@import url('https://fonts.googleapis.com/css2?family=Atkinson+Hyperlegible:wght@400;700&display=swap');

/* ── 基础变量 ── */
:root {
  --c-black: #000000;
  --c-white: #ffffff;
  --c-gray-1: #111111;
  --c-gray-2: #333333;
  --c-gray-3: #666666;
  --c-gray-4: #999999;
  --c-gray-5: #cccccc;
  --c-gray-6: #e8e8e8;
  --c-gray-7: #f4f4f4;
  --unit: 8px;
  --radius-card: 18px;
  --font-body: 'Atkinson Hyperlegible', Helvetica Neue, Helvetica, Arial, sans-serif;
  --nav-h: 64px;
  --transition: 0.18s ease;
  --shadow-card: 0 4px 24px rgba(0,0,0,0.10), 0 1px 4px rgba(0,0,0,0.06);
}

html {
  scroll-behavior: smooth;
  font-size: 17px;
  -webkit-text-size-adjust: 100%;
}

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

body {
  font-family: var(--font-body);
  font-weight: 400;
  line-height: 1.65;
  color: var(--c-black);
  background: var(--c-white);
  overflow-x: hidden;
  max-width: 100vw;
}

body.single-page {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

/* ── 无障碍隐藏 ── */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0,0,0,0);
  white-space: nowrap;
  border: 0;
}

/* ── article 锚点偏移（吸顶导航）── */
article[id] {
  scroll-margin-top: calc(var(--nav-h) + 16px);
}

/* ══════════════════════════════════════
   导航：aside > nav > ul > li > a
   品牌居中，左右各 3 项
══════════════════════════════════════ */
.site-aside-nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--c-black);
  color: var(--c-white);
  width: 100%;
  height: var(--nav-h);
  display: flex;
  align-items: stretch;
  overflow: hidden;
}

.site-aside-nav nav {
  width: 100%;
  max-width: 1440px;
  margin: 0 auto;
  padding: 0 calc(var(--unit) * 3);
  display: flex;
  align-items: center;
  gap: calc(var(--unit) * 2);
  overflow: hidden;
}

.site-aside-nav nav ul {
  list-style: none;
  display: flex;
  align-items: center;
  gap: 0;
  flex: 1;
  min-width: 0;
}

.nav-left {
  justify-content: flex-start;
}

.nav-right {
  justify-content: flex-end;
}

.site-aside-nav nav ul li a {
  display: flex;
  align-items: center;
  padding: 0 calc(var(--unit) * 1.5);
  color: var(--c-white);
  text-decoration: none;
  font-size: 0.82rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  white-space: nowrap;
  min-height: 44px;
  height: 44px;
  border-bottom: 2px solid transparent;
  transition: border-color var(--transition), color var(--transition);
}

.site-aside-nav nav ul li a:hover,
.site-aside-nav nav ul li a:focus-visible {
  border-bottom-color: var(--c-white);
  outline: none;
}

/* 品牌中心 */
.brand-center {
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  padding: 0 calc(var(--unit) * 2);
  text-decoration: none;
  min-height: 44px;
  height: 44px;
}

.site-logo {
  height: 36px;
  width: auto;
  display: block;
}

.site-brand-text {
  font-size: 0.9rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  color: var(--c-white);
  white-space: nowrap;
  border: 2px solid var(--c-white);
  padding: 4px 10px;
  text-transform: none;
  display: inline-block;
}

/* 搜索框 */
.nav-search {
  display: flex;
  align-items: center;
  flex-shrink: 0;
  gap: 0;
  border: 1px solid rgba(255,255,255,0.3);
  border-radius: 4px;
  overflow: hidden;
  height: 40px;
}

.nav-search input {
  background: transparent;
  border: none;
  color: var(--c-white);
  font-family: var(--font-body);
  font-size: 0.82rem;
  padding: 0 10px;
  width: 120px;
  outline: none;
  height: 40px;
  min-height: 40px;
}

.nav-search input::placeholder {
  color: rgba(255,255,255,0.45);
}

.nav-search button {
  background: none;
  border: none;
  color: var(--c-white);
  cursor: pointer;
  padding: 0 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  height: 40px;
  min-height: 40px;
  min-width: 40px;
  transition: background var(--transition);
}

.nav-search button:hover {
  background: rgba(255,255,255,0.1);
}

/* ══════════════════════════════════════
   Hero 区块
══════════════════════════════════════ */
.hero-block {
  background: var(--c-white);
  border-bottom: 2px solid var(--c-black);
  min-height: 45vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: calc(var(--unit) * 5) calc(var(--unit) * 3);
}

.hero-inner {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: calc(var(--unit) * 3);
  text-align: center;
  flex-direction: column;
  max-width: 680px;
  width: 100%;
}

.hero-icon {
  flex-shrink: 0;
  opacity: 0.85;
}

.hero-text h1 {
  font-size: clamp(1.8rem, 5vw, 3.5rem);
  font-weight: 700;
  line-height: 1.15;
  letter-spacing: -0.02em;
  color: var(--c-black);
  margin-bottom: calc(var(--unit) * 1.5);
}

.hero-desc {
  font-size: 1.05rem;
  color: var(--c-gray-2);
  max-width: 520px;
  margin: 0 auto;
}

/* ══════════════════════════════════════
   正文主容器：main > div.wrap > article > section
══════════════════════════════════════ */
main {
  flex: 1;
  min-width: 0;
  width: 100%;
}

main > div.wrap {
  max-width: 900px;
  margin: 0 auto;
  padding: calc(var(--unit) * 6) calc(var(--unit) * 3);
  display: grid;
  grid-template-columns: repeat(12, 1fr);
  gap: calc(var(--unit) * 2);
  box-sizing: border-box;
  width: 100%;
}

main > div.wrap > article {
  grid-column: 1 / -1;
  min-width: 0;
}

main > div.wrap > article > section.content-article {
  font-size: 1rem;
  line-height: 1.75;
  color: var(--c-gray-1);
  word-wrap: break-word;
  overflow-wrap: break-word;
  min-width: 0;
}

/* ── 正文内容排版 ── */
.content-article h2 {
  font-size: clamp(1.2rem, 2.5vw, 1.8rem);
  font-weight: 700;
  letter-spacing: -0.01em;
  margin-top: calc(var(--unit) * 6);
  margin-bottom: calc(var(--unit) * 1.5);
  padding-bottom: calc(var(--unit) * 1);
  border-bottom: 2px solid var(--c-black);
  color: var(--c-black);
}

.content-article h2:first-child {
  margin-top: 0;
}

.content-article h3 {
  font-size: 1.1rem;
  font-weight: 700;
  margin-top: calc(var(--unit) * 4);
  margin-bottom: var(--unit);
  color: var(--c-gray-1);
}

.content-article p {
  margin-bottom: calc(var(--unit) * 2);
}

.content-article p.subtitle,
.content-article p.subhead,
.content-article p.lead,
.content-article p.desc {
  font-size: 1.05rem;
  color: var(--c-gray-3);
  margin-top: calc(var(--unit) * -1);
  margin-bottom: calc(var(--unit) * 2);
  letter-spacing: 0.01em;
}

.content-article ul,
.content-article ol {
  padding-left: calc(var(--unit) * 3);
  margin-bottom: calc(var(--unit) * 2);
}

.content-article li {
  margin-bottom: calc(var(--unit) * 0.75);
}

.content-article blockquote {
  border-left: 4px solid var(--c-black);
  padding: calc(var(--unit) * 2) calc(var(--unit) * 3);
  margin: calc(var(--unit) * 3) 0;
  background: var(--c-gray-7);
  color: var(--c-gray-2);
  font-style: italic;
}

.content-article a {
  color: var(--c-black);
  text-decoration: underline;
  text-underline-offset: 3px;
  transition: opacity var(--transition);
}

.content-article a:hover {
  opacity: 0.6;
}

.content-article img {
  max-width: 100%;
  height: auto;
  border-radius: 4px;
  display: block;
  margin: calc(var(--unit) * 2) 0;
}

.content-article table {
  width: 100%;
  border-collapse: collapse;
  margin: calc(var(--unit) * 3) 0;
  font-size: 0.93rem;
  display: block;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

.content-article th,
.content-article td {
  border: 1px solid var(--c-gray-5);
  padding: calc(var(--unit) * 1.25) calc(var(--unit) * 1.5);
  text-align: left;
  white-space: nowrap;
}

.content-article th {
  background: var(--c-black);
  color: var(--c-white);
  font-weight: 700;
}

.content-article tr:nth-child(even) td {
  background: var(--c-gray-7);
}

/* article 分隔 */
.content-article article {
  padding-top: calc(var(--unit) * 5);
  margin-top: calc(var(--unit) * 5);
  border-top: 1px solid var(--c-gray-6);
  min-width: 0;
}

.content-article article:first-child {
  padding-top: 0;
  margin-top: 0;
  border-top: none;
}

/* ── 副标题约束（build2 自动补 .subtitle）── */
h2 + p.subtitle,
h2 + p.subhead,
h2 + p.desc,
h2 + p.lead {
  color: var(--c-gray-3);
  font-size: 1rem;
  margin-top: calc(var(--unit) * -1);
  margin-bottom: calc(var(--unit) * 2);
}

/* ══════════════════════════════════════
   页脚
══════════════════════════════════════ */
footer {
  background: var(--c-black);
  color: var(--c-white);
  padding-top: calc(var(--unit) * 6);
  width: 100%;
}

/* 大 CTA 块 */
.footer-cta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: calc(var(--unit) * 2);
  max-width: 1200px;
  margin: 0 auto;
  padding: calc(var(--unit) * 4);
  border-bottom: 1px solid rgba(255,255,255,0.15);
  flex-wrap: wrap;
  box-sizing: border-box;
  width: 100%;
}

.footer-cta-text {
  font-size: 1.05rem;
  font-weight: 700;
  letter-spacing: 0.01em;
  color: var(--c-white);
}

.footer-cta-btn {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  padding: 10px 24px;
  background: var(--c-white);
  color: var(--c-black);
  font-family: var(--font-body);
  font-size: 0.9rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  text-decoration: none;
  border-radius: 4px;
  transition: background var(--transition), color var(--transition), transform var(--transition);
  white-space: nowrap;
}

.footer-cta-btn:hover {
  background: var(--c-gray-6);
  transform: translateY(-2px);
}

/* 三栏 dl */
.footer-cols {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: calc(var(--unit) * 4);
  max-width: 1200px;
  margin: 0 auto;
  padding: calc(var(--unit) * 5) calc(var(--unit) * 4);
  border-bottom: 1px solid rgba(255,255,255,0.1);
  box-sizing: border-box;
  width: 100%;
}

.footer-cols dl {
  display: flex;
  flex-direction: column;
  gap: calc(var(--unit) * 1);
  min-width: 0;
}

.footer-cols dt {
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: rgba(255,255,255,0.45);
  margin-bottom: calc(var(--unit) * 0.5);
}

.footer-cols dd {
  font-size: 0.88rem;
  color: rgba(255,255,255,0.8);
  line-height: 1.55;
  margin-left: 0;
  word-wrap: break-word;
  overflow-wrap: break-word;
}

.footer-cols dd a {
  color: rgba(255,255,255,0.8);
  text-decoration: none;
  transition: color var(--transition);
  display: inline-flex;
  min-height: 40px;
  align-items: center;
}

.footer-cols dd a:hover {
  color: var(--c-white);
}

/* 底栏 */
.footer-bottom {
  max-width: 1200px;
  margin: 0 auto;
  padding: calc(var(--unit) * 2.5) calc(var(--unit) * 4);
  text-align: center;
  box-sizing: border-box;
  width: 100%;
}

.footer-bottom p {
  font-size: 0.8rem;
  color: rgba(255,255,255,0.35);
  letter-spacing: 0.03em;
}

/* ══════════════════════════════════════
   卡片（正文内 .card 类，可选）
══════════════════════════════════════ */
.card {
  background: var(--c-white);
  border: 1px solid var(--c-gray-6);
  border-radius: var(--radius-card);
  box-shadow: var(--shadow-card);
  padding: calc(var(--unit) * 3);
  transition: transform var(--transition), box-shadow var(--transition);
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 32px rgba(0,0,0,0.14), 0 2px 8px rgba(0,0,0,0.08);
}

/* ══════════════════════════════════════
   动效
══════════════════════════════════════ */
@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
}

/* 视差辅助 */
.parallax-layer {
  will-change: transform;
}

/* ══════════════════════════════════════
   移动端断点
══════════════════════════════════════ */
@media (max-width: 900px) {
  .footer-cols {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 680px) {
  :root {
    --nav-h: 56px;
  }

  .site-aside-nav {
    overflow: hidden;
  }

  .site-aside-nav nav {
    padding: 0 calc(var(--unit) * 1);
    gap: 4px;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    scrollbar-width: none;
    width: 100%;
    max-width: 100%;
  }

  .site-aside-nav nav::-webkit-scrollbar {
    display: none;
  }

  .site-aside-nav nav ul {
    flex-shrink: 0;
  }

  .site-aside-nav nav ul li a {
    padding: 0 calc(var(--unit) * 0.75);
    font-size: 0.72rem;
    min-height: 44px;
    height: 44px;
  }

  .brand-center {
    flex-shrink: 0;
    padding: 0 6px;
  }

  .site-brand-text {
    font-size: 0.75rem;
    padding: 3px 6px;
    letter-spacing: 0.04em;
  }

  .nav-search {
    flex-shrink: 0;
    height: 40px;
  }

  .nav-search input {
    width: 70px;
    font-size: 0.72rem;
    padding: 0 6px;
    height: 40px;
    min-height: 40px;
  }

  .nav-search button {
    padding: 0 8px;
    height: 40px;
    min-height: 40px;
    min-width: 40px;
  }

  .hero-block {
    min-height: 38vh;
    padding: calc(var(--unit) * 3) calc(var(--unit) * 2);
  }

  .hero-inner {
    gap: calc(var(--unit) * 2);
    width: 100%;
    max-width: 100%;
  }

  .hero-text h1 {
    font-size: 1.6rem;
    word-wrap: break-word;
    overflow-wrap: break-word;
  }

  .hero-desc {
    font-size: 0.95rem;
    max-width: 100%;
  }

  main > div.wrap {
    padding: calc(var(--unit) * 3) calc(var(--unit) * 2);
    grid-template-columns: 1fr;
    gap: var(--unit);
    max-width: 100%;
  }

  .footer-cta {
    flex-direction: column;
    align-items: flex-start;
    padding: calc(var(--unit) * 3) calc(var(--unit) * 2);
    width: 100%;
  }

  .footer-cols {
    grid-template-columns: 1fr;
    padding: calc(var(--unit) * 3) calc(var(--unit) * 2);
    gap: calc(var(--unit) * 3);
    width: 100%;
  }

  .footer-bottom {
    padding: calc(var(--unit) * 2) calc(var(--unit) * 2);
    width: 100%;
  }

  .content-article h2 {
    font-size: 1.2rem;
  }

  .content-article h3 {
    font-size: 1rem;
  }
}

@media (max-width: 400px) {
  .hero-text h1 {
    font-size: 1.4rem;
  }

  .site-brand-text {
    font-size: 0.7rem;
    padding: 2px 5px;
  }

  .nav-search input {
    width: 50px;
  }
}