/* =============================================================
   云博赛场 · 共享样式 /assets/site.css
   赛场夜灯下的数据作战室：深空蓝底 + 切角浮岛 + 等宽数据层
   ============================================================= */

/* ---------- 1. Reset ---------- */
*, *::before, *::after { box-sizing: border-box; }
html {
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: 118px;
}
body, h1, h2, h3, h4, h5, p, figure, blockquote, dl, dd { margin: 0; }
ul { margin: 0; padding: 0; list-style: none; }
ol { margin: 0; padding-left: 1.3em; }
img, svg, video { display: block; max-width: 100%; }
button { font: inherit; color: inherit; background: none; border: 0; padding: 0; cursor: pointer; }
input, select, textarea { font: inherit; color: inherit; }
table { width: 100%; border-collapse: collapse; }
[hidden] { display: none !important; }

/* ---------- 2. CSS 变量 ---------- */
:root {
  --yb-deep: #0B1E3A;
  --yb-abyss: #071227;
  --yb-room: #10294C;
  --yb-signal: #1FE0C8;
  --yb-whistle: #F5C542;
  --yb-ember: #FF6B35;
  --yb-paper: #F2E9DA;
  --yb-ink: #1A140F;
  --yb-steel: #C9D4E4;
  --yb-mute: #7E8DA6;
  --yb-red: #D6432F;

  --yb-line: rgba(31, 224, 200, 0.24);
  --yb-line-soft: rgba(201, 212, 228, 0.16);
  --yb-line-faint: rgba(201, 212, 228, 0.08);

  --yb-font-sans: system-ui, -apple-system, "PingFang SC", "Hiragino Sans GB", "Source Han Sans SC", "Noto Sans SC", "Microsoft YaHei", sans-serif;
  --yb-font-mono: ui-monospace, "SF Mono", "JetBrains Mono", "IBM Plex Mono", Menlo, Consolas, monospace;
  --yb-font-serif: "Songti SC", "Source Han Serif SC", "Noto Serif SC", Georgia, "SimSun", serif;

  --yb-cut-lt: polygon(12px 0, 100% 0, 100% 100%, 0 100%, 0 12px);
  --yb-cut-rb: polygon(0 0, 100% 0, 100% calc(100% - 12px), calc(100% - 12px) 100%, 0 100%);

  --yb-max: 1440px;
  --yb-gutter: clamp(16px, 4vw, 44px);
  --yb-ease: cubic-bezier(0.2, 0.7, 0.2, 1);
  --yb-shadow-up: 0 1px 0 rgba(31, 224, 200, 0.12);
  --yb-shadow-deep: 0 24px 60px rgba(0, 0, 0, 0.45);
}

/* ---------- 3. 基础与中文排版 ---------- */
body {
  margin: 0;
  background: var(--yb-deep);
  color: var(--yb-steel);
  font-family: var(--yb-font-sans);
  font-size: 17px;
  line-height: 1.85;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}
h1, h2, h3, h4 { color: var(--yb-paper); font-weight: 600; line-height: 1.15; }
p { max-width: 38em; }
strong, b { color: var(--yb-paper); font-weight: 600; }
a { color: var(--yb-signal); text-decoration: none; }
a:hover { text-decoration: underline; text-underline-offset: 3px; text-decoration-thickness: 1px; }
:focus-visible { outline: 1px solid var(--yb-signal); outline-offset: 2px; box-shadow: 0 0 0 2px rgba(11, 30, 58, 0.9); }
::selection { background: rgba(31, 224, 200, 0.28); color: var(--yb-paper); }

.yb-visually-hidden {
  position: absolute; 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;
}

/* ---------- 4. 跳过链接 ---------- */
.yb-skip {
  position: fixed; left: 16px; top: 12px; z-index: 120;
  padding: 11px 18px;
  background: var(--yb-whistle); color: var(--yb-ink);
  font-size: 14px; font-weight: 700; letter-spacing: 0.04em;
  border-radius: 2px;
  box-shadow: 0 0 0 2px rgba(11, 30, 58, 0.9);
  transform: translateY(-180%);
  transition: transform 0.16s var(--yb-ease);
}
.yb-skip:focus-visible { transform: translateY(0); text-decoration: none; }

/* ---------- 5. 顶栏：悬浮胶囊 ---------- */
.yb-header {
  position: sticky; top: 0; z-index: 90;
  padding: 12px 0 22px;
  background: linear-gradient(180deg, rgba(7, 18, 39, 0.98) 0%, rgba(7, 18, 39, 0.88) 48%, rgba(7, 18, 39, 0) 100%);
  transition: padding 0.16s var(--yb-ease);
}
.yb-header__inner {
  position: relative;
  display: flex; align-items: center; justify-content: space-between; gap: 12px;
  max-width: var(--yb-max); margin: 0 auto;
  padding: 0 var(--yb-gutter);
}
.yb-island {
  display: flex; align-items: center;
  background: rgba(7, 18, 39, 0.94);
  box-shadow: inset 0 0 0 1px var(--yb-line);
  filter: drop-shadow(0 14px 26px rgba(0, 0, 0, 0.5));
}
.yb-island--brand { clip-path: var(--yb-cut-lt); padding: 6px 18px 6px 13px; }
.yb-island--nav { clip-path: var(--yb-cut-rb); padding: 6px 8px; gap: 6px; margin-left: auto; }

/* 品牌 */
.yb-brand { display: flex; align-items: center; gap: 11px; text-decoration: none; }
.yb-brand:hover { text-decoration: none; }
.yb-brand__mark {
  width: 12px; height: 28px; flex: none;
  background: linear-gradient(180deg, var(--yb-signal), rgba(31, 224, 200, 0.12));
  transform: skewX(-18deg);
}
.yb-brand__text { display: flex; flex-direction: column; line-height: 1.15; }
.yb-brand__name { color: var(--yb-paper); font-size: 17px; font-weight: 700; letter-spacing: 0.1em; }
.yb-brand__sub { color: var(--yb-mute); font-family: var(--yb-font-mono); font-size: 10.5px; letter-spacing: 0.06em; }

/* 导航 */
.yb-nav { display: flex; align-items: center; gap: 8px; min-width: 0; }
.yb-nav__list { display: flex; align-items: center; gap: 2px; }
.yb-nav__list a {
  position: relative; display: block;
  padding: 9px 11px;
  color: var(--yb-steel); font-size: 13.5px; letter-spacing: 0.05em;
  white-space: nowrap; text-decoration: none;
  transition: color 0.16s var(--yb-ease), background-color 0.16s var(--yb-ease);
}
.yb-nav__list a::after {
  content: ""; position: absolute; left: 11px; right: 11px; bottom: 3px; height: 2px;
  background: var(--yb-signal);
  transform: scaleX(0) skewX(-18deg); transform-origin: left center;
  transition: transform 0.16s var(--yb-ease);
}
.yb-nav__list a:hover { color: var(--yb-paper); background: rgba(31, 224, 200, 0.07); text-decoration: none; }
.yb-nav__list a:hover::after { transform: scaleX(1) skewX(-18deg); }
.yb-nav__list a[aria-current="page"] { color: var(--yb-paper); }
.yb-nav__list a[aria-current="page"]::after { transform: scaleX(1) skewX(-18deg); background: var(--yb-whistle); }

/* 快捷入口 */
.yb-quick { display: flex; align-items: center; gap: 6px; padding-left: 10px; box-shadow: inset 1px 0 0 var(--yb-line); }
.yb-quick__link {
  display: block; padding: 8px 12px; border-radius: 2px;
  font-size: 12px; letter-spacing: 0.16em;
  color: var(--yb-steel); text-decoration: none; white-space: nowrap;
  box-shadow: inset 0 0 0 1px var(--yb-line-faint);
  transition: background-color 0.16s var(--yb-ease), color 0.16s var(--yb-ease), box-shadow 0.16s var(--yb-ease);
}
.yb-quick__link:hover { text-decoration: none; }
.yb-quick__link--app { background: var(--yb-paper); color: var(--yb-ink); font-weight: 700; box-shadow: none; }
.yb-quick__link--app:hover { background: #ffffff; }
.yb-quick__link--quota { color: var(--yb-signal); box-shadow: inset 0 0 0 1px rgba(31, 224, 200, 0.5); }
.yb-quick__link--quota:hover { background: rgba(31, 224, 200, 0.14); }
.yb-quick__link--stoppage { color: var(--yb-ember); background: rgba(255, 107, 53, 0.1); box-shadow: inset 0 0 0 1px rgba(255, 107, 53, 0.55); }
.yb-quick__link--stoppage:hover { background: rgba(255, 107, 53, 0.2); }

/* 栏目筛选 */
.yb-index { position: relative; display: flex; align-items: center; padding-left: 10px; box-shadow: inset 1px 0 0 var(--yb-line); }
.yb-index__label {
  position: absolute; 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;
}
.yb-index__input {
  width: 130px; padding: 9px 11px; border: 0; border-radius: 2px;
  background: rgba(11, 30, 58, 0.85); color: var(--yb-paper);
  box-shadow: inset 0 0 0 1px var(--yb-line-faint);
  font-size: 13px; letter-spacing: 0.04em;
}
.yb-index__input::placeholder { color: var(--yb-mute); }
.yb-index__results {
  position: absolute; top: calc(100% + 10px); right: 0; z-index: 6;
  min-width: 212px; max-height: 288px; overflow: auto;
  padding: 6px; margin: 0; border-radius: 2px;
  background: var(--yb-abyss);
  box-shadow: inset 0 0 0 1px var(--yb-line), 0 20px 44px rgba(0, 0, 0, 0.55);
}
.yb-index__results a {
  display: block; padding: 8px 10px; border-radius: 2px;
  color: var(--yb-steel); font-size: 13px; text-decoration: none;
}
.yb-index__results a:hover { background: rgba(31, 224, 200, 0.12); color: var(--yb-paper); text-decoration: none; }

/* 移动导航按钮 */
.yb-navtoggle {
  display: none; align-items: center; gap: 9px;
  padding: 9px 13px; border-radius: 2px;
  color: var(--yb-paper); font-size: 14px; letter-spacing: 0.08em;
  box-shadow: inset 0 0 0 1px var(--yb-line);
  transition: background-color 0.16s var(--yb-ease);
}
.yb-navtoggle:hover { background: rgba(31, 224, 200, 0.1); }
.yb-navtoggle__bars { position: relative; width: 16px; height: 11px; flex: none; }
.yb-navtoggle__bars::before,
.yb-navtoggle__bars::after {
  content: ""; position: absolute; left: 0; right: 0; height: 2px;
  background: var(--yb-signal); transform: skewX(-18deg);
  transition: transform 0.16s var(--yb-ease);
}
.yb-navtoggle__bars::before { top: 0; }
.yb-navtoggle__bars::after { bottom: 0; }
.yb-navtoggle[aria-expanded="true"] .yb-navtoggle__bars::before { transform: translateY(4.5px) skewX(-18deg); }
.yb-navtoggle[aria-expanded="true"] .yb-navtoggle__bars::after { transform: translateY(-4.5px) skewX(-18deg); }

/* 滚动进度线 */
.yb-progress {
  position: absolute; left: 0; bottom: 0; width: 100%; height: 2px;
  background: linear-gradient(90deg, var(--yb-signal), var(--yb-whistle) 68%, var(--yb-ember));
  transform: scaleX(0); transform-origin: left center;
}

/* 滚动收窄 */
.yb-header[data-scrolled="true"] { padding: 8px 0 15px; }
.yb-header[data-scrolled="true"] .yb-brand__sub { display: none; }
.yb-header[data-scrolled="true"] .yb-nav__list a { padding: 7px 9px; font-size: 13px; }
.yb-header[data-scrolled="true"] .yb-quick__link { padding: 7px 11px; }
.yb-header[data-scrolled="true"] .yb-index__input { width: 108px; padding: 7px 10px; }

/* ---------- 6. 页脚 ---------- */
.yb-footer {
  position: relative;
  margin-top: 96px;
  background: var(--yb-abyss);
  border-top: 1px solid var(--yb-line);
}
.yb-footer::before {
  content: ""; position: absolute; inset: 0; z-index: 0; pointer-events: none;
  background-image: radial-gradient(rgba(201, 212, 228, 0.6) 0.8px, transparent 0.8px);
  background-size: 8px 8px; opacity: 0.06;
}
.yb-footer__grid {
  position: relative; z-index: 1;
  display: grid;
  grid-template-columns: 1.9fr repeat(4, 1fr) 1.5fr;
  gap: 40px 28px;
  max-width: var(--yb-max); margin: 0 auto;
  padding: 72px var(--yb-gutter) 44px;
}
.yb-footer__name { font-size: 24px; font-weight: 700; letter-spacing: 0.12em; color: var(--yb-paper); max-width: none; }
.yb-footer__line { margin-top: 6px; font-size: 14px; color: var(--yb-mute); letter-spacing: 0.04em; max-width: none; }
.yb-footer__season { margin-top: 16px; font-size: 13px; line-height: 1.9; color: var(--yb-mute); max-width: 24em; }
.yb-mono { font-family: var(--yb-font-mono); letter-spacing: 0.04em; font-variant-numeric: tabular-nums; }
.yb-footer__title {
  margin-bottom: 16px;
  font-family: var(--yb-font-mono); font-size: 11px; font-weight: 500;
  letter-spacing: 0.16em; text-transform: uppercase; color: var(--yb-mute);
}
.yb-footer__list { display: flex; flex-direction: column; gap: 10px; }
.yb-footer__list a {
  font-size: 14px; color: var(--yb-steel); text-decoration: none;
  transition: color 0.16s var(--yb-ease);
}
.yb-footer__list a:hover { color: var(--yb-signal); text-decoration: none; }
.yb-footer__contact p { font-size: 14px; line-height: 1.8; color: var(--yb-steel); max-width: none; }
.yb-footer__tel { margin-top: 12px; }
.yb-footer__addr { margin-top: 12px; font-size: 13px; color: var(--yb-mute); }
.yb-copy {
  display: inline-flex; align-items: center;
  margin-top: 10px; padding: 7px 12px; border-radius: 2px;
  font-size: 12px; letter-spacing: 0.12em;
  color: var(--yb-signal);
  box-shadow: inset 0 0 0 1px rgba(31, 224, 200, 0.35);
  transition: background-color 0.16s var(--yb-ease), color 0.16s var(--yb-ease), box-shadow 0.16s var(--yb-ease);
}
.yb-copy:hover { background: rgba(31, 224, 200, 0.12); }
.yb-copy[data-copied="true"] { color: var(--yb-whistle); box-shadow: inset 0 0 0 1px rgba(245, 197, 66, 0.5); }
.yb-footer__base {
  position: relative; z-index: 1;
  display: flex; flex-wrap: wrap; gap: 12px 32px;
  align-items: baseline; justify-content: space-between;
  max-width: var(--yb-max); margin: 0 auto;
  padding: 24px var(--yb-gutter) 44px;
  border-top: 1px solid var(--yb-line-faint);
}
.yb-footer__meta { font-size: 13px; line-height: 1.8; color: var(--yb-mute); max-width: 46em; }
.yb-footer__copy { font-family: var(--yb-font-mono); font-size: 13px; letter-spacing: 0.04em; color: var(--yb-mute); max-width: none; }

/* ---------- 7. 通用容器与网格 ---------- */
.yb-main { display: block; min-height: 60vh; }
.yb-wrap { width: 100%; max-width: var(--yb-max); margin: 0 auto; padding: 0 var(--yb-gutter); }
.yb-section { padding: 96px 0; }
.yb-section--tight { padding: 56px 0; }
.yb-section--loose { padding: 144px 0; }
.yb-grid { display: grid; grid-template-columns: repeat(12, 1fr); gap: 20px; }
.yb-col-3 { grid-column: span 3; }
.yb-col-4 { grid-column: span 4; }
.yb-col-5 { grid-column: span 5; }
.yb-col-6 { grid-column: span 6; }
.yb-col-7 { grid-column: span 7; }
.yb-col-8 { grid-column: span 8; }
.yb-col-12 { grid-column: span 12; }

/* ---------- 8. 文字阶梯 ---------- */
.yb-display { font-size: clamp(40px, 7vw, 96px); font-weight: 300; letter-spacing: -0.02em; line-height: 1.04; color: var(--yb-paper); }
.yb-h1 { font-size: clamp(32px, 4.4vw, 56px); font-weight: 600; letter-spacing: -0.01em; line-height: 1.12; }
.yb-h2 { font-size: clamp(24px, 2.6vw, 36px); font-weight: 600; line-height: 1.2; }
.yb-h3 { font-size: 22px; font-weight: 600; line-height: 1.3; }
.yb-lede { font-size: 19px; line-height: 1.8; color: var(--yb-steel); max-width: 34em; }
.yb-label {
  display: inline-block;
  font-family: var(--yb-font-mono); font-size: 12px;
  letter-spacing: 0.16em; text-transform: uppercase; color: var(--yb-mute);
}
.yb-label--signal { color: var(--yb-signal); }
.yb-label--ember { color: var(--yb-ember); }
.yb-quick-read {
  display: block; margin-top: 14px; padding-left: 14px;
  font-size: 14px; line-height: 1.7; color: var(--yb-mute); max-width: 44em;
  box-shadow: inset 2px 0 0 var(--yb-line);
}

/* ---------- 9. 面板块与按钮 ---------- */
.yb-panel {
  position: relative;
  padding: 24px;
  background: var(--yb-room);
  color: var(--yb-steel);
  clip-path: var(--yb-cut-lt);
}
.yb-panel--rb { clip-path: var(--yb-cut-rb); }
.yb-panel--paper { background: var(--yb-paper); color: var(--yb-ink); }
.yb-panel--paper .yb-h1, .yb-panel--paper .yb-h2, .yb-panel--paper .yb-h3, .yb-panel--paper strong { color: var(--yb-ink); }
.yb-panel--paper .yb-label { color: #7A6A58; }
.yb-panel--paper .yb-quick-read { color: #5A4E42; box-shadow: inset 2px 0 0 rgba(26, 20, 15, 0.22); }
.yb-panel--quote {
  padding: 32px;
  background: var(--yb-paper); color: var(--yb-ink);
  font-family: var(--yb-font-serif); font-size: 20px; line-height: 1.9;
}
.yb-btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 13px 22px; border-radius: 2px;
  font-size: 13px; letter-spacing: 0.14em;
  color: var(--yb-paper); text-decoration: none;
  box-shadow: inset 0 0 0 1px var(--yb-line);
  transition: background-color 0.16s var(--yb-ease), color 0.16s var(--yb-ease), box-shadow 0.16s var(--yb-ease);
}
.yb-btn:hover { text-decoration: none; background: rgba(31, 224, 200, 0.1); box-shadow: inset 0 0 0 1px var(--yb-signal); }
.yb-btn--signal { background: var(--yb-signal); color: var(--yb-ink); font-weight: 700; box-shadow: none; }
.yb-btn--signal:hover { background: #5CF0DC; box-shadow: none; }
.yb-btn--paper { background: var(--yb-paper); color: var(--yb-ink); font-weight: 700; box-shadow: none; }
.yb-btn--paper:hover { background: #ffffff; box-shadow: none; }
.yb-btn--ember { color: var(--yb-ember); box-shadow: inset 0 0 0 1px rgba(255, 107, 53, 0.55); }
.yb-btn--ember:hover { background: rgba(255, 107, 53, 0.14); box-shadow: inset 0 0 0 1px var(--yb-ember); }

/* ---------- 10. 面包屑 / 索引 / 标签 ---------- */
.yb-breadcrumb {
  font-family: var(--yb-font-mono); font-size: 12px; letter-spacing: 0.08em; color: var(--yb-mute);
}
.yb-breadcrumb ol { display: flex; flex-wrap: wrap; gap: 8px; padding: 0; margin: 0; list-style: none; }
.yb-breadcrumb li + li::before {
  content: "／"; display: inline-block; margin-right: 8px;
  color: var(--yb-red); transform: skewX(-18deg);
}
.yb-breadcrumb a { color: var(--yb-mute); text-decoration: none; }
.yb-breadcrumb a:hover { color: var(--yb-signal); }
.yb-breadcrumb [aria-current="page"] { color: var(--yb-steel); }

.yb-toc { position: sticky; top: 118px; font-size: 14px; }
.yb-toc__title {
  font-family: var(--yb-font-mono); font-size: 11px;
  letter-spacing: 0.16em; text-transform: uppercase; color: var(--yb-mute);
}
.yb-toc__list { display: flex; flex-direction: column; gap: 2px; margin-top: 14px; }
.yb-toc__list a {
  display: block; padding: 9px 10px 9px 14px;
  color: var(--yb-mute); text-decoration: none;
  box-shadow: inset 2px 0 0 var(--yb-line-faint);
  transition: color 0.16s var(--yb-ease), box-shadow 0.16s var(--yb-ease);
}
.yb-toc__list a:hover { color: var(--yb-steel); text-decoration: none; }
.yb-toc__list a[aria-current="true"] { color: var(--yb-signal); box-shadow: inset 2px 0 0 var(--yb-signal); }

.yb-tag {
  display: inline-block; padding: 4px 9px; border-radius: 2px;
  font-family: var(--yb-font-mono); font-size: 11px; letter-spacing: 0.14em;
  background: var(--yb-red); color: var(--yb-paper);
}
.yb-tag--signal { background: rgba(31, 224, 200, 0.16); color: var(--yb-signal); }
.yb-tag--ember { background: rgba(255, 107, 53, 0.16); color: var(--yb-ember); }
.yb-tag--mute { background: rgba(201, 212, 228, 0.12); color: var(--yb-steel); }

/* ---------- 11. 图片容器（页面阶段放图） ---------- */
.yb-media {
  position: relative; display: block; overflow: hidden;
  background: var(--yb-room); aspect-ratio: 16 / 9;
}
.yb-media img { width: 100%; height: 100%; object-fit: cover; filter: saturate(0.92) contrast(1.05); }
.yb-media--wide { aspect-ratio: 21 / 9; }
.yb-media--4x3 { aspect-ratio: 4 / 3; }
.yb-media--tall { aspect-ratio: 3 / 4; }
.yb-media--square { aspect-ratio: 1 / 1; }
.yb-media__tag {
  position: absolute; left: 12px; bottom: 12px;
  padding: 6px 10px; border-radius: 2px;
  background: rgba(11, 30, 58, 0.62); color: var(--yb-signal);
  font-family: var(--yb-font-mono); font-size: 11px; letter-spacing: 0.08em;
  backdrop-filter: blur(4px);
}
.yb-media__tag--ember { color: var(--yb-ember); }
.yb-media__tag--top { top: 12px; bottom: auto; }

/* ---------- 12. 横向带 / 徽章 / 底纹 ---------- */
.yb-band {
  position: relative;
  padding: 32px 0;
  background: var(--yb-abyss);
  box-shadow: inset 0 1px 0 var(--yb-line-faint), inset 0 -1px 0 var(--yb-line-faint);
}
.yb-badge {
  display: flex; align-items: center; justify-content: center;
  min-height: 96px; padding: 16px; border-radius: 2px;
  background: var(--yb-room); color: var(--yb-steel);
  font-family: var(--yb-font-mono); font-size: 13px; letter-spacing: 0.06em;
  box-shadow: inset 0 0 0 1px var(--yb-line-faint);
}
.yb-dotfield { position: relative; }
.yb-dotfield::before {
  content: ""; position: absolute; inset: 0; z-index: 0; pointer-events: none;
  background-image: radial-gradient(rgba(201, 212, 228, 0.6) 0.8px, transparent 0.8px);
  background-size: 8px 8px; opacity: 0.06;
}

/* ---------- 13. 动效与返回顶部 ---------- */
.yb-js [data-reveal] {
  opacity: 0; transform: translateY(12px);
  transition: opacity 0.2s var(--yb-ease), transform 0.2s var(--yb-ease);
}
.yb-js [data-reveal].is-in { opacity: 1; transform: none; }

.yb-to-top {
  position: fixed; right: clamp(16px, 3vw, 32px); bottom: clamp(16px, 3vw, 32px); z-index: 70;
  display: inline-flex; align-items: center; gap: 8px;
  padding: 12px 16px; border-radius: 2px;
  background: rgba(7, 18, 39, 0.94); color: var(--yb-paper);
  font-size: 14px; letter-spacing: 0.08em;
  box-shadow: inset 0 0 0 1px var(--yb-line), 0 18px 40px rgba(0, 0, 0, 0.45);
  opacity: 0; pointer-events: none; transform: translateY(8px);
  transition: opacity 0.2s var(--yb-ease), transform 0.2s var(--yb-ease);
}
.yb-to-top[data-visible="true"] { opacity: 1; pointer-events: auto; transform: none; }
.yb-to-top:hover { box-shadow: inset 0 0 0 1px var(--yb-signal), 0 18px 40px rgba(0, 0, 0, 0.45); }

/* ---------- 14. 断点 ---------- */
@media (max-width: 1200px) {
  .yb-index__input { width: 108px; }
  .yb-footer__grid { grid-template-columns: 1.7fr repeat(2, 1fr); }
  .yb-footer__brand { grid-column: span 2; }
  .yb-footer__contact { grid-column: span 3; }
}

@media (max-width: 991px) {
  .yb-header { padding: 10px 0 16px; }
  .yb-header[data-scrolled="true"] { padding: 8px 0 12px; }
  .yb-island--brand { min-width: 0; }
  .yb-island--nav { padding: 6px; }
  .yb-navtoggle { display: inline-flex; }
  .yb-nav {
    position: absolute; top: calc(100% + 8px);
    left: var(--yb-gutter); right: var(--yb-gutter);
    display: none; flex-direction: column; align-items: stretch; gap: 12px;
    max-height: min(70vh, 560px); overflow: auto;
    padding: 14px; border-radius: 2px;
    background: var(--yb-abyss);
    box-shadow: inset 0 0 0 1px var(--yb-line), 0 28px 60px rgba(0, 0, 0, 0.6);
  }
  .yb-nav[data-open] { display: flex; }
  .yb-nav__list { flex-direction: column; align-items: stretch; gap: 2px; }
  .yb-nav__list a { padding: 12px 10px; font-size: 15px; }
  .yb-nav__list a::after { left: 10px; right: auto; width: 18px; bottom: 6px; }
  .yb-quick {
    flex-wrap: wrap; padding-left: 0; padding-top: 12px;
    box-shadow: none; border-top: 1px solid var(--yb-line-faint);
  }
  .yb-index { padding-left: 0; box-shadow: none; }
  .yb-index__input { width: 100%; }
  .yb-index__results { left: 0; right: 0; min-width: 0; }
  .yb-section { padding: 72px 0; }
  .yb-section--loose { padding: 96px 0; }
  .yb-col-3, .yb-col-4, .yb-col-5 { grid-column: span 6; }
  .yb-col-7, .yb-col-8 { grid-column: span 12; }
  .yb-toc { position: static; }
}

@media (max-width: 768px) {
  body { font-size: 16px; }
  .yb-footer { margin-top: 72px; }
  .yb-footer__grid { grid-template-columns: 1fr 1fr; gap: 32px 20px; padding-top: 56px; }
  .yb-footer__brand { grid-column: span 2; }
  .yb-footer__contact { grid-column: span 2; }
  .yb-footer__base { padding-bottom: 32px; }
  .yb-grid { gap: 16px; }
  .yb-col-3, .yb-col-4, .yb-col-5, .yb-col-6 { grid-column: span 12; }
  .yb-display { letter-spacing: -0.01em; }
}

@media (max-width: 480px) {
  .yb-brand__sub { display: none; }
  .yb-brand__name { font-size: 15px; letter-spacing: 0.08em; }
  .yb-island--brand { padding: 6px 12px 6px 11px; }
  .yb-navtoggle { padding: 9px 11px; }
  .yb-footer__grid { grid-template-columns: 1fr; }
  .yb-footer__brand, .yb-footer__contact { grid-column: span 1; }
  .yb-to-top { right: 14px; bottom: 14px; padding: 11px 14px; }
}

/* ---------- 15. 动效降级 ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
  }
  .yb-js [data-reveal] { opacity: 1 !important; transform: none !important; }
  .yb-to-top { transform: none !important; }
  .yb-skip { transition: none; }
}