/* ============================================================
   乐发平台主页 · 共享样式 / assets/site.css
   坐标定位体系：午夜蓝底图 + 刻度线 + 信号橙节点
   ============================================================ */

/* ---------- 1. Reset ---------- */
*,
*::before,
*::after { box-sizing: border-box; }

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

body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 1rem;
  line-height: 1.75;
  color: var(--ink-700);
  background-color: var(--mist);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

h1, h2, h3, h4, h5, h6, p, figure, blockquote, dl, dd { margin: 0; }

ul, ol { margin: 0; padding: 0; list-style: none; }

img, picture, svg, video { display: block; max-width: 100%; }

button, input, select, textarea { font: inherit; color: inherit; }

a { color: inherit; }

:focus-visible {
  outline: 2px solid var(--orange);
  outline-offset: 3px;
}

::selection { background-color: var(--orange); color: #101C2B; }

/* ---------- 2. 变量 ---------- */
:root {
  --ink-900: #071426;
  --ink-800: #0B1F3A;
  --ink-700: #162A46;
  --orange: #FF6B35;
  --orange-soft: #FFB08F;
  --grid: #C9D6E3;
  --mist: #F4F7FA;
  --green: #2EC4B6;
  --text-light: #E8EEF5;
  --muted: #67788C;

  --line-dark: rgba(201, 214, 227, 0.22);
  --line-dark-soft: rgba(201, 214, 227, 0.12);
  --line-light: rgba(11, 31, 58, 0.14);

  --font-sans: "Helvetica Neue", "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", system-ui, -apple-system, sans-serif;
  --font-mono: ui-monospace, "SFMono-Regular", "Menlo", "Consolas", "PingFang SC", monospace;

  --fs-display: clamp(3rem, 7vw, 7.5rem);
  --fs-h2: clamp(1.6rem, 3vw, 2.8rem);
  --fs-h3: clamp(1.1rem, 1.7vw, 1.4rem);

  --wrap: 1240px;
  --gutter: clamp(1.1rem, 3.2vw, 3rem);
  --ease: cubic-bezier(0.2, 0.7, 0.3, 1);
}

/* ---------- 3. 排版基座 ---------- */
h1, h2, h3, h4 {
  font-weight: 400;
  line-height: 1.22;
  letter-spacing: -0.01em;
  color: var(--ink-800);
}

h1 { font-size: var(--fs-display); font-weight: 300; letter-spacing: -0.02em; }
h2 { font-size: var(--fs-h2); }
h3 { font-size: var(--fs-h3); }

p { overflow-wrap: break-word; }

strong, b { font-weight: 700; }

#main-content { scroll-margin-top: 132px; }

/* ---------- 4. 布局容器 ---------- */
.wrap {
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.wrap--narrow { max-width: 900px; }

.section { padding-block: clamp(2.5rem, 6vw, 5rem); }
.section--dark { background-color: var(--ink-800); color: var(--text-light); }
.section--deep { background-color: var(--ink-900); color: var(--text-light); }

.section__head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 0.75rem 1.25rem;
  padding-bottom: 1rem;
  margin-bottom: clamp(1.5rem, 3vw, 2.5rem);
  border-bottom: 1px solid var(--line-light);
}

.section--dark .section__head,
.section--deep .section__head { border-bottom-color: var(--line-dark); }

.section__title {
  margin: 0;
  font-size: var(--fs-h2);
  font-weight: 300;
  letter-spacing: -0.015em;
}

.section--dark .section__title,
.section--deep .section__title,
.section--dark h2,
.section--dark h3,
.section--deep h2,
.section--deep h3 { color: var(--text-light); }

.section-index {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.2em;
  color: var(--orange);
  text-transform: uppercase;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 0.55rem;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--orange);
}

.eyebrow::before {
  content: "";
  display: inline-block;
  width: 24px;
  height: 1px;
  background-color: currentColor;
}

.lead {
  font-size: clamp(1.05rem, 1.5vw, 1.2rem);
  line-height: 1.8;
  color: var(--muted);
  max-width: 62ch;
}

.section--dark .lead,
.section--deep .lead { color: rgba(232, 238, 245, 0.75); }

/* ---------- 5. 网格 ---------- */
.grid {
  display: grid;
  gap: clamp(1rem, 2vw, 1.75rem);
}

.grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }

.grid--split {
  grid-template-columns: minmax(0, 220px) minmax(0, 1fr);
  gap: clamp(1.5rem, 3vw, 3rem);
  align-items: start;
}

/* ---------- 6. 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.8rem 1.35rem;
  border: 1px solid transparent;
  border-radius: 0;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  letter-spacing: 0.08em;
  line-height: 1.2;
  text-decoration: none;
  cursor: pointer;
  transition: background-color 0.2s var(--ease), color 0.2s var(--ease), border-color 0.2s var(--ease);
}

.btn--primary {
  background-color: var(--orange);
  color: #101C2B;
  font-weight: 700;
}

.btn--primary:hover { background-color: var(--orange-soft); }

.btn--ghost {
  border-color: rgba(201, 214, 227, 0.42);
  color: var(--text-light);
}

.btn--ghost:hover {
  border-color: var(--orange);
  color: #FFFFFF;
}

.btn--dark {
  border-color: var(--line-light);
  color: var(--ink-700);
}

.btn--dark:hover {
  border-color: var(--orange);
  color: var(--ink-800);
}

/* ---------- 7. 面包屑 ---------- */
.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.5rem;
  padding-block: 1.1rem;
  border-bottom: 1px solid var(--line-light);
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.12em;
  color: var(--muted);
}

.breadcrumb a { text-decoration: none; }
.breadcrumb a:hover { color: var(--orange); }

.breadcrumb__sep { color: rgba(103, 120, 140, 0.55); }

.breadcrumb [aria-current="page"] { color: var(--ink-800); }

/* ---------- 8. 正文 ---------- */
.prose {
  max-width: 68ch;
  font-size: 1.0625rem;
  line-height: 1.9;
  letter-spacing: 0.01em;
  color: var(--ink-700);
}

.prose p { margin-bottom: 1.1em; }
.prose h2 { margin: 1.8em 0 0.6em; font-size: var(--fs-h3); font-weight: 700; }
.prose h3 { margin: 1.6em 0 0.5em; font-size: 1.1rem; font-weight: 700; }

.prose ul,
.prose ol {
  margin: 0 0 1.1em;
  padding-left: 1.35em;
  list-style: disc;
}

.prose ol { list-style: decimal; }
.prose li { margin-bottom: 0.45em; }

.prose a {
  color: var(--ink-800);
  text-decoration: underline;
  text-underline-offset: 3px;
  text-decoration-color: var(--orange);
}

.prose strong { color: var(--ink-800); }

.section--dark .prose,
.section--deep .prose { color: rgba(232, 238, 245, 0.82); }

.section--dark .prose strong,
.section--deep .prose strong { color: #FFFFFF; }

/* ---------- 9. 卡片 ---------- */
.card {
  position: relative;
  padding: clamp(1.1rem, 2.2vw, 1.75rem);
  background-color: #FFFFFF;
  border: 1px solid var(--line-light);
  transition: border-color 0.2s var(--ease);
}

.card:hover { border-color: var(--orange); }

.card__index {
  display: block;
  margin-bottom: 0.75rem;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.18em;
  color: var(--orange);
}

.card__title {
  margin: 0 0 0.5rem;
  font-size: 1.1rem;
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--ink-800);
}

.card__text {
  margin: 0;
  font-size: 0.95rem;
  line-height: 1.8;
  color: var(--muted);
}

.card--dark {
  background-color: var(--ink-900);
  border-color: var(--line-dark);
}

.card--dark .card__title { color: var(--text-light); }
.card--dark .card__text { color: rgba(232, 238, 245, 0.7); }

/* ---------- 10. 标签 / 状态 ---------- */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.32rem 0.6rem;
  border: 1px solid var(--line-light);
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.12em;
  color: var(--ink-700);
}

.tag--orange {
  border-color: var(--orange);
  color: var(--orange);
}

.section--dark .tag,
.section--deep .tag {
  border-color: var(--line-dark);
  color: rgba(232, 238, 245, 0.8);
}

.status-dot {
  display: inline-block;
  width: 0.5rem;
  height: 0.5rem;
  border-radius: 50%;
  background-color: var(--green);
  box-shadow: 0 0 0 3px rgba(46, 196, 182, 0.18);
  flex: 0 0 auto;
}

/* ---------- 11. 步骤（技能树式路径） ---------- */
.steps {
  display: grid;
  gap: 0;
  list-style: none;
  margin: 0;
  padding: 0;
}

.steps__item {
  display: grid;
  grid-template-columns: 2.5rem minmax(0, 1fr);
  gap: 0.9rem;
  padding: 1rem 0;
  border-top: 1px solid var(--line-light);
}

.section--dark .steps__item,
.section--deep .steps__item { border-top-color: var(--line-dark); }

.steps__num {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  letter-spacing: 0.1em;
  color: var(--orange);
  padding-top: 0.15rem;
}

.steps__title {
  margin: 0 0 0.3rem;
  font-size: 1rem;
  font-weight: 700;
  color: var(--ink-800);
}

.steps__body {
  margin: 0;
  font-size: 0.95rem;
  line-height: 1.8;
  color: var(--muted);
}

.section--dark .steps__title,
.section--deep .steps__title { color: var(--text-light); }

.section--dark .steps__body,
.section--deep .steps__body { color: rgba(232, 238, 245, 0.7); }

.steps__item[data-done="true"] .steps__num { color: var(--green); }

/* ---------- 12. 纵向标签轨道 ---------- */
.rail { align-self: start; }

.rail__list {
  display: grid;
  gap: 0.15rem;
  margin: 0;
  padding: 0;
  list-style: none;
  border-left: 1px solid var(--line-light);
}

.rail__link {
  display: block;
  margin-left: -1px;
  padding: 0.6rem 0.75rem 0.6rem 1rem;
  border-left: 2px solid transparent;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.12em;
  color: var(--muted);
  text-decoration: none;
  transition: color 0.2s var(--ease), border-color 0.2s var(--ease);
}

.rail__link:hover {
  color: var(--ink-800);
  border-left-color: var(--orange-soft);
}

.rail__link[aria-current="page"] {
  color: var(--ink-800);
  border-left-color: var(--orange);
}

/* ---------- 13. 图片容器基础规则 ---------- */
.media {
  position: relative;
  overflow: hidden;
  border: 1px solid var(--line-dark);
  background-color: var(--ink-900);
}

.media::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background-image:
    linear-gradient(rgba(201, 214, 227, 0.13) 1px, transparent 1px),
    linear-gradient(90deg, rgba(201, 214, 227, 0.13) 1px, transparent 1px);
  background-size: 32px 32px;
}

.media img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.media--16x9 { aspect-ratio: 16 / 9; }
.media--4x3 { aspect-ratio: 4 / 3; }
.media--1x1 { aspect-ratio: 1 / 1; }
.media--wide { aspect-ratio: 21 / 9; }

.media__caption {
  margin-top: 0.6rem;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.12em;
  color: var(--muted);
}

/* ---------- 14. 滚动进度 + 跳转链接 ---------- */
.scroll-progress {
  position: fixed;
  inset: 0 0 auto 0;
  height: 2px;
  z-index: 120;
  background-color: rgba(201, 214, 227, 0.14);
  pointer-events: none;
}

.scroll-progress__bar {
  display: block;
  width: 100%;
  height: 100%;
  background-color: var(--orange);
  transform: scaleX(0);
  transform-origin: 0 50%;
}

.skip-link {
  position: absolute;
  top: -100px;
  left: var(--gutter);
  z-index: 300;
  padding: 0.65rem 1rem;
  background-color: var(--orange);
  color: #101C2B;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  letter-spacing: 0.08em;
  text-decoration: none;
  transition: top 0.2s var(--ease);
}

.skip-link:focus,
.skip-link:focus-visible { top: 0.6rem; }

/* ---------- 15. 头部 ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 80;
  background-color: var(--ink-800);
  color: var(--text-light);
  border-bottom: 1px solid var(--line-dark);
}

.site-header__ruler {
  position: relative;
  height: 9px;
  background-color: var(--ink-900);
  background-image:
    repeating-linear-gradient(90deg, rgba(201, 214, 227, 0.5) 0 1px, transparent 1px 48px),
    repeating-linear-gradient(90deg, rgba(201, 214, 227, 0.2) 0 1px, transparent 1px 8px);
}

.site-header__ruler::after {
  content: "";
  position: absolute;
  inset: 0 auto 0 0;
  width: clamp(56px, 18vw, 150px);
  background-image: linear-gradient(90deg, var(--orange), rgba(255, 107, 53, 0));
}

/* 上层：品牌说明 */
.utility-bar {
  background-color: var(--ink-900);
  border-bottom: 1px solid var(--line-dark-soft);
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.06em;
}

.utility-bar__inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 0.4rem 1.5rem;
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding: 0.5rem var(--gutter);
  color: rgba(232, 238, 245, 0.66);
}

.utility-bar__brand {
  margin: 0;
  color: var(--text-light);
  letter-spacing: 0.1em;
}

.utility-bar__meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.35rem 1.35rem;
  margin: 0;
}

.utility-bar__meta-item {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  white-space: nowrap;
}

.meta-label { color: var(--orange-soft); }

.utility-bar__email { color: rgba(232, 238, 245, 0.66); }

/* 下层：主航道 */
.masthead { position: relative; }

.masthead__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.25rem;
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding: 0.85rem var(--gutter);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.7rem;
  flex: 0 0 auto;
  color: inherit;
  text-decoration: none;
}

.brand__mark {
  display: grid;
  place-items: center;
  width: 2.4rem;
  height: 2.4rem;
  border: 1px solid var(--orange);
  color: var(--orange);
  font-family: var(--font-mono);
  font-size: 0.78rem;
  letter-spacing: 0.08em;
}

.brand__text {
  display: flex;
  flex-direction: column;
  line-height: 1.2;
}

.brand__name {
  font-size: 1.02rem;
  font-weight: 600;
  letter-spacing: 0.02em;
  color: var(--text-light);
}

.brand__sub {
  font-family: var(--font-mono);
  font-size: 0.64rem;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: rgba(232, 238, 245, 0.5);
}

.brand:hover .brand__mark {
  background-color: var(--orange);
  color: #101C2B;
}

/* 导航 */
.site-nav__list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: clamp(0.6rem, 1.6vw, 1.6rem);
  margin: 0;
  padding: 0;
  list-style: none;
}

.site-nav__link {
  position: relative;
  display: inline-flex;
  align-items: baseline;
  gap: 0.4rem;
  padding: 0.68rem 0;
  border-bottom: 2px solid transparent;
  color: rgba(232, 238, 245, 0.76);
  font-size: 0.95rem;
  letter-spacing: 0.02em;
  text-decoration: none;
  white-space: nowrap;
  transition: color 0.2s var(--ease), border-color 0.2s var(--ease);
}

.site-nav__index {
  font-family: var(--font-mono);
  font-size: 0.64rem;
  letter-spacing: 0.1em;
  color: rgba(232, 238, 245, 0.38);
  transition: color 0.2s var(--ease);
}

.site-nav__link:hover { color: #FFFFFF; }
.site-nav__link:hover .site-nav__index { color: var(--orange-soft); }

.site-nav__link[aria-current="page"] {
  color: #FFFFFF;
  border-bottom-color: var(--orange);
}

.site-nav__link[aria-current="page"] .site-nav__index { color: var(--orange); }

/* 移动导航按钮 */
.nav-toggle {
  display: none;
  align-items: center;
  gap: 0.6rem;
  padding: 0.55rem 0.8rem;
  background-color: transparent;
  border: 1px solid rgba(201, 214, 227, 0.38);
  color: var(--text-light);
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.16em;
  cursor: pointer;
}

.nav-toggle:hover { border-color: var(--orange); }

.nav-toggle__bars {
  display: flex;
  flex-direction: column;
  gap: 4px;
  width: 16px;
}

.nav-toggle__bar {
  display: block;
  width: 100%;
  height: 1px;
  background-color: currentColor;
  transition: transform 0.25s var(--ease), opacity 0.25s var(--ease);
}

.nav-toggle[aria-expanded="true"] .nav-toggle__bar:first-child {
  transform: translateY(2.5px) rotate(45deg);
}

.nav-toggle[aria-expanded="true"] .nav-toggle__bar:last-child {
  transform: translateY(-2.5px) rotate(-45deg);
}

.nav-toggle__label { line-height: 1; }

/* ---------- 16. 页脚 ---------- */
.site-footer {
  position: relative;
  overflow: hidden;
  background-color: var(--ink-900);
  color: var(--text-light);
  border-top: 1px solid var(--line-dark);
  background-image:
    linear-gradient(rgba(201, 214, 227, 0.05) 1px, transparent 1px),
    linear-gradient(90deg, rgba(201, 214, 227, 0.05) 1px, transparent 1px);
  background-size: 56px 56px;
}

.site-footer::before {
  content: "";
  position: absolute;
  inset: 0 auto 0 0;
  width: clamp(4px, 1vw, 6px);
  background-image: linear-gradient(180deg, var(--orange), rgba(255, 107, 53, 0));
}

.site-footer__inner {
  position: relative;
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding: clamp(2rem, 5vw, 3.5rem) var(--gutter) 1.5rem;
}

.site-footer__grid {
  display: grid;
  grid-template-columns: 1.5fr 0.9fr 0.9fr 1.2fr;
  gap: clamp(1.5rem, 3vw, 2.75rem);
}

.footer-brand__name {
  margin-bottom: 0.65rem;
  font-size: 1.15rem;
  font-weight: 600;
  letter-spacing: 0.01em;
  color: var(--text-light);
}

.footer-brand__summary {
  max-width: 30ch;
  margin-bottom: 1.1rem;
  font-size: 0.95rem;
  line-height: 1.8;
  color: rgba(232, 238, 245, 0.66);
}

.footer-status {
  display: inline-flex;
  align-items: center;
  gap: 0.55rem;
  padding: 0.4rem 0.7rem;
  border: 1px solid var(--line-dark);
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.1em;
  color: rgba(232, 238, 245, 0.72);
}

.footer-col__title {
  margin-bottom: 1rem;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 400;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--orange-soft);
}

.footer-links {
  display: grid;
  gap: 0.55rem;
  margin: 0;
  padding: 0;
  list-style: none;
}

.footer-link {
  display: inline-block;
  padding-bottom: 1px;
  border-bottom: 1px solid transparent;
  color: rgba(232, 238, 245, 0.78);
  font-size: 0.95rem;
  text-decoration: none;
  transition: color 0.2s var(--ease), border-color 0.2s var(--ease);
}

.footer-link:hover {
  color: #FFFFFF;
  border-bottom-color: var(--orange);
}

.footer-contact {
  display: grid;
  gap: 0.9rem;
  margin-bottom: 1.1rem;
}

.footer-contact__row {
  display: grid;
  justify-items: start;
  gap: 0.18rem;
}

.footer-contact__label {
  font-family: var(--font-mono);
  font-size: 0.66rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: rgba(232, 238, 245, 0.42);
}

.footer-contact__value {
  margin: 0;
  font-size: 0.92rem;
  line-height: 1.65;
  color: rgba(232, 238, 245, 0.86);
  overflow-wrap: break-word;
}

.copy-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  margin-top: 0.3rem;
  padding: 0.32rem 0.55rem;
  background-color: transparent;
  border: 1px solid rgba(201, 214, 227, 0.32);
  color: rgba(232, 238, 245, 0.76);
  font-family: var(--font-mono);
  font-size: 0.66rem;
  letter-spacing: 0.1em;
  cursor: pointer;
  transition: border-color 0.2s var(--ease), color 0.2s var(--ease);
}

.copy-btn:hover {
  border-color: var(--orange);
  color: #FFFFFF;
}

.copy-btn[data-copied="true"] {
  border-color: var(--green);
  color: var(--green);
}

.footer-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
}

.footer-legal {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: 0.6rem 1.75rem;
  margin-top: clamp(1.75rem, 4vw, 2.75rem);
  padding-top: 1.25rem;
  border-top: 1px solid var(--line-dark);
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.06em;
  color: rgba(232, 238, 245, 0.5);
}

.footer-legal__icp {
  margin: 0;
  color: rgba(232, 238, 245, 0.72);
}

.footer-legal__note {
  flex: 1 1 320px;
  margin: 0;
  line-height: 1.8;
  color: rgba(232, 238, 245, 0.55);
}

.footer-legal__copyright { margin: 0; }

/* ---------- 17. 动效协议 ---------- */
[data-reveal="pending"] {
  opacity: 0;
  transform: translateY(16px);
}

[data-reveal="shown"] {
  opacity: 1;
  transform: none;
  transition: opacity 0.55s var(--ease), transform 0.55s var(--ease);
}

/* ---------- 18. 响应式 ---------- */
@media (max-width: 1080px) {
  .site-nav {
    flex: 1 1 auto;
    min-width: 0;
    overflow-x: auto;
    scrollbar-width: thin;
    -webkit-overflow-scrolling: touch;
  }

  .site-nav::-webkit-scrollbar { height: 3px; }
  .site-nav::-webkit-scrollbar-thumb { background-color: rgba(201, 214, 227, 0.35); }

  .site-nav__list { flex-wrap: nowrap; }

  .site-footer__grid { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 880px) {
  .masthead__inner { flex-wrap: nowrap; }

  .nav-toggle { display: inline-flex; }

  .site-nav {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    z-index: 90;
    max-height: 0;
    overflow: hidden;
    visibility: hidden;
    background-color: var(--ink-900);
    border-bottom: 1px solid var(--line-dark);
    transition: max-height 0.34s var(--ease), visibility 0.34s step-end;
  }

  .site-nav[data-open="true"] {
    max-height: calc(100vh - 110px);
    overflow-y: auto;
    visibility: visible;
    transition: max-height 0.34s var(--ease), visibility 0s linear;
  }

  .site-nav__list {
    flex-direction: column;
    flex-wrap: nowrap;
    gap: 0;
    padding: 0.35rem var(--gutter) 1.1rem;
  }

  .site-nav__item { border-top: 1px solid var(--line-dark-soft); }
  .site-nav__item:first-child { border-top: 0; }

  .site-nav__link {
    width: 100%;
    justify-content: flex-start;
    padding: 0.95rem 0;
    border-bottom: 0;
    font-size: 1rem;
  }

  .site-nav__link[aria-current="page"] {
    border-bottom: 0;
    color: var(--orange);
  }

  .grid--2,
  .grid--3,
  .grid--split { grid-template-columns: minmax(0, 1fr); }

  .rail { position: static; }
  .rail__list { grid-auto-flow: row; }

  #main-content { scroll-margin-top: 96px; }
}

@media (max-width: 640px) {
  .utility-bar__email { display: none; }
  .utility-bar__inner { justify-content: flex-start; }
  .utility-bar__brand { font-size: 0.68rem; }
  .brand__sub { display: none; }

  .site-footer__grid { grid-template-columns: minmax(0, 1fr); }
  .footer-legal { flex-direction: column; align-items: flex-start; }
  .footer-actions .btn { flex: 1 1 auto; }
}

/* ---------- 19. 减少动态偏好 ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }

  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
    scroll-behavior: auto !important;
  }

  [data-reveal="pending"],
  [data-reveal="shown"] {
    opacity: 1 !important;
    transform: none !important;
    transition: none !important;
  }
}