/* ==========================================================================
   6号平台中心 · 共享样式表 /assets/site.css
   手册式卡片语言：墨蓝基底 · 2px 粗描边 · 6px 硬投影 · 等宽索引
   ========================================================================== */

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

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  --scroll-progress: 0;
}

body { margin: 0; }

h1, h2, h3, h4, h5, h6, p, figure, blockquote, dl, dd { margin: 0; }

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

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

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

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

/* 2. 变量
   ========================================================================== */
:root {
  /* 色彩 */
  --ink: #0E1B2C;
  --ink-2: #16283D;
  --line: #24374F;
  --amber: #F2A03D;
  --amber-press: #C97C1B;
  --mist: #A9B4C2;
  --cream: #F6F2E9;
  --paper: #FFFFFF;
  --grid-blue: #DDE5EF;
  --pass: #2F8A6A;
  --text-ink: #0A1420;
  --text-muted: #4A5A6E;

  /* 版式 */
  --font-sans: "Noto Sans SC", "Source Han Sans SC", "PingFang SC", "Microsoft YaHei", system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-mono: "JetBrains Mono", "IBM Plex Mono", ui-monospace, "SFMono-Regular", Consolas, "Liberation Mono", monospace;
  --page-max: 1160px;
  --gap: 24px;
  --header-h: 76px;

  /* 形状 */
  --radius: 4px;
  --shadow-hard: 6px 6px 0 var(--line);
  --shadow-btn: 3px 3px 0 var(--line);
}

/* 3. 基础排版
   ========================================================================== */
body {
  background-color: var(--ink);
  color: var(--cream);
  font-family: var(--font-sans);
  font-size: 17px;
  font-weight: 400;
  line-height: 1.8;
  letter-spacing: 0;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

@media (min-width: 1024px) {
  body { font-size: 18px; }
}

h1, h2, h3, h4 {
  font-weight: 900;
  line-height: 1.15;
  letter-spacing: -0.01em;
}

strong { font-weight: 800; }

code, kbd, samp, .u-mono {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  letter-spacing: 0.06em;
}

/* 4. 焦点与无障碍
   ========================================================================== */
:where(a, button, input, select, textarea, summary, [tabindex]):focus-visible {
  outline: 3px solid var(--amber);
  outline-offset: 3px;
  border-radius: 2px;
}

.skip-link {
  position: fixed;
  top: 8px;
  left: 8px;
  z-index: 200;
  padding: 10px 16px;
  background: var(--amber);
  color: var(--text-ink);
  font-weight: 800;
  font-size: 14px;
  border: 2px solid var(--text-ink);
  border-radius: var(--radius);
  box-shadow: var(--shadow-btn);
  transform: translateY(-160%);
  transition: transform 160ms ease;
}

.skip-link:focus-visible {
  transform: translateY(0);
}

/* 5. 容器与骨架
   ========================================================================== */
.container {
  width: min(100% - 40px, var(--page-max));
  margin-inline: auto;
}

.page-main {
  display: block;
  min-height: 60vh;
}

.section {
  padding-block: clamp(36px, 6vw, 64px);
}

.section + .section {
  border-top: 2px solid var(--line);
}

.section--light {
  background-color: var(--cream);
  color: var(--text-ink);
}

.section--light + .section--light {
  border-top-color: var(--grid-blue);
}

.section--light .eyebrow { color: var(--text-muted); }
.section--light .section-lead { color: var(--text-muted); }
.section--light .rule { background: var(--grid-blue); }

.section-head {
  display: grid;
  gap: 6px;
  margin-bottom: clamp(20px, 3vw, 32px);
  max-width: 40em;
}

.eyebrow {
  font-family: var(--font-mono);
  font-size: 12px;
  font-variant-numeric: tabular-nums;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--mist);
}

.section-title {
  font-size: clamp(22px, 5vw, 34px);
  font-weight: 900;
}

.section-lead {
  max-width: 34em;
  font-size: 17px;
  line-height: 1.8;
  color: var(--mist);
}

/* 6. 网格与堆叠
   ========================================================================== */
.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)); }

@media (max-width: 768px) {
  .grid--2,
  .grid--3 { grid-template-columns: minmax(0, 1fr); }
}

.stack > * + * { margin-top: var(--stack-gap, 16px); }

/* 7. 按钮
   ========================================================================== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 11px 18px;
  font-family: var(--font-sans);
  font-size: 15px;
  font-weight: 800;
  line-height: 1.2;
  color: var(--text-ink);
  background-color: var(--amber);
  border: 2px solid var(--text-ink);
  border-radius: var(--radius);
  box-shadow: var(--shadow-btn);
  cursor: pointer;
  white-space: nowrap;
  transition: transform 140ms ease, box-shadow 140ms ease, background-color 140ms ease, border-color 140ms ease, color 140ms ease;
}

.btn:hover {
  transform: translate(-1px, -1px);
  box-shadow: 4px 4px 0 var(--line);
}

.btn:active {
  transform: translate(2px, 2px);
  box-shadow: 1px 1px 0 var(--line);
  background-color: var(--amber-press);
}

.btn--ghost {
  color: var(--cream);
  background-color: transparent;
  border-color: var(--line);
  box-shadow: none;
}

.btn--ghost:hover {
  color: var(--amber);
  border-color: var(--amber);
  box-shadow: none;
  transform: none;
}

.btn--ghost:active {
  background-color: var(--ink-2);
  color: var(--amber-press);
  border-color: var(--amber-press);
  transform: none;
}

.section--light .btn--ghost {
  color: var(--text-ink);
  border-color: var(--text-ink);
}

.text-link {
  color: var(--amber);
  font-weight: 700;
  border-bottom: 1px solid currentColor;
  padding-bottom: 1px;
  transition: color 140ms ease, border-color 140ms ease;
}

.text-link:hover { color: var(--amber-press); }

.section--light .text-link { color: var(--amber-press); }

/* 8. 头部
   ========================================================================== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 90;
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  align-items: stretch;
  min-height: var(--header-h);
  background-color: var(--ink);
  color: var(--cream);
  border-bottom: 2px solid var(--line);
}

/* 滚动进度：左侧 2px 琥珀橙竖条 */
.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  z-index: 95;
  width: 2px;
  height: 100vh;
  height: 100dvh;
  background-color: var(--amber);
  transform: scaleY(var(--scroll-progress, 0));
  transform-origin: top center;
  transition: transform 90ms linear;
  pointer-events: none;
}

/* 品牌轨道 */
.header-rail {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 2px;
  padding: 12px 20px;
  min-width: 0;
  background-color: var(--ink-2);
  border-right: 2px solid var(--line);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  min-width: 0;
}

.brand-mark {
  display: inline-grid;
  place-items: center;
  flex: none;
  width: 30px;
  height: 30px;
  background-color: var(--amber);
  color: var(--text-ink);
  font-family: var(--font-mono);
  font-size: 16px;
  font-weight: 700;
  line-height: 1;
  border: 2px solid var(--text-ink);
  border-radius: var(--radius);
  box-shadow: 2px 2px 0 var(--line);
}

.brand-name {
  font-size: 17px;
  font-weight: 900;
  letter-spacing: -0.01em;
  white-space: nowrap;
}

.header-domain {
  display: block;
  font-family: var(--font-mono);
  font-size: 10.5px;
  font-variant-numeric: tabular-nums;
  letter-spacing: 0.06em;
  color: var(--mist);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

/* 导航 */
.site-nav {
  display: flex;
  align-items: center;
  min-width: 0;
}

.nav-list {
  display: flex;
  align-items: center;
  gap: 2px;
  padding: 0 12px;
  height: 100%;
}

.nav-item { display: flex; }

.nav-link {
  display: inline-flex;
  align-items: baseline;
  gap: 6px;
  padding: 10px 10px;
  font-size: 15px;
  font-weight: 700;
  color: var(--cream);
  border-bottom: 2px solid transparent;
  transition: color 140ms ease, border-color 140ms ease;
}

.nav-link:hover {
  color: var(--paper);
  border-bottom-color: var(--mist);
}

.nav-index {
  font-family: var(--font-mono);
  font-size: 10px;
  font-variant-numeric: tabular-nums;
  letter-spacing: 0.08em;
  color: var(--mist);
}

.nav-label { white-space: nowrap; }

.nav-link[aria-current="page"] {
  color: var(--amber);
  border-bottom-color: var(--amber);
}

.nav-link[aria-current="page"] .nav-index { color: var(--amber); }

.nav-drawer-foot {
  display: none;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.06em;
  color: var(--mist);
}

/* 头部操作区 */
.header-actions {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 0 20px 0 12px;
}

.nav-toggle {
  display: none;
  align-items: center;
  gap: 8px;
  padding: 10px 12px;
  font-size: 13px;
  font-weight: 800;
  color: var(--cream);
  border: 2px solid var(--line);
  border-radius: var(--radius);
  cursor: pointer;
  transition: color 140ms ease, border-color 140ms ease;
}

.nav-toggle:hover { border-color: var(--mist); }

.nav-toggle-bars {
  display: grid;
  gap: 3px;
  width: 16px;
}

.nav-toggle-bars span {
  display: block;
  height: 2px;
  background-color: currentColor;
  transition: transform 160ms ease, opacity 160ms ease;
}

.nav-toggle-label { line-height: 1; }

.site-header[data-open] .nav-toggle {
  color: var(--amber);
  border-color: var(--amber);
}

.site-header[data-open] .nav-toggle-bars span:nth-child(1) { transform: translateY(5px) rotate(45deg); }
.site-header[data-open] .nav-toggle-bars span:nth-child(2) { opacity: 0; }
.site-header[data-open] .nav-toggle-bars span:nth-child(3) { transform: translateY(-5px) rotate(-45deg); }

/* 9. 头部响应式
   ========================================================================== */
@media (max-width: 1120px) {
  .header-rail { padding-inline: 14px; }
  .nav-list { padding-inline: 6px; }
  .nav-link { padding: 10px 8px; font-size: 14px; }
  .header-actions { padding-inline: 14px 14px; gap: 8px; }
}

@media (max-width: 1024px) {
  .nav-index { display: none; }
  .header-secondary { display: none; }
}

@media (max-width: 899px) {
  :root { --header-h: 64px; }

  .site-header {
    grid-template-columns: minmax(0, 1fr) auto;
  }

  .header-rail {
    background-color: transparent;
    border-right: 0;
    padding: 10px 14px;
  }

  .header-domain { display: none; }

  .header-actions {
    padding: 0 12px;
    gap: 8px;
  }

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

  .site-nav {
    position: fixed;
    top: var(--header-h);
    left: 0;
    right: 0;
    z-index: 88;
    display: block;
    max-height: calc(100vh - var(--header-h));
    max-height: calc(100dvh - var(--header-h));
    overflow-y: auto;
    padding: 14px 16px 22px;
    background-color: var(--ink-2);
    border-bottom: 2px solid var(--amber);
    box-shadow: 0 20px 40px -24px #000000;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: opacity 160ms ease, transform 160ms ease, visibility 160ms ease;
  }

  .site-header[data-open] .site-nav {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
  }

  .nav-list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 0;
    height: auto;
  }

  .nav-item { display: block; }

  .nav-link {
    display: flex;
    align-items: baseline;
    gap: 10px;
    padding: 14px 4px;
    font-size: 17px;
    border-bottom: 2px solid var(--line);
  }

  .nav-index { display: inline; font-size: 11px; }

  .nav-link[aria-current="page"] {
    border-bottom-color: var(--amber);
  }

  .nav-drawer-foot {
    display: block;
    margin-top: 18px;
    padding-top: 14px;
    border-top: 2px dashed var(--line);
  }
}

@media (max-width: 420px) {
  .brand-name { font-size: 15px; }
  .brand-mark { width: 26px; height: 26px; font-size: 14px; }
  .header-primary { padding: 10px 12px; font-size: 13.5px; }
  .nav-toggle { padding: 9px 10px; }
  .nav-toggle-label { display: none; }
}

/* 10. 页脚
   ========================================================================== */
.site-footer {
  margin-top: clamp(48px, 7vw, 76px);
  background-color: var(--ink);
  color: var(--cream);
  border-top: 2px solid var(--line);
}

.footer-inner {
  width: min(100% - 40px, var(--page-max));
  margin-inline: auto;
  display: grid;
  grid-template-columns: minmax(250px, 1.6fr) repeat(3, minmax(0, 1fr));
  gap: 40px 28px;
  padding-block: clamp(36px, 5vw, 56px) 44px;
}

.footer-brand {
  display: grid;
  gap: 10px;
  align-content: start;
}

.footer-brand-link {
  font-size: 22px;
  font-weight: 900;
  letter-spacing: -0.01em;
  border-bottom: 2px solid transparent;
  justify-self: start;
  transition: color 140ms ease, border-color 140ms ease;
}

.footer-brand-link:hover {
  color: var(--amber);
  border-bottom-color: var(--amber);
}

.footer-tagline {
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.08em;
  color: var(--mist);
}

.footer-contact {
  display: grid;
  gap: 4px;
  margin-top: 6px;
  padding: 12px 14px;
  border: 2px solid var(--line);
  border-radius: var(--radius);
  background-color: var(--ink-2);
}

.footer-contact-line {
  display: flex;
  gap: 10px;
  align-items: baseline;
  font-size: 13.5px;
  line-height: 1.6;
}

.footer-contact-key {
  flex: none;
  width: 2.6em;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--mist);
}

.footer-contact-value {
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.02em;
  word-break: break-word;
  color: var(--cream);
}

.footer-note {
  font-size: 13px;
  line-height: 1.7;
  color: var(--mist);
  max-width: 32em;
}

.footer-col { display: grid; gap: 12px; align-content: start; }

.footer-title {
  font-family: var(--font-mono);
  font-size: 11.5px;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--mist);
  padding-bottom: 8px;
  border-bottom: 2px solid var(--line);
}

.footer-list { display: grid; gap: 10px; }

.footer-link {
  font-size: 15px;
  font-weight: 600;
  color: var(--cream);
  border-bottom: 1px solid transparent;
  transition: color 140ms ease, border-color 140ms ease;
}

.footer-link:hover {
  color: var(--amber);
  border-bottom-color: var(--amber);
}

.footer-bottom {
  border-top: 2px solid var(--line);
}

.footer-bottom-inner {
  width: min(100% - 40px, var(--page-max));
  margin-inline: auto;
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 8px 24px;
  padding-block: 18px 28px;
}

.footer-legal,
.footer-meta {
  font-family: var(--font-mono);
  font-size: 12px;
  font-variant-numeric: tabular-nums;
  letter-spacing: 0.06em;
  color: var(--mist);
}

@media (max-width: 899px) {
  .footer-inner {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 32px 20px;
  }
  .footer-brand { grid-column: 1 / -1; }
}

@media (max-width: 560px) {
  .footer-inner { grid-template-columns: minmax(0, 1fr); }
  .footer-bottom-inner { flex-direction: column; }
}

/* 11. 通用卡片与索引件
   ========================================================================== */
.panel {
  background-color: var(--ink-2);
  border: 2px solid var(--line);
  border-radius: var(--radius);
  padding: clamp(18px, 3vw, 26px);
  box-shadow: var(--shadow-hard);
}

.section--light .panel {
  background-color: var(--paper);
  color: var(--text-ink);
  border-color: var(--text-ink);
  box-shadow: 6px 6px 0 var(--grid-blue);
}

.tag {
  display: inline-block;
  padding: 4px 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  font-variant-numeric: tabular-nums;
  letter-spacing: 0.08em;
  color: var(--mist);
  border: 1px solid var(--line);
  border-radius: 2px;
  background-color: transparent;
}

.section--light .tag {
  color: var(--text-muted);
  border-color: var(--grid-blue);
}

.step-index {
  display: block;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(28px, 6vw, 44px);
  font-weight: 700;
  line-height: 1;
  letter-spacing: 0.02em;
  color: var(--amber);
}

.rule {
  height: 2px;
  border: 0;
  margin: 0;
  background-color: var(--line);
}

/* 12. 面包屑
   ========================================================================== */
.breadcrumb {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--mist);
  padding-block: 18px 0;
}

.breadcrumb-list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
}

.breadcrumb-item { display: inline-flex; align-items: center; }

.breadcrumb-item + .breadcrumb-item::before {
  content: "/";
  margin-inline: 8px;
  color: var(--line);
}

.breadcrumb-link {
  color: inherit;
  border-bottom: 1px solid transparent;
  transition: color 140ms ease, border-color 140ms ease;
}

.breadcrumb-link:hover {
  color: var(--amber);
  border-bottom-color: var(--amber);
}

.breadcrumb-item[aria-current="page"] { color: var(--cream); }

/* 13. 图片容器（页面阶段放置占位）
   ========================================================================== */
.media-frame {
  position: relative;
  display: block;
  overflow: hidden;
  border: 2px solid var(--line);
  border-radius: var(--radius);
  background-color: var(--cream);
  background-image:
    linear-gradient(var(--grid-blue) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid-blue) 1px, transparent 1px);
  background-size: 16px 16px;
  box-shadow: var(--shadow-hard);
}

.media-frame > img,
.media-frame > picture > img,
.media-frame > svg,
.media-frame > video {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.media-frame--phone { aspect-ratio: 9 / 19.5; }
.media-frame--wide { aspect-ratio: 16 / 9; }
.media-frame--thumb { aspect-ratio: 4 / 3; }
.media-frame--square { aspect-ratio: 1 / 1; }

.media-caption {
  margin-top: 10px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.06em;
  color: var(--mist);
}

.section--light .media-caption { color: var(--text-muted); }

/* 14. 网格底纹
   ========================================================================== */
.grid-backdrop {
  background-image:
    linear-gradient(var(--grid-blue) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid-blue) 1px, transparent 1px);
  background-size: 32px 32px;
}

.grid-backdrop--dark {
  background-image:
    linear-gradient(var(--line) 1px, transparent 1px),
    linear-gradient(90deg, var(--line) 1px, transparent 1px);
  background-size: 32px 32px;
}

/* 15. 显现动效
   ========================================================================== */
.js [data-reveal] {
  opacity: 0;
  transform: translateY(12px);
  transition: opacity 420ms ease, transform 420ms ease;
  will-change: opacity, transform;
}

.js [data-reveal].is-visible {
  opacity: 1;
  transform: none;
}

/* 16. 减弱动效
   ========================================================================== */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }

  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }

  .scroll-progress { transition: none; }

  .js [data-reveal] {
    opacity: 1;
    transform: none;
    transition: none;
  }

  .btn:hover,
  .btn:active { transform: none; }
}