/* =========================================================
   /assets/site.css — 九洲中国区 · 全站共享外壳
   奶油纸底 / 深夜墨蓝 / 江水青绿 / 铜金索引 / 灯塔暖橙高亮
   ========================================================= */

:root {
  --paper: #F4EFE4;
  --paper-2: #EFE8DA;
  --card-bg: #FBF7EC;
  --ink: #10233A;
  --night: #0B1420;
  --river: #1F6F6B;
  --river-light: #46A69A;
  --copper: #B07A2B;
  --beacon: #E4712F;
  --brown: #2A211C;
  --taupe: #7A6E63;
  --sand: #DAD2C2;
  --line: rgba(16, 35, 58, 0.16);
  --on-dark: rgba(244, 239, 228, 0.78);
  --on-dark-strong: #F4EFE4;

  --container: 1200px;
  --gut: clamp(18px, 4vw, 46px);
  --radius: 2px;

  --font-sans: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC",
    "Source Han Sans SC", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --font-serif: "Songti SC", "STSong", "Noto Serif SC", "Source Han Serif SC", "SimSun",
    Georgia, "Times New Roman", serif;
  --font-mono: ui-monospace, "SFMono-Regular", "JetBrains Mono", "Cascadia Mono",
    "Roboto Mono", Menlo, Consolas, "Courier New", monospace;

  --ease: cubic-bezier(0.22, 0.61, 0.36, 1);
  --dur: 200ms;
  --shadow-soft: 0 10px 30px -22px rgba(16, 35, 58, 0.55);
}

/* 对照键开启：提高纸底明度、加深描边与辅助文字，形成本地对照视图 */
html[data-lens="on"] {
  --paper: #FFFCF4;
  --paper-2: #F3ECDD;
  --card-bg: #FFFDF8;
  --sand: #BFB3A0;
  --taupe: #5A5048;
  --line: rgba(16, 35, 58, 0.3);
  --river: #186460;
}

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

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

body {
  margin: 0;
  background-color: var(--paper);
  color: var(--brown);
  font-family: var(--font-sans);
  font-size: 17px;
  line-height: 1.8;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  transition: background-color var(--dur) var(--ease), color var(--dur) var(--ease);
}

h1, h2, h3, h4, h5, h6 {
  margin: 0 0 0.6em;
  color: var(--ink);
  font-family: var(--font-serif);
  font-weight: 700;
  letter-spacing: -0.01em;
  line-height: 1.3;
}

p { margin: 0 0 1em; }

a {
  color: var(--river);
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
}

a:hover { color: var(--copper); }

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

button { font: inherit; color: inherit; }

ul, ol { margin: 0 0 1em; padding-left: 1.25em; }

hr { border: 0; border-top: 1px solid var(--sand); margin: 2em 0; }

::selection { background: rgba(70, 166, 154, 0.28); color: var(--ink); }

:focus-visible {
  outline: 2px solid var(--copper);
  outline-offset: 1px;
  border-radius: 1px;
}

.site-header :focus-visible,
.site-footer :focus-visible { outline-color: var(--beacon); }

#main-content { display: block; scroll-margin-top: 120px; }

/* ---------- 布局基元 ---------- */
.container {
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: var(--gut);
}

.container--narrow { max-width: 72ch; }

.stack > * + * { margin-top: clamp(14px, 2vw, 24px); }

.cluster {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: clamp(10px, 1.6vw, 20px);
}

.grid {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  gap: clamp(20px, 2.4vw, 34px);
}

.grid--cards > * { grid-column: span 4; }

@media (max-width: 900px) {
  .grid--cards > * { grid-column: span 6; }
}

@media (max-width: 620px) {
  .grid--cards > * { grid-column: 1 / -1; }
}

/* 错落卡片：半格纵向偏移，避免等距网格感 */
@media (min-width: 860px) {
  .stagger > *:nth-child(even) { margin-top: clamp(18px, 2.6vw, 38px); }
}

/* ---------- 章节抬头 ---------- */
.section-head {
  display: grid;
  gap: 10px;
  margin-bottom: clamp(24px, 3vw, 42px);
}

.section-idx {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--copper);
  text-transform: uppercase;
}

.section-title {
  margin: 0;
  font-size: clamp(26px, 3.4vw, 44px);
  line-height: 1.24;
  color: var(--ink);
}

.section-lede {
  margin: 0;
  max-width: 62ch;
  color: var(--taupe);
  font-size: 16px;
}

.chapter { margin-block: clamp(34px, 5vw, 72px); }

.chapter-head {
  display: flex;
  align-items: baseline;
  gap: 14px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--line);
}

.chapter-num {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--copper);
  flex: 0 0 auto;
}

.river-rule {
  height: 1px;
  border: 0;
  margin-block: clamp(32px, 5vw, 66px);
  background: linear-gradient(90deg, var(--river) 0%, rgba(31, 111, 107, 0.35) 42%, rgba(31, 111, 107, 0) 100%);
}

/* ---------- 卡片 ---------- */
.card {
  position: relative;
  display: block;
  background: var(--card-bg);
  border: 1px solid var(--sand);
  border-radius: var(--radius);
  padding: clamp(20px, 2.4vw, 30px);
  color: var(--brown);
  text-decoration: none;
  box-shadow: var(--shadow-soft);
  transition: transform var(--dur) var(--ease), border-color var(--dur) var(--ease),
    box-shadow var(--dur) var(--ease), background-color var(--dur) var(--ease);
}

.card:hover,
.card:focus-visible {
  transform: translateY(-3px);
  border-color: var(--copper);
  box-shadow: 0 16px 34px -22px rgba(16, 35, 58, 0.65);
}

.card-idx {
  display: block;
  margin-bottom: 12px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--copper);
}

.card-title {
  margin: 0 0 10px;
  font-size: clamp(19px, 2vw, 23px);
  line-height: 1.35;
}

.card-text {
  margin: 0;
  font-size: 15.5px;
  line-height: 1.75;
  color: var(--taupe);
}

/* ---------- 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 11px 20px;
  border: 1px solid transparent;
  border-radius: var(--radius);
  background: transparent;
  font-family: var(--font-sans);
  font-size: 15px;
  line-height: 1.4;
  text-decoration: none;
  cursor: pointer;
  transition: transform var(--dur) var(--ease), background-color var(--dur) var(--ease),
    border-color var(--dur) var(--ease), color var(--dur) var(--ease);
}

.btn:hover { transform: translateY(-2px); }

.btn--primary { background: var(--ink); color: var(--paper); }
.btn--primary:hover { background: var(--river); color: #FFFFFF; }

.btn--river { background: var(--river); color: #FFFFFF; }
.btn--river:hover { background: var(--ink); color: var(--on-dark-strong); }

.btn--ghost {
  border-color: var(--line);
  color: var(--ink);
}
.btn--ghost:hover { border-color: var(--copper); color: var(--copper); }

.btn--onDark {
  border-color: rgba(244, 239, 228, 0.32);
  color: var(--on-dark-strong);
}
.btn--onDark:hover {
  background: var(--beacon);
  border-color: var(--beacon);
  color: var(--night);
}

/* ---------- 面包屑 ---------- */
.breadcrumb {
  padding-block: 20px 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--taupe);
}

.breadcrumb ol {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  list-style: none;
  margin: 0;
  padding: 0;
}

.breadcrumb li { display: flex; align-items: center; gap: 8px; }

.breadcrumb li + li::before {
  content: "/";
  color: var(--sand);
}

.breadcrumb a {
  color: var(--taupe);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.breadcrumb a:hover {
  color: var(--river);
  border-bottom-color: var(--river);
}

/* ---------- 正文长文 ---------- */
.prose {
  max-width: 68ch;
  font-size: 17px;
  line-height: 1.8;
  color: var(--brown);
}

.prose h2 {
  margin-top: 2em;
  font-size: clamp(22px, 2.4vw, 30px);
}

.prose h3 {
  margin-top: 1.6em;
  font-size: clamp(18px, 1.8vw, 22px);
}

.prose ul,
.prose ol { padding-left: 1.4em; }

.prose li { margin-bottom: 0.5em; }

.prose blockquote {
  margin: 1.6em 0;
  padding: 4px 0 4px 20px;
  border-left: 2px solid var(--copper);
  color: var(--taupe);
}

.prose code {
  font-family: var(--font-mono);
  font-size: 0.9em;
  padding: 1px 5px;
  background: var(--paper-2);
  border: 1px solid var(--sand);
  border-radius: var(--radius);
}

/* ---------- 提示块与标签 ---------- */
.note {
  padding: clamp(18px, 2.2vw, 26px);
  background: var(--paper-2);
  border: 1px solid var(--sand);
  border-left: 3px solid var(--river);
  border-radius: var(--radius);
  font-size: 15.5px;
  line-height: 1.75;
  color: var(--taupe);
}

.tag {
  display: inline-block;
  padding: 3px 9px;
  border: 1px solid var(--sand);
  border-radius: var(--radius);
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.1em;
  color: var(--taupe);
  background: transparent;
}

/* ---------- 响应式图片容器 ---------- */
.media-frame {
  position: relative;
  overflow: hidden;
  aspect-ratio: 16 / 10;
  border: 1px solid var(--sand);
  border-radius: var(--radius);
  background-image: linear-gradient(150deg, #1F6F6B 0%, #10233A 100%);
  background-size: cover;
  background-position: center;
}

.media-frame img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

.media-frame--wide { aspect-ratio: 21 / 9; }
.media-frame--tall { aspect-ratio: 3 / 4; }
.media-frame--square { aspect-ratio: 1 / 1; }

.media-caption {
  margin-top: 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--taupe);
}

/* =========================================================
   页头
   ========================================================= */

.skip-link {
  position: absolute;
  left: 14px;
  top: -120px;
  z-index: 120;
  padding: 11px 18px;
  background: var(--beacon);
  color: var(--night);
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.08em;
  text-decoration: none;
  border-radius: var(--radius);
  transition: top var(--dur) var(--ease);
}

.skip-link:focus { top: 14px; color: var(--night); }

.site-header {
  position: sticky;
  top: 0;
  z-index: 80;
  background: var(--ink);
  color: var(--on-dark-strong);
  border-bottom: 1px solid rgba(244, 239, 228, 0.14);
}

/* 工具行 */
.header-utility {
  background: var(--night);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
}

.header-utility-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  min-height: 38px;
}

.header-update {
  display: flex;
  align-items: center;
  gap: 9px;
  margin: 0;
  color: rgba(244, 239, 228, 0.66);
}

.header-dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--river-light);
  box-shadow: 0 0 0 3px rgba(70, 166, 154, 0.18);
}

.utility-list {
  display: flex;
  align-items: center;
  gap: 18px;
  list-style: none;
  margin: 0;
  padding: 0;
  color: rgba(244, 239, 228, 0.5);
}

.utility-list li + li::before {
  content: "·";
  margin-right: 18px;
  color: rgba(244, 239, 228, 0.3);
}

/* 命令栏 */
.header-bar-inner {
  display: flex;
  align-items: center;
  gap: clamp(12px, 2vw, 28px);
  min-height: 74px;
}

.brand {
  display: flex;
  flex-direction: column;
  gap: 1px;
  flex: 0 0 auto;
  text-decoration: none;
  color: var(--on-dark-strong);
}

.brand:hover { color: var(--on-dark-strong); }

.brand-name {
  display: flex;
  align-items: center;
  gap: 9px;
  font-family: var(--font-serif);
  font-size: 21px;
  font-weight: 700;
  letter-spacing: 0.01em;
  line-height: 1.2;
}

.brand-suffix {
  font-family: var(--font-mono);
  font-size: 10.5px;
  font-weight: 400;
  letter-spacing: 0.16em;
  color: var(--copper);
  border: 1px solid rgba(176, 122, 43, 0.55);
  border-radius: var(--radius);
  padding: 1px 5px;
  line-height: 1.5;
}

.brand-tagline {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: rgba(244, 239, 228, 0.52);
}

/* 导航 */
.site-nav { margin-left: auto; }

.site-nav-list {
  display: flex;
  align-items: stretch;
  gap: 2px;
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav-link {
  display: flex;
  align-items: baseline;
  gap: 7px;
  padding: 10px 13px;
  color: rgba(244, 239, 228, 0.82);
  font-size: 15px;
  line-height: 1.5;
  text-decoration: none;
  border-bottom: 2px solid transparent;
  transition: background-color var(--dur) var(--ease), color var(--dur) var(--ease),
    border-color var(--dur) var(--ease);
}

.nav-idx {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--copper);
  transition: color var(--dur) var(--ease);
}

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

.nav-link:hover {
  background: rgba(244, 239, 228, 0.07);
  color: var(--on-dark-strong);
  border-bottom-color: var(--copper);
}

.nav-link:hover .nav-idx { color: var(--river-light); }

.nav-link[aria-current="page"] {
  color: var(--on-dark-strong);
  background: rgba(228, 113, 47, 0.1);
  border-bottom-color: var(--beacon);
}

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

/* 移动菜单按钮 */
.nav-toggle {
  display: none;
  align-items: center;
  gap: 9px;
  margin-left: auto;
  padding: 9px 12px;
  background: transparent;
  border: 1px solid rgba(244, 239, 228, 0.28);
  border-radius: var(--radius);
  color: var(--on-dark-strong);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.12em;
  cursor: pointer;
  transition: border-color var(--dur) var(--ease), color var(--dur) var(--ease);
}

.nav-toggle:hover { border-color: var(--copper); color: var(--river-light); }

.nav-toggle-bars {
  display: inline-flex;
  flex-direction: column;
  justify-content: center;
  gap: 3px;
  width: 15px;
}

.nav-toggle-bars i {
  display: block;
  height: 1px;
  width: 100%;
  background: currentColor;
}

.nav-toggle-bars i:nth-child(2) { width: 68%; }

/* 对照键 */
.contrast-key {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  flex: 0 0 auto;
  padding: 9px 14px;
  background: transparent;
  border: 1px solid rgba(244, 239, 228, 0.3);
  border-radius: var(--radius);
  color: var(--on-dark-strong);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  cursor: pointer;
  transition: border-color var(--dur) var(--ease), color var(--dur) var(--ease),
    background-color var(--dur) var(--ease);
}

.contrast-key:hover { border-color: var(--beacon); color: var(--beacon); }

.contrast-dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  border: 1px solid var(--copper);
  background: transparent;
  transition: background-color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.contrast-key[aria-pressed="true"] {
  background: var(--beacon);
  border-color: var(--beacon);
  color: var(--night);
}

.contrast-key[aria-pressed="true"] .contrast-dot {
  background: var(--night);
  border-color: var(--night);
}

/* 滚动进度 */
.scroll-progress {
  position: absolute;
  left: 0;
  bottom: -1px;
  width: 100%;
  height: 2px;
  background: linear-gradient(90deg, var(--river-light), var(--beacon));
  transform: scaleX(0);
  transform-origin: 0 50%;
  will-change: transform;
}

/* ---------- 页头响应式 ---------- */
@media (max-width: 1080px) {
  .nav-link { padding: 10px 10px; font-size: 14.5px; }
}

@media (max-width: 900px) {
  .nav-toggle { display: inline-flex; }

  .site-nav {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    display: none;
    margin: 0;
    background: var(--night);
    border-top: 1px solid rgba(244, 239, 228, 0.14);
    box-shadow: 0 26px 42px -28px rgba(0, 0, 0, 0.9);
    max-height: calc(100vh - 100px);
    overflow-y: auto;
  }

  .site-nav[data-open] { display: block; }

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

  .site-nav-list > li { border-bottom: 1px solid rgba(244, 239, 228, 0.08); }

  .nav-link {
    padding: 15px 20px;
    border-bottom: 0;
    border-left: 3px solid transparent;
    font-size: 16px;
  }

  .nav-link:hover { border-left-color: var(--copper); }

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

  .header-bar-inner { min-height: 64px; }
  .brand-name { font-size: 18px; }
  .brand-tagline { font-size: 10px; letter-spacing: 0.12em; }
  .contrast-key { padding: 8px 11px; }
  .contrast-key-text { display: none; }
}

@media (max-width: 720px) {
  .utility-list { display: none; }
  .header-utility-inner { justify-content: flex-start; }
}

/* =========================================================
   页脚
   ========================================================= */

.site-footer {
  margin-top: clamp(64px, 10vw, 140px);
  background: var(--night);
  color: var(--on-dark);
  font-size: 15px;
}

.footer-river {
  height: 1px;
  background: linear-gradient(90deg,
    rgba(70, 166, 154, 0) 0%,
    rgba(70, 166, 154, 0.6) 18%,
    rgba(176, 122, 43, 0.75) 56%,
    rgba(228, 113, 47, 0) 100%);
}

.footer-main {
  display: grid;
  grid-template-columns: 1.5fr 1fr 1fr 1.25fr;
  gap: clamp(28px, 4vw, 60px);
  padding-block: clamp(44px, 6vw, 78px);
}

.footer-brand-name {
  display: flex;
  align-items: center;
  gap: 9px;
  margin: 0 0 8px;
  font-family: var(--font-serif);
  font-size: 24px;
  font-weight: 700;
  color: var(--on-dark-strong);
  letter-spacing: 0.01em;
}

.footer-brand-tagline {
  margin: 0 0 16px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--copper);
}

.footer-brand-note {
  max-width: 34ch;
  margin: 0 0 20px;
  font-size: 14.5px;
  line-height: 1.75;
  color: rgba(244, 239, 228, 0.6);
}

.footer-week {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  margin: 0;
  padding: 6px 12px;
  border: 1px solid rgba(70, 166, 154, 0.4);
  border-radius: var(--radius);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--river-light);
}

.footer-week-key {
  color: rgba(244, 239, 228, 0.5);
}

.footer-heading {
  margin: 0 0 16px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  font-weight: 400;
  letter-spacing: 0.18em;
  color: var(--copper);
}

.footer-links {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 10px;
}

.footer-links a {
  color: rgba(244, 239, 228, 0.78);
  font-size: 15px;
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.footer-links a:hover {
  color: var(--beacon);
  border-bottom-color: rgba(228, 113, 47, 0.55);
}

.footer-contact {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 11px;
  font-size: 14.5px;
  line-height: 1.7;
}

.footer-contact li { color: rgba(244, 239, 228, 0.7); }

.footer-mail,
.footer-tel {
  font-family: var(--font-mono);
  font-size: 13.5px;
  letter-spacing: 0.02em;
  color: var(--river-light);
  word-break: break-all;
}

.footer-addr { max-width: 30ch; }

.footer-hours {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: rgba(244, 239, 228, 0.5);
}

.footer-legal {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 10px 24px;
  padding-block: 22px;
  border-top: 1px solid rgba(244, 239, 228, 0.12);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: rgba(244, 239, 228, 0.52);
}

.footer-legal-links {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin: 0;
}

.footer-legal-links a {
  color: rgba(244, 239, 228, 0.72);
  text-decoration: none;
  transition: color var(--dur) var(--ease);
}

.footer-legal-links a:hover { color: var(--beacon); }

.footer-legal-meta { margin: 0; }

@media (max-width: 1040px) {
  .footer-main {
    grid-template-columns: 1fr 1fr;
    gap: 34px 44px;
  }
  .footer-brand { grid-column: 1 / -1; }
}

@media (max-width: 620px) {
  .footer-main { grid-template-columns: 1fr; }
  .footer-brand-note { max-width: none; }
}

/* =========================================================
   动效与降级
   ========================================================= */

html.js [data-reveal] {
  opacity: 0;
  transform: translateY(12px);
  transition: opacity 420ms var(--ease), transform 420ms var(--ease);
}

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

@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;
  }

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

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

  .scroll-progress { display: none; }
}