/* ============================================================
   亚娱真人会馆 · 简体中文版 / assets/site.css
   共享外壳样式：reset / 变量 / 中文排版 / 页头 / 页脚 / 基础组件
   ============================================================ */

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

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: 24px;
}

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

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

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

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

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

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

hr { border: 0; }

/* ---------- 2. Design tokens ---------- */
:root {
  /* 色板 */
  --ink: #14100F;          /* 墨岩黑 */
  --ink-deep: #0B0908;     /* 夜会馆黑 */
  --danxia: #B33A24;       /* 丹霞赭红 · 品牌锚点 */
  --danxia-deep: #7E2716;  /* 赭红深阶 */
  --sand: #D9A441;         /* 沙金 */
  --sand-light: #F1D9A6;   /* 沙金浅阶 */
  --paper: #F7F2EA;        /* 宣纸白 */
  --stone: #E6DFD4;        /* 石灰白 */
  --violet: #5B2E7E;       /* 夜宴紫 · 仅装饰 */
  --neon: #2BB3A3;         /* 霓虹青 · 聚焦描边 */
  --muted: #8A8078;        /* 旁注灰 */

  --ink-a06: rgba(20, 16, 15, .06);
  --ink-a12: rgba(20, 16, 15, .12);
  --paper-a16: rgba(247, 242, 234, .16);
  --paper-a60: rgba(247, 242, 234, .62);
  --paper-a80: rgba(247, 242, 234, .84);

  /* 字体 */
  --font-display: "Source Han Sans SC", "Noto Sans SC", "PingFang SC",
                  "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --font-body: "Source Han Sans SC", "Noto Sans SC", "PingFang SC",
               "Hiragino Sans GB", "Microsoft YaHei", system-ui, sans-serif;
  --font-mono: "JetBrains Mono", "IBM Plex Mono", "SFMono-Regular",
               Consolas, "Courier New", monospace;

  /* 尺度 */
  --shell: 1240px;
  --pad-x: clamp(16px, 4vw, 48px);
  --gap: clamp(20px, 3vw, 40px);
  --section-y: clamp(40px, 6vw, 84px);

  --shadow-1: 0 1px 2px rgba(20, 16, 15, .06);
  --shadow-2: 0 10px 30px rgba(20, 16, 15, .10);
  --hair: 1px solid var(--stone);
  --hair-dark: 1px solid rgba(247, 242, 234, .16);

  --ease: cubic-bezier(.22, .61, .36, 1);
  --radius: 2px;
}

/* ---------- 3. 基础排版 ---------- */
body {
  font-family: var(--font-body);
  font-size: 17px;
  line-height: 1.85;
  letter-spacing: .012em;
  color: var(--ink);
  background-color: var(--paper);
  background-image:
    radial-gradient(1100px 560px at 10% -12%, rgba(217, 164, 65, .10), transparent 62%),
    radial-gradient(900px 520px at 92% -4%, rgba(91, 46, 126, .075), transparent 58%);
  background-attachment: fixed;
  min-height: 100vh;
  text-rendering: optimizeLegibility;
}

#main-content { display: block; scroll-margin-top: 24px; }

/* ---------- 4. 布局容器 ---------- */
.yy-shell {
  width: 100%;
  max-width: var(--shell);
  margin-inline: auto;
  padding-inline: var(--pad-x);
}

.yy-section { padding-block: var(--section-y); }

.yy-rule {
  height: 1px;
  background: var(--stone);
  margin-block: clamp(28px, 4vw, 48px);
}

.yy-rule--dark { background: var(--paper-a16); }

.yy-grid {
  display: grid;
  gap: var(--gap);
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
}

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

/* 左右分屏系统 */
.yy-split {
  display: grid;
  grid-template-columns: minmax(0, 4fr) minmax(0, 8fr);
  gap: var(--gap);
  align-items: start;
}

.yy-split--42 { grid-template-columns: minmax(0, 42fr) minmax(0, 58fr); }
.yy-split--33 { grid-template-columns: minmax(0, 33fr) minmax(0, 67fr); }
.yy-split--25 { grid-template-columns: minmax(0, 25fr) minmax(0, 75fr); }

.yy-aside { position: sticky; top: 28px; }
.yy-col-main { min-width: 0; }

/* 深色分区 */
.yy-dark {
  background: var(--ink-deep);
  color: var(--paper);
  padding-block: var(--section-y);
}

.yy-dark .yy-title,
.yy-dark .yy-mega { color: var(--paper); }
.yy-dark .yy-note { color: var(--paper-a60); }
.yy-dark .yy-text { color: var(--paper-a80); }
.yy-dark .yy-eyebrow { color: var(--paper-a60); }
.yy-dark .yy-card {
  background: rgba(247, 242, 234, .04);
  border-color: var(--paper-a16);
  box-shadow: none;
}
.yy-dark .yy-card:hover { border-color: var(--sand); }
.yy-dark .yy-plate {
  background: rgba(247, 242, 234, .04);
  border-color: var(--paper-a16);
}
.yy-dark .yy-plate__label { color: var(--paper-a60); }
.yy-dark .yy-plate__value { color: var(--paper); }
.yy-dark .yy-tag {
  background: transparent;
  border-color: rgba(217, 164, 65, .5);
  color: var(--sand-light);
}
.yy-dark .yy-accordion,
.yy-dark .yy-accordion__item { border-color: var(--paper-a16); }
.yy-dark .yy-accordion__trigger { color: var(--paper); }
.yy-dark .yy-accordion__panel { color: var(--paper-a80); }
.yy-dark .yy-timeline::before { background: var(--paper-a16); }
.yy-dark .yy-timeline__item::before {
  background: var(--ink-deep);
  border-color: var(--sand);
}

/* ---------- 5. 标题与文字层级 ---------- */
.yy-eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .24em;
  color: var(--muted);
  margin-bottom: 14px;
}

.yy-eyebrow::before {
  content: "";
  width: 26px;
  height: 1px;
  background: var(--danxia);
}

/* 高对比粗黑体标题 · 字距放大 */
.yy-title {
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(28px, 3.4vw, 48px);
  line-height: 1.26;
  letter-spacing: .10em;
  color: var(--ink);
}

/* 细字重超大字号 · 字距收紧（巨型编号 / 批次数字 / 目录页码） */
.yy-mega {
  font-family: var(--font-display);
  font-weight: 200;
  font-size: clamp(56px, 9vw, 148px);
  line-height: 1;
  letter-spacing: -.02em;
  color: var(--ink);
}

.yy-lede {
  font-size: clamp(17px, 1.4vw, 19px);
  line-height: 1.9;
  color: var(--ink);
  max-width: 46em;
}

.yy-text { font-size: 16.5px; color: var(--ink); }

.yy-note {
  font-size: 13.5px;
  line-height: 1.8;
  color: var(--muted);
}

/* ---------- 6. 按钮 / 标签 / 复制 ---------- */
.yy-btn {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 13px 26px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 13px;
  letter-spacing: .18em;
  line-height: 1.4;
  color: var(--ink);
  background: transparent;
  border: 1px solid var(--ink);
  border-radius: var(--radius);
  transition: background .24s var(--ease), color .24s var(--ease),
              border-color .24s var(--ease);
}

.yy-btn--primary {
  background: var(--danxia);
  border-color: var(--danxia);
  color: #FFF6EC;
}
.yy-btn--primary:hover {
  background: var(--danxia-deep);
  border-color: var(--danxia-deep);
}

.yy-btn--ghost:hover {
  background: var(--ink);
  color: var(--paper);
}

.yy-btn--light {
  border-color: var(--paper);
  color: var(--paper);
}
.yy-btn--light:hover {
  background: var(--sand);
  border-color: var(--sand);
  color: var(--ink-deep);
}

.yy-tag {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 5px 11px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .14em;
  line-height: 1.6;
  color: var(--ink);
  background: var(--sand-light);
  border: 1px solid var(--stone);
  border-radius: var(--radius);
  white-space: nowrap;
}

.yy-tag--sand {
  background: var(--sand);
  border-color: var(--sand);
  color: var(--ink-deep);
}

.yy-tag--danxia {
  background: var(--danxia);
  border-color: var(--danxia);
  color: #FFF6EC;
}

.yy-tag--outline {
  background: transparent;
  border-color: var(--ink);
  color: var(--ink);
}

/* 批次号 / 版本号 / 编号复制 */
.yy-copy {
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: .06em;
  color: var(--danxia-deep);
  padding: 0;
  border-bottom: 1px dashed currentColor;
  word-break: break-all;
  text-align: left;
  transition: color .2s var(--ease), border-color .2s var(--ease);
}

.yy-copy:hover { color: var(--danxia); }
.yy-copy[data-copied] { color: var(--neon); border-bottom-color: transparent; }

/* ---------- 7. 说明牌 / 卡片 / 图注 ---------- */
.yy-plate {
  padding: 18px 20px;
  background: var(--paper);
  border: var(--hair);
  border-radius: var(--radius);
  box-shadow: var(--shadow-1);
}

.yy-plate__label {
  display: block;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .20em;
  color: var(--muted);
  margin-bottom: 6px;
}

.yy-plate__value {
  display: block;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 15px;
  letter-spacing: .08em;
  line-height: 1.6;
  color: var(--ink);
}

.yy-card {
  padding: clamp(20px, 2.4vw, 30px);
  background: var(--paper);
  border: var(--hair);
  border-radius: var(--radius);
  box-shadow: var(--shadow-1);
  transition: transform .22s var(--ease), border-color .22s var(--ease),
              box-shadow .22s var(--ease);
}

.yy-card:hover {
  transform: translateY(-2px);
  border-color: var(--danxia);
  box-shadow: var(--shadow-2);
}

/* 图片容器基础规则 */
.yy-figure { margin: 0; }

.yy-figure__media {
  position: relative;
  overflow: hidden;
  aspect-ratio: 16 / 10;
  border: var(--hair);
  border-radius: var(--radius);
  background-color: var(--ink-deep);
  background-image:
    linear-gradient(135deg, #0B0908 0%, #3B1C18 40%, #7E2716 70%, #D9A441 100%);
}

.yy-figure__media--tall { aspect-ratio: 3 / 4; }
.yy-figure__media--wide { aspect-ratio: 21 / 9; }

.yy-figure__media img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  filter: saturate(.94) contrast(1.04);
}

.yy-figure__media::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background: linear-gradient(180deg, rgba(11, 9, 8, 0) 42%, rgba(11, 9, 8, .52) 100%);
}

.yy-figure__caption {
  display: flex;
  gap: 10px;
  margin-top: 10px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .08em;
  line-height: 1.7;
  color: var(--muted);
}

.yy-figure__caption::before {
  content: "图";
  flex: 0 0 auto;
  color: var(--danxia);
}

/* ---------- 8. 批次标签带 ---------- */
.yy-band {
  border-block: var(--hair);
  background: linear-gradient(90deg, rgba(241, 217, 166, .58), rgba(241, 217, 166, 0));
  overflow: hidden;
}

.yy-band__track {
  display: flex;
  gap: 14px;
  padding: 14px 0;
  overflow-x: auto;
  cursor: grab;
  touch-action: pan-x;
  scrollbar-width: none;
  -ms-overflow-style: none;
  scroll-behavior: smooth;
}

.yy-band__track::-webkit-scrollbar { display: none; }
.yy-band__track[data-dragging] { cursor: grabbing; scroll-behavior: auto; }
.yy-band__track[data-dragging] .yy-band__item { pointer-events: none; }

.yy-band__item { flex: 0 0 auto; }

/* ---------- 9. 时间轴 ---------- */
.yy-timeline {
  position: relative;
  padding-left: 28px;
}

.yy-timeline::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 8px;
  bottom: 8px;
  width: 1px;
  background: var(--stone);
}

.yy-timeline__item {
  position: relative;
  padding-bottom: 28px;
}

.yy-timeline__item::before {
  content: "";
  position: absolute;
  left: -28px;
  top: 9px;
  width: 11px;
  height: 11px;
  border-radius: 50%;
  background: var(--paper);
  border: 2px solid var(--sand);
}

.yy-timeline__item[data-node="current"]::before {
  background: var(--danxia);
  border-color: var(--danxia);
}

.yy-timeline__code {
  display: block;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .12em;
  color: var(--danxia-deep);
  margin-bottom: 4px;
}

.yy-timeline__title {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 17px;
  letter-spacing: .08em;
  line-height: 1.6;
  color: var(--ink);
}

.yy-dark .yy-timeline__code { color: var(--sand); }
.yy-dark .yy-timeline__title { color: var(--paper); }

/* ---------- 10. 折叠问答块 ---------- */
.yy-accordion { border-top: var(--hair); }

.yy-accordion__item { border-bottom: var(--hair); }

.yy-accordion__trigger {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 18px;
  width: 100%;
  padding: 18px 2px;
  text-align: left;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 16px;
  letter-spacing: .08em;
  line-height: 1.7;
  color: var(--ink);
}

.yy-accordion__mark {
  flex: 0 0 auto;
  font-family: var(--font-mono);
  font-size: 17px;
  line-height: 1.6;
  color: var(--danxia);
  transition: transform .24s var(--ease);
}

.yy-accordion__trigger[aria-expanded="true"] .yy-accordion__mark { transform: rotate(45deg); }

.yy-accordion__panel {
  padding: 0 2px 22px;
  font-size: 16px;
  line-height: 1.85;
  color: var(--ink);
}

.yy-accordion__panel[hidden] { display: none; }

/* ---------- 11. 面包屑 ---------- */
.yy-breadcrumb { padding-top: 18px; }

.yy-breadcrumb__list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .10em;
  color: var(--muted);
}

.yy-breadcrumb__item { display: inline-flex; align-items: center; gap: 6px; }

.yy-breadcrumb__item::after {
  content: "/";
  color: var(--stone);
}

.yy-breadcrumb__item:last-child::after { display: none; }

.yy-breadcrumb__link:hover { color: var(--danxia); }
.yy-breadcrumb__current { color: var(--ink); }

/* ---------- 12. 反馈条 ---------- */
.yy-feedback {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  padding: clamp(18px, 2.4vw, 26px);
  background: var(--sand-light);
  border: var(--hair);
  border-radius: var(--radius);
}

.yy-feedback__text {
  flex: 1 1 22ch;
  font-size: 15.5px;
  line-height: 1.8;
  color: var(--ink);
}

/* ============================================================
   13. 页头
   ============================================================ */
.site-header {
  position: relative;
  z-index: 120;
  background: rgba(247, 242, 234, .96);
  border-top: 1px solid var(--ink);
  border-bottom: var(--hair);
  backdrop-filter: blur(8px);
}

.skip-link {
  position: absolute;
  left: 16px;
  top: -120px;
  z-index: 200;
  padding: 10px 18px;
  font-size: 13px;
  letter-spacing: .14em;
  color: #FFF6EC;
  background: var(--danxia);
  border-radius: var(--radius);
  transition: top .2s var(--ease);
}

.skip-link:focus { top: 14px; }

.yy-masthead { position: relative; }

.yy-masthead__inner {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto minmax(0, 1fr);
  grid-template-areas: "sig brand idx";
  align-items: center;
  column-gap: 24px;
  width: 100%;
  max-width: var(--shell);
  margin-inline: auto;
  padding: 22px var(--pad-x) 18px;
}

.yy-signature {
  grid-area: sig;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .16em;
  line-height: 1.6;
  color: var(--muted);
  white-space: nowrap;
}

.yy-brand {
  grid-area: brand;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 6px;
  text-align: center;
}

.yy-brand__cn {
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(22px, 2.6vw, 34px);
  line-height: 1.12;
  letter-spacing: .24em;
  text-indent: .24em;
  color: var(--ink);
}

.yy-brand__sub {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .28em;
  text-indent: .28em;
  line-height: 1.6;
  color: var(--muted);
}

.yy-indexbar {
  grid-area: idx;
  justify-self: end;
  display: flex;
  align-items: center;
  gap: 18px;
}

.yy-indexbar__item {
  display: flex;
  flex-direction: column;
  gap: 2px;
  min-width: 0;
}

.yy-indexbar__label {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: .20em;
  line-height: 1.5;
  color: var(--muted);
}

.yy-indexbar__value {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .06em;
  line-height: 1.6;
  color: var(--ink);
  white-space: nowrap;
}

.yy-indexbar__link {
  flex: 0 0 auto;
  padding: 8px 14px;
  font-size: 12px;
  letter-spacing: .14em;
  line-height: 1.5;
  color: var(--ink);
  border: 1px solid var(--ink);
  border-radius: var(--radius);
  transition: background .22s var(--ease), color .22s var(--ease),
              border-color .22s var(--ease);
}

.yy-indexbar__link:hover {
  background: var(--danxia);
  border-color: var(--danxia);
  color: #FFF6EC;
}

.yy-nav-toggle {
  display: none;
  grid-area: toggle;
  justify-self: end;
  align-items: center;
  gap: 10px;
  padding: 8px 12px;
  font-size: 12px;
  letter-spacing: .16em;
  line-height: 1.5;
  color: var(--ink);
  border: 1px solid var(--ink);
  border-radius: var(--radius);
}

.yy-nav-toggle__label { font-family: var(--font-display); font-weight: 700; }

.yy-nav-toggle__bars {
  position: relative;
  display: block;
  width: 18px;
  height: 1px;
  background: var(--ink);
}

.yy-nav-toggle__bars::before,
.yy-nav-toggle__bars::after {
  content: "";
  position: absolute;
  left: 0;
  width: 18px;
  height: 1px;
  background: var(--ink);
  transition: transform .22s var(--ease), top .22s var(--ease);
}

.yy-nav-toggle__bars::before { top: -5px; }
.yy-nav-toggle__bars::after { top: 5px; }

/* 栏目导航 */
.yy-nav { border-top: var(--hair); }

.yy-nav__list {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 4px clamp(14px, 3vw, 40px);
  width: 100%;
  max-width: var(--shell);
  margin-inline: auto;
  padding-inline: var(--pad-x);
}

.yy-nav__item { position: relative; }

.yy-nav__link {
  position: relative;
  display: inline-block;
  padding: 14px 2px 16px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 13px;
  letter-spacing: .20em;
  line-height: 1.5;
  color: var(--ink);
}

.yy-nav__link::after {
  content: "";
  position: absolute;
  left: 50%;
  bottom: 8px;
  width: 100%;
  height: 2px;
  background: var(--danxia);
  transform: translateX(-50%) scaleX(0);
  transform-origin: center;
  transition: transform .28s var(--ease);
}

.yy-nav__link:hover::after { transform: translateX(-50%) scaleX(1); }

.yy-nav__link[aria-current="page"] { color: var(--danxia-deep); }
.yy-nav__link[aria-current="page"]::after { transform: translateX(-50%) scaleX(1); }

.yy-nav__foot { display: none; }

/* ============================================================
   14. 页脚
   ============================================================ */
.site-footer {
  position: relative;
  margin-top: clamp(56px, 8vw, 110px);
  background: var(--ink-deep);
  color: var(--paper);
  border-top: 3px solid var(--danxia);
}

.yy-footer__grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: clamp(24px, 3vw, 44px);
  padding: clamp(40px, 6vw, 72px) 0 clamp(28px, 4vw, 44px);
}

.yy-footer__col { min-width: 0; }

.yy-footer__title {
  margin-bottom: 16px;
  padding-bottom: 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 400;
  letter-spacing: .24em;
  line-height: 1.6;
  color: var(--sand);
  border-bottom: 1px solid rgba(217, 164, 65, .28);
}

.yy-footer__list {
  display: flex;
  flex-direction: column;
  gap: 9px;
}

.yy-footer__link {
  font-size: 14.5px;
  line-height: 1.7;
  letter-spacing: .04em;
  color: var(--paper-a80);
  transition: color .2s var(--ease);
}

.yy-footer__link:hover { color: var(--sand-light); }

.yy-footer__meta {
  display: flex;
  flex-direction: column;
  gap: 13px;
}

.yy-footer__meta-row {
  display: flex;
  flex-direction: column;
  gap: 3px;
}

.yy-footer__meta-row dt {
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: .18em;
  line-height: 1.6;
  color: rgba(247, 242, 234, .5);
}

.yy-footer__meta-row dd {
  font-size: 14px;
  line-height: 1.75;
  color: var(--paper);
  word-break: break-word;
}

.site-footer .yy-copy { color: var(--sand); }
.site-footer .yy-copy:hover { color: var(--sand-light); }
.site-footer .yy-copy[data-copied] { color: var(--neon); border-bottom-color: transparent; }

.yy-footer__text {
  margin-bottom: 18px;
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--paper-a80);
}

.yy-footer__hint {
  margin-top: 14px;
  font-size: 12.5px;
  line-height: 1.75;
  color: rgba(247, 242, 234, .55);
}

.yy-footer__bar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 10px 28px;
  padding: 20px 0 32px;
  border-top: var(--hair-dark);
}

.yy-footer__copy {
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .08em;
  line-height: 1.7;
  color: rgba(247, 242, 234, .55);
}

/* ============================================================
   15. 滚动进度 / 返回页首
   ============================================================ */
.yy-progress {
  position: fixed;
  left: 0;
  top: 0;
  z-index: 200;
  width: 100%;
  height: 2px;
  pointer-events: none;
  background: transparent;
}

.yy-progress__bar {
  display: block;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, var(--danxia) 0%, var(--sand) 100%);
  transform: scaleX(0);
  transform-origin: left center;
}

.yy-backtop {
  position: fixed;
  right: clamp(14px, 3vw, 32px);
  bottom: clamp(14px, 3vw, 32px);
  z-index: 150;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 11px 16px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .14em;
  line-height: 1.5;
  color: var(--paper);
  background: var(--ink);
  border: 1px solid var(--ink);
  border-radius: var(--radius);
  box-shadow: var(--shadow-2);
  transition: background .24s var(--ease), border-color .24s var(--ease),
              opacity .24s var(--ease);
}

.yy-backtop[hidden] { display: none; }

.yy-backtop:hover {
  background: var(--danxia);
  border-color: var(--danxia);
}

/* ============================================================
   16. 聚焦态 / 动效偏好
   ============================================================ */
:focus-visible {
  outline: 2px solid var(--neon);
  outline-offset: 3px;
  border-radius: var(--radius);
}

.site-footer :focus-visible,
.yy-dark :focus-visible,
.yy-btn--primary:focus-visible {
  outline: 2px solid var(--neon);
  outline-offset: 3px;
}

@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;
  }
}

/* ============================================================
   17. 响应式
   ============================================================ */
@media (max-width: 1024px) {
  .yy-footer__grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .yy-grid--3 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (max-width: 960px) {
  .yy-masthead__inner {
    grid-template-columns: minmax(0, 1fr) auto;
    grid-template-areas:
      "brand toggle"
      "idx idx";
    row-gap: 14px;
    padding-top: 18px;
  }

  .yy-signature { display: none; }

  .yy-brand { align-items: flex-start; text-align: left; }
  .yy-brand__cn { font-size: 22px; letter-spacing: .18em; text-indent: .18em; }
  .yy-brand__sub { letter-spacing: .2em; text-indent: .2em; }

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

  .yy-indexbar {
    justify-self: stretch;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 10px 16px;
    padding-top: 12px;
    border-top: var(--hair);
  }

  /* 抽屉式导航 */
  .yy-nav {
    max-height: 0;
    overflow: hidden;
    opacity: 0;
    transition: max-height .34s var(--ease), opacity .26s var(--ease);
  }

  .yy-nav[data-open] {
    max-height: 40rem;
    opacity: 1;
  }

  .yy-nav__list {
    flex-direction: column;
    flex-wrap: nowrap;
    justify-content: flex-start;
    gap: 0;
    padding-inline: clamp(16px, 5vw, 32px);
  }

  .yy-nav__item { border-bottom: var(--hair); }

  .yy-nav__link {
    display: block;
    padding: 15px 0;
    font-size: 15px;
    letter-spacing: .16em;
  }

  .yy-nav__link::after {
    left: 0;
    bottom: 10px;
    width: 22px;
    transform: translateX(0) scaleX(0);
    transform-origin: left center;
  }

  .yy-nav__link:hover::after,
  .yy-nav__link[aria-current="page"]::after { transform: translateX(0) scaleX(1); }

  .yy-nav__foot {
    display: flex;
    flex-direction: column;
    gap: 10px;
    padding: 18px clamp(16px, 5vw, 32px) 22px;
  }

  .yy-nav__foot-text {
    font-family: var(--font-mono);
    font-size: 11.5px;
    letter-spacing: .06em;
    line-height: 1.7;
    color: var(--muted);
  }

  .yy-nav__foot-link {
    align-self: flex-start;
    font-size: 13px;
    letter-spacing: .14em;
    line-height: 1.6;
    color: var(--danxia-deep);
    border-bottom: 1px solid currentColor;
  }

  /* 分屏坍缩为单栏，窄栏转为顶部导读条 */
  .yy-split,
  .yy-split--42,
  .yy-split--33,
  .yy-split--25 {
    grid-template-columns: minmax(0, 1fr);
  }

  .yy-aside { position: static; top: auto; }
}

@media (max-width: 720px) {
  body { font-size: 16.5px; }
  .yy-grid--2, .yy-grid--3 { grid-template-columns: minmax(0, 1fr); }
  .yy-lede { font-size: 17px; }
}

@media (max-width: 620px) {
  .yy-footer__grid { grid-template-columns: minmax(0, 1fr); }
  .yy-footer__bar { flex-direction: column; align-items: flex-start; }
  .yy-indexbar__link { padding: 7px 12px; }
  .yy-timeline { padding-left: 24px; }
  .yy-timeline__item::before { left: -24px; }
}