@import url('https://fonts.googleapis.com/css2?family=Figtree:wght@300;400;500;600;700&family=Noto+Sans:wght@300;400;500;700&display=swap');

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

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

body {
  background-color: #fdfbf7;
  color: #1a1a1a;
  font-family: 'Noto Sans', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
  line-height: 1.75;
  min-height: 100vh;
  position: relative;
  overflow-x: hidden;
}

/* ===== 纸质肌理叠加 ===== */
.paper-texture {
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 0;
  opacity: 0.04;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='300' height='300'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.85' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='300' height='300' filter='url(%23n)' opacity='1'/%3E%3C/svg%3E");
  background-repeat: repeat;
}

/* ===== scroll-margin-top ===== */
section[id] {
  scroll-margin-top: 108px;
}

/* ===== 主导航 ===== */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 200;
  background: #fdfbf7;
  border-bottom: 1px solid #1a1a1a;
}

.main-nav {
  position: relative;
}

.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 24px;
  height: 60px;
  gap: 16px;
}

.nav-list {
  display: flex;
  list-style: none;
  gap: 0;
  align-items: center;
  flex: 1;
}

.nav-list--left {
  justify-content: flex-end;
  padding-right: 32px;
}

.nav-list--right {
  justify-content: flex-start;
  padding-left: 32px;
  gap: 0;
}

.nav-list li a {
  display: block;
  padding: 10px 12px;
  font-family: 'Figtree', sans-serif;
  font-size: 0.82rem;
  font-weight: 500;
  letter-spacing: 0.04em;
  color: #1a1a1a;
  text-decoration: none;
  border-bottom: 2px solid transparent;
  transition: none;
  min-height: 40px;
  line-height: 20px;
  display: flex;
  align-items: center;
}

.nav-list li a:hover,
.nav-list li a:focus-visible {
  border-bottom-color: #1a1a1a;
}

/* 品牌居中 */
.nav-brand {
  flex-shrink: 0;
  text-align: center;
}

.brand-link {
  text-decoration: none;
  color: inherit;
  display: flex;
  align-items: center;
}

.brand-text {
  font-family: 'Figtree', serif;
  font-weight: 700;
  font-size: 1rem;
  letter-spacing: 0.06em;
  color: #1a1a1a;
  white-space: nowrap;
}

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

/* CTA 按钮 */
.nav-cta-item {
  margin-left: 8px;
}

.nav-cta {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 8px 18px;
  min-height: 40px;
  background: #1a1a1a;
  color: #fdfbf7;
  font-family: 'Figtree', sans-serif;
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.05em;
  text-decoration: none;
  border: 1px solid #1a1a1a;
  cursor: pointer;
}

.nav-cta:hover,
.nav-cta:focus-visible {
  background: #fdfbf7;
  color: #1a1a1a;
}

/* ===== details 汉堡菜单（移动端） ===== */
.mobile-nav-details {
  display: none;
  position: absolute;
  top: 0;
  right: 16px;
  z-index: 210;
}

.mobile-nav-toggle {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 44px;
  height: 60px;
  cursor: pointer;
  list-style: none;
}

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

.hamburger-line {
  display: block;
  width: 24px;
  height: 2px;
  background: #1a1a1a;
}

.mobile-menu {
  position: fixed;
  top: 60px;
  left: 0;
  right: 0;
  background: #fdfbf7;
  border-bottom: 1px solid #1a1a1a;
  list-style: none;
  padding: 8px 0;
}

.mobile-menu li a {
  display: block;
  padding: 14px 24px;
  font-family: 'Noto Sans', sans-serif;
  font-size: 0.95rem;
  font-weight: 500;
  color: #1a1a1a;
  text-decoration: none;
  border-bottom: 1px solid #f5f5f5;
  min-height: 48px;
}

.mobile-menu li a:hover {
  background: #f5f5f5;
}

/* ===== 粘性锚点条 ===== */
.anchor-bar {
  position: sticky;
  top: 60px;
  z-index: 190;
  background: #f5f5f5;
  border-bottom: 1px solid #d0d0d0;
  display: flex;
  align-items: center;
  overflow-x: auto;
  scrollbar-width: none;
  padding: 0 24px;
  gap: 0;
  -webkit-overflow-scrolling: touch;
}

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

.anchor-bar a {
  display: inline-flex;
  align-items: center;
  padding: 10px 14px;
  min-height: 44px;
  font-family: 'Figtree', sans-serif;
  font-size: 0.78rem;
  font-weight: 500;
  letter-spacing: 0.03em;
  color: #1a1a1a;
  text-decoration: none;
  white-space: nowrap;
  border-right: 1px solid #d0d0d0;
  flex-shrink: 0;
}

.anchor-bar a:last-child { border-right: none; }

.anchor-bar a:hover,
.anchor-bar a:focus-visible {
  background: #1a1a1a;
  color: #fdfbf7;
}

/* ===== Hero ===== */
.hero-wrap {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: flex-end;
  justify-content: flex-end;
  padding: 140px 48px 80px;
  overflow: hidden;
  border-bottom: 1px solid #1a1a1a;
}

.hero-bg-text {
  position: absolute;
  top: 50%;
  left: -2%;
  transform: translateY(-50%);
  font-family: 'Figtree', serif;
  font-weight: 700;
  font-size: clamp(100px, 18vw, 260px);
  color: #1a1a1a;
  opacity: 0.04;
  white-space: nowrap;
  pointer-events: none;
  user-select: none;
  letter-spacing: -0.02em;
  line-height: 1;
}

.hero-serial {
  position: absolute;
  top: 140px;
  left: 48px;
  font-family: 'Figtree', sans-serif;
  font-weight: 300;
  font-size: clamp(80px, 12vw, 180px);
  color: #1a1a1a;
  opacity: 0.06;
  line-height: 1;
  pointer-events: none;
  user-select: none;
}

.hero-inner {
  position: relative;
  z-index: 2;
  text-align: right;
  max-width: 680px;
}

.hero-eyebrow {
  display: inline-block;
  font-family: 'Figtree', sans-serif;
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.18em;
  color: #555;
  text-transform: none;
  margin-bottom: 20px;
  border-top: 2px solid #1a1a1a;
  padding-top: 8px;
}

.hero-title {
  font-family: 'Noto Sans', serif;
  font-weight: 700;
  font-size: clamp(2rem, 5vw, 3.8rem);
  line-height: 1.25;
  letter-spacing: -0.01em;
  color: #1a1a1a;
  margin-bottom: 24px;
}

.hero-desc {
  font-size: 1rem;
  line-height: 1.75;
  color: #444;
  margin-bottom: 36px;
  max-width: 480px;
  margin-left: auto;
}

.hero-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 14px 36px;
  min-height: 48px;
  border: 1px solid #1a1a1a;
  background: transparent;
  color: #1a1a1a;
  font-family: 'Figtree', sans-serif;
  font-size: 0.9rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-decoration: none;
  cursor: pointer;
  position: relative;
  overflow: hidden;
}

.hero-btn::after {
  content: '';
  position: absolute;
  inset: 0;
  background: #1a1a1a;
  transform: translateX(-100%);
  transition: none;
}

.hero-btn:hover::after {
  transform: translateX(0);
}

.hero-btn:hover {
  color: #fdfbf7;
}

.hero-btn span {
  position: relative;
  z-index: 1;
}

/* ===== 主内容 ===== */
.site-main {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 24px 80px;
}

/* 正文 section 结构 */
.content-section {
  display: grid;
  grid-template-columns: 1fr 280px;
  grid-template-rows: auto 1fr;
  gap: 0 48px;
  padding-top: 64px;
  position: relative;
}

/* figure 装饰 */
.content-figure {
  grid-column: 1 / 2;
  grid-row: 1 / 2;
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 32px;
  padding-bottom: 16px;
  border-bottom: 1px solid #1a1a1a;
}

.figure-rule {
  width: 40px;
  height: 2px;
  background: #1a1a1a;
  flex-shrink: 0;
}

.figure-caption {
  font-family: 'Figtree', sans-serif;
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.16em;
  color: #777;
}

/* 正文内容 */
.content-body {
  grid-column: 1 / 2;
  grid-row: 2 / 3;
  min-width: 0;
}

/* ===== 正文内部元素样式 ===== */
.content-body h1,
.content-body h2,
.content-body h3,
.content-body h4 {
  font-family: 'Noto Sans', serif;
  font-weight: 700;
  line-height: 1.35;
  color: #1a1a1a;
  margin-top: 2.5em;
  margin-bottom: 0.75em;
}

.content-body h2 {
  font-size: 1.55rem;
  border-bottom: 1px solid #e0e0e0;
  padding-bottom: 12px;
}

.content-body h3 {
  font-size: 1.2rem;
}

.content-body p {
  margin-bottom: 1.25em;
  color: #222;
  font-size: 1rem;
  line-height: 1.85;
}

.content-body ul,
.content-body ol {
  padding-left: 1.5em;
  margin-bottom: 1.25em;
}

.content-body li {
  margin-bottom: 0.5em;
  line-height: 1.75;
}

.content-body a {
  color: #1a1a1a;
  text-decoration: underline;
  text-underline-offset: 3px;
}

.content-body a:hover {
  text-decoration-thickness: 2px;
}

.content-body strong {
  font-weight: 700;
}

.content-body blockquote {
  border-left: 3px solid #1a1a1a;
  margin: 1.5em 0;
  padding: 12px 24px;
  background: #f5f5f5;
  color: #333;
}

.content-body section {
  padding-top: 40px;
  padding-bottom: 40px;
  border-bottom: 1px solid #e8e8e8;
}

.content-body section:last-child {
  border-bottom: none;
}

/* small 眉题紧邻 h2/h3 */
.content-body small + h2,
.content-body small + h3 {
  margin-top: 0.25em;
}

.content-body small {
  display: block;
  font-family: 'Figtree', sans-serif;
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.16em;
  color: #888;
  margin-top: 2.5em;
}

/* ===== aside 侧栏 ===== */
.content-aside {
  grid-column: 2 / 3;
  grid-row: 1 / 3;
  position: sticky;
  top: 116px;
  align-self: start;
  border: 1px solid #d0d0d0;
  padding: 28px 24px;
  background: #f5f5f5;
}

.aside-eyebrow {
  display: block;
  font-family: 'Figtree', sans-serif;
  font-size: 0.7rem;
  font-weight: 600;
  letter-spacing: 0.16em;
  color: #888;
  margin-bottom: 8px;
}

.aside-title {
  font-family: 'Noto Sans', serif;
  font-size: 1rem;
  font-weight: 700;
  color: #1a1a1a;
  margin-bottom: 16px;
  padding-bottom: 10px;
  border-bottom: 1px solid #d0d0d0;
}

.aside-list {
  list-style: none;
  padding: 0;
  margin-bottom: 20px;
}

.aside-list li {
  font-size: 0.85rem;
  line-height: 1.6;
  color: #444;
  padding: 6px 0;
  border-bottom: 1px solid #e8e8e8;
}

.aside-list li:last-child { border-bottom: none; }

.aside-list li::before {
  content: '—';
  margin-right: 8px;
  color: #aaa;
}

.aside-note {
  display: block;
  font-size: 0.72rem;
  color: #999;
  line-height: 1.6;
}

/* ===== 页脚（仅 p + small） ===== */
.site-footer {
  background: #1a1a1a;
  color: #fdfbf7;
  text-align: center;
  padding: 60px 24px 40px;
  border-top: 2px solid #1a1a1a;
  position: relative;
  overflow: hidden;
}

.footer-brand {
  font-family: 'Figtree', serif;
  font-weight: 700;
  font-size: clamp(2.5rem, 8vw, 6rem);
  letter-spacing: -0.02em;
  color: #fdfbf7;
  opacity: 0.9;
  line-height: 1;
  margin-bottom: 32px;
}

.footer-copy {
  display: block;
  font-family: 'Noto Sans', sans-serif;
  font-size: 0.78rem;
  color: #888;
  letter-spacing: 0.04em;
  line-height: 1.8;
}

/* ===== Hover 微交互与列表交错 ===== */
@media (prefers-reduced-motion: no-preference) {
  .nav-list li a {
    transition: border-color 0.15s;
  }
  .anchor-bar a {
    transition: background 0.15s, color 0.15s;
  }
  .nav-cta {
    transition: background 0.15s, color 0.15s;
  }
  .hero-btn::after {
    transition: transform 0.25s cubic-bezier(0.4, 0, 0.2, 1);
  }
  .content-body section {
    opacity: 0;
    transform: translateY(16px);
    animation: fadeUp 0.5s ease forwards;
  }
  .content-body section:nth-child(1) { animation-delay: 0.05s; }
  .content-body section:nth-child(2) { animation-delay: 0.10s; }
  .content-body section:nth-child(3) { animation-delay: 0.15s; }
  .content-body section:nth-child(4) { animation-delay: 0.20s; }
  .content-body section:nth-child(5) { animation-delay: 0.25s; }
  .content-body section:nth-child(6) { animation-delay: 0.30s; }
  .content-body section:nth-child(7) { animation-delay: 0.35s; }

  @keyframes fadeUp {
    to { opacity: 1; transform: none; }
  }

  .aside-list li {
    transition: background 0.12s;
  }
  .aside-list li:hover {
    background: #eaeaea;
    padding-left: 6px;
  }
}

/* ===== 卡片（正文内可能含） ===== */
.content-body .card,
.content-body [class*="card"] {
  border-radius: 10px;
  box-shadow: 0 2px 12px rgba(26,26,26,0.07);
  border: 1px solid #e0e0e0;
  transition: box-shadow 0.15s;
}

.content-body .card:hover {
  box-shadow: 0 6px 24px rgba(26,26,26,0.12);
}

/* ===== 响应式断点 ===== */
@media (max-width: 960px) {
  .content-section {
    grid-template-columns: 1fr;
    grid-template-rows: auto auto auto;
  }
  .content-figure {
    grid-row: 1;
  }
  .content-body {
    grid-column: 1;
    grid-row: 2;
  }
  .content-aside {
    grid-column: 1;
    grid-row: 3;
    position: static;
    margin-top: 48px;
  }
}

@media (max-width: 768px) {
  html { font-size: 16px; }

  .nav-inner {
    padding: 0 16px;
  }

  .nav-list--left,
  .nav-list--right {
    display: none;
  }

  .mobile-nav-details {
    display: block;
  }

  .anchor-bar {
    padding: 0 12px;
    top: 60px;
  }

  .anchor-bar a {
    font-size: 0.72rem;
    padding: 10px 10px;
  }

  .hero-wrap {
    padding: 120px 24px 60px;
    align-items: center;
    justify-content: center;
    text-align: center;
  }

  .hero-inner {
    text-align: center;
  }

  .hero-desc {
    margin-left: auto;
    margin-right: auto;
  }

  .hero-bg-text {
    left: 50%;
    transform: translate(-50%, -50%);
  }

  .hero-serial {
    left: 16px;
    top: 80px;
    font-size: 60px;
  }

  .site-main {
    padding: 0 16px 60px;
  }

  .content-section {
    padding-top: 40px;
  }

  section[id] {
    scroll-margin-top: 116px;
  }

  .footer-brand {
    font-size: clamp(2rem, 10vw, 3.5rem);
  }
}

@media (max-width: 375px) {
  .hero-title {
    font-size: 1.75rem;
  }
  .hero-btn {
    width: 100%;
    justify-content: center;
  }
  .anchor-bar a {
    padding: 10px 8px;
    font-size: 0.68rem;
  }
}

button[aria-expanded]{min-width:44px;min-height:44px}