/* ==========================================================================
   OB Play — 全站共享 CSS  /assets/site.css
   深空蓝底 + 炽热橙红 + 电光黄 + 数据青
   框架式导航 / 海报式分层 / 精密网格 / 展览标签
   ========================================================================== */

/* ---------- Reset ---------- */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

/* ---------- 变量 ---------- */
:root {
  --c-bg: #0A1B2B;
  --c-bg-alt: #122A40;
  --c-cta: #FF6B2C;
  --c-warn: #FFE135;
  --c-data: #00E5FF;
  --c-text: #FFFFFF;
  --c-muted: #B8C4D0;
  --c-line: #2E4A62;
  --glass-gradient: linear-gradient(135deg, rgba(255,255,255,0.12) 0%, rgba(255,255,255,0.03) 100%);

  --font-display: "Arial Black", Impact, "Helvetica Neue", "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", sans-serif;
  --font-body: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", sans-serif;
  --font-mono: "SFMono-Regular", "Roboto Mono", Menlo, Consolas, "Liberation Mono", monospace;

  --container-w: 1200px;
  --header-h: 72px;
  --rail-w: 240px;
  --rail-w-collapsed: 76px;
  --dur: 0.2s;
}

/* ---------- 基础排版 ---------- */
html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-h) + 16px);
}

body {
  position: relative;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  background-color: var(--c-bg);
  background-image:
    radial-gradient(ellipse 80% 50% at 78% -10%, rgba(255, 107, 44, 0.06) 0%, transparent 55%),
    radial-gradient(ellipse 50% 40% at 8% 15%, rgba(0, 229, 255, 0.04) 0%, transparent 55%);
  color: var(--c-text);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-display);
  line-height: 1.25;
  color: var(--c-text);
  font-weight: 900;
}

h1, h2 {
  font-style: italic;
}

h3, h4, h5, h6 {
  font-style: normal;
  font-weight: 700;
}

p + p {
  margin-top: 1em;
}

a {
  color: var(--c-text);
  text-decoration: none;
  transition: color var(--dur) ease, background-color var(--dur) ease, border-color var(--dur) ease, box-shadow var(--dur) ease, opacity var(--dur) ease;
}

a:hover {
  color: var(--c-cta);
}

ul,
ol {
  list-style: none;
}

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

button,
input,
select,
textarea {
  font: inherit;
  color: inherit;
}

button {
  background: none;
  border: none;
  cursor: pointer;
}

:focus-visible {
  outline: 2px solid var(--c-warn);
  outline-offset: 3px;
}

::selection {
  background: var(--c-cta);
  color: var(--c-bg);
}

#main-content {
  outline: none;
  scroll-margin-top: var(--header-h);
}

#main-content:focus {
  outline: 2px solid var(--c-warn);
  outline-offset: -2px;
}

main {
  flex: 1 0 auto;
  width: auto;
  margin-left: var(--rail-w);
}

/* ---------- 容器与栅格 ---------- */
.container {
  width: 100%;
  max-width: var(--container-w);
  margin: 0 auto;
  padding: 0 24px;
}

.section-pad {
  padding: 72px 0;
}

.grid-2,
.grid-3 {
  display: grid;
  gap: 24px;
}

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

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

/* ---------- 头部 ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: rgba(10, 27, 43, 0.88);
  -webkit-backdrop-filter: blur(12px);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--c-line);
}

.skip-link {
  position: absolute;
  top: -100px;
  left: 32px;
  z-index: 1002;
  padding: 8px 16px;
  background: var(--c-cta);
  color: var(--c-bg);
  font-size: 14px;
  font-weight: 700;
  border-radius: 0;
  transition: top var(--dur) ease;
}

.skip-link:focus {
  top: 12px;
}

.header-frame {
  width: 100%;
  max-width: 1440px;
  margin: 0 auto;
  padding: 0 32px;
  height: var(--header-h);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  position: relative;
}

.brand-lockup {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-shrink: 0;
}

.brand-glyph {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  background: var(--c-cta);
  color: var(--c-bg);
  font-family: var(--font-display);
  font-style: italic;
  font-weight: 900;
  font-size: 20px;
  letter-spacing: -0.02em;
  transform: skewX(-4deg);
  box-shadow: 0 0 18px rgba(255, 107, 44, 0.35);
}

.brand-copy {
  display: flex;
  flex-direction: column;
  line-height: 1.1;
}

.brand-text {
  font-family: var(--font-display);
  font-style: italic;
  font-weight: 900;
  font-size: 18px;
  letter-spacing: 0.04em;
  color: var(--c-text);
}

.brand-sub {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.18em;
  color: var(--c-data);
}

.header-toggle {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 44px;
  height: 44px;
  padding: 12px;
  border: 1px solid var(--c-line);
  background: transparent;
  cursor: pointer;
  flex-shrink: 0;
  transition: border-color var(--dur) ease;
}

.header-toggle:hover {
  border-color: var(--c-cta);
}

.toggle-line {
  display: block;
  height: 2px;
  width: 100%;
  background: var(--c-text);
  transition: transform var(--dur) ease, opacity var(--dur) ease, background-color var(--dur) ease;
}

.header-toggle[aria-expanded="true"] .toggle-line:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.header-toggle[aria-expanded="true"] .toggle-line:nth-child(2) {
  opacity: 0;
}

.header-toggle[aria-expanded="true"] .toggle-line:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

.header-progress {
  position: absolute;
  bottom: -1px;
  left: 0;
  height: 3px;
  width: 0%;
  background: linear-gradient(90deg, var(--c-cta), var(--c-warn));
  z-index: 1001;
  pointer-events: none;
  transition: width 0.08s linear;
}

/* ---------- 左侧导航竖轨 ---------- */
.site-rail {
  position: fixed;
  top: var(--header-h);
  left: 0;
  bottom: 0;
  z-index: 950;
  width: var(--rail-w);
  background: linear-gradient(180deg, var(--c-bg-alt) 0%, rgba(10, 27, 43, 0.96) 100%);
  border-right: 1px solid var(--c-line);
  display: flex;
  flex-direction: column;
  padding: 16px 12px;
  gap: 0;
  overflow-y: auto;
  transition: width var(--dur) ease;
}

body[data-rail-collapsed="true"] .site-rail {
  width: var(--rail-w-collapsed);
}

body[data-rail-collapsed="true"] .rail-label,
body[data-rail-collapsed="true"] .rail-meta {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

body[data-rail-collapsed="true"] .rail-link {
  justify-content: center;
  padding-left: 0;
  padding-right: 0;
}

.rail-link {
  position: relative;
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 14px 16px;
  min-height: 48px;
  font-size: 14px;
  font-weight: 500;
  color: var(--c-muted);
  border-bottom: 1px solid var(--c-line);
  transition: background-color var(--dur) ease, color var(--dur) ease, padding-left var(--dur) ease;
}

.rail-link::before {
  content: attr(data-index);
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--c-data);
  letter-spacing: 0.02em;
  flex-shrink: 0;
}

.rail-link:hover {
  color: var(--c-text);
  background: rgba(255, 255, 255, 0.04);
}

.rail-link[aria-current="page"] {
  color: var(--c-cta);
  background: rgba(255, 107, 44, 0.08);
}

.rail-link[aria-current="page"]::before {
  color: var(--c-cta);
}

.rail-link[aria-current="page"]::after {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 3px;
  background: var(--c-cta);
}

.rail-link:last-of-type {
  border-bottom: none;
}

.rail-meta {
  margin-top: auto;
  padding: 16px;
  border-top: 1px solid var(--c-line);
}

.rail-meta-line {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.18em;
  color: var(--c-muted);
  white-space: nowrap;
}

/* ---------- 页脚 ---------- */
.site-footer {
  flex-shrink: 0;
  margin-left: var(--rail-w);
  background: linear-gradient(180deg, var(--c-bg) 0%, #071120 100%);
  border-top: 1px solid var(--c-line);
}

.footer-grid {
  max-width: var(--container-w);
  margin: 0 auto;
  padding: 56px 24px 40px;
  display: grid;
  grid-template-columns: 1.2fr 1fr 1.2fr;
  gap: 48px;
}

.footer-eyebrow {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.2em;
  color: var(--c-data);
  margin-bottom: 8px;
}

.footer-brandline {
  font-family: var(--font-display);
  font-style: italic;
  font-weight: 900;
  font-size: 24px;
  color: var(--c-text);
  margin-bottom: 12px;
}

.footer-trust {
  font-size: 14px;
  color: var(--c-muted);
  line-height: 1.7;
  max-width: 340px;
}

.footer-title {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--c-warn);
  margin-bottom: 16px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--c-line);
}

.footer-links li + li {
  margin-top: 8px;
}

.footer-links a {
  font-size: 14px;
  color: var(--c-muted);
  display: inline-flex;
  gap: 8px;
  transition: color var(--dur) ease, padding-left var(--dur) ease;
}

.footer-links a::before {
  content: "→";
  font-family: var(--font-mono);
  color: var(--c-cta);
}

.footer-links a:hover {
  color: var(--c-text);
  padding-left: 4px;
}

.footer-meta li {
  font-size: 14px;
  color: var(--c-muted);
  padding-left: 16px;
  position: relative;
  line-height: 1.5;
  margin-bottom: 8px;
}

.footer-meta li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.5em;
  width: 6px;
  height: 6px;
  background: var(--c-data);
  transform: rotate(45deg);
}

.footer-compliance {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 20px;
}

.footer-compliance a {
  font-size: 13px;
  color: var(--c-muted);
  border: 1px solid var(--c-line);
  padding: 4px 12px;
  transition: color var(--dur) ease, border-color var(--dur) ease, background-color var(--dur) ease;
}

.footer-compliance a:hover {
  color: var(--c-cta);
  border-color: var(--c-cta);
  background: rgba(255, 107, 44, 0.06);
}

.footer-legal {
  border-top: 1px solid var(--c-line);
}

.footer-legal-inner {
  max-width: var(--container-w);
  margin: 0 auto;
  padding: 16px 24px;
  display: flex;
  flex-wrap: wrap;
  gap: 12px 24px;
  justify-content: space-between;
  align-items: center;
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--c-muted);
}

/* ---------- 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 28px;
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 0.04em;
  line-height: 1.4;
  color: var(--c-text);
  background: transparent;
  border: 1px solid var(--c-line);
  cursor: pointer;
  position: relative;
  overflow: hidden;
  transition: background-color var(--dur) ease, border-color var(--dur) ease, color var(--dur) ease, box-shadow var(--dur) ease, transform var(--dur) ease;
}

.btn::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: 0;
  height: 2px;
  background: var(--c-cta);
  transition: width var(--dur) ease;
}

.btn:hover {
  border-color: var(--c-cta);
  color: var(--c-text);
}

.btn:hover::after {
  width: 100%;
}

.btn:active {
  transform: translateY(1px);
}

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  pointer-events: none;
}

.btn-primary {
  background: var(--c-cta);
  border-color: var(--c-cta);
  color: var(--c-bg);
  box-shadow: 0 0 0 0 rgba(255, 107, 44, 0.4);
}

.btn-primary::after {
  background: var(--c-warn);
}

.btn-primary:hover {
  background: #FF8247;
  color: var(--c-bg);
  box-shadow: 0 4px 20px rgba(255, 107, 44, 0.3);
}

.btn-ghost {
  border-color: var(--c-line);
  color: var(--c-muted);
}

.btn-ghost:hover {
  border-color: var(--c-data);
  color: var(--c-data);
  background: rgba(0, 229, 255, 0.04);
}

/* ---------- 章节标题 ---------- */
.section-title {
  display: flex;
  align-items: baseline;
  gap: 16px;
  font-family: var(--font-display);
  font-style: italic;
  font-weight: 900;
  font-size: 32px;
  line-height: 1.2;
  color: var(--c-text);
  margin-bottom: 24px;
}

.section-title::before {
  content: attr(data-index);
  flex-shrink: 0;
  font-family: var(--font-mono);
  font-style: normal;
  font-weight: 400;
  font-size: 13px;
  color: var(--c-data);
  border: 1px solid var(--c-line);
  padding: 4px 10px;
  transform: skewX(-8deg);
  letter-spacing: 0.04em;
}

.eyebrow {
  display: block;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.24em;
  text-transform: uppercase;
  color: var(--c-cta);
  margin-bottom: 8px;
}

/* ---------- 面包屑 ---------- */
.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  padding: 16px 0;
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--c-muted);
}

.breadcrumb a {
  color: var(--c-muted);
}

.breadcrumb a:hover {
  color: var(--c-cta);
}

.crumb-sep {
  color: var(--c-line);
}

.crumb-current {
  color: var(--c-cta);
  font-weight: 500;
}

/* ---------- 卡片 ---------- */
.card {
  background: var(--c-bg-alt);
  border: 1px solid var(--c-line);
  border-radius: 0;
  padding: 24px;
  transition: border-color var(--dur) ease, transform var(--dur) ease, box-shadow var(--dur) ease;
}

.card:hover {
  border-color: var(--c-cta);
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.3);
}

.card--glass {
  background: linear-gradient(135deg, rgba(255,255,255,0.12) 0%, rgba(255,255,255,0.03) 100%);
  -webkit-backdrop-filter: blur(10px);
  backdrop-filter: blur(10px);
  border-color: rgba(255, 255, 255, 0.14);
}

/* ---------- 标签 ---------- */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 4px 14px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--c-data);
  border: 1px solid var(--c-line);
  background: var(--c-bg-alt);
}

.tag::before {
  content: "";
  width: 6px;
  height: 6px;
  background: var(--c-data);
  transform: rotate(45deg);
  flex-shrink: 0;
}

.tag--hot {
  color: var(--c-cta);
  border-color: var(--c-cta);
  background: rgba(255, 107, 44, 0.06);
}

.tag--hot::before {
  background: var(--c-cta);
}

/* ---------- 数据文本 ---------- */
.data-num {
  font-family: var(--font-mono);
  font-size: 32px;
  font-weight: 600;
  color: var(--c-data);
  letter-spacing: -0.02em;
  line-height: 1;
}

.data-label {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--c-muted);
}

/* ---------- 图片容器占位 ---------- */
.img-frame {
  position: relative;
  overflow: hidden;
  background: linear-gradient(135deg, rgba(255, 107, 44, 0.05), rgba(0, 229, 255, 0.02)), var(--c-bg-alt);
  border: 1px solid var(--c-line);
}

.img-frame::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 2;
  background-image:
    linear-gradient(var(--c-line) 1px, transparent 1px),
    linear-gradient(90deg, var(--c-line) 1px, transparent 1px);
  background-size: 32px 32px;
  opacity: 0.35;
  pointer-events: none;
}

.img-frame::after {
  content: attr(data-label);
  position: absolute;
  left: 0;
  bottom: 0;
  z-index: 3;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--c-muted);
  background: rgba(10, 27, 43, 0.78);
  padding: 6px 12px;
  border-left: 3px solid var(--c-cta);
  max-width: 100%;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.img-frame > img,
.img-frame > picture,
.img-frame > canvas {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  z-index: 1;
}

.img-frame--wide {
  aspect-ratio: 21 / 9;
}

.img-frame--standard {
  aspect-ratio: 16 / 9;
}

.img-frame--portrait {
  aspect-ratio: 3 / 4;
}

.img-frame--card {
  aspect-ratio: 4 / 3;
}

/* ---------- 箭头链接 ---------- */
.link-arrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 14px;
  font-weight: 700;
  color: var(--c-data);
  transition: color var(--dur) ease;
}

.link-arrow::after {
  content: "→";
  font-family: var(--font-mono);
  transition: transform var(--dur) ease;
}

.link-arrow:hover {
  color: var(--c-warn);
}

.link-arrow:hover::after {
  transform: translateX(4px);
}

/* ---------- 响应式 ---------- */
@media (min-width: 961px) {
  main,
  .site-footer {
    transition: margin-left var(--dur) ease;
  }
}

@media (max-width: 1200px) {
  .grid-3 {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 1100px) {
  .footer-grid {
    grid-template-columns: 1fr 1fr;
    gap: 40px;
  }

  .footer-about {
    grid-column: 1 / -1;
  }
}

@media (max-width: 960px) {
  :root {
    --header-h: 64px;
  }

  .site-rail,
  body[data-rail-collapsed="true"] .site-rail {
    top: var(--header-h);
    left: 0;
    right: 0;
    bottom: auto;
    width: 100%;
    max-height: calc(100vh - var(--header-h));
    display: none;
    background: rgba(10, 27, 43, 0.98);
    border-right: none;
    border-bottom: 1px solid var(--c-line);
    box-shadow: 0 16px 32px rgba(0, 0, 0, 0.45);
    padding: 8px 16px 16px;
  }

  .site-rail[data-open="true"],
  body[data-rail-collapsed="true"] .site-rail[data-open="true"] {
    display: flex;
  }

  body[data-rail-collapsed="true"] .rail-link,
  .site-rail .rail-link {
    justify-content: flex-start;
    padding-left: 16px;
    padding-right: 16px;
  }

  body[data-rail-collapsed="true"] .rail-label,
  .site-rail .rail-label {
    position: static;
    width: auto;
    height: auto;
    padding: 0;
    margin: 0;
    overflow: visible;
    clip: auto;
    white-space: normal;
    border: 0;
  }

  body[data-rail-collapsed="true"] .rail-meta,
  .site-rail .rail-meta {
    position: static;
    width: auto;
    height: auto;
    padding: 16px;
    margin-top: auto;
    overflow: visible;
    clip: auto;
    white-space: normal;
    border: 0;
  }

  body[data-rail-collapsed="true"] main,
  body[data-rail-collapsed="true"] .site-footer,
  main,
  .site-footer {
    margin-left: 0;
  }

  .footer-grid {
    grid-template-columns: 1fr;
    gap: 32px;
  }

  .footer-about {
    grid-column: auto;
  }
}

@media (max-width: 640px) {
  :root {
    --header-h: 60px;
  }

  .header-frame {
    padding: 0 16px;
  }

  .skip-link {
    left: 16px;
  }

  .container {
    padding: 0 16px;
  }

  .section-pad {
    padding: 48px 0;
  }

  .grid-2,
  .grid-3 {
    grid-template-columns: 1fr;
    gap: 16px;
  }

  .brand-sub {
    display: none;
  }

  .brand-text {
    font-size: 16px;
  }

  .brand-glyph {
    width: 40px;
    height: 40px;
    font-size: 18px;
  }

  .footer-grid {
    padding: 40px 16px 32px;
  }

  .footer-legal-inner {
    padding: 14px 16px;
    flex-direction: column;
    gap: 8px;
    align-items: flex-start;
  }
}

/* ---------- 减弱动效 ---------- */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }

  .card:hover,
  .btn:hover {
    transform: none;
    box-shadow: none;
  }
}