/* =====================================================================
   长城看台 · 共享样式 /assets/site.css
   L0 状态条 — L1 拼贴首屏 — L2 数据锚点 — L3 错落卡片 — L4 刻度收束
   ===================================================================== */

/* ---------- 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, figure, blockquote, dl, dd, ul, ol {
  margin: 0;
}

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

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

button, input, select, textarea {
  font: inherit;
  color: inherit;
  background: none;
  border: 0;
  border-radius: 0;
}

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

main { display: block; }

[hidden] { display: none !important; }

/* ---------- 2. 变量 ---------- */
:root {
  /* 色彩体系 */
  --night: #0D141B;
  --slate: #1B2A38;
  --concrete: #E8E4DC;
  --fog: #F7F5F1;
  --brick: #A8A29A;
  --amber: #F2A03D;
  --amber-deep: #C9761A;
  --alert: #D3442F;
  --jade: #2FA36B;
  --blue: #3E7CB1;

  /* 框架尺寸 */
  --rail: 76px;
  --bar-h: 60px;

  /* 网格 */
  --max: 1320px;
  --gut: 24px;

  /* 字体 */
  --font-display: "Oswald", "Source Han Sans SC", "HarmonyOS Sans", "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
  --font-body: "Source Han Sans SC", "HarmonyOS Sans", "PingFang SC", "Microsoft YaHei", system-ui, -apple-system, sans-serif;
  --font-data: "JetBrains Mono", "DM Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;

  --ease: cubic-bezier(.22, .61, .36, 1);
}

/* ---------- 3. 基础排版 ---------- */
body {
  min-height: 100vh;
  padding-top: var(--bar-h);
  padding-left: var(--rail);
  font-family: var(--font-body);
  font-size: 17px;
  line-height: 1.75;
  color: var(--fog);
  background-color: var(--night);
  background-image:
    radial-gradient(circle at 84% -8%, rgba(62, 124, 177, .20), transparent 56%),
    radial-gradient(circle at 6% 108%, rgba(242, 160, 61, .10), transparent 52%),
    repeating-linear-gradient(180deg, rgba(168, 162, 154, .05) 0 1px, transparent 1px 32px);
  background-attachment: fixed;
  transition: padding-left .25s var(--ease);
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-display);
  font-weight: 700;
  line-height: 1.12;
  letter-spacing: .04em;
}

p { max-width: 72ch; }

::selection {
  background: var(--amber);
  color: var(--night);
}

:where(a, button, input, [tabindex]):focus-visible {
  outline: 2px solid var(--amber);
  outline-offset: 3px;
}

/* ---------- 4. Skip link ---------- */
.skip-link {
  position: fixed;
  top: 10px;
  left: 10px;
  z-index: 200;
  padding: 10px 20px;
  background: var(--amber);
  color: var(--night);
  font-family: var(--font-data);
  font-size: 13px;
  letter-spacing: .1em;
  transform: translateY(-180%);
  transition: transform .18s var(--ease);
}

.skip-link:focus,
.skip-link:focus-visible {
  transform: translateY(0);
  outline: 2px solid var(--fog);
  outline-offset: 3px;
}

/* ---------- 5. 页头：看台边框 ---------- */
.site-header {
  position: fixed;
  inset: 0;
  z-index: 90;
  pointer-events: none;
}

/* 5.1 左侧竖向索引条 */
.site-rail {
  position: absolute;
  top: 0;
  left: 0;
  bottom: 0;
  width: var(--rail);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 26px;
  padding: 16px 0 24px;
  overflow-y: auto;
  scrollbar-width: none;
  pointer-events: auto;
  background-color: var(--night);
  background-image:
    linear-gradient(180deg, rgba(242, 160, 61, .12), transparent 42%),
    repeating-linear-gradient(180deg, rgba(168, 162, 154, .08) 0 1px, transparent 1px 26px);
  border-right: 1px solid rgba(168, 162, 154, .22);
}

.site-rail::-webkit-scrollbar { width: 0; }

.rail-brand {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
  padding: 4px 0 14px;
  border-bottom: 1px solid rgba(168, 162, 154, .2);
  transition: opacity .16s var(--ease);
}

.rail-brand__mark {
  writing-mode: vertical-rl;
  font-family: var(--font-display);
  font-size: 17px;
  font-weight: 700;
  letter-spacing: .22em;
  color: var(--fog);
}

.rail-brand__tag {
  writing-mode: vertical-rl;
  font-family: var(--font-data);
  font-size: 9px;
  letter-spacing: .34em;
  color: var(--amber);
}

.rail-brand:hover .rail-brand__mark { color: var(--amber); }

.rail-nav { width: 100%; }

.rail-nav__list {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2px;
}

.rail-nav__item { width: 100%; }

.rail-nav__link {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 7px;
  padding: 11px 0;
  color: var(--brick);
  transition: color .16s var(--ease), background-color .16s var(--ease);
}

.rail-nav__link::before {
  content: "";
  position: absolute;
  top: 10%;
  bottom: 10%;
  left: 0;
  width: 2px;
  background: var(--amber);
  transform: scaleY(0);
  transform-origin: top;
  transition: transform .22s var(--ease);
}

.rail-nav__index {
  font-family: var(--font-data);
  font-size: 10px;
  letter-spacing: .12em;
  color: var(--brick);
  transition: color .16s var(--ease);
}

.rail-nav__label {
  writing-mode: vertical-rl;
  font-size: 12px;
  letter-spacing: .16em;
  line-height: 1.2;
}

.rail-nav__link:hover {
  color: var(--fog);
  background-color: rgba(247, 245, 241, .05);
}

.rail-nav__link:hover::before { transform: scaleY(1); }
.rail-nav__link:hover .rail-nav__index { color: var(--amber); }

.rail-nav__link[aria-current="page"] {
  color: var(--fog);
  background-color: rgba(242, 160, 61, .13);
}

.rail-nav__link[aria-current="page"]::before { transform: scaleY(1); }
.rail-nav__link[aria-current="page"] .rail-nav__index { color: var(--amber); }

/* 5.2 顶部贯通状态条 */
.site-topbar {
  position: absolute;
  top: 0;
  left: var(--rail);
  right: 0;
  height: var(--bar-h);
  display: flex;
  align-items: center;
  gap: 18px;
  padding: 0 22px 0 20px;
  pointer-events: auto;
  background: rgba(13, 20, 27, .94);
  -webkit-backdrop-filter: blur(10px);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid rgba(168, 162, 154, .22);
  transition: border-color .2s var(--ease), box-shadow .2s var(--ease);
}

.site-header[data-scrolled] .site-topbar {
  border-bottom-color: rgba(242, 160, 61, .45);
  box-shadow: 0 12px 30px rgba(0, 0, 0, .45);
}

.top-status {
  display: flex;
  align-items: center;
  gap: 8px;
  flex: none;
  max-width: none;
  font-family: var(--font-data);
  font-size: 11px;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--brick);
  white-space: nowrap;
}

.top-status__dot {
  width: 6px;
  height: 6px;
  flex: none;
  border-radius: 50%;
  background: var(--jade);
  box-shadow: 0 0 0 3px rgba(47, 163, 107, .18);
}

.top-status__sep { color: rgba(168, 162, 154, .6); }

.top-status__ver { color: var(--amber); }

/* 5.3 站内检索 */
.site-search {
  position: relative;
  display: flex;
  align-items: center;
  gap: 10px;
  flex: 1 1 auto;
  max-width: 380px;
  margin-left: auto;
  padding-bottom: 4px;
  border-bottom: 1px solid rgba(168, 162, 154, .42);
  transition: border-color .16s var(--ease);
}

.site-search:focus-within { border-bottom-color: var(--blue); }

.site-search__label {
  flex: none;
  font-family: var(--font-data);
  font-size: 10px;
  letter-spacing: .18em;
  text-transform: uppercase;
  color: var(--brick);
}

.site-search__input {
  flex: 1 1 auto;
  min-width: 0;
  padding: 2px 0;
  font-family: var(--font-body);
  font-size: 14px;
  line-height: 1.4;
  color: var(--fog);
  outline: none;
}

.site-search__input::placeholder { color: rgba(168, 162, 154, .78); }

.site-search__input::-webkit-search-cancel-button { -webkit-appearance: none; }

.site-search__clear {
  flex: none;
  padding: 2px 7px;
  font-family: var(--font-data);
  font-size: 10px;
  letter-spacing: .12em;
  color: var(--brick);
  cursor: pointer;
  transition: color .16s var(--ease);
}

.site-search__clear:hover { color: var(--amber); }

/* 5.4 视图切换 */
.view-switch {
  display: inline-flex;
  flex: none;
  border: 1px solid rgba(168, 162, 154, .38);
}

.view-switch__btn {
  padding: 6px 12px;
  font-family: var(--font-data);
  font-size: 11px;
  letter-spacing: .14em;
  color: var(--brick);
  cursor: pointer;
  transition: background-color .16s var(--ease), color .16s var(--ease);
}

.view-switch__btn + .view-switch__btn {
  border-left: 1px solid rgba(168, 162, 154, .38);
}

.view-switch__btn:hover { color: var(--fog); }

.view-switch__btn[aria-pressed="true"] {
  background: var(--amber);
  color: var(--night);
}

/* 5.5 移动导航按钮 */
.nav-toggle {
  display: none;
  flex: none;
  align-items: center;
  justify-content: center;
  padding: 8px 14px;
  font-family: var(--font-data);
  font-size: 11px;
  letter-spacing: .16em;
  color: var(--fog);
  border: 1px solid rgba(168, 162, 154, .45);
  cursor: pointer;
  transition: background-color .16s var(--ease), color .16s var(--ease), border-color .16s var(--ease);
}

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

.nav-toggle[aria-expanded="true"] {
  background: var(--amber);
  border-color: var(--amber);
  color: var(--night);
}

/* 5.6 滚动进度 */
.scroll-progress {
  position: absolute;
  left: 0;
  bottom: -1px;
  width: 0;
  height: 2px;
  pointer-events: none;
  background: linear-gradient(90deg, var(--amber), var(--jade));
  transition: width .12s linear;
}

/* ---------- 6. 页脚：四段刻度条 ---------- */
.site-footer {
  position: relative;
  margin-top: clamp(56px, 8vw, 120px);
  color: var(--fog);
  background-color: var(--night);
  background-image:
    repeating-linear-gradient(180deg, rgba(168, 162, 154, .055) 0 1px, transparent 1px 28px);
  border-top: 1px solid rgba(168, 162, 154, .26);
}

.footer-inner {
  max-width: var(--max);
  margin-inline: auto;
  padding: clamp(36px, 5vw, 64px) clamp(20px, 4vw, 40px) clamp(28px, 4vw, 44px);
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 34px 42px;
  border-bottom: 1px solid rgba(168, 162, 154, .16);
}

.footer-col { min-width: 0; }

.footer-col__title {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 18px;
  font-family: var(--font-display);
  font-size: 13px;
  font-weight: 600;
  letter-spacing: .18em;
  color: var(--fog);
  white-space: nowrap;
}

.footer-col__title::after {
  content: "";
  flex: 1 1 auto;
  min-width: 20px;
  height: 8px;
  background-image: repeating-linear-gradient(90deg, var(--brick) 0 1px, transparent 1px 7px);
  opacity: .45;
}

.footer-col__idx {
  font-family: var(--font-data);
  font-size: 11px;
  letter-spacing: .1em;
  color: var(--amber);
}

.footer-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.footer-list__item {
  display: flex;
  align-items: flex-start;
  gap: 9px;
  font-size: 15px;
  line-height: 1.65;
  color: var(--brick);
  overflow-wrap: anywhere;
}

.footer-tick {
  flex: none;
  width: 7px;
  height: 7px;
  margin-top: 9px;
  background: var(--brick);
}

.footer-list__item[data-tone="amber"] .footer-tick { background: var(--amber); }
.footer-list__item[data-tone="alert"] .footer-tick { background: var(--alert); }
.footer-list__item[data-tone="jade"] .footer-tick { background: var(--jade); }
.footer-list__item[data-tone="blue"] .footer-tick { background: var(--blue); }

.footer-link {
  position: relative;
  display: inline-block;
  color: var(--brick);
  transition: color .16s var(--ease);
}

.footer-link::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: -2px;
  height: 1px;
  background: var(--amber);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform .22s var(--ease);
}

.footer-link:hover { color: var(--fog); }
.footer-link:hover::after { transform: scaleX(1); }

.footer-base {
  max-width: var(--max);
  margin-inline: auto;
  padding: 20px clamp(20px, 4vw, 40px) clamp(30px, 4vw, 44px);
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 10px 28px;
  font-family: var(--font-data);
  font-size: 12px;
  letter-spacing: .1em;
  color: var(--brick);
}

.footer-brand {
  max-width: none;
  display: inline-flex;
  align-items: baseline;
  gap: 10px;
  font-family: var(--font-display);
  font-size: 14px;
  font-weight: 700;
  letter-spacing: .22em;
  color: var(--fog);
}

.footer-brand__tag {
  font-family: var(--font-data);
  font-size: 10px;
  font-weight: 400;
  letter-spacing: .24em;
  color: var(--amber);
}

.footer-copy { max-width: none; margin-left: auto; }

.footer-note { max-width: none; color: rgba(168, 162, 154, .8); }

/* ---------- 7. 通用容器与板块 ---------- */
.shell {
  width: 100%;
  max-width: var(--max);
  margin-inline: auto;
  padding-inline: clamp(20px, 4vw, 40px);
}

.section { padding-block: clamp(48px, 7vw, 96px); }
.section--tight { padding-block: clamp(30px, 4vw, 56px); }
.section--slate { background: var(--slate); }
.section--concrete {
  background: var(--concrete);
  color: var(--slate);
}
.section--concrete .lede,
.section--concrete .eyebrow { color: #4C5763; }
.section--concrete .section__idx { color: var(--amber-deep); }
.section--concrete .section__head { border-bottom-color: rgba(27, 42, 56, .25); }

.section__head {
  display: flex;
  align-items: baseline;
  flex-wrap: wrap;
  gap: 8px 14px;
  padding-bottom: 14px;
  margin-bottom: 30px;
  border-bottom: 1px solid rgba(168, 162, 154, .3);
}

.section__idx {
  font-family: var(--font-data);
  font-size: 12px;
  letter-spacing: .18em;
  color: var(--amber);
}

.section__title {
  font-size: clamp(24px, 3vw, 40px);
  letter-spacing: .04em;
}

.eyebrow {
  font-family: var(--font-data);
  font-size: 12px;
  letter-spacing: .18em;
  text-transform: uppercase;
  color: var(--brick);
}

.lede {
  max-width: 62ch;
  font-size: clamp(17px, 1.5vw, 20px);
  line-height: 1.78;
  color: var(--brick);
}

.rule {
  height: 1px;
  border: 0;
  margin: 0;
  background: rgba(168, 162, 154, .32);
}

/* ---------- 8. 按钮 ---------- */
.btn {
  position: relative;
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 12px 24px;
  isolation: isolate;
  overflow: hidden;
  font-family: var(--font-data);
  font-size: 13px;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: var(--fog);
  border: 1px solid rgba(247, 245, 241, .5);
  cursor: pointer;
  transition: color .22s var(--ease), border-color .16s var(--ease);
}

.btn::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: -1;
  background: var(--amber);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform .22s var(--ease);
}

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

.btn:hover::before,
.btn:focus-visible::before { transform: scaleX(1); }

.btn--solid {
  color: var(--night);
  background: var(--amber);
  border-color: var(--amber);
}

.btn--solid::before { background: var(--fog); }

/* ---------- 9. 面包屑 ---------- */
.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  padding-block: 20px;
  font-family: var(--font-data);
  font-size: 12px;
  letter-spacing: .14em;
  color: var(--brick);
}

.breadcrumb__item {
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

.breadcrumb__item + .breadcrumb__item::before {
  content: "/";
  color: rgba(168, 162, 154, .55);
}

.breadcrumb a { transition: color .16s var(--ease); }
.breadcrumb a:hover { color: var(--amber); }

/* ---------- 10. 图片容器 ---------- */
.media-frame {
  position: relative;
  display: block;
  overflow: hidden;
  background: var(--slate);
  border-radius: 2px;
}

.media-frame--16x9 { aspect-ratio: 16 / 9; }

.media-frame--badge {
  aspect-ratio: 1 / 1;
  border-radius: 50%;
  border: 1px solid rgba(168, 162, 154, .35);
}

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

.media-frame__label {
  position: absolute;
  right: 10px;
  bottom: 10px;
  padding: 3px 9px;
  font-family: var(--font-data);
  font-size: 11px;
  letter-spacing: .12em;
  color: var(--fog);
  background: rgba(13, 20, 27, .74);
  -webkit-backdrop-filter: blur(4px);
  backdrop-filter: blur(4px);
}

/* ---------- 11. 标签与数字 ---------- */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 3px 9px;
  font-family: var(--font-data);
  font-size: 11px;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--brick);
  border: 1px solid currentColor;
}

.tag--amber { color: var(--amber); }
.tag--alert { color: var(--alert); }
.tag--jade { color: var(--jade); }
.tag--blue { color: var(--blue); }

.section--concrete .tag--amber { color: var(--amber-deep); }

.data-num {
  font-family: var(--font-data);
  font-variant-numeric: tabular-nums;
  letter-spacing: .02em;
}

/* ---------- 12. 网格 ---------- */
.grid {
  display: grid;
  gap: var(--gut);
}

.grid--12 { grid-template-columns: repeat(12, minmax(0, 1fr)); }

/* ---------- 13. 工具类 ---------- */
.visually-hidden {
  position: absolute !important;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  clip-path: inset(50%);
  white-space: nowrap;
  border: 0;
}

/* ---------- 14. 视图切换实际效果 ---------- */
html[data-view="mobile"] main {
  max-width: 520px;
  margin-inline: auto;
  border-inline: 1px solid rgba(168, 162, 154, .18);
  transition: max-width .3s var(--ease);
}

html[data-view="mobile"] .footer-inner { max-width: 520px; }

/* ---------- 15. 响应式 ---------- */
@media (max-width: 1100px) {
  .footer-inner { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .site-search { max-width: 300px; }
}

@media (max-width: 900px) {
  :root {
    --rail: 0px;
    --bar-h: 56px;
  }

  body { padding-left: 0; }

  /* 索引条变为下滑面板 */
  .site-rail {
    top: var(--bar-h);
    bottom: auto;
    left: 0;
    width: 100%;
    max-height: calc(100vh - var(--bar-h));
    align-items: stretch;
    gap: 0;
    padding: 6px 0 18px;
    overflow-y: auto;
    border-right: 0;
    border-bottom: 1px solid rgba(168, 162, 154, .26);
    background-color: var(--night);
    background-image: repeating-linear-gradient(180deg, rgba(168, 162, 154, .06) 0 1px, transparent 1px 26px);
    transform: translateY(-14px);
    opacity: 0;
    visibility: hidden;
    transition: opacity .2s var(--ease), transform .2s var(--ease), visibility .2s linear;
  }

  .site-rail[data-open] {
    transform: translateY(0);
    opacity: 1;
    visibility: visible;
  }

  .rail-brand {
    flex-direction: row;
    align-items: baseline;
    justify-content: flex-start;
    gap: 12px;
    padding: 12px 20px 16px;
    border-bottom: 1px solid rgba(168, 162, 154, .18);
  }

  .rail-brand__mark,
  .rail-brand__tag,
  .rail-nav__label { writing-mode: horizontal-tb; }

  .rail-brand__mark { font-size: 18px; letter-spacing: .2em; }
  .rail-brand__tag { font-size: 10px; letter-spacing: .28em; }

  .rail-nav__list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
  }

  .rail-nav__link {
    flex-direction: row;
    align-items: center;
    justify-content: flex-start;
    gap: 14px;
    padding: 14px 20px;
    border-bottom: 1px solid rgba(168, 162, 154, .12);
  }

  .rail-nav__link::before {
    top: 0;
    bottom: 0;
    left: 0;
    width: 3px;
    transform: scaleY(0);
    transform-origin: center;
  }

  .rail-nav__link:hover::before,
  .rail-nav__link[aria-current="page"]::before { transform: scaleY(1); }

  .rail-nav__index { font-size: 11px; width: 22px; }
  .rail-nav__label { font-size: 15px; letter-spacing: .1em; }

  .site-topbar {
    left: 0;
    gap: 12px;
    padding: 0 14px 0 16px;
  }

  .site-search { max-width: none; }
  .top-status { font-size: 10px; letter-spacing: .12em; }
  .nav-toggle { display: inline-flex; }
}

@media (max-width: 680px) {
  .view-switch { display: none; }
  .top-status__sep,
  .top-status__ver { display: none; }
  .site-search { flex: 1 1 auto; min-width: 0; }
  .site-search__label { display: none; }
  .site-search__input { font-size: 13px; }
  .site-search__input::placeholder { font-size: 12px; }
  .site-search__clear { padding: 2px 4px; }

  .footer-inner {
    grid-template-columns: 1fr;
    gap: 28px;
  }

  .footer-copy { margin-left: 0; width: 100%; }
  .footer-note { width: 100%; }

  .grid--12 { grid-template-columns: repeat(6, minmax(0, 1fr)); }

  html[data-view="mobile"] main { border-inline: 0; }
}

/* ---------- 16. 减少动效 ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }

  *,
  *::before,
  *::after {
    animation-duration: .001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .001ms !important;
    scroll-behavior: auto !important;
  }

  .scroll-progress { transition: none; }
}