 0 36px; font-size: 16px; font-weight: 600; white-space: nowrap; }
  .about-promises { gap: 10px; }
  .about-promises article { min-height: 127px; padding: 29px 14px 14px; border-radius: 15px; }
  .about-promises h2 { top: -21px; padding: 5px 10px; border-radius: 10px; font-size: 16px; }
  .about-promises article > div { gap: 6px 10px; }
  .about-promises span { padding-left: 10px; font-size: 14px; white-space: nowrap; }
  .about-stats { margin-top: 34px; }
  .about-stats div:not(:last-child)::after { top: 4px; height: 44px; }
  .about-stats strong { font-size: 22px; }
  .about-stats strong small { font-size: 10px; }
  .about-stats span { font-size: 12px; }

  .about-body { width: 100%; margin-top: -20px; padding: 17px 16px 70px; border-radius: 18px 18px 0 0; }
  .about-tabs { top: calc(var(--about-header-height) + 5px); gap: 4px; padding: 4px; border-radius: 12px; }
  .about-tabs a { height: 46px; border-radius: 9px; font-size: 16px; }
  .about-section { padding-top: 60px; scroll-margin-top: 108px; }
  .about-eyebrow { font-size: 9px; }
  .about-section > h2 { margin-bottom: 18px; font-size: 22px; }
  .about-positioning > h2 { font-size: 21px; white-space: nowrap; }
  .about-positioning > h2 span { margin-right: 6px; font-size: 44px; vertical-align: -15px; }
  .about-copy { font-size: 16px; line-height: 1.8; }
  .about-copy p { margin-bottom: 22px; }
  .about-value-grid { margin-top: 32px; grid-template-columns: 1fr; gap: 10px; }
  .about-value-grid article { min-height: 0; padding: 20px; }
  .about-value-grid strong { font-size: 18px; }
  .qualification-layout { grid-template-columns: 1fr; gap: 20px; padding: 22px; }
  .qualification-icon { height: 150px; }
  .qualification-icon img { width: 78px; height: 78px; }
  .qualification-copy h3 { font-size: 19px; }
  .qualification-copy dl div { grid-template-columns: 74px 1fr; font-size: 13px; }
  .story-list article { padding: 20px; grid-template-columns: 44px 1fr; gap: 14px; }
  .story-list b { width: 42px; height: 42px; }
  .story-list h3 { font-size: 18px; }
  .story-list p { font-size: 14px; }
  .about-api-gallery { grid-template-columns: 1fr; }
  .about-api-timeline { padding-left: 14px; }
  .about-footer { padding: 26px 16px; flex-direction: column; gap: 5px; }
}

@media (max-width: 350px) {
  .about-hero h1 { font-size: 15px; }
  .about-promises span { font-size: 12px; }
  .about-positioning > h2 { font-size: 18px; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition-duration: .01ms !important; }
}