/* ============================================================
   3499游戏主站 · 共享样式 /assets/site.css
   深空仪表盘 + 奶油档案卡 + 五档色阶
   ============================================================ */

/* ---------- 1. 变量 ---------- */
:root {
  --bg: #070C16;
  --panel: #0E1626;
  --line: #1E2B42;
  --line-soft: rgba(30, 43, 66, 0.6);
  --paper: #F2E7D2;
  --paper-ink: #1B120C;
  --cyan: #2BE3D6;
  --magenta: #FF3E8F;
  --amber: #FFB33C;
  --rust: #C93C1B;
  --gray: #8A9AB2;

  --t1: #5FD1E8;
  --t2: #2BE3D6;
  --t3: #FFB33C;
  --t4: #FF3E8F;
  --t5: #C93C1B;

  --fg: #EFE6D6;
  --fg-2: #B6C2D2;

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

  --ease: cubic-bezier(0.22, 0.61, 0.36, 1);
  --dur: 160ms;

  --rail-w: 132px;
  --bar-h: 56px;
  --util-h: 26px;
  --rail-bar: 42px;
  --header-h: calc(var(--bar-h) + var(--util-h));
}

[data-tier="1"] { --tier: var(--t1); }
[data-tier="2"] { --tier: var(--t2); }
[data-tier="3"] { --tier: var(--t3); }
[data-tier="4"] { --tier: var(--t4); }
[data-tier="5"] { --tier: var(--t5); }

/* ---------- 2. Reset ---------- */
*,
*::before,
*::after { box-sizing: border-box; }

html {
  -webkit-text-size-adjust: 100%;
  scroll-padding-top: calc(var(--header-h) + 24px);
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: var(--font-body);
  font-size: 16px;
  font-weight: 400;
  line-height: 1.7;
  padding-top: calc(var(--bar-h) + var(--util-h) + var(--rail-bar));
  padding-left: 0;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

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

h1, h2, h3, h4, h5, h6 { margin: 0; font-weight: 700; line-height: 1.25; }

p { margin: 0 0 1em; }

ul, ol { margin: 0; }

button { font: inherit; color: inherit; }

table { border-collapse: collapse; }

a {
  color: var(--cyan);
  text-decoration: none;
  transition: color var(--dur) var(--ease), background-color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

a:hover { text-decoration: underline; text-underline-offset: 3px; }

:where(a, button, input, [tabindex]):focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 2px;
  box-shadow: 0 0 0 1px var(--bg);
}

.visually-hidden {
  position: absolute !important;
  width: 1px; height: 1px;
  margin: -1px; padding: 0;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
  border: 0;
}

/* ---------- 3. 跳转链接 ---------- */
.skip-link {
  position: fixed;
  top: 8px;
  left: 8px;
  z-index: 200;
  padding: 10px 18px;
  background: var(--cyan);
  color: #04120F;
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 0.04em;
  transform: translateY(-180%);
  transition: transform var(--dur) var(--ease);
}

.skip-link:focus {
  transform: translateY(0);
  text-decoration: none;
}

/* ---------- 4. 容器与栅格 ---------- */
.shell {
  width: 100%;
  max-width: 1240px;
  margin: 0 auto;
  padding: 0 24px;
}

.grid { display: grid; gap: 20px; }
.grid--12 { grid-template-columns: repeat(12, minmax(0, 1fr)); }
.grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid--4 { grid-template-columns: repeat(4, minmax(0, 1fr)); }
.grid--auto { grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); }

/* ---------- 5. 页头外壳 ---------- */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 80;
  background: var(--panel);
  border-bottom: 1px solid var(--line);
}

.scroll-progress {
  position: absolute;
  left: 0;
  bottom: -1px;
  width: 100%;
  height: 2px;
  background: var(--cyan);
  transform: scaleX(0);
  transform-origin: 0 50%;
  opacity: 0.9;
  pointer-events: none;
}

/* ---------- 6. 命令栏 ---------- */
.command-bar {
  display: flex;
  align-items: stretch;
  min-height: var(--bar-h);
}

.brand {
  flex: 0 0 var(--rail-w);
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding: 0 14px;
  border-right: 1px solid var(--line);
  color: var(--fg);
  text-decoration: none;
}

.brand:hover {
  background: rgba(43, 227, 214, 0.06);
  text-decoration: none;
}

.brand__mark {
  font-family: var(--font-mono);
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.08em;
  line-height: 1.15;
  color: var(--cyan);
}

.brand__name {
  font-family: var(--font-display);
  font-size: 12px;
  letter-spacing: 0.1em;
  line-height: 1.3;
  color: var(--fg-2);
}

.brand__sub {
  font-size: 10px;
  letter-spacing: 0.04em;
  line-height: 1.3;
  color: var(--gray);
}

/* 迷你档位尺 */
.tier-mini {
  display: none;
  align-items: stretch;
  border-right: 1px solid var(--line);
}

.tier-mini__btn {
  width: 34px;
  padding: 0;
  background: transparent;
  border: 0;
  border-top: 3px solid var(--tier, var(--line));
  color: var(--gray);
  font-family: var(--font-mono);
  font-size: 13px;
  cursor: pointer;
  transition: color var(--dur) var(--ease), background-color var(--dur) var(--ease);
}

.tier-mini__btn:hover { color: var(--fg); background: rgba(239, 230, 214, 0.05); }

.tier-mini__btn[data-active="true"] {
  color: var(--tier);
  background: rgba(43, 227, 214, 0.1);
}

/* 命令栏工具区 */
.command-bar__tools {
  margin-left: auto;
  display: flex;
  align-items: stretch;
}

.search-field {
  display: none;
  align-items: center;
  gap: 6px;
  padding: 0 12px;
  border-left: 1px solid var(--line);
}

.search-field__key {
  font-family: var(--font-mono);
  font-size: 11px;
  line-height: 1.4;
  color: var(--gray);
  border: 1px solid var(--line);
  padding: 0 5px;
}

.search-field__input {
  width: 116px;
  padding: 4px 0;
  background: transparent;
  border: 0;
  color: var(--fg);
  font-family: var(--font-body);
  font-size: 13px;
}

.search-field__input::placeholder { color: #5A6A82; }

.search-field:focus-within { background: rgba(43, 227, 214, 0.06); }
.search-field:focus-within .search-field__key { color: var(--cyan); border-color: var(--cyan); }

.fix-link {
  display: inline-flex;
  align-items: center;
  padding: 0 14px;
  border-left: 1px solid var(--line);
  color: var(--gray);
  font-size: 12.5px;
  letter-spacing: 0.06em;
  white-space: nowrap;
  text-decoration: none;
}

.fix-link:hover {
  color: var(--cyan);
  background: rgba(43, 227, 214, 0.07);
  text-decoration: none;
}

.nav-toggle {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 0 16px;
  background: transparent;
  border: 0;
  border-left: 1px solid var(--line);
  color: var(--fg);
  font-size: 13px;
  letter-spacing: 0.04em;
  cursor: pointer;
  transition: background-color var(--dur) var(--ease), color var(--dur) var(--ease);
}

.nav-toggle:hover { background: rgba(43, 227, 214, 0.08); color: var(--cyan); }

.nav-toggle__bars {
  position: relative;
  width: 16px;
  height: 10px;
}

.nav-toggle__bars::before,
.nav-toggle__bars::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  height: 2px;
  background: var(--cyan);
  transition: transform var(--dur) var(--ease);
}

.nav-toggle__bars::before { top: 0; }
.nav-toggle__bars::after { bottom: 0; }

.nav-toggle[aria-expanded="true"] .nav-toggle__bars::before { transform: translateY(4px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle__bars::after { transform: translateY(-4px) rotate(-45deg); }

/* 更新节奏条 */
.utility-strip {
  display: block;
  height: var(--util-h);
  margin: 0;
  padding: 0 16px;
  border-top: 1px solid var(--line);
  background: rgba(7, 12, 22, 0.6);
  color: var(--gray);
  font-family: var(--font-mono);
  font-size: 11.5px;
  line-height: var(--util-h);
  letter-spacing: 0.03em;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

/* ---------- 7. 主导航（移动端折叠面板） ---------- */
.main-nav {
  position: fixed;
  top: var(--header-h);
  left: 0;
  right: 0;
  z-index: 90;
  display: none;
  max-height: calc(100vh - var(--header-h));
  overflow-y: auto;
  background: var(--panel);
  border-bottom: 1px solid var(--line);
}

.main-nav[data-open="true"] { display: block; }

.main-nav__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
}

.main-nav__item {
  display: flex;
  border-bottom: 1px solid var(--line);
}

.main-nav__link {
  display: flex;
  align-items: center;
  gap: 10px;
  width: 100%;
  padding: 14px 18px;
  border-right: 1px solid var(--line);
  color: var(--fg-2);
  font-size: 15px;
  letter-spacing: 0.02em;
  text-decoration: none;
}

.main-nav__link:hover {
  color: var(--cyan);
  background: rgba(43, 227, 214, 0.07);
  text-decoration: none;
}

.main-nav__link[data-hit="false"] { opacity: 0.32; }

.main-nav__link[aria-current="page"],
.main-nav__link[data-active="true"] {
  color: var(--cyan);
  background: rgba(43, 227, 214, 0.09);
  box-shadow: inset 3px 0 0 var(--cyan);
}

.main-nav__num {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.06em;
  color: var(--gray);
}

.main-nav__link[aria-current="page"] .main-nav__num,
.main-nav__link[data-active="true"] .main-nav__num { color: var(--cyan); }

.main-nav__label { display: inline-block; }

/* ---------- 8. 左侧导览轨（移动端为横向档位条） ---------- */
.tier-rail {
  position: fixed;
  top: var(--header-h);
  left: 0;
  right: 0;
  z-index: 70;
  height: var(--rail-bar);
  display: flex;
  flex-direction: row;
  align-items: center;
  gap: 10px;
  padding: 0 8px;
  background: var(--panel);
  border-bottom: 1px solid var(--line);
  overflow-x: auto;
  overflow-y: hidden;
}

.tier-rail__scale {
  display: flex;
  align-items: center;
  gap: 8px;
  flex: 0 0 auto;
}

.tier-rail__cats { display: none; }

.tier-rail__title {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.14em;
  color: var(--gray);
  white-space: nowrap;
}

.tier-scale {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: row;
  gap: 4px;
}

.tier-scale__item { display: block; }

.tier-scale__btn {
  display: flex;
  align-items: center;
  gap: 6px;
  width: auto;
  padding: 4px 8px;
  background: transparent;
  border: 1px solid transparent;
  border-left: 3px solid var(--tier, var(--line));
  color: var(--fg-2);
  text-align: left;
  cursor: pointer;
  transition: background-color var(--dur) var(--ease), border-color var(--dur) var(--ease), color var(--dur) var(--ease);
}

.tier-scale__btn:hover {
  background: rgba(43, 227, 214, 0.08);
  color: var(--fg);
}

.tier-scale__btn[data-active="true"] {
  border-color: var(--cyan);
  border-left-color: var(--tier);
  background: rgba(43, 227, 214, 0.12);
}

.tier-scale__no {
  font-family: var(--font-mono);
  font-size: 15px;
  font-weight: 700;
  line-height: 1;
  color: var(--tier);
}

.tier-scale__range {
  display: none;
  font-family: var(--font-mono);
  font-size: 9.5px;
  letter-spacing: -0.01em;
  color: var(--gray);
  white-space: nowrap;
}

.cat-axis {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
}

.cat-axis__item { border-bottom: 1px solid var(--line-soft); }

.cat-axis__link {
  display: block;
  padding: 5px 2px;
  color: #9FB0C6;
  font-size: 12px;
  letter-spacing: 0.02em;
  text-decoration: none;
  transition: color var(--dur) var(--ease), padding-left var(--dur) var(--ease);
}

.cat-axis__link:hover {
  color: var(--cyan);
  padding-left: 8px;
  text-decoration: none;
}

/* ---------- 9. 通用按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 18px;
  background: transparent;
  border: 1px solid var(--line);
  color: var(--cyan);
  font-family: var(--font-body);
  font-size: 14px;
  letter-spacing: 0.02em;
  text-decoration: none;
  cursor: pointer;
  transition: background-color var(--dur) var(--ease), border-color var(--dur) var(--ease), transform var(--dur) var(--ease);
}

.btn:hover {
  border-color: var(--cyan);
  background: rgba(43, 227, 214, 0.08);
  transform: translateY(-2px);
  text-decoration: none;
}

.btn--solid {
  background: var(--cyan);
  border-color: var(--cyan);
  color: #04120F;
  font-weight: 700;
}

.btn--solid:hover { background: #57F0E4; border-color: #57F0E4; }

.btn--ghost { color: var(--fg-2); }

.btn--ghost:hover { color: var(--cyan); }

/* ---------- 10. 面包屑 ---------- */
.breadcrumb {
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.02em;
  color: var(--gray);
}

.breadcrumb ol {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 0;
  margin: 0;
  padding: 0;
}

.breadcrumb li { display: inline-flex; align-items: center; }

.breadcrumb li + li::before {
  content: "/";
  margin: 0 7px;
  color: var(--line);
}

.breadcrumb a { color: var(--gray); }
.breadcrumb a:hover { color: var(--cyan); }
.breadcrumb [aria-current="page"] { color: var(--fg-2); }

/* ---------- 11. 正文区 ---------- */
.prose {
  max-width: 38em;
  color: var(--fg-2);
  font-size: 16px;
}

.prose h2 {
  font-family: var(--font-display);
  font-size: 26px;
  letter-spacing: 0.02em;
  color: var(--fg);
  margin: 40px 0 12px;
}

.prose h3 {
  font-size: 19px;
  color: var(--cyan);
  margin: 28px 0 10px;
}

.prose p { margin: 0 0 16px; }

.prose ul,
.prose ol { margin: 0 0 16px; padding-left: 20px; }

.prose li { margin-bottom: 6px; }

.prose code {
  font-family: var(--font-mono);
  font-size: 0.92em;
  background: rgba(43, 227, 214, 0.1);
  color: var(--cyan);
  padding: 1px 5px;
}

/* ---------- 12. 章节编号 ---------- */
.chapter-no {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(40px, 7vw, 96px);
  font-weight: 700;
  line-height: 0.9;
  letter-spacing: -0.03em;
  color: rgba(255, 179, 60, 0.18);
}

.chapter-title {
  font-family: var(--font-display);
  font-size: 22px;
  letter-spacing: 0.02em;
  color: var(--fg);
}

/* ---------- 13. 档案纸卡 ---------- */
.paper-card {
  background: var(--paper);
  color: var(--paper-ink);
  border: 1px solid rgba(27, 18, 12, 0.16);
  box-shadow: 0 1px 0 rgba(0, 0, 0, 0.35);
  padding: 22px 24px;
  transition: box-shadow var(--dur) var(--ease), transform var(--dur) var(--ease);
}

.paper-card--lift:hover {
  transform: translateY(-2px);
  box-shadow: 0 3px 0 rgba(0, 0, 0, 0.4);
}

.paper-card h2,
.paper-card h3,
.paper-card h4 { color: var(--paper-ink); }

.paper-card a { color: var(--rust); }
.paper-card a:hover { color: #8F2A12; }

.paper-card code {
  background: rgba(27, 18, 12, 0.08);
  color: var(--paper-ink);
}

/* ---------- 14. 状态标签 ---------- */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  padding: 2px 8px;
  border: 1px solid currentColor;
  color: var(--gray);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.06em;
  line-height: 1.5;
  white-space: nowrap;
}

.tag--new { color: var(--magenta); }
.tag--review { color: var(--cyan); }
.tag--archived { color: #6C7C93; }

.tag--expire {
  background: var(--rust);
  border-color: var(--rust);
  color: var(--paper);
  font-weight: 700;
}

/* ---------- 15. 数据表与定义列表 ---------- */
.data-table {
  width: 100%;
  font-size: 14px;
  border-collapse: collapse;
}

.data-table caption {
  text-align: left;
  padding-bottom: 8px;
  color: var(--gray);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
}

.data-table th,
.data-table td {
  border: 1px solid var(--line);
  padding: 9px 12px;
  text-align: left;
  vertical-align: top;
}

.data-table thead th {
  background: rgba(43, 227, 214, 0.08);
  color: var(--cyan);
  font-size: 12.5px;
  font-weight: 600;
  letter-spacing: 0.04em;
}

.data-table tbody tr:nth-child(even) { background: rgba(14, 22, 38, 0.55); }

.data-table .num { font-family: var(--font-mono); color: var(--amber); }

.paper-card .data-table th,
.paper-card .data-table td {
  border-color: rgba(27, 18, 12, 0.18);
  color: var(--paper-ink);
}

.paper-card .data-table thead th {
  background: rgba(27, 18, 12, 0.07);
  color: var(--paper-ink);
}

.paper-card .data-table tbody tr:nth-child(even) { background: rgba(27, 18, 12, 0.04); }

.paper-card .data-table .num { color: #8F2A12; }

.def-list {
  display: grid;
  grid-template-columns: minmax(110px, auto) 1fr;
  gap: 6px 16px;
  margin: 0;
  font-size: 14px;
}

.def-list dt {
  font-family: var(--font-mono);
  font-size: 12.5px;
  color: var(--gray);
}

.def-list dd {
  margin: 0;
  color: var(--fg-2);
}

.paper-card .def-list dt { color: rgba(27, 18, 12, 0.6); }
.paper-card .def-list dd { color: var(--paper-ink); }

/* ---------- 16. 图片容器 ---------- */
.media-frame {
  position: relative;
  display: block;
  width: 100%;
  overflow: hidden;
  aspect-ratio: 16 / 9;
  background: var(--panel);
  border: 1px solid var(--line);
}

.media-frame > img,
.media-frame > picture > img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.media-frame--wide { aspect-ratio: 21 / 9; }
.media-frame--square { aspect-ratio: 1 / 1; }
.media-frame--tilt { clip-path: polygon(0 0, 100% 4%, 100% 100%, 0 96%); }

.media-frame__scan {
  position: absolute;
  inset: 0;
  background-image: repeating-linear-gradient(180deg, rgba(43, 227, 214, 0.6) 0 1px, transparent 1px 4px);
  opacity: 0.06;
  pointer-events: none;
}

/* ---------- 17. 页脚 ---------- */
.site-footer {
  position: relative;
  margin-top: 72px;
  background: var(--panel);
  border-top: 1px solid var(--line);
  color: var(--fg-2);
}

.tier-band {
  height: 3px;
  width: 100%;
  background: linear-gradient(90deg,
    var(--t1) 0 20%,
    var(--t2) 20% 40%,
    var(--t3) 40% 60%,
    var(--t4) 60% 80%,
    var(--t5) 80% 100%);
}

.site-footer__inner {
  display: grid;
  grid-template-columns: 1fr;
  gap: 32px;
  padding-top: 44px;
  padding-bottom: 32px;
}

.site-footer__logo {
  margin: 0 0 6px;
  font-family: var(--font-display);
  font-size: 20px;
  letter-spacing: 0.04em;
  color: var(--fg);
}

.site-footer__line {
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.06em;
  color: var(--cyan);
}

.site-footer__meta {
  margin: 0;
  font-size: 12.5px;
  line-height: 1.8;
  color: var(--gray);
}

.footer-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 24px 20px;
}

.footer-col__title {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.14em;
  color: var(--gray);
}

.footer-col__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 7px;
}

.footer-col__link {
  color: var(--fg-2);
  font-size: 13.5px;
  text-decoration: none;
}

.footer-col__link:hover { color: var(--cyan); text-decoration: none; }

.footer-contact__item {
  display: flex;
  flex-direction: column;
  gap: 2px;
  margin-bottom: 14px;
}

.footer-contact__label {
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.12em;
  color: var(--gray);
}

.footer-contact__value {
  font-size: 13.5px;
  color: var(--fg);
  word-break: break-all;
}

.footer-contact__note {
  margin: 0;
  font-size: 12px;
  line-height: 1.7;
  color: var(--gray);
}

.copy-btn {
  align-self: flex-start;
  margin-top: 6px;
  padding: 3px 9px;
  background: transparent;
  border: 1px solid var(--line);
  color: var(--gray);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.06em;
  cursor: pointer;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

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

.footer-legal { border-top: 1px solid var(--line); }

.footer-legal__inner {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 20px;
  padding-top: 18px;
  padding-bottom: 30px;
  font-size: 12px;
  line-height: 1.7;
  color: var(--gray);
}

.footer-legal__icp { font-family: var(--font-mono); letter-spacing: 0.04em; }
.footer-legal__copy { color: var(--gray); }
.footer-legal__note { color: #6C7C93; }

/* ---------- 18. 显现 ---------- */
html.is-reveal-ready [data-reveal] {
  opacity: 0;
  transform: translateY(8px);
  transition: opacity 200ms var(--ease), transform 200ms var(--ease);
}

html.is-reveal-ready [data-reveal].is-visible {
  opacity: 1;
  transform: none;
}

/* ---------- 19. 平板 720px+ ---------- */
@media (min-width: 720px) {
  .search-field { display: flex; }

  .site-footer__inner {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 36px 32px;
  }

  .site-footer__brand { grid-column: 1 / -1; }
  .footer-grid { grid-template-columns: repeat(4, minmax(0, 1fr)); }
}

/* ---------- 20. 桌面 1080px+ ---------- */
@media (min-width: 1080px) {
  body {
    padding-top: var(--header-h);
    padding-left: var(--rail-w);
  }

  .tier-mini { display: flex; }

  .nav-toggle { display: none; }

  .main-nav {
    position: static;
    display: block;
    flex: 1 1 auto;
    min-width: 0;
    max-height: none;
    overflow: visible;
    background: transparent;
    border-bottom: 0;
  }

  .main-nav__list {
    flex-direction: row;
    align-items: stretch;
    height: 100%;
  }

  .main-nav__item {
    border-bottom: 0;
    height: 100%;
  }

  .main-nav__link {
    width: auto;
    height: 100%;
    padding: 0 13px;
    font-size: 13.5px;
    white-space: nowrap;
  }

  .main-nav__link[aria-current="page"],
  .main-nav__link[data-active="true"] { box-shadow: inset 0 -2px 0 var(--cyan); }

  .search-field__input { width: 116px; }

  .tier-rail {
    top: var(--header-h);
    right: auto;
    bottom: 0;
    width: var(--rail-w);
    height: auto;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 0;
    border-right: 1px solid var(--line);
    border-bottom: 0;
    overflow-x: hidden;
    overflow-y: auto;
  }

  .tier-rail__scale {
    display: block;
    padding: 14px 10px;
    border-bottom: 1px solid var(--line);
    flex: 0 0 auto;
  }

  .tier-rail__cats {
    display: block;
    padding: 14px 10px;
    flex: 1 1 auto;
  }

  .tier-rail__title { margin: 0 0 10px; }

  .tier-scale {
    flex-direction: column;
    gap: 6px;
  }

  .tier-scale__btn {
    width: 100%;
    padding: 5px 6px;
  }

  .tier-scale__range { display: inline; }

  .site-footer__inner {
    grid-template-columns: minmax(200px, 1fr) minmax(0, 2.4fr) minmax(230px, 1.2fr);
    gap: 40px 32px;
    padding-top: 52px;
  }

  .site-footer__brand { grid-column: auto; }
}

/* ---------- 21. 栅格降级 ---------- */
@media (max-width: 1023px) {
  .grid--12 { grid-template-columns: repeat(6, minmax(0, 1fr)); }
  .grid--4 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (max-width: 899px) {
  .grid--3 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (max-width: 700px) {
  .search-field { display: none; }
}

@media (max-width: 559px) {
  .grid--12,
  .grid--2,
  .grid--3,
  .grid--4 { grid-template-columns: 1fr; }

  .shell { padding: 0 18px; }

  .paper-card { padding: 18px 16px; }

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

  .def-list { grid-template-columns: 1fr; gap: 2px 0; }
  .def-list dd { margin-bottom: 10px; }
}

/* ---------- 22. 降低动效 ---------- */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }

  html.is-reveal-ready [data-reveal] {
    opacity: 1;
    transform: none;
  }

  .btn:hover,
  .paper-card--lift:hover { transform: none; }
}