/* ============================================================
   PG游艺 · /assets/site.css
   共享外壳：reset / 变量 / 中文排版 / 左侧轨道头部 / 页脚 / 基础组件
   ============================================================ */

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

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

body,
h1, h2, h3, h4, h5, h6,
p, ul, ol, li, figure, figcaption, blockquote, dl, dd {
  margin: 0;
  padding: 0;
}

ul, ol { list-style: none; }

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

button {
  font: inherit;
  color: inherit;
  background: none;
  border: 0;
  cursor: pointer;
}

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

table { border-collapse: collapse; width: 100%; }

/* ---------- 2. 变量 ---------- */
:root {
  --ink: #0A1220;
  --panel: #16202E;
  --edge: #2B3746;
  --cyan: #3FE0D0;
  --violet: #9A6BFF;
  --amber: #F0B457;
  --clay: #C8703F;
  --moss: #6E9C7F;
  --paper: #F3EFE4;
  --mist: #A8B4C2;

  --rail-w: 96px;
  --rail-w-compact: 56px;
  --shell-pad: clamp(18px, 4vw, 56px);

  --font-display: "Noto Sans SC", "Source Han Sans SC", "PingFang SC", system-ui, sans-serif;
  --font-body: "Noto Sans SC", "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
  --font-mono: "JetBrains Mono", "IBM Plex Mono", ui-monospace, SFMono-Regular, monospace;

  --line: 2px solid var(--edge);
  --radius: 4px;
  --shadow-hard: 6px 6px 0 rgba(0, 0, 0, 0.45);
  --shadow-hard-sm: 3px 3px 0 rgba(0, 0, 0, 0.4);
}

/* ---------- 3. 基底与中文排版 ---------- */
html, body { min-height: 100%; }

body {
  background-color: var(--ink);
  color: var(--paper);
  font-family: var(--font-body);
  font-size: 17px;
  font-weight: 350;
  line-height: 1.85;
  letter-spacing: 0.01em;
  overflow-x: hidden;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}

/* 旧街机屏幕颗粒 */
body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: 4;
  pointer-events: none;
  background-image:
    radial-gradient(rgba(243, 239, 228, 0.05) 1px, transparent 1px),
    radial-gradient(rgba(63, 224, 208, 0.045) 1px, transparent 1px);
  background-size: 3px 3px, 7px 7px;
  background-position: 0 0, 2px 3px;
}

::selection {
  background: rgba(63, 224, 208, 0.28);
  color: var(--paper);
}

h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: 700;
  line-height: 1.25;
  letter-spacing: 0.06em;
}

#main-content {
  position: relative;
  z-index: 1;
  display: block;
  scroll-margin-top: 96px;
}

/* ---------- 4. 聚焦与跳过链接 ---------- */
:where(a, button, summary, [tabindex]):focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 3px;
  border-radius: 2px;
}

.skip-link {
  position: fixed;
  left: 12px;
  top: -80px;
  z-index: 200;
  padding: 10px 18px;
  background: var(--cyan);
  color: var(--ink);
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.18em;
  border-radius: 2px;
  box-shadow: var(--shadow-hard-sm);
  transition: top 0.2s ease;
}

.skip-link:focus { top: 12px; }

/* ---------- 5. 阅读进度 ---------- */
.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  z-index: 130;
  background: rgba(43, 55, 70, 0.55);
  pointer-events: none;
}

.scroll-progress__bar {
  display: block;
  width: 0;
  height: 100%;
  background: linear-gradient(90deg, var(--cyan) 0%, rgba(63, 224, 208, 0.15) 100%);
  transition: width 0.12s linear;
}

/* ---------- 6. 头部：移动端顶部条 ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
  padding: 12px 16px;
  background: rgba(10, 18, 32, 0.95);
  border-bottom: var(--line);
  transition: padding 0.28s ease;
}

/* 品牌 */
.rail-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  min-width: 0;
}

.rail-brand__mark {
  display: inline-block;
  padding: 3px 7px;
  background: var(--cyan);
  color: var(--ink);
  font-family: var(--font-mono);
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.14em;
  line-height: 1.3;
  border-radius: 2px;
  box-shadow: 2px 2px 0 rgba(63, 224, 208, 0.25);
}

.rail-brand__name {
  font-family: var(--font-display);
  font-size: 17px;
  font-weight: 700;
  letter-spacing: 0.12em;
  white-space: nowrap;
}

.rail-brand__sub { display: none; }

/* 移动导航按钮 */
.nav-toggle {
  position: relative;
  z-index: 122;
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 8px 12px;
  border: 2px solid var(--edge);
  border-radius: 2px;
  background: rgba(22, 32, 46, 0.9);
  color: var(--paper);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.18em;
  transition: border-color 0.2s ease, color 0.2s ease;
}

.nav-toggle:hover,
.nav-toggle:focus-visible {
  border-color: var(--cyan);
  color: var(--cyan);
}

.nav-toggle__bars {
  display: grid;
  gap: 4px;
  width: 18px;
}

.nav-toggle__bars span {
  display: block;
  height: 2px;
  background: currentColor;
  transform-origin: center;
  transition: transform 0.2s ease, opacity 0.2s ease, width 0.2s ease;
}

.nav-toggle__bars span:nth-child(2) { width: 70%; }

.nav-toggle[aria-expanded="true"] .nav-toggle__bars span:nth-child(1) { transform: translateY(6px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle__bars span:nth-child(2) { opacity: 0; }
.nav-toggle[aria-expanded="true"] .nav-toggle__bars span:nth-child(3) { transform: translateY(-6px) rotate(-45deg); }

/* ---------- 7. 导航：移动端全屏抽屉 ---------- */
.site-nav {
  position: fixed;
  inset: 0;
  z-index: 120;
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding: 96px 24px 128px;
  overflow-y: auto;
  background:
    linear-gradient(160deg, #0A1220 0%, #101B2B 58%, #0A1220 100%);
  border-top: 2px solid var(--cyan);
  opacity: 0;
  visibility: hidden;
  transform: translateY(-10px);
  transition: opacity 0.24s ease, transform 0.24s ease, visibility 0.24s ease;
}

.site-header[data-open] .site-nav {
  opacity: 1;
  visibility: visible;
  transform: none;
}

.site-nav__list {
  display: flex;
  flex-direction: column;
  width: 100%;
}

.site-nav__item { border-bottom: 1px solid rgba(43, 55, 70, 0.85); }
.site-nav__item:last-child { border-bottom: 0; }

.site-nav__link {
  display: flex;
  align-items: baseline;
  gap: 14px;
  padding: 15px 4px;
  transition: color 0.2s ease, background 0.2s ease;
}

.site-nav__num {
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.14em;
  color: var(--mist);
  opacity: 0.65;
}

.site-nav__label {
  font-family: var(--font-display);
  font-size: 22px;
  font-weight: 700;
  letter-spacing: 0.14em;
}

.site-nav__link:hover,
.site-nav__link:focus-visible { color: var(--cyan); }

.site-nav__link[aria-current="page"] { color: var(--cyan); }
.site-nav__link[aria-current="page"] .site-nav__num { color: var(--amber); opacity: 1; }

/* 轨道底部（移动端隐藏） */
.rail-foot { display: none; }

/* ---------- 8. 移动端底部快捷条 ---------- */
.quick-bar {
  position: fixed;
  left: 0;
  right: 0;
  bottom: 0;
  z-index: 100;
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  background: rgba(10, 18, 32, 0.97);
  border-top: 2px solid var(--edge);
  padding-bottom: env(safe-area-inset-bottom, 0);
}

.quick-bar__item {
  display: block;
  padding: 13px 6px;
  text-align: center;
  border-right: 1px solid rgba(43, 55, 70, 0.75);
  transition: color 0.2s ease, background 0.2s ease;
}

.quick-bar__item:last-child { border-right: 0; }

.quick-bar__label {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--mist);
}

.quick-bar__item:hover .quick-bar__label,
.quick-bar__item:focus-visible .quick-bar__label { color: var(--cyan); }

.quick-bar__item:hover,
.quick-bar__item:focus-visible { background: rgba(63, 224, 208, 0.06); }

/* ---------- 9. 页脚 ---------- */
.site-footer {
  position: relative;
  margin-top: clamp(64px, 10vw, 140px);
  padding: clamp(48px, 6vw, 84px) var(--shell-pad) calc(96px + env(safe-area-inset-bottom, 0));
  background: linear-gradient(180deg, #0C1524 0%, #0A1220 100%);
  border-top: var(--line);
}

.site-footer::before {
  content: "";
  position: absolute;
  top: -2px;
  left: 0;
  width: clamp(120px, 24vw, 300px);
  height: 2px;
  background: linear-gradient(90deg, var(--cyan), var(--violet), rgba(154, 107, 255, 0));
}

.footer-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(32px, 4vw, 52px);
  max-width: 1440px;
  margin: 0 auto;
}

.footer-brand__link {
  display: inline-block;
  font-family: var(--font-display);
  font-size: clamp(24px, 3vw, 32px);
  font-weight: 700;
  letter-spacing: 0.22em;
  color: var(--paper);
  transition: color 0.2s ease;
}

.footer-brand__link:hover,
.footer-brand__link:focus-visible { color: var(--cyan); }

.footer-brand__sub {
  margin-top: 8px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.28em;
  color: var(--cyan);
  opacity: 0.85;
}

.footer-brand__note {
  margin-top: 14px;
  max-width: 30em;
  font-size: 15px;
  line-height: 1.8;
  color: rgba(168, 180, 194, 0.82);
}

.footer-brand__version {
  margin-top: 16px;
  display: inline-block;
  padding: 5px 10px;
  border: 2px solid rgba(240, 180, 87, 0.45);
  border-radius: 2px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.12em;
  color: var(--amber);
}

.footer-col__title {
  position: relative;
  padding-bottom: 12px;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.24em;
  color: var(--mist);
}

.footer-col__title::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: 26px;
  height: 2px;
  background: var(--clay);
}

.footer-col__list { display: grid; gap: 12px; }

.footer-link {
  display: inline-block;
  font-size: 15px;
  color: rgba(243, 239, 228, 0.78);
  transition: color 0.2s ease, transform 0.2s ease;
}

.footer-link:hover,
.footer-link:focus-visible {
  color: var(--cyan);
  transform: translateX(3px);
}

.footer-contact__list { display: grid; gap: 12px; }

.footer-contact__row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
}

.footer-contact__key {
  min-width: 36px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.2em;
  color: var(--mist);
}

.footer-contact__value {
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.02em;
  color: var(--paper);
  word-break: break-word;
}

.copy-btn {
  padding: 3px 9px;
  border: 2px solid var(--edge);
  border-radius: 2px;
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.14em;
  color: var(--mist);
  transition: border-color 0.2s ease, color 0.2s ease;
}

.copy-btn:hover,
.copy-btn:focus-visible {
  border-color: var(--cyan);
  color: var(--cyan);
}

.copy-btn.is-done {
  border-color: var(--moss);
  color: var(--moss);
}

.footer-contact__note {
  margin-top: 16px;
  max-width: 32em;
  font-size: 13px;
  line-height: 1.8;
  color: rgba(168, 180, 194, 0.72);
}

.footer-base {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
  max-width: 1440px;
  margin: clamp(36px, 5vw, 64px) auto 0;
  padding-top: 22px;
  border-top: 2px solid var(--edge);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--mist);
}

.footer-base__legal { color: rgba(243, 239, 228, 0.72); }
.footer-base__meta { color: rgba(168, 180, 194, 0.6); }

.to-top {
  position: fixed;
  right: 16px;
  bottom: calc(72px + env(safe-area-inset-bottom, 0));
  z-index: 96;
  padding: 10px 14px;
  border: 2px solid var(--edge);
  border-radius: 2px;
  background: rgba(22, 32, 46, 0.95);
  color: var(--paper);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  box-shadow: var(--shadow-hard-sm);
  opacity: 0;
  visibility: hidden;
  transform: translateY(6px);
  transition: opacity 0.2s ease, transform 0.2s ease, visibility 0.2s ease,
              border-color 0.2s ease, color 0.2s ease;
}

.to-top.is-visible {
  opacity: 1;
  visibility: visible;
  transform: none;
}

.to-top:hover,
.to-top:focus-visible {
  border-color: var(--cyan);
  color: var(--cyan);
}

/* ---------- 10. 通用按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 12px 20px;
  border: 2px solid var(--edge);
  border-radius: 2px;
  background: var(--panel);
  color: var(--paper);
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.16em;
  box-shadow: var(--shadow-hard-sm);
  transition: border-color 0.2s ease, color 0.2s ease, background 0.2s ease, transform 0.2s ease;
}

.btn:hover,
.btn:focus-visible {
  border-color: var(--cyan);
  color: var(--cyan);
  transform: translate(-1px, -1px);
}

.btn--primary {
  background: var(--cyan);
  border-color: var(--cyan);
  color: var(--ink);
}

.btn--primary:hover,
.btn--primary:focus-visible {
  background: #63F0E3;
  border-color: #63F0E3;
  color: var(--ink);
}

.btn--ghost { background: transparent; }

.btn-row {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
}

/* ---------- 11. 容器与栅格 ---------- */
.container {
  width: 100%;
  max-width: 1240px;
  margin: 0 auto;
  padding-left: var(--shell-pad);
  padding-right: var(--shell-pad);
}

.container--narrow { max-width: 820px; }

.stack { display: grid; gap: var(--stack-gap, 24px); }

.grid { display: grid; gap: clamp(20px, 3vw, 36px); grid-template-columns: 1fr; }
.grid--2 { grid-template-columns: 1fr; }
.grid--3 { grid-template-columns: 1fr; }

.split {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(24px, 3vw, 48px);
}

/* ---------- 12. 文字层级 ---------- */
.prose {
  max-width: 34em;
  font-size: 17px;
  font-weight: 350;
  line-height: 1.85;
  color: rgba(243, 239, 228, 0.82);
}

.prose p + p { margin-top: 1.1em; }

.lede {
  max-width: 34em;
  font-size: clamp(17px, 1.6vw, 20px);
  line-height: 1.8;
  color: rgba(243, 239, 228, 0.88);
}

.eyebrow {
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.24em;
  text-transform: uppercase;
  color: var(--mist);
}

.data-num {
  font-family: var(--font-mono);
  font-size: 1em;
  font-weight: 600;
  letter-spacing: 0.06em;
  color: var(--amber);
}

.note {
  max-width: 34em;
  font-size: 14px;
  line-height: 1.8;
  color: rgba(168, 180, 194, 0.75);
}

.divider {
  height: 2px;
  border: 0;
  background: var(--edge);
}

/* ---------- 13. 卡片 / 标签 / 表格 / 章节 ---------- */
.card {
  position: relative;
  padding: clamp(20px, 2.4vw, 32px);
  background: var(--panel);
  border: 2px solid var(--edge);
  border-radius: var(--radius);
  box-shadow: var(--shadow-hard);
  transition: border-color 0.2s ease;
}

.card:hover { border-color: rgba(63, 224, 208, 0.55); }

.card__head {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 14px;
}

.card__title {
  font-family: var(--font-display);
  font-size: clamp(18px, 2vw, 24px);
  font-weight: 700;
  letter-spacing: 0.06em;
  line-height: 1.4;
}

.card__body {
  max-width: 34em;
  font-size: 16px;
  line-height: 1.85;
  color: rgba(243, 239, 228, 0.78);
}

.card__meta {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--mist);
  opacity: 0.8;
}

.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 3px 9px;
  border: 2px solid var(--edge);
  border-radius: 2px;
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.16em;
  color: var(--mist);
  white-space: nowrap;
}

.tag--cyan { border-color: rgba(63, 224, 208, 0.5); color: var(--cyan); }
.tag--violet { border-color: rgba(154, 107, 255, 0.55); color: var(--violet); }
.tag--amber { border-color: rgba(240, 180, 87, 0.5); color: var(--amber); }
.tag--moss { border-color: rgba(110, 156, 127, 0.6); color: var(--moss); }

.ledger {
  overflow: hidden;
  background: var(--panel);
  border: 2px solid var(--edge);
  border-radius: var(--radius);
  box-shadow: var(--shadow-hard);
}

.ledger__row {
  display: grid;
  grid-template-columns: 1fr;
  gap: 6px;
  padding: 14px 18px;
  border-bottom: 1px solid rgba(43, 55, 70, 0.9);
}

.ledger__row:last-child { border-bottom: 0; }

.ledger__key {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--mist);
}

.ledger__value {
  font-size: 16px;
  color: rgba(243, 239, 228, 0.86);
}

.chapter-marker {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 14px 0;
  border-top: 2px solid var(--edge);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.24em;
  color: var(--mist);
  transition: color 0.2s ease, border-color 0.2s ease;
}

.chapter-marker::before {
  content: "";
  flex: 0 0 auto;
  width: 48px;
  height: 2px;
  background: var(--clay);
}

.chapter-marker__num {
  font-weight: 600;
  color: var(--amber);
}

.chapter-marker__label { letter-spacing: 0.18em; }

.chapter-marker.is-current {
  color: var(--cyan);
  border-top-color: rgba(63, 224, 208, 0.5);
}

.chapter-marker.is-current .chapter-marker__num { color: var(--cyan); }

/* ---------- 14. 图片容器 ---------- */
.media-frame {
  position: relative;
  overflow: hidden;
  background: var(--panel);
  border: 2px solid var(--edge);
  border-radius: var(--radius);
  box-shadow: var(--shadow-hard);
}

.media-frame__media {
  position: relative;
  aspect-ratio: 16 / 9;
  background:
    linear-gradient(135deg, rgba(63, 224, 208, 0.13), rgba(154, 107, 255, 0.13)),
    repeating-linear-gradient(90deg, rgba(43, 55, 70, 0.6) 0 1px, transparent 1px 22px),
    repeating-linear-gradient(0deg, rgba(43, 55, 70, 0.6) 0 1px, transparent 1px 22px),
    var(--panel);
}

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

.media-frame--wide .media-frame__media { aspect-ratio: 21 / 9; }
.media-frame--tall .media-frame__media { aspect-ratio: 4 / 5; }

.media-frame__cap {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  padding: 10px 14px;
  border-top: 2px solid var(--edge);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--mist);
}

/* ---------- 15. 面包屑 ---------- */
.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--mist);
}

.breadcrumb__item {
  display: inline-flex;
  align-items: center;
  gap: 10px;
}

.breadcrumb__item + .breadcrumb__item::before {
  content: "/";
  color: rgba(168, 180, 194, 0.4);
}

.breadcrumb__item[aria-current="page"] { color: var(--paper); }

.breadcrumb__item a:hover,
.breadcrumb__item a:focus-visible { color: var(--cyan); }

/* ---------- 16. 滚动显现 ---------- */
[data-reveal] {
  opacity: 0.6;
  transition: opacity 0.24s ease;
}

[data-reveal].is-visible { opacity: 1; }

/* ---------- 17. 平板 ---------- */
@media (min-width: 720px) {
  .footer-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }

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

  .ledger__row {
    grid-template-columns: 168px minmax(0, 1fr) auto;
    align-items: center;
    gap: 18px;
  }
}

/* ---------- 18. 桌面：左侧固定轨道 ---------- */
@media (min-width: 1024px) {
  body { padding-left: var(--rail-w); }

  .site-header {
    position: fixed;
    top: 0;
    bottom: 0;
    left: 0;
    width: var(--rail-w);
    height: 100vh;
    flex-direction: column;
    align-items: stretch;
    justify-content: flex-start;
    gap: 0;
    padding: 22px 0 18px;
    background: transparent;
    border-bottom: 0;
  }

  .site-header::before {
    content: "";
    position: absolute;
    inset: 0 auto 0 0;
    z-index: -1;
    width: 100%;
    background: linear-gradient(180deg, var(--panel) 0%, #101927 62%, var(--ink) 100%);
    border-right: var(--line);
    transition: width 0.28s ease, border-color 0.28s ease;
  }

  .site-header[data-condensed] { padding-right: calc(var(--rail-w) - var(--rail-w-compact)); }
  .site-header[data-condensed]::before {
    width: var(--rail-w-compact);
    border-right-color: rgba(63, 224, 208, 0.6);
  }

  /* 品牌竖排 */
  .rail-brand {
    flex-direction: column;
    align-items: center;
    gap: 12px;
    padding: 0 6px 20px;
  }

  .rail-brand__mark {
    writing-mode: horizontal-tb;
    text-orientation: mixed;
    font-size: 14px;
    padding: 3px 6px;
  }

  .rail-brand__name {
    writing-mode: vertical-rl;
    text-orientation: upright;
    font-size: 14px;
    letter-spacing: 0.3em;
    transition: opacity 0.2s ease, visibility 0.2s ease;
  }

  .rail-brand__sub {
    display: block;
    writing-mode: vertical-rl;
    text-orientation: upright;
    font-family: var(--font-mono);
    font-size: 10px;
    letter-spacing: 0.3em;
    color: var(--mist);
    opacity: 0.6;
    transition: opacity 0.2s ease, visibility 0.2s ease;
  }

  .site-header[data-condensed] .rail-brand__name,
  .site-header[data-condensed] .rail-brand__sub {
    opacity: 0;
    visibility: hidden;
  }

  /* 导航竖排标签列 */
  .site-nav {
    position: static;
    inset: auto;
    z-index: auto;
    flex: 1 1 auto;
    justify-content: flex-start;
    align-items: center;
    padding: 16px 0;
    background: none;
    border-top: 0;
    overflow-y: auto;
    opacity: 1;
    visibility: visible;
    transform: none;
    scrollbar-width: none;
    transition: none;
  }

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

  .site-nav__list {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 16px;
    width: auto;
  }

  .site-nav__item { border-bottom: 0; }

  .site-nav__link {
    display: block;
    writing-mode: vertical-rl;
    text-orientation: upright;
    padding: 10px 5px;
    font-size: 14px;
    border: 2px solid transparent;
    border-radius: 2px;
    transition: color 0.2s ease, border-color 0.2s ease, background 0.2s ease, box-shadow 0.2s ease;
  }

  .site-nav__num {
    display: inline;
    font-size: 10px;
    letter-spacing: 0.2em;
    margin-right: 0;
  }

  .site-nav__label {
    font-size: 14px;
    font-weight: 600;
    letter-spacing: 0.28em;
  }

  .site-nav__link:hover,
  .site-nav__link:focus-visible {
    color: var(--cyan);
    border-color: var(--edge);
    background: rgba(22, 32, 46, 0.9);
  }

  .site-nav__link[aria-current="page"] {
    color: var(--cyan);
    border-color: rgba(63, 224, 208, 0.5);
    background: rgba(63, 224, 208, 0.07);
    box-shadow: 0 0 18px rgba(63, 224, 208, 0.16);
  }

  .rail-foot {
    display: block;
    padding: 16px 6px 0;
    border-top: 1px solid rgba(43, 55, 70, 0.85);
    text-align: center;
  }

  .rail-foot__code {
    display: inline-block;
    writing-mode: vertical-rl;
    text-orientation: upright;
    font-family: var(--font-mono);
    font-size: 9px;
    letter-spacing: 0.2em;
    color: var(--mist);
    opacity: 0.55;
  }

  .nav-toggle,
  .quick-bar { display: none; }

  .site-footer { padding-bottom: clamp(48px, 6vw, 84px); }

  .to-top { right: 32px; bottom: 32px; }

  .split { grid-template-columns: minmax(180px, 240px) minmax(0, 1fr); }
}

/* ---------- 19. 宽屏 ---------- */
@media (min-width: 1080px) {
  .grid--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
}

@media (min-width: 1180px) {
  .footer-grid { grid-template-columns: 1.3fr 0.8fr 0.8fr 1.5fr; }
}

/* ---------- 20. 减弱动效 ---------- */
@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;
  }

  [data-reveal] { opacity: 1; }

  .to-top,
  .scroll-progress__bar { transition: none; }
}