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

/* ============================================
   CSS 自定义属性
   ============================================ */
:root {
  --color-paper: #fdfbf7;
  --color-paper-alt: #f5f5f5;
  --color-ink: #1a1a1a;
  --color-ink-muted: #4a4a4a;
  --color-ink-faint: #8a8a8a;
  --color-border: #d8d4cc;
  --color-border-light: #e8e4de;
  --color-accent: #2c2c2c;
  --color-accent-hover: #1a1a1a;
  --font-main: 'Atkinson Hyperlegible', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-serif: Georgia, 'Times New Roman', serif;
  --radius-pill: 999px;
  --radius-card: 28px;
  --shadow-card: 0 2px 12px rgba(26,26,26,0.08), 0 1px 3px rgba(26,26,26,0.05);
  --header-h: 68px;
  --anchor-h: 44px;
  --transition: none;
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation: none !important;
    transition: none !important;
  }
}

body {
  font-family: var(--font-main);
  background-color: var(--color-paper);
  color: var(--color-ink);
  line-height: 1.7;
  min-height: 100vh;
  position: relative;
  overflow-x: hidden;
}

/* ============================================
   纸张纹理
   ============================================ */
.paper-texture {
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 1000;
  opacity: 0.028;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='300' height='300'%3E%3Cfilter id='noise'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.85' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='300' height='300' filter='url(%23noise)'/%3E%3C/svg%3E");
  background-repeat: repeat;
}

img {
  display: block;
  max-width: 100%;
  height: auto;
}

ul, ol { list-style: none; }

a {
  color: inherit;
  text-decoration: none;
}

/* ============================================
   scroll-margin for sticky nav
   ============================================ */
section[id] {
  scroll-margin-top: calc(var(--header-h) + var(--anchor-h) + 12px);
}

/* ============================================
   页头
   ============================================ */
.site-header {
  position: sticky;
  top: 0;
  z-index: 200;
  background: var(--color-paper);
  border-bottom: 1px solid var(--color-border);
  height: var(--header-h);
}

.header-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
  height: 100%;
  display: flex;
  align-items: center;
  position: relative;
}

/* 桌面导航 */
.nav-desktop {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
}

.nav-left,
.nav-right {
  display: flex;
  align-items: center;
  gap: 6px;
  flex-wrap: wrap;
}

.nav-pill {
  display: inline-flex;
  align-items: center;
  height: 36px;
  padding: 0 14px;
  border-radius: var(--radius-pill);
  border: 1px solid var(--color-border);
  font-size: 13px;
  font-weight: 400;
  color: var(--color-ink);
  background: transparent;
  white-space: nowrap;
  cursor: pointer;
}

.nav-pill:hover {
  background: var(--color-paper-alt);
  border-color: var(--color-ink-muted);
}

/* 品牌居中 */
.brand-center {
  position: absolute;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  align-items: center;
  gap: 8px;
  text-decoration: none;
}

.brand-mark {
  height: 36px;
  width: auto;
}

.brand-text {
  font-size: 17px;
  font-weight: 700;
  letter-spacing: 0.04em;
  color: var(--color-ink);
  white-space: nowrap;
}

/* 移动端 details/summary 导航 */
.nav-details {
  display: none;
  position: relative;
}

.nav-toggle {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 44px;
  height: 44px;
  cursor: pointer;
  list-style: none;
  padding: 10px;
  border: 1px solid var(--color-border);
  border-radius: 8px;
  background: transparent;
}

.nav-toggle::-webkit-details-marker { display: none; }

.toggle-bar {
  display: block;
  width: 20px;
  height: 2px;
  background: var(--color-ink);
  border-radius: 2px;
}

menu.nav-mobile-menu {
  position: absolute;
  top: calc(100% + 8px);
  left: 0;
  background: var(--color-paper);
  border: 1px solid var(--color-border);
  border-radius: 12px;
  padding: 8px;
  min-width: 200px;
  box-shadow: var(--shadow-card);
  z-index: 300;
  display: block;
}

menu.nav-mobile-menu li { display: block; }

menu.nav-mobile-menu li a {
  display: block;
  padding: 10px 16px;
  font-size: 15px;
  color: var(--color-ink);
  border-radius: 8px;
  min-height: 40px;
  line-height: 1.4;
}

menu.nav-mobile-menu li a:hover {
  background: var(--color-paper-alt);
}

/* ============================================
   粘性锚点条
   ============================================ */
.sticky-anchor-bar {
  position: sticky;
  top: var(--header-h);
  z-index: 190;
  background: var(--color-paper-alt);
  border-bottom: 1px solid var(--color-border-light);
  height: var(--anchor-h);
  overflow: hidden;
}

.anchor-bar-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
  height: 100%;
  display: flex;
  align-items: center;
  gap: 4px;
  overflow-x: auto;
  scrollbar-width: none;
  -ms-overflow-style: none;
}

.anchor-bar-inner::-webkit-scrollbar { display: none; }

.anchor-pill {
  display: inline-flex;
  align-items: center;
  height: 30px;
  padding: 0 12px;
  border-radius: var(--radius-pill);
  font-size: 12px;
  color: var(--color-ink-muted);
  white-space: nowrap;
  border: 1px solid transparent;
  flex-shrink: 0;
}

.anchor-pill:hover {
  color: var(--color-ink);
  border-color: var(--color-border);
  background: var(--color-paper);
}

/* ============================================
   主体结构
   ============================================ */
main {
  min-height: 60vh;
}

main > div.wrap {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ============================================
   Hero 区块
   ============================================ */
.hero-section {
  padding: 60px 0 48px;
  border-bottom: 1px solid var(--color-border-light);
}

.hero-article {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 48px;
  align-items: center;
  min-height: calc(70vh - var(--header-h) - var(--anchor-h));
}

.hero-text {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 20px;
}

.hero-badge {
  display: inline-block;
  padding: 4px 14px;
  border: 1px solid var(--color-ink);
  border-radius: var(--radius-pill);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--color-ink);
  background: transparent;
  text-transform: none;
}

.hero-h1 {
  font-size: clamp(28px, 4vw, 52px);
  font-weight: 700;
  line-height: 1.2;
  letter-spacing: -0.01em;
  color: var(--color-ink);
}

.hero-lead {
  font-size: 17px;
  line-height: 1.7;
  color: var(--color-ink-muted);
  max-width: 480px;
}

.hero-cta {
  display: inline-flex;
  align-items: center;
  height: 48px;
  padding: 0 28px;
  background: var(--color-ink);
  color: var(--color-paper);
  border-radius: var(--radius-pill);
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.02em;
  border: 2px solid var(--color-ink);
  min-height: 44px;
}

.hero-cta:hover {
  background: var(--color-accent);
  border-color: var(--color-accent);
}

.hero-media {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
}

.hero-img {
  width: 100%;
  max-height: 480px;
  object-fit: cover;
  border-radius: var(--radius-card);
  border: 1px solid var(--color-border);
}

.hero-placeholder {
  width: 100%;
  aspect-ratio: 4/3;
  background: var(--color-paper-alt);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-card);
  display: flex;
  align-items: center;
  justify-content: center;
}

.hero-placeholder-inner {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
}

.hero-placeholder-icon {
  font-size: 64px;
  line-height: 1;
  opacity: 0.6;
}

.hero-placeholder-label {
  font-size: 18px;
  font-weight: 700;
  color: var(--color-ink-muted);
  letter-spacing: 0.06em;
}

.hero-float-badge {
  position: absolute;
  top: -12px;
  right: -12px;
  width: 64px;
  height: 64px;
  border-radius: 50%;
  background: var(--color-ink);
  color: var(--color-paper);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.08em;
  border: 3px solid var(--color-paper);
  box-shadow: 0 2px 8px rgba(26,26,26,0.15);
}

/* ============================================
   正文内容区
   ============================================ */
.content-section {
  padding: 56px 0;
}

.content-article {
  display: block;
}

.content-with-aside {
  display: grid;
  grid-template-columns: 1fr 280px;
  gap: 48px;
  align-items: flex-start;
}

.content-main {
  min-width: 0;
}

/* 正文内容排版 */
.content-main h2 {
  font-size: 24px;
  font-weight: 700;
  line-height: 1.3;
  margin-top: 48px;
  margin-bottom: 16px;
  color: var(--color-ink);
  border-bottom: 2px solid var(--color-ink);
  padding-bottom: 8px;
}

.content-main h3 {
  font-size: 19px;
  font-weight: 700;
  line-height: 1.4;
  margin-top: 32px;
  margin-bottom: 12px;
  color: var(--color-ink);
}

.content-main p {
  font-size: 16px;
  line-height: 1.8;
  color: var(--color-ink);
  margin-bottom: 16px;
}

.content-main ul,
.content-main ol {
  margin-bottom: 16px;
  padding-left: 0;
}

.content-main ul li,
.content-main ol li {
  font-size: 16px;
  line-height: 1.7;
  color: var(--color-ink);
  padding: 4px 0 4px 20px;
  position: relative;
  list-style: none;
}

.content-main ul li::before {
  content: '—';
  position: absolute;
  left: 0;
  color: var(--color-ink-muted);
  font-size: 14px;
}

.content-main ol { counter-reset: ol-counter; }

.content-main ol li::before {
  content: counter(ol-counter) '.';
  counter-increment: ol-counter;
  position: absolute;
  left: 0;
  color: var(--color-ink-muted);
  font-size: 13px;
  font-weight: 700;
  top: 5px;
}

.content-main article {
  padding-top: 16px;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--color-border-light);
}

.content-main article:last-child {
  border-bottom: none;
}

.content-main a {
  color: var(--color-ink);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.content-main a:hover {
  color: var(--color-ink-muted);
}

.content-main small {
  display: block;
  font-size: 12px;
  color: var(--color-ink-faint);
  letter-spacing: 0.08em;
  margin-bottom: 4px;
}

.content-main h2 + small,
.content-main small + h2 { margin-top: 0; }

/* small 眉题紧邻 h2/h3 */
.content-main small:has(+ h2),
.content-main small:has(+ h3) {
  margin-bottom: 2px;
}

/* ============================================
   侧边栏
   ============================================ */
.content-aside {
  display: flex;
  flex-direction: column;
  gap: 20px;
  position: sticky;
  top: calc(var(--header-h) + var(--anchor-h) + 16px);
}

.aside-card {
  background: var(--color-paper);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-card);
  padding: 24px;
  backdrop-filter: blur(0px);
  box-shadow: var(--shadow-card);
  /* 玻璃拟态变体（纸质感适配） */
  background: rgba(253, 251, 247, 0.92);
}

.aside-card--info {
  background: rgba(245, 245, 245, 0.85);
}

.aside-eyebrow {
  display: block;
  font-size: 11px;
  letter-spacing: 0.12em;
  color: var(--color-ink-faint);
  margin-bottom: 6px;
  text-transform: none;
}

.aside-title {
  font-size: 15px;
  font-weight: 700;
  color: var(--color-ink);
  margin-bottom: 14px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--color-border-light);
}

.aside-nav-list {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.aside-link {
  display: block;
  padding: 7px 10px;
  font-size: 13px;
  color: var(--color-ink-muted);
  border-radius: 8px;
  line-height: 1.4;
  min-height: 34px;
  display: flex;
  align-items: center;
}

.aside-link:hover {
  background: var(--color-paper-alt);
  color: var(--color-ink);
}

.aside-desc {
  font-size: 13px;
  line-height: 1.6;
  color: var(--color-ink-muted);
}

/* ============================================
   页脚
   ============================================ */
.site-footer {
  background: var(--color-paper-alt);
  border-top: 2px solid var(--color-ink);
  margin-top: 40px;
}

/* 品牌大字区 */
.footer-brand-section {
  padding: 56px 24px 40px;
  border-bottom: 1px solid var(--color-border);
}

.footer-brand-inner {
  max-width: 1200px;
  margin: 0 auto;
}

.footer-brand-logo {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 16px;
}

.footer-brand-name {
  font-size: clamp(36px, 6vw, 80px);
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--color-ink);
  line-height: 1;
}

.footer-brand-desc {
  font-size: 16px;
  color: var(--color-ink-muted);
  max-width: 600px;
  line-height: 1.6;
}

/* 四栏网格 */
.footer-main-section {
  padding: 48px 24px;
  border-bottom: 1px solid var(--color-border);
}

.footer-grid {
  max-width: 1200px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 40px;
}

.footer-col-eyebrow {
  display: block;
  font-size: 11px;
  letter-spacing: 0.12em;
  color: var(--color-ink-faint);
  margin-bottom: 8px;
}

.footer-col-title {
  font-size: 15px;
  font-weight: 700;
  color: var(--color-ink);
  margin-bottom: 16px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--color-border);
}

.footer-link-list {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.footer-link {
  display: block;
  font-size: 13px;
  color: var(--color-ink-muted);
  padding: 4px 0;
  line-height: 1.5;
  min-height: 28px;
}

.footer-link:hover {
  color: var(--color-ink);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.footer-text-item {
  display: block;
  font-size: 13px;
  color: var(--color-ink-muted);
  padding: 4px 0;
}

.footer-col-text {
  font-size: 13px;
  line-height: 1.7;
  color: var(--color-ink-muted);
}

/* 底栏 */
.footer-bottom-section {
  padding: 24px;
}

.footer-bottom-inner {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 6px;
  text-align: center;
}

.footer-copyright {
  font-size: 13px;
  color: var(--color-ink-muted);
}

.footer-icp {
  font-size: 12px;
  color: var(--color-ink-faint);
}

/* ============================================
   Hover 微交互（纯 CSS）
   ============================================ */
@media (prefers-reduced-motion: no-preference) {
  .nav-pill {
    transition: background 0.12s, border-color 0.12s;
  }
  .hero-cta {
    transition: background 0.12s, border-color 0.12s;
  }
  .aside-link {
    transition: background 0.1s, color 0.1s;
  }
  .footer-link {
    transition: color 0.1s;
  }
  .anchor-pill {
    transition: background 0.1s, color 0.1s, border-color 0.1s;
  }
}

/* ============================================
   响应式 — 平板
   ============================================ */
@media (max-width: 960px) {
  .footer-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 28px;
  }

  .content-with-aside {
    grid-template-columns: 1fr;
  }

  .content-aside {
    position: static;
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 16px;
  }

  .hero-article {
    grid-template-columns: 1fr;
    min-height: auto;
    gap: 32px;
  }

  .hero-media {
    order: -1;
  }

  .hero-float-badge {
    top: -8px;
    right: -8px;
  }

  .nav-desktop {
    gap: 12px;
  }
}

/* ============================================
   响应式 — 手机
   ============================================ */
@media (max-width: 640px) {
  :root {
    --header-h: 60px;
  }

  .header-inner {
    padding: 0 16px;
    justify-content: space-between;
  }

  .nav-desktop {
    display: none;
  }

  .nav-details {
    display: block;
  }

  .brand-center {
    position: static;
    transform: none;
  }

  .brand-text {
    font-size: 15px;
  }

  .sticky-anchor-bar {
    top: var(--header-h);
  }

  .anchor-bar-inner {
    padding: 0 16px;
    gap: 3px;
  }

  .anchor-pill {
    font-size: 11px;
    padding: 0 10px;
    height: 28px;
  }

  main > div.wrap {
    padding: 0 16px;
  }

  .hero-section {
    padding: 32px 0 28px;
  }

  .hero-h1 {
    font-size: 26px;
  }

  .hero-lead {
    font-size: 15px;
  }

  .hero-cta {
    height: 48px;
    font-size: 15px;
    width: 100%;
    justify-content: center;
  }

  .hero-placeholder {
    aspect-ratio: 16/9;
  }

  .hero-placeholder-icon {
    font-size: 48px;
  }

  .content-section {
    padding: 32px 0;
  }

  .content-with-aside {
    grid-template-columns: 1fr;
    gap: 28px;
  }

  .content-aside {
    grid-template-columns: 1fr;
    position: static;
  }

  .content-main h2 {
    font-size: 20px;
    margin-top: 32px;
  }

  .content-main h3 {
    font-size: 17px;
  }

  .footer-brand-section {
    padding: 32px 16px 24px;
  }

  .footer-brand-name {
    font-size: 36px;
  }

  .footer-main-section {
    padding: 32px 16px;
  }

  .footer-grid {
    grid-template-columns: 1fr;
    gap: 24px;
  }

  .footer-bottom-section {
    padding: 20px 16px;
  }

  .hero-float-badge {
    width: 48px;
    height: 48px;
    font-size: 11px;
    top: -6px;
    right: -6px;
  }

  article[id] {
    scroll-margin-top: calc(var(--header-h) + var(--anchor-h) + 8px);
  }
}