/* ============================================================
   site.css —— 百家平台乐 · 共享外壳与通用组件
   分区：1 变量与重置 / 2 中文排版 / 3 通用布局 / 4 页头
        5 页脚 / 6 通用组件 / 7 媒体容器 / 8 响应式 / 9 可达性
   ============================================================ */

/* ---------- 1. 变量与重置 ---------- */
:root {
  --paper: #F4EFE4;
  --ink-slate: #3F4A4D;
  --mist: #D9E0DE;
  --ink: #1E2426;
  --cinnabar: #C74E32;
  --indigo: #2F4A78;
  --bamboo: #7D9A7F;
  --stone: #6C7270;
  --sand: #E5D6BC;
  --indigo-soft: #A9B8D2;

  --line: rgba(30, 36, 38, 0.14);
  --line-strong: rgba(30, 36, 38, 0.28);
  --line-light: rgba(244, 239, 228, 0.18);

  --font-head: "Noto Sans SC", "Source Han Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-body: "Noto Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-mono: "IBM Plex Mono", "SFMono-Regular", Consolas, monospace;

  --max: 1180px;
  --gutter: clamp(16px, 4vw, 40px);
  --gap: clamp(16px, 2.6vw, 32px);

  --radius-lg: 28px;
  --radius-md: 18px;
  --radius-sm: 10px;

  --ease: 180ms ease;
}

*,
*::before,
*::after { box-sizing: border-box; }

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: 150px;
}

body,
h1, h2, h3, h4, h5, h6,
p, ul, ol, li, figure, figcaption, blockquote, dl, dd, table, th, td {
  margin: 0;
  padding: 0;
}

ul, ol { list-style: none; }
img, svg, video { display: block; max-width: 100%; height: auto; }
a { color: inherit; text-decoration: none; }
button { font: inherit; color: inherit; background: none; border: 0; cursor: pointer; }
table { border-collapse: collapse; width: 100%; }

/* ---------- 2. 中文排版 ---------- */
body {
  font-family: var(--font-body);
  font-size: clamp(15px, 0.5vw + 13.6px, 17px);
  line-height: 1.75;
  font-weight: 400;
  color: var(--ink);
  background-color: var(--paper);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

h1, h2, h3, h4 {
  font-family: var(--font-head);
  font-weight: 800;
  line-height: 1.18;
  letter-spacing: -0.012em;
  color: var(--ink);
}

p { max-width: 42em; }

strong { font-weight: 700; }

.mono {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  letter-spacing: 0.01em;
}

.display-title {
  font-family: var(--font-head);
  font-weight: 900;
  font-size: clamp(2.6rem, 6vw, 5.4rem);
  line-height: 1.02;
  letter-spacing: -0.03em;
  color: var(--ink);
}

.lede {
  font-size: clamp(1rem, 1.15vw, 1.15rem);
  line-height: 1.85;
  color: var(--ink-slate);
  max-width: 38em;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-size: 0.72rem;
  letter-spacing: 0.2em;
  color: var(--stone);
  font-weight: 500;
}
.eyebrow::before {
  content: "";
  display: block;
  width: 26px;
  height: 2px;
  background: var(--cinnabar);
}

.note {
  font-size: 0.82rem;
  line-height: 1.7;
  color: var(--stone);
  border-left: 3px solid var(--mist);
  padding-left: 14px;
  max-width: 40em;
}

/* ---------- 3. 通用布局 ---------- */
.wrap,
.header-inner,
.index-strip-inner,
.footer-inner {
  width: calc(100% - (2 * var(--gutter)));
  max-width: var(--max);
  margin-inline: auto;
}

.section { padding-block: clamp(36px, 6vw, 76px); }

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

.divider {
  height: 0;
  border: 0;
  border-top: 1px solid var(--line);
  margin-block: clamp(28px, 4vw, 48px);
}

#main-content { display: block; scroll-margin-top: 150px; }

/* ---------- 4. 页头 ---------- */
.skip-link {
  position: fixed;
  top: 12px;
  left: 12px;
  z-index: 200;
  padding: 10px 20px;
  border-radius: 999px;
  background: var(--ink);
  color: var(--paper);
  font-size: 0.85rem;
  letter-spacing: 0.04em;
  transform: translateY(-180%);
  transition: transform var(--ease);
}
.skip-link:focus { transform: translateY(0); }

.site-header {
  position: sticky;
  top: 0;
  z-index: 90;
  background: var(--paper);
  color: var(--ink);
  border-bottom: 1px solid var(--line);
  border-top: 3px solid var(--cinnabar);
}

.scroll-progress {
  position: absolute;
  left: 0;
  right: 0;
  bottom: -1px;
  height: 2px;
  overflow: hidden;
  pointer-events: none;
}
.scroll-progress-bar {
  display: block;
  width: 100%;
  height: 100%;
  background: var(--cinnabar);
  transform: scaleX(0);
  transform-origin: left center;
  transition: transform 120ms linear;
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: clamp(14px, 3vw, 48px);
  padding-block: 14px;
}

.brand-block { flex: 0 1 auto; min-width: 0; }

.brand-link {
  display: flex;
  align-items: baseline;
  flex-wrap: wrap;
  gap: 4px 12px;
}

.brand-name {
  font-family: var(--font-head);
  font-weight: 900;
  font-size: clamp(1.15rem, 1.6vw, 1.5rem);
  letter-spacing: 0.02em;
  color: var(--ink);
  transition: color var(--ease);
}
.brand-link:hover .brand-name,
.brand-link:focus-visible .brand-name { color: var(--indigo); }

.brand-tagline {
  font-size: 0.72rem;
  letter-spacing: 0.18em;
  color: var(--stone);
  border-left: 1px solid var(--line-strong);
  padding-left: 12px;
}

.nav-toggle {
  display: none;
  align-items: center;
  gap: 9px;
  padding: 8px 14px;
  border: 1px solid var(--line-strong);
  border-radius: 999px;
  font-size: 0.76rem;
  letter-spacing: 0.14em;
  color: var(--ink-slate);
  background: transparent;
  transition: border-color var(--ease), color var(--ease), background-color var(--ease);
}
.nav-toggle:hover,
.nav-toggle:focus-visible { border-color: var(--cinnabar); color: var(--cinnabar); }

.nav-toggle-bars {
  display: inline-flex;
  flex-direction: column;
  justify-content: space-between;
  width: 16px;
  height: 11px;
}
.nav-toggle-bars span {
  display: block;
  height: 2px;
  width: 100%;
  border-radius: 1px;
  background: currentColor;
  transition: transform var(--ease), opacity var(--ease);
}
.nav-toggle[aria-expanded="true"] .nav-toggle-bars span:nth-child(1) { transform: translateY(4.5px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle-bars span:nth-child(2) { opacity: 0; }
.nav-toggle[aria-expanded="true"] .nav-toggle-bars span:nth-child(3) { transform: translateY(-4.5px) rotate(-45deg); }

.site-nav { flex: 0 1 auto; }

.nav-list {
  display: flex;
  align-items: center;
  gap: clamp(4px, 1.5vw, 24px);
  padding-left: 10px;
}

.nav-link {
  position: relative;
  display: inline-block;
  padding: 8px 2px;
  font-size: 0.9rem;
  letter-spacing: 0.04em;
  color: var(--ink-slate);
  border-bottom: 2px solid transparent;
  transition: color var(--ease), border-color var(--ease);
}
.nav-link:hover,
.nav-link:focus-visible { color: var(--indigo); border-bottom-color: var(--cinnabar); }

.nav-link[aria-current="page"] { color: var(--indigo); font-weight: 700; }
.nav-link[aria-current="page"]::before {
  content: "";
  position: absolute;
  left: -9px;
  top: 50%;
  width: 3px;
  height: 15px;
  border-radius: 2px;
  background: var(--indigo);
  transform: translateY(-50%);
}

.index-strip {
  background: var(--ink-slate);
  color: var(--paper);
  border-top: 2px solid var(--cinnabar);
}

.index-strip-inner {
  padding-block: 9px;
  overflow-x: auto;
  scrollbar-width: thin;
  scrollbar-color: rgba(244, 239, 228, 0.35) transparent;
}
.index-strip-inner::-webkit-scrollbar { height: 4px; }
.index-strip-inner::-webkit-scrollbar-thumb {
  background: rgba(244, 239, 228, 0.35);
  border-radius: 4px;
}

.strip-list {
  display: flex;
  flex-wrap: nowrap;
  gap: 8px;
  padding-left: 2px;
}
.strip-item { flex: 0 0 auto; }

.strip-tag {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  white-space: nowrap;
  padding: 5px 13px;
  border-radius: 999px;
  border: 1px solid rgba(244, 239, 228, 0.16);
  background: rgba(244, 239, 228, 0.05);
  color: rgba(244, 239, 228, 0.86);
  font-size: 0.72rem;
  letter-spacing: 0.12em;
  transition: background-color var(--ease), color var(--ease), border-color var(--ease);
}
.strip-tag:hover {
  background: var(--mist);
  color: var(--ink-slate);
  border-color: var(--mist);
}

.strip-dot {
  flex: 0 0 auto;
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--paper);
}
.strip-tag[data-tone="1"] .strip-dot { background: #C74E32; }
.strip-tag[data-tone="2"] .strip-dot { background: #A9B8D2; }
.strip-tag[data-tone="3"] .strip-dot { background: #7D9A7F; }
.strip-tag[data-tone="4"] .strip-dot { background: #E5D6BC; }
.strip-tag[data-tone="5"] .strip-dot { background: #D9E0DE; }
.strip-tag[data-tone="6"] .strip-dot { background: #F4EFE4; }
.strip-tag[data-tone="7"] .strip-dot { background: #2F4A78; box-shadow: 0 0 0 1px #A9B8D2; }
.strip-tag[data-tone="8"] .strip-dot { background: #3F4A4D; box-shadow: 0 0 0 1px #7D9A7F; }

/* ---------- 5. 页脚 ---------- */
.site-footer {
  margin-top: clamp(48px, 8vw, 96px);
  background: var(--ink-slate);
  color: rgba(244, 239, 228, 0.82);
  border-top: 3px solid var(--cinnabar);
}

.footer-inner { padding-block: clamp(40px, 6vw, 68px) 0; }

.footer-top {
  display: grid;
  grid-template-columns: minmax(220px, 1.5fr) repeat(3, minmax(140px, 1fr));
  gap: clamp(24px, 3vw, 48px);
}

.footer-brand-name {
  font-family: var(--font-head);
  font-weight: 900;
  font-size: 1.3rem;
  letter-spacing: 0.03em;
  color: var(--paper);
}

.footer-tagline {
  margin-top: 6px;
  font-size: 0.74rem;
  letter-spacing: 0.18em;
  color: var(--sand);
}

.footer-note {
  margin-top: 16px;
  font-size: 0.85rem;
  line-height: 1.8;
  color: rgba(244, 239, 228, 0.66);
  max-width: 26em;
}

.footer-heading {
  font-family: var(--font-head);
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.18em;
  color: var(--sand);
  margin-bottom: 14px;
}

.footer-links { display: grid; gap: 2px; }
.footer-links--plain { gap: 10px; }

.footer-link {
  display: inline-block;
  padding: 4px 0;
  font-size: 0.9rem;
  color: rgba(244, 239, 228, 0.78);
  border-bottom: 1px solid transparent;
  transition: color var(--ease), border-color var(--ease);
}
.footer-link:hover,
.footer-link:focus-visible {
  color: var(--paper);
  border-bottom-color: var(--cinnabar);
}

.footer-contact-line { display: grid; gap: 1px; }

.footer-label {
  font-size: 0.68rem;
  letter-spacing: 0.16em;
  color: rgba(229, 214, 188, 0.75);
}

.footer-value {
  font-size: 0.86rem;
  line-height: 1.6;
  color: rgba(244, 239, 228, 0.92);
  word-break: break-word;
}

.footer-hint {
  margin-top: 16px;
  font-size: 0.76rem;
  line-height: 1.7;
  color: rgba(244, 239, 228, 0.58);
  max-width: 24em;
}

.footer-bottom {
  margin-top: clamp(30px, 4vw, 48px);
  padding-block: 18px 22px;
  border-top: 1px solid var(--line-light);
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 10px 24px;
  font-size: 0.78rem;
  color: rgba(244, 239, 228, 0.6);
}

.footer-legal { letter-spacing: 0.02em; }
.footer-meta { letter-spacing: 0.04em; }

/* ---------- 6. 通用组件 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 11px 24px;
  border-radius: 999px;
  border: 1.5px solid var(--ink-slate);
  background: transparent;
  color: var(--ink-slate);
  font-size: 0.9rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  transition: background-color var(--ease), color var(--ease), border-color var(--ease);
}
.btn:hover,
.btn:focus-visible {
  background: var(--ink-slate);
  border-color: var(--ink-slate);
  color: var(--paper);
}

.btn--solid {
  background: var(--cinnabar);
  border-color: var(--cinnabar);
  color: var(--paper);
}
.btn--solid:hover,
.btn--solid:focus-visible {
  background: var(--ink-slate);
  border-color: var(--ink-slate);
  color: var(--paper);
}

.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 11px;
  border-radius: 999px;
  border: 1px solid transparent;
  background: var(--mist);
  color: var(--ink-slate);
  font-size: 0.72rem;
  letter-spacing: 0.12em;
  line-height: 1.6;
}

.card {
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  padding: clamp(18px, 2.4vw, 28px);
  transition: border-color var(--ease), transform var(--ease), background-color var(--ease);
}
.card:hover {
  border-color: var(--cinnabar);
  transform: translateY(-2px);
}

.breadcrumb { font-size: 0.78rem; color: var(--stone); }
.crumb-list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
}
.crumb-item { display: flex; align-items: center; gap: 8px; }
.crumb-item + .crumb-item::before {
  content: "/";
  color: var(--indigo-soft);
}
.crumb-link {
  color: var(--stone);
  border-bottom: 1px solid transparent;
  transition: color var(--ease), border-color var(--ease);
}
.crumb-link:hover,
.crumb-link:focus-visible {
  color: var(--indigo);
  border-bottom-color: var(--indigo);
}
.crumb-current { color: var(--ink); }

/* 页内目录（供二级页使用） */
[data-toc-link] {
  display: block;
  padding: 7px 0 7px 14px;
  border-left: 2px solid var(--line);
  font-size: 0.88rem;
  color: var(--ink-slate);
  transition: color var(--ease), border-color var(--ease), background-color var(--ease);
}
[data-toc-link]:hover { color: var(--indigo); border-left-color: var(--indigo-soft); }
[data-toc-link][aria-current="true"] {
  color: var(--indigo);
  font-weight: 700;
  border-left-color: var(--indigo);
  background: rgba(47, 74, 120, 0.05);
}

/* ---------- 7. 媒体容器 ---------- */
.media-frame {
  position: relative;
  display: block;
  overflow: hidden;
  border-radius: var(--radius-md);
  border: 1px solid var(--line);
  background: var(--mist);
  aspect-ratio: 16 / 10;
}
.media-frame img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 220ms ease;
}
.media-frame--wide { aspect-ratio: 21 / 9; }
.media-frame--tall { aspect-ratio: 4 / 5; }
.media-frame--square { aspect-ratio: 1 / 1; }

.media-frame--pattern {
  background-image:
    repeating-linear-gradient(135deg, rgba(63, 74, 77, 0.10) 0 12px, rgba(63, 74, 77, 0) 12px 24px),
    linear-gradient(160deg, var(--sand), var(--mist) 58%, var(--paper));
}

.media-frame__label {
  position: absolute;
  left: 12px;
  bottom: 12px;
  padding: 4px 11px;
  border-radius: 999px;
  background: rgba(30, 36, 38, 0.74);
  color: var(--paper);
  font-size: 0.7rem;
  letter-spacing: 0.1em;
  line-height: 1.6;
}

/* ---------- 8. 响应式 ---------- */
@media (max-width: 960px) {
  .grid--3 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .footer-top { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .footer-brand { grid-column: 1 / -1; }
}

@media (max-width: 860px) {
  html { scroll-padding-top: 132px; }

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

  .site-nav {
    position: absolute;
    left: 0;
    right: 0;
    top: 100%;
    display: none;
    padding: 10px var(--gutter) 18px;
    max-height: calc(100vh - 150px);
    overflow-y: auto;
    background: var(--paper);
    border-top: 1px solid var(--line);
    border-bottom: 1px solid var(--line);
    box-shadow: 0 26px 46px -30px rgba(30, 36, 38, 0.6);
  }
  .site-nav[data-open="true"] { display: block; }

  .nav-list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding-left: 0;
  }
  .nav-item + .nav-item { border-top: 1px solid var(--line); }

  .nav-link {
    display: block;
    padding: 14px 12px;
    font-size: 1rem;
    border-bottom: 0;
    border-left: 3px solid transparent;
  }
  .nav-link:hover,
  .nav-link:focus-visible { border-left-color: var(--cinnabar); }

  .nav-link[aria-current="page"] { border-left-color: var(--indigo); }
  .nav-link[aria-current="page"]::before { display: none; }
}

@media (max-width: 640px) {
  .grid--2,
  .grid--3 { grid-template-columns: minmax(0, 1fr); }

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

  .brand-tagline { display: none; }

  .display-title { letter-spacing: -0.02em; }

  .index-strip-inner { padding-block: 8px; }
}

/* ---------- 9. 可达性与动效偏好 ---------- */
:focus-visible {
  outline: 2px solid var(--indigo);
  outline-offset: 3px;
  border-radius: 4px;
}
.site-footer :focus-visible,
.index-strip :focus-visible { outline-color: var(--sand); }

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

@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;
    scroll-behavior: auto !important;
  }

  .card:hover,
  .media-frame:hover img { transform: none !important; }
}