/* =========================================================
   北单中心 · /assets/site.css
   共享层：reset / 变量 / 中文排版 / 页头 / 页脚 / 通用组件
   ========================================================= */

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

html {
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: 96px;
}

body {
  margin: 0;
  min-height: 100vh;
  background-color: var(--paper);
  background-image:
    linear-gradient(rgba(17, 23, 19, 0.035) 1px, transparent 1px),
    linear-gradient(90deg, rgba(17, 23, 19, 0.035) 1px, transparent 1px);
  background-size: 64px 64px;
  color: var(--ink);
  font-family: var(--font-body);
  font-size: var(--fs-body);
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

a { color: inherit; }

h1, h2, h3, h4 {
  margin: 0;
  font-family: var(--font-title);
  font-weight: 700;
  line-height: 1.15;
  letter-spacing: -0.01em;
}

p { margin: 0; }
ul, ol { margin: 0; padding: 0; list-style: none; }
figure, blockquote, dl, dd { margin: 0; }
button { font: inherit; color: inherit; }

hr,
.hairline {
  border: 0;
  height: 1px;
  background: var(--line);
  margin: 0;
}

/* ---------- 2. 变量 ---------- */
:root {
  /* 色板 */
  --ink: #111713;
  --ink-80: rgba(17, 23, 19, 0.8);
  --ink-60: rgba(17, 23, 19, 0.6);
  --ink-40: rgba(17, 23, 19, 0.4);
  --paper: #F5F2EA;
  --paper-2: #EDE9DE;
  --green: #1F4D3A;
  --green-deep: #0E2A20;
  --amber: #E8A33D;
  --amber-soft: #F6D9A8;
  --steel: #5B7C99;
  --steel-soft: #DCE5EC;
  --ok: #2F7D5C;
  --warn: #B45F2A;

  /* 线条 */
  --line: rgba(17, 23, 19, 0.16);
  --line-strong: rgba(17, 23, 19, 0.42);
  --line-light: rgba(245, 242, 234, 0.16);

  /* 字体 */
  --font-title: "HarmonyOS Sans SC", "Source Han Sans SC", "Noto Sans SC", "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
  --font-body: "Source Han Serif SC", "Noto Serif SC", "Songti SC", STSong, "SimSun", serif;
  --font-mono: "JetBrains Mono", "IBM Plex Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;

  /* 字号 */
  --fs-h1: clamp(40px, 6vw, 72px);
  --fs-h2: clamp(28px, 3.4vw, 40px);
  --fs-h3: clamp(20px, 2vw, 26px);
  --fs-body: 17px;
  --fs-meta: 12.5px;

  /* 尺寸 */
  --shell: 1240px;
  --pad: clamp(18px, 4vw, 56px);
  --header-h: 76px;
  --ease: cubic-bezier(0.22, 0.61, 0.36, 1);
}

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

.skip-link {
  position: absolute;
  left: 12px;
  top: -140px;
  z-index: 1200;
  padding: 12px 20px;
  background: var(--ink);
  color: var(--paper);
  font-family: var(--font-title);
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-decoration: none;
  border: 1px solid var(--amber);
  transition: top 0.2s var(--ease);
}
.skip-link:focus { top: 12px; }

/* ---------- 4. 页头（框架式导航） ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 300;
  background: var(--green-deep);
  color: var(--paper);
  box-shadow: 0 14px 28px -24px rgba(0, 0, 0, 0.9);
}

.site-header__frame {
  position: relative;
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  align-items: stretch;
  gap: clamp(10px, 1.6vw, 24px);
  width: 100%;
  max-width: var(--shell);
  margin-inline: auto;
  padding-inline: var(--pad);
  min-height: var(--header-h);
}

/* 品牌 */
.brand {
  display: inline-flex;
  align-items: center;
  align-self: center;
  gap: 10px;
  padding-block: 10px;
  color: inherit;
  text-decoration: none;
}
.brand__mark {
  position: relative;
  display: grid;
  place-items: center;
  flex: 0 0 auto;
  width: 26px;
  height: 26px;
  border: 1px solid var(--amber);
}
.brand__mark::after {
  content: "";
  position: absolute;
  top: -1px;
  right: -6px;
  bottom: -1px;
  width: 1px;
  background: rgba(232, 163, 61, 0.45);
}
.brand__pulse { display: block; width: 8px; height: 8px; background: var(--amber); }
.brand__text { display: flex; flex-direction: column; line-height: 1.15; }
.brand__name {
  font-family: var(--font-title);
  font-size: 17px;
  font-weight: 700;
  letter-spacing: 0.08em;
}
.brand__meta {
  font-family: var(--font-mono);
  font-size: 9.5px;
  letter-spacing: 0.2em;
  color: rgba(245, 242, 234, 0.5);
}

.brand--footer { padding-block: 0; }
.brand--footer .brand__name { color: var(--paper); }
.brand--footer .brand__meta { color: rgba(245, 242, 234, 0.55); }

/* 导航 */
.site-nav {
  display: flex;
  align-items: stretch;
  justify-content: flex-end;
  min-width: 0;
}
.site-nav__list { display: flex; align-items: stretch; }
.site-nav__item { display: flex; }
.site-nav__link {
  position: relative;
  display: inline-flex;
  align-items: center;
  gap: 7px;
  padding-inline: clamp(8px, 1.1vw, 15px);
  border-left: 1px solid rgba(245, 242, 234, 0.1);
  color: rgba(245, 242, 234, 0.76);
  font-family: var(--font-title);
  font-size: 14.5px;
  font-weight: 500;
  letter-spacing: 0.04em;
  text-decoration: none;
  white-space: nowrap;
  transition: color 0.2s var(--ease), background-color 0.2s var(--ease);
}
.site-nav__link:hover { color: var(--paper); background: rgba(245, 242, 234, 0.06); }
.site-nav__idx {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.08em;
  color: var(--amber);
  opacity: 0.72;
}
.site-nav__label { display: inline-block; }
.site-nav__link[aria-current="page"] {
  color: var(--paper);
  background: rgba(232, 163, 61, 0.14);
}
.site-nav__link[aria-current="page"] .site-nav__idx { opacity: 1; }
.site-nav__link[aria-current="page"]::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 2px;
  background: var(--amber);
}

/* 页头操作区 */
.site-header__actions {
  display: flex;
  align-items: center;
  gap: 10px;
  align-self: center;
}
.site-header__cta { white-space: nowrap; }

/* 移动导航按钮 */
.nav-toggle {
  display: none;
  align-items: center;
  gap: 8px;
  padding: 9px 12px;
  background: transparent;
  border: 1px solid rgba(245, 242, 234, 0.36);
  color: var(--paper);
  font-family: var(--font-title);
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.08em;
  cursor: pointer;
  transition: border-color 0.2s var(--ease), color 0.2s var(--ease);
}
.nav-toggle:hover { border-color: var(--amber); color: var(--amber-soft); }
.nav-toggle__bars {
  display: inline-flex;
  flex-direction: column;
  justify-content: center;
  gap: 4px;
  width: 16px;
}
.nav-toggle__bars > span {
  display: block;
  height: 2px;
  background: var(--amber);
  transition: transform 0.2s var(--ease), opacity 0.2s var(--ease);
}
.nav-toggle[aria-expanded="true"] .nav-toggle__bars > span:nth-child(1) { transform: translateY(6px) 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(-6px) rotate(-45deg); }
.nav-toggle__text { display: inline-block; min-width: 2.2em; }

/* 阅读进度轨 */
.read-progress {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 3px;
  background: rgba(232, 163, 61, 0.18);
  overflow: hidden;
  pointer-events: none;
}
.read-progress__bar {
  display: block;
  width: 0;
  height: 100%;
  background: var(--amber);
  transition: width 0.12s linear;
}

/* ---------- 5. 页脚 ---------- */
.site-footer {
  position: relative;
  background-color: var(--green-deep);
  background-image:
    linear-gradient(rgba(245, 242, 234, 0.04) 1px, transparent 1px),
    linear-gradient(90deg, rgba(245, 242, 234, 0.04) 1px, transparent 1px);
  background-size: 48px 48px;
  color: rgba(245, 242, 234, 0.78);
  border-top: 3px solid var(--amber);
}

.site-footer__inner {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 2.1fr);
  gap: clamp(24px, 4vw, 64px);
  width: 100%;
  max-width: var(--shell);
  margin-inline: auto;
  padding-inline: var(--pad);
  padding-block: clamp(36px, 5vw, 64px);
}

.site-footer__brandcol { display: flex; flex-direction: column; gap: 14px; }

.site-footer__note {
  font-family: var(--font-body);
  font-size: 14px;
  line-height: 1.7;
  color: rgba(245, 242, 234, 0.66);
  max-width: 30ch;
}

.site-footer__stamp {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.06em;
  color: rgba(245, 242, 234, 0.7);
}

.site-footer__cols {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: clamp(20px, 3vw, 40px);
}

.footer-nav { min-width: 0; }
.footer-nav__title {
  margin: 0 0 12px;
  padding-bottom: 8px;
  border-bottom: 1px solid rgba(245, 242, 234, 0.14);
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.2em;
  color: var(--amber-soft);
}
.footer-nav__list { display: flex; flex-direction: column; }
.footer-nav__list a {
  display: inline-block;
  padding-block: 5px;
  color: rgba(245, 242, 234, 0.78);
  font-family: var(--font-title);
  font-size: 14px;
  letter-spacing: 0.03em;
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 0.18s var(--ease), border-color 0.18s var(--ease);
}
.footer-nav__list a:hover { color: var(--paper); border-bottom-color: var(--amber); }

.footer-contact { min-width: 0; }
.footer-contact__list { display: flex; flex-direction: column; gap: 8px; }
.footer-contact__list li { display: flex; flex-wrap: wrap; gap: 6px 10px; align-items: baseline; }
.footer-contact__key {
  flex: 0 0 auto;
  min-width: 34px;
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.14em;
  color: rgba(245, 242, 234, 0.45);
}
.footer-contact__val {
  font-family: var(--font-mono);
  font-size: 12px;
  line-height: 1.6;
  letter-spacing: 0.01em;
  color: rgba(245, 242, 234, 0.86);
  overflow-wrap: anywhere;
}

.site-footer__base { border-top: 1px solid rgba(245, 242, 234, 0.14); }

.site-footer__inner--base {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 8px 24px;
  padding-block: 16px 20px;
}

.site-footer__legal {
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.04em;
  color: rgba(245, 242, 234, 0.62);
}
.site-footer__legal-note {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.04em;
  color: rgba(245, 242, 234, 0.4);
}

/* ---------- 6. 通用布局 ---------- */
.container {
  width: 100%;
  max-width: var(--shell);
  margin-inline: auto;
  padding-inline: var(--pad);
}

.section { padding-block: clamp(44px, 7vw, 96px); }

.section__head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: 10px 20px;
  padding-bottom: 14px;
  margin-bottom: clamp(20px, 3vw, 36px);
  border-bottom: 1px solid var(--line-strong);
}
.section__title {
  font-size: var(--fs-h2);
  letter-spacing: -0.015em;
}

.grid { display: grid; gap: clamp(18px, 3vw, 36px); }
.grid--3-9 { grid-template-columns: minmax(0, 3fr) minmax(0, 9fr); }
.grid--4-8 { grid-template-columns: minmax(0, 4fr) minmax(0, 8fr); }
.grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }

/* ---------- 7. 面板与条带 ---------- */
.panel {
  position: relative;
  background: var(--paper);
  border: 1px solid var(--line-strong);
  padding: clamp(20px, 3vw, 34px);
}

.panel--cut {
  background: var(--green);
  color: var(--paper);
  border: 0;
  padding: clamp(22px, 3.2vw, 38px);
  clip-path: polygon(
    0 0,
    calc(100% - 24px) 0,
    100% 24px,
    100% 100%,
    24px 100%,
    0 calc(100% - 24px)
  );
}
.panel--cut a { color: var(--amber-soft); }

.strip {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px clamp(12px, 2vw, 26px);
  padding: clamp(14px, 2vw, 20px) var(--pad);
  background: var(--amber-soft);
  color: var(--ink);
  border-block: 1px solid var(--amber);
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.04em;
}

/* ---------- 8. 文本原子 ---------- */
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.2em;
  color: var(--green);
  text-transform: uppercase;
}
.eyebrow::before {
  content: "";
  width: 26px;
  height: 1px;
  background: var(--amber);
  flex: 0 0 auto;
}

.meta-list { display: grid; gap: 14px; }
.meta-list__key {
  display: block;
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--ink-60);
}
.meta-list__val {
  display: block;
  font-family: var(--font-mono);
  font-size: 12.5px;
  line-height: 1.6;
  color: var(--ink);
  overflow-wrap: anywhere;
}

/* ---------- 9. 标签与状态 ---------- */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 3px 9px;
  border: 1px solid var(--line-strong);
  background: transparent;
  color: var(--ink);
  font-family: var(--font-mono);
  font-size: 11px;
  line-height: 1.5;
  letter-spacing: 0.08em;
  white-space: nowrap;
}
.tag--amber { background: var(--amber-soft); border-color: var(--amber); color: var(--ink); }
.tag--steel { background: var(--steel-soft); border-color: var(--steel); color: var(--ink); }
.tag--ok { background: var(--ok); border-color: var(--ok); color: var(--paper); }
.tag--warn { background: var(--warn); border-color: var(--warn); color: var(--paper); }

.status-dot {
  display: inline-block;
  width: 7px;
  height: 7px;
  flex: 0 0 auto;
  background: var(--ok);
  box-shadow: 0 0 0 3px rgba(47, 125, 92, 0.18);
}

/* ---------- 10. 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 22px;
  border: 1px solid transparent;
  background: transparent;
  color: var(--ink);
  font-family: var(--font-title);
  font-size: 15px;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-decoration: none;
  cursor: pointer;
  transition:
    background-color 0.18s var(--ease),
    color 0.18s var(--ease),
    border-color 0.18s var(--ease);
}
.btn--primary { background: var(--green); border-color: var(--green); color: var(--paper); }
.btn--primary:hover { background: var(--green-deep); border-color: var(--green-deep); }
.btn--outline { background: transparent; border-color: var(--ink); color: var(--ink); }
.btn--outline:hover { background: var(--ink); color: var(--paper); }
.btn--amber { background: var(--amber); border-color: var(--amber); color: var(--ink); }
.btn--amber:hover { background: var(--amber-soft); border-color: var(--amber-soft); }
.btn--ghost { background: transparent; border-color: rgba(245, 242, 234, 0.4); color: var(--paper); }
.btn--ghost:hover { border-color: var(--amber); color: var(--amber-soft); }
.btn--sm { padding: 8px 14px; font-size: 13px; }

/* ---------- 11. 面包屑 ---------- */
.breadcrumb {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--ink-60);
}
.breadcrumb__list { display: flex; flex-wrap: wrap; align-items: center; }
.breadcrumb__item { display: flex; align-items: center; }
.breadcrumb__item + .breadcrumb__item::before {
  content: "/";
  margin-inline: 8px;
  color: var(--amber);
}
.breadcrumb__item a { color: var(--green); text-decoration: none; }
.breadcrumb__item a:hover { text-decoration: underline; text-underline-offset: 3px; }
.breadcrumb__item[aria-current="page"] { color: var(--ink); }

/* ---------- 12. 长文 ---------- */
.prose {
  font-family: var(--font-body);
  font-size: var(--fs-body);
  line-height: 1.75;
  color: var(--ink);
  max-width: 68ch;
}
.prose > * + * { margin-top: 1.1em; }
.prose h2 {
  margin-top: 1.9em;
  font-size: var(--fs-h2);
  line-height: 1.2;
}
.prose h3 {
  margin-top: 1.6em;
  font-size: var(--fs-h3);
  line-height: 1.3;
}
.prose ul,
.prose ol { padding-left: 1.4em; }
.prose ul { list-style: square; }
.prose ol { list-style: decimal; }
.prose li + li { margin-top: 0.4em; }
.prose a {
  color: var(--green);
  text-decoration: underline;
  text-underline-offset: 3px;
}
.prose code {
  font-family: var(--font-mono);
  font-size: 0.88em;
  padding: 1px 5px;
  background: var(--steel-soft);
  color: var(--ink);
}

/* ---------- 13. 图片容器（页面阶段放置占位） ---------- */
.figure { display: grid; gap: 10px; margin: 0; }
.figure__media {
  position: relative;
  width: 100%;
  aspect-ratio: 16 / 9;
  background: var(--steel-soft);
  border: 1px solid var(--line);
  overflow: hidden;
}
.figure__media > img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.figure__media--tall { aspect-ratio: 4 / 5; }
.figure__media--square { aspect-ratio: 1 / 1; }
.figure__media--grid {
  background-color: var(--paper-2);
  background-image:
    linear-gradient(var(--line) 1px, transparent 1px),
    linear-gradient(90deg, var(--line) 1px, transparent 1px);
  background-size: 24px 24px;
}
.figure__caption {
  font-family: var(--font-mono);
  font-size: 11.5px;
  line-height: 1.6;
  letter-spacing: 0.04em;
  color: var(--ink-60);
}

/* ---------- 14. 显现动画 ---------- */
.has-js [data-reveal] {
  opacity: 0;
  transform: translateY(12px);
  transition: opacity 0.24s var(--ease), transform 0.24s var(--ease);
}
.has-js [data-reveal].is-in {
  opacity: 1;
  transform: none;
}

/* ---------- 15. 响应式 ---------- */
@media (max-width: 1200px) {
  .site-nav__idx { display: none; }
  .site-nav__link { font-size: 13.5px; padding-inline: 10px; }
}

@media (max-width: 1024px) {
  :root { --header-h: 64px; }

  .site-header__frame {
    grid-template-columns: minmax(0, 1fr) auto;
    align-items: center;
    justify-content: space-between;
  }

  .site-nav {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    display: none;
    justify-content: stretch;
    background: var(--green-deep);
    border-top: 1px solid var(--line-light);
    border-bottom: 3px solid var(--amber);
    max-height: calc(100vh - 64px);
    overflow-y: auto;
    z-index: 20;
  }
  .site-header[data-open] .site-nav { display: block; }

  .site-nav__list { flex-direction: column; }
  .site-nav__item { display: block; }
  .site-nav__link {
    width: 100%;
    padding: 15px var(--pad);
    border-left: 0;
    border-bottom: 1px solid var(--line-light);
    font-size: 16px;
    letter-spacing: 0.05em;
  }
  .site-nav__idx { display: inline; font-size: 11px; }
  .site-nav__link[aria-current="page"]::after {
    top: 0;
    bottom: 0;
    left: 0;
    right: auto;
    width: 3px;
    height: auto;
  }

  .site-header__cta { display: none; }
  .nav-toggle { display: inline-flex; }

  .site-footer__inner { grid-template-columns: minmax(0, 1fr); }
  .site-footer__note { max-width: none; }
}

@media (max-width: 900px) {
  .grid--3-9,
  .grid--4-8,
  .grid--2,
  .grid--3 { grid-template-columns: minmax(0, 1fr); }

  .site-footer__cols { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (max-width: 560px) {
  .site-footer__cols { grid-template-columns: minmax(0, 1fr); }
  .site-footer__inner--base { flex-direction: column; align-items: flex-start; }
  .brand__meta { letter-spacing: 0.14em; }
  .panel { padding: 18px; }
}

/* ---------- 16. 动效偏好 ---------- */
@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;
  }

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

  .read-progress__bar { transition: none; }
}