/* =========================================================
   利博指南 · 共享样式  /assets/site.css
   ========================================================= */

/* ---------- 1. Reset ---------- */
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
body, h1, h2, h3, h4, h5, h6, p, ul, ol, li, figure, figcaption, blockquote, dl, dd { margin: 0; }
ul, ol { padding: 0; list-style: none; }
img, svg, video { display: block; max-width: 100%; }
button, input, select, textarea { font: inherit; color: inherit; }
button { background: none; border: 0; padding: 0; cursor: pointer; }
a { color: inherit; text-decoration: none; }
table { border-collapse: collapse; width: 100%; }
hr { border: 0; border-top: 1px solid var(--line); }

/* ---------- 2. 变量 ---------- */
:root {
  --ink-900: #0B1B2B;
  --indigo-700: #1F2A6B;
  --teal-800: #0E4A4A;
  --wine-700: #7A1F35;
  --tech-blue-500: #1E6BFF;
  --orange-500: #FF7A29;
  --paper-050: #F7F8FA;
  --gray-300: #D5DAE3;
  --gray-600: #5C6673;
  --mint-200: #BFE3DC;
  --sand-200: #F0E4D2;

  --surface: #FFFFFF;
  --line: var(--gray-300);
  --text: var(--ink-900);
  --text-muted: var(--gray-600);

  --font-sans: "PingFang SC", "Hiragino Sans GB", "Source Han Sans SC", "Noto Sans SC", "Microsoft YaHei", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, "Liberation Mono", monospace;

  --fs-display: clamp(2.2rem, 6.4vw, 5.6rem);
  --fs-h2: clamp(1.6rem, 3.4vw, 2.6rem);
  --fs-h3: clamp(1.15rem, 1.8vw, 1.4rem);
  --fs-body: 1.0625rem;
  --fs-meta: 0.8125rem;

  --gutter: clamp(1.25rem, 4vw, 2.5rem);
  --maxw: 1240px;
  --radius-s: 6px;
  --radius-m: 16px;
  --radius-pill: 999px;

  --ease-out: cubic-bezier(0.22, 0.61, 0.36, 1);
  --lb-progress: 0;
}

/* ---------- 3. 基础排版 ---------- */
body {
  background: var(--paper-050);
  color: var(--text);
  font-family: var(--font-sans);
  font-size: var(--fs-body);
  font-weight: 400;
  line-height: 1.75;
  font-variant-numeric: tabular-nums;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
h1, h2, h3, h4, h5 { font-weight: 900; line-height: 1.06; letter-spacing: -0.02em; }
h1 { font-size: var(--fs-display); line-height: 0.98; }
h2 { font-size: var(--fs-h2); }
h3 { font-size: var(--fs-h3); font-weight: 700; }
strong, b { font-weight: 700; }
code, kbd, samp { font-family: var(--font-mono); font-size: 0.9em; }
::selection { background: var(--orange-500); color: var(--ink-900); }
#main-content { display: block; scroll-margin-top: 5.5rem; }

/* ---------- 4. 焦点 ---------- */
:focus { outline: none; }
:focus-visible {
  outline: 2px solid var(--tech-blue-500);
  outline-offset: 2px;
  border-radius: 2px;
}
.lb-header :focus-visible,
.lb-footer :focus-visible { outline-color: var(--orange-500); }

/* ---------- 5. 布局容器 ---------- */
.lb-container {
  width: 100%;
  max-width: var(--maxw);
  margin-inline: auto;
  padding-inline: var(--gutter);
}
.lb-section { padding-block: clamp(2.5rem, 6vw, 5rem); }
.lb-section--tight { padding-block: clamp(1.5rem, 3vw, 2.5rem); }
.lb-stack > * + * { margin-top: 1rem; }
.lb-on-dark { --text: var(--paper-050); --text-muted: rgba(247, 248, 250, 0.74); color: var(--paper-050); }

/* ---------- 6. 色带 ---------- */
.lb-band { padding-block: clamp(2rem, 5vw, 4rem); }
.lb-band--indigo, .lb-band--teal, .lb-band--wine, .lb-band--ink {
  --text: var(--paper-050);
  --text-muted: rgba(247, 248, 250, 0.74);
  color: var(--paper-050);
}
.lb-band--paper, .lb-band--sand, .lb-band--mint {
  --text: var(--ink-900);
  --text-muted: var(--gray-600);
  color: var(--ink-900);
}
.lb-band--indigo { background: var(--indigo-700); }
.lb-band--teal { background: var(--teal-800); }
.lb-band--wine { background: var(--wine-700); }
.lb-band--ink { background: var(--ink-900); }
.lb-band--paper { background: var(--paper-050); }
.lb-band--sand { background: var(--sand-200); }
.lb-band--mint { background: var(--mint-200); }

/* ---------- 7. 文字工具 ---------- */
.lb-display {
  font-size: var(--fs-display);
  font-weight: 900;
  line-height: 0.98;
  letter-spacing: -0.02em;
}
.lb-eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 0.55rem;
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--text-muted);
}
.lb-eyebrow::before {
  content: "";
  flex: none;
  width: 1.4rem;
  height: 2px;
  background: var(--orange-500);
}
.lb-meta, .lb-note {
  font-size: var(--fs-meta);
  letter-spacing: 0.08em;
  color: var(--text-muted);
}
.lb-num { font-variant-numeric: tabular-nums; font-weight: 700; letter-spacing: 0.02em; }
.lb-vnote {
  writing-mode: vertical-rl;
  text-orientation: mixed;
  font-size: 0.6875rem;
  letter-spacing: 0.28em;
  text-transform: uppercase;
  color: var(--text-muted);
}
.lb-prose {
  max-width: 62ch;
  font-size: var(--fs-body);
  line-height: 1.75;
  color: var(--text);
}
.lb-prose p + p { margin-top: 1.1em; }
.lb-prose h2 { font-size: var(--fs-h2); margin: 2.2em 0 0.6em; }
.lb-prose h3 { font-size: var(--fs-h3); margin: 1.8em 0 0.5em; }
.lb-prose ul, .lb-prose ol { margin: 1em 0; padding-left: 1.35em; }
.lb-prose ul { list-style: disc; }
.lb-prose ol { list-style: decimal; }
.lb-prose li + li { margin-top: 0.4em; }
.lb-prose a { color: var(--tech-blue-500); border-bottom: 1px solid rgba(30, 107, 255, 0.4); }
.lb-prose a:hover { border-bottom-color: var(--tech-blue-500); }
.lb-prose blockquote {
  margin: 1.5em 0;
  padding-left: 1.1rem;
  border-left: 3px solid var(--wine-700);
  color: var(--text-muted);
}

/* ---------- 8. 网格 ---------- */
.lb-grid { display: grid; gap: clamp(1rem, 2.4vw, 1.75rem); }
.lb-grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.lb-grid--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.lb-grid--4 { grid-template-columns: repeat(4, minmax(0, 1fr)); }
.lb-grid--auto { grid-template-columns: repeat(auto-fit, minmax(min(100%, 250px), 1fr)); }
.lb-grid--sidebar {
  grid-template-columns: minmax(0, 220px) minmax(0, 1fr);
  gap: clamp(1.5rem, 4vw, 3.5rem);
}

/* ---------- 9. 信息单元 ---------- */
.lb-tile {
  background: var(--surface);
  border-top: 3px solid var(--tech-blue-500);
  border-radius: var(--radius-m);
  padding: 1.35rem 1.4rem 1.5rem;
  transition: transform 0.18s var(--ease-out), box-shadow 0.18s var(--ease-out);
}
.lb-tile:hover { transform: translateY(-3px); box-shadow: 0 14px 30px rgba(11, 27, 43, 0.09); }
.lb-tile--wine { border-top-color: var(--wine-700); }
.lb-tile--teal { border-top-color: var(--teal-800); }
.lb-tile--orange { border-top-color: var(--orange-500); }
.lb-tile__title { font-size: 1.1rem; font-weight: 900; letter-spacing: -0.01em; margin-bottom: 0.4rem; }
.lb-tile__text { font-size: 0.95rem; line-height: 1.7; color: var(--text-muted); }

/* ---------- 10. 坐标索引 ---------- */
.lb-coord {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  font-size: var(--fs-meta);
  letter-spacing: 0.06em;
  color: var(--text-muted);
}
.lb-coord__box {
  display: grid;
  place-items: center;
  flex: none;
  width: 1.9rem;
  height: 1.9rem;
  border-radius: var(--radius-s);
  background: var(--sand-200);
  color: var(--wine-700);
  font-size: var(--fs-meta);
  font-weight: 900;
  font-variant-numeric: tabular-nums;
  transition: transform 0.16s var(--ease-out), background-color 0.16s var(--ease-out), color 0.16s var(--ease-out);
}
.lb-coord:hover .lb-coord__box,
.lb-coord:focus-within .lb-coord__box,
.lb-coord:focus-visible .lb-coord__box {
  transform: scale(1.06);
  background: var(--orange-500);
  color: var(--ink-900);
}
.lb-coord__note {
  font-size: 0.75rem;
  letter-spacing: 0.08em;
  opacity: 0;
  transform: translateX(-4px);
  transition: opacity 0.16s var(--ease-out), transform 0.16s var(--ease-out);
}
.lb-coord:hover .lb-coord__note,
.lb-coord:focus-within .lb-coord__note { opacity: 1; transform: none; }

/* ---------- 11. 标签与按钮 ---------- */
.lb-tag {
  display: inline-block;
  padding: 0.2rem 0.65rem;
  border-radius: var(--radius-pill);
  background: var(--wine-700);
  color: var(--paper-050);
  font-size: 0.6875rem;
  font-weight: 700;
  letter-spacing: 0.12em;
}
.lb-tag--mint { background: var(--mint-200); color: var(--teal-800); }
.lb-tag--orange { background: var(--orange-500); color: var(--ink-900); }
.lb-tag--ghost { background: transparent; border: 1px solid var(--line); color: var(--gray-600); }

.lb-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.72rem 1.35rem;
  border: 1px solid transparent;
  border-radius: var(--radius-pill);
  font-size: 0.9375rem;
  font-weight: 700;
  line-height: 1.2;
  letter-spacing: 0.02em;
  transition: background-color 0.16s var(--ease-out), color 0.16s var(--ease-out),
    border-color 0.16s var(--ease-out), transform 0.16s var(--ease-out);
}
.lb-btn:active { transform: translateY(1px); }
.lb-btn--primary { background: var(--tech-blue-500); color: #fff; }
.lb-btn--primary:hover { background: var(--ink-900); }
.lb-btn--accent { background: var(--orange-500); color: var(--ink-900); }
.lb-btn--accent:hover { background: var(--sand-200); }
.lb-btn--ghost { background: transparent; border-color: var(--line); color: var(--ink-900); }
.lb-btn--ghost:hover { border-color: var(--ink-900); background: var(--surface); }
.lb-btn--onDark { background: transparent; border-color: rgba(247, 248, 250, 0.42); color: var(--paper-050); }
.lb-btn--onDark:hover { background: rgba(247, 248, 250, 0.14); }

/* ---------- 12. 面包屑 ---------- */
.lb-breadcrumb { padding-block: 1rem; font-size: var(--fs-meta); letter-spacing: 0.06em; color: var(--text-muted); }
.lb-breadcrumb ol { display: flex; flex-wrap: wrap; align-items: center; gap: 0.5rem; }
.lb-breadcrumb li { display: flex; align-items: center; gap: 0.5rem; }
.lb-breadcrumb li + li::before { content: "/"; color: var(--gray-300); }
.lb-breadcrumb a:hover { color: var(--text); }
.lb-breadcrumb [aria-current="page"] { color: var(--text); font-weight: 700; }

/* ---------- 13. 图片容器（页面阶段放图） ---------- */
.lb-media {
  position: relative;
  display: block;
  width: 100%;
  overflow: hidden;
  border-radius: var(--radius-m);
  background: linear-gradient(135deg, var(--gray-300), var(--paper-050));
}
.lb-media > img,
.lb-media > svg,
.lb-media > picture > img,
.lb-media > video { width: 100%; height: 100%; object-fit: cover; display: block; }
.lb-media--16x9 { aspect-ratio: 16 / 9; }
.lb-media--4x3 { aspect-ratio: 4 / 3; }
.lb-media--3x4 { aspect-ratio: 3 / 4; }
.lb-media--1x1 { aspect-ratio: 1 / 1; }
.lb-media--21x9 { aspect-ratio: 21 / 9; }
.lb-media--outline { box-shadow: inset 0 0 0 1px var(--line); }
.lb-media__tag { position: absolute; left: 0.75rem; top: 0.75rem; z-index: 2; }
.lb-media__caption { margin-top: 0.6rem; font-size: 0.75rem; letter-spacing: 0.08em; color: var(--text-muted); }

/* ---------- 14. 页头 ---------- */
.lb-header {
  position: sticky;
  top: 0;
  z-index: 70;
  background: var(--indigo-700);
  color: var(--paper-050);
  border-bottom: 1px solid rgba(247, 248, 250, 0.16);
  transition: background-color 0.22s var(--ease-out);
}
.lb-header[data-scrolled="true"] { background: var(--ink-900); }

.lb-skip {
  position: absolute;
  left: var(--gutter);
  top: -4rem;
  z-index: 90;
  padding: 0.55rem 1rem;
  border-radius: var(--radius-s);
  background: var(--orange-500);
  color: var(--ink-900);
  font-size: 0.875rem;
  font-weight: 700;
  transition: top 0.18s var(--ease-out);
}
.lb-skip:focus { top: 0.7rem; }

.lb-header__inner {
  position: relative;
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  align-items: center;
  gap: 1rem;
  padding-block: 1rem;
  transition: padding-block 0.22s var(--ease-out);
}
.lb-header[data-scrolled="true"] .lb-header__inner { padding-block: 0.6rem; }

.lb-brand { display: flex; align-items: center; }
.lb-brand__link {
  display: inline-flex;
  align-items: center;
  gap: 0.7rem;
  padding: 0.15rem;
  border-radius: var(--radius-s);
}
.lb-brand__mark {
  display: grid;
  place-items: center;
  flex: none;
  width: 2.4rem;
  height: 2.4rem;
  border-radius: var(--radius-s);
  background: var(--orange-500);
  color: var(--ink-900);
  font-size: 0.9375rem;
  font-weight: 900;
  letter-spacing: 0.02em;
  transition: background-color 0.16s var(--ease-out), color 0.16s var(--ease-out);
}
.lb-brand__link:hover .lb-brand__mark { background: var(--paper-050); color: var(--indigo-700); }
.lb-brand__text { display: flex; flex-direction: column; line-height: 1.15; }
.lb-brand__name { font-size: 1.05rem; font-weight: 900; letter-spacing: 0.06em; }
.lb-brand__tagline {
  display: block;
  max-height: 2rem;
  overflow: hidden;
  font-size: 0.6875rem;
  letter-spacing: 0.18em;
  color: rgba(247, 248, 250, 0.62);
  transition: max-height 0.22s var(--ease-out), opacity 0.18s linear;
}
.lb-header[data-scrolled="true"] .lb-brand__tagline { max-height: 0; opacity: 0; }

.lb-header__coord {
  display: none;
  justify-self: start;
  padding-left: 0.9rem;
  border-left: 1px solid rgba(247, 248, 250, 0.24);
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.28em;
  color: rgba(247, 248, 250, 0.42);
  white-space: nowrap;
}
@media (min-width: 1024px) { .lb-header__coord { display: block; } }

.lb-header__actions {
  justify-self: end;
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

/* 移动导航按钮 */
.lb-nav-toggle {
  display: inline-flex;
  align-items: center;
  gap: 0.55rem;
  padding: 0.55rem 0.95rem;
  border: 1px solid rgba(247, 248, 250, 0.34);
  border-radius: var(--radius-pill);
  color: var(--paper-050);
  font-size: var(--fs-meta);
  font-weight: 700;
  letter-spacing: 0.12em;
  transition: background-color 0.16s var(--ease-out), border-color 0.16s var(--ease-out), color 0.16s var(--ease-out);
}
.lb-nav-toggle:hover { background: rgba(247, 248, 250, 0.12); }
.lb-nav-toggle__bars {
  position: relative;
  width: 1rem;
  height: 2px;
  border-radius: 2px;
  background: currentColor;
  transition: background-color 0.16s var(--ease-out);
}
.lb-nav-toggle__bars::before,
.lb-nav-toggle__bars::after {
  content: "";
  position: absolute;
  left: 0;
  width: 100%;
  height: 2px;
  border-radius: 2px;
  background: currentColor;
  transition: transform 0.18s var(--ease-out), top 0.18s var(--ease-out);
}
.lb-nav-toggle__bars::before { top: -6px; }
.lb-nav-toggle__bars::after { top: 6px; }
.lb-nav-toggle[aria-expanded="true"] {
  background: var(--orange-500);
  border-color: var(--orange-500);
  color: var(--ink-900);
}
.lb-nav-toggle[aria-expanded="true"] .lb-nav-toggle__bars { background: transparent; }
.lb-nav-toggle[aria-expanded="true"] .lb-nav-toggle__bars::before { top: 0; transform: rotate(45deg); }
.lb-nav-toggle[aria-expanded="true"] .lb-nav-toggle__bars::after { top: 0; transform: rotate(-45deg); }

/* 导航 */
.lb-nav { display: flex; align-items: center; gap: clamp(0.9rem, 2vw, 1.9rem); }
.lb-nav__list { display: flex; align-items: center; gap: clamp(0.7rem, 1.6vw, 1.35rem); }
.lb-nav__link {
  display: inline-block;
  padding: 0.35rem 0;
  border-bottom: 2px solid transparent;
  font-size: 0.9375rem;
  font-weight: 500;
  letter-spacing: 0.04em;
  color: rgba(247, 248, 250, 0.82);
  transition: color 0.16s var(--ease-out), border-color 0.16s var(--ease-out);
}
.lb-nav__link:hover { color: #fff; border-bottom-color: var(--orange-500); }
.lb-nav__link[aria-current="page"] {
  color: #fff;
  font-weight: 700;
  border-bottom-color: var(--orange-500);
}
.lb-nav__cta {
  display: inline-flex;
  align-items: center;
  padding: 0.5rem 1rem;
  border-radius: var(--radius-pill);
  background: var(--orange-500);
  color: var(--ink-900);
  font-size: var(--fs-meta);
  font-weight: 700;
  letter-spacing: 0.08em;
  white-space: nowrap;
  transition: background-color 0.16s var(--ease-out), color 0.16s var(--ease-out);
}
.lb-nav__cta:hover { background: var(--paper-050); }

/* 滚动进度 */
.lb-progress {
  position: absolute;
  left: 0;
  right: 0;
  bottom: -1px;
  height: 3px;
  background: rgba(247, 248, 250, 0.14);
  pointer-events: none;
}
.lb-progress__bar {
  display: block;
  height: 100%;
  background: linear-gradient(90deg, var(--orange-500), var(--tech-blue-500));
  transform: scaleX(var(--lb-progress));
  transform-origin: left center;
}

/* ---------- 15. 页脚 ---------- */
.lb-footer {
  position: relative;
  background: var(--ink-900);
  color: var(--paper-050);
  margin-top: clamp(3rem, 8vw, 6rem);
}
.lb-footer__strip {
  height: 6px;
  background: linear-gradient(90deg,
    var(--indigo-700) 0 34%,
    var(--teal-800) 34% 67%,
    var(--wine-700) 67% 100%);
}
.lb-footer__grid {
  display: grid;
  grid-template-columns: 1.35fr 1fr 1fr 1.15fr;
  gap: clamp(1.5rem, 3vw, 2.75rem);
  padding-block: clamp(2.5rem, 5vw, 4rem) 0;
}
.lb-footer__col { min-width: 0; }
.lb-footer__brand {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  font-size: 1.15rem;
  font-weight: 900;
  letter-spacing: 0.08em;
}
.lb-footer__mark {
  display: grid;
  place-items: center;
  flex: none;
  width: 1.9rem;
  height: 1.9rem;
  border-radius: var(--radius-s);
  background: var(--tech-blue-500);
  color: #fff;
  font-size: 0.75rem;
  font-weight: 900;
}
.lb-footer__note {
  margin-top: 0.85rem;
  max-width: 34ch;
  font-size: 0.875rem;
  line-height: 1.75;
  color: rgba(247, 248, 250, 0.72);
}
.lb-footer__facts {
  margin-top: 1.1rem;
  display: grid;
  gap: 0.45rem;
  font-size: var(--fs-meta);
  color: var(--gray-300);
}
.lb-footer__facts li { display: flex; gap: 0.6rem; align-items: baseline; }
.lb-footer__fact-key {
  flex: none;
  min-width: 3em;
  font-size: 0.6875rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  color: var(--mint-200);
}
.lb-footer__value { color: var(--gray-300); word-break: break-word; }
.lb-footer__title {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-bottom: 0.9rem;
  font-size: var(--fs-meta);
  font-weight: 700;
  letter-spacing: 0.18em;
  color: var(--paper-050);
}
.lb-footer__title::before {
  content: "";
  flex: none;
  width: 14px;
  height: 2px;
  background: var(--orange-500);
}
.lb-footer__list { display: grid; gap: 0.45rem; }
.lb-footer__list a {
  font-size: 0.9375rem;
  color: rgba(247, 248, 250, 0.78);
  border-bottom: 1px solid transparent;
  transition: color 0.16s var(--ease-out), border-color 0.16s var(--ease-out);
}
.lb-footer__list a:hover { color: var(--orange-500); border-bottom-color: var(--orange-500); }
.lb-footer__list--plain li { display: flex; gap: 0.6rem; align-items: baseline; font-size: var(--fs-meta); }
.lb-footer__bottom {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 0.6rem 1.75rem;
  margin-top: clamp(2rem, 4vw, 3rem);
  padding-block: 1.1rem 1.4rem;
  border-top: 1px solid rgba(247, 248, 250, 0.16);
  font-size: var(--fs-meta);
  color: var(--gray-300);
}
.lb-footer__meta { letter-spacing: 0.06em; }
.lb-footer__inspection { letter-spacing: 0.06em; color: var(--mint-200); }
.lb-footer__legal { display: flex; flex-wrap: wrap; gap: 1.25rem; }
.lb-footer__legal a {
  border-bottom: 1px solid transparent;
  transition: color 0.16s var(--ease-out), border-color 0.16s var(--ease-out);
}
.lb-footer__legal a:hover { color: var(--paper-050); border-bottom-color: var(--orange-500); }

/* ---------- 16. 滚动显现 ---------- */
.lb-js [data-reveal] {
  opacity: 0;
  transform: translateY(12px);
  transition: opacity 0.22s ease-out, transform 0.22s ease-out;
}
.lb-js [data-reveal].is-visible { opacity: 1; transform: none; }

/* ---------- 17. 响应式 ---------- */
@media (max-width: 1080px) {
  .lb-grid--4 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .lb-footer__grid { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 960px) {
  .lb-header__inner {
    grid-template-columns: minmax(0, 1fr) auto;
    padding-block: 0.7rem;
  }
  .lb-header[data-scrolled="true"] .lb-header__inner { padding-block: 0.55rem; }
  .lb-header__coord { display: none; }
  .lb-header__actions { justify-self: end; gap: 0; }
  .lb-nav-toggle { display: inline-flex; }
  .lb-nav {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 0.4rem 0 1.1rem;
    background: var(--ink-900);
    border-top: 3px solid var(--orange-500);
    box-shadow: 0 18px 40px rgba(11, 27, 43, 0.38);
  }
  .lb-nav[data-open="true"] { display: flex; }
  .lb-nav__list { flex-direction: column; align-items: stretch; gap: 0; }
  .lb-nav__link {
    display: block;
    padding: 0.85rem var(--gutter);
    border-bottom: 1px solid rgba(247, 248, 250, 0.1);
    border-left: 3px solid transparent;
    font-size: 1rem;
    color: rgba(247, 248, 250, 0.86);
  }
  .lb-nav__link:hover {
    color: #fff;
    background: rgba(247, 248, 250, 0.06);
    border-bottom-color: rgba(247, 248, 250, 0.1);
    border-left-color: var(--orange-500);
  }
  .lb-nav__link[aria-current="page"] {
    color: #fff;
    background: rgba(30, 107, 255, 0.2);
    border-bottom-color: rgba(247, 248, 250, 0.1);
    border-left-color: var(--orange-500);
  }
  .lb-nav__cta {
    justify-content: center;
    margin: 0.9rem var(--gutter) 0;
    padding: 0.7rem 1rem;
  }
  .lb-grid--3 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .lb-grid--sidebar { grid-template-columns: minmax(0, 1fr); }
}
@media (max-width: 680px) {
  .lb-grid--2, .lb-grid--3, .lb-grid--4 { grid-template-columns: minmax(0, 1fr); }
  .lb-footer__grid { grid-template-columns: minmax(0, 1fr); }
  .lb-footer__bottom { flex-direction: column; align-items: flex-start; }
  .lb-footer__note { max-width: none; }
}
@media (min-width: 961px) {
  .lb-nav-toggle { display: none; }
  .lb-nav { display: flex; }
}

/* ---------- 18. 降级动效 ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
  }
  .lb-js [data-reveal] { opacity: 1; transform: none; }
  .lb-progress__bar { transition: none; }
  .lb-tile:hover { transform: none; }
  .lb-coord:hover .lb-coord__box,
  .lb-coord:focus-within .lb-coord__box { transform: none; }
}