/* ==========================================================================
   28圈中心 · quan-28circle.com.cn
   共享样式表 /assets/site.css
   墨海基底 · 琥珀橙（公告）/ 电子青（专栏）双强调 · 圈层编号坐标
   ========================================================================== */

/* ---------- 1. 变量 ---------- */
:root {
  --ink-900: #08131F;
  --panel-800: #0F2430;
  --panel-750: #14303E;
  --indigo-600: #2A2E5C;
  --accent-amber: #FFA23A;
  --accent-amber-soft: #FFB65C;
  --accent-cyan: #2FE0C8;
  --wine-700: #8C2447;
  --paper: #F4EFE4;
  --paper-dim: #E4DBC8;
  --ink-text: #121A22;
  --muted: #9FB2C0;
  --white: #FFFFFF;
  --body-text: #D8E3EC;

  --line-print: rgba(255, 255, 255, .16);
  --line-soft: rgba(255, 255, 255, .09);
  --line-dark: rgba(159, 178, 192, .24);
  --line-amber: rgba(255, 162, 58, .55);
  --line-cyan: rgba(47, 224, 200, .52);

  --shell: 1280px;
  --shell-narrow: 900px;
  --gutter: 24px;
  --rail: 240px;

  --font-display: "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", system-ui, -apple-system, sans-serif;
  --font-body: system-ui, -apple-system, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --font-mono: ui-monospace, "SFMono-Regular", "SF Mono", Menlo, Consolas, "Liberation Mono", "Courier New", monospace;

  --ease: cubic-bezier(.22, .61, .36, 1);
  --dur: 160ms;
  --radius-sm: 2px;
  --radius-md: 4px;
}

/* ---------- 2. Reset ---------- */
*,
*::before,
*::after { box-sizing: border-box; }

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

body {
  margin: 0;
  background: var(--ink-900);
  color: var(--body-text);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

h1, h2, h3, h4, h5, h6, p, figure, blockquote, dl, dd, pre { margin: 0; }
ul, ol { margin: 0; padding: 0; list-style: none; }
img, svg, video { max-width: 100%; }
img { display: block; height: auto; }
button, input, select, textarea { font: inherit; color: inherit; }
button { background: none; border: 0; padding: 0; cursor: pointer; }
a { color: inherit; }
table { border-collapse: collapse; width: 100%; }

:focus-visible {
  outline: 2px solid var(--accent-cyan);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}

.visually-hidden {
  position: absolute !important;
  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;
}

/* ---------- 3. 版式与文字 ---------- */
.shell {
  width: 100%;
  max-width: var(--shell);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.display {
  font-family: var(--font-display);
  font-weight: 800;
  font-stretch: condensed;
  line-height: .98;
  letter-spacing: -.012em;
  color: var(--white);
}

.display--xl { font-size: clamp(44px, 8vw, 88px); }
.display--lg { font-size: clamp(36px, 5.6vw, 64px); }
.display--md { font-size: clamp(27px, 4vw, 44px); }

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--accent-cyan);
}

.section-num {
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 500;
  letter-spacing: .14em;
  color: var(--accent-amber);
}

.lede {
  font-size: 17px;
  line-height: 1.75;
  color: var(--muted);
  max-width: 38em;
}

.prose {
  max-width: 40em;
  font-size: 17px;
  line-height: 1.78;
  color: var(--ink-text);
}

.prose p + p { margin-top: 1.1em; }
.prose h3 {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 22px;
  line-height: 1.3;
  margin-top: 1.6em;
  color: var(--ink-text);
}
.prose ul { list-style: disc; padding-left: 1.3em; margin-top: .8em; }
.prose li { margin-block: .35em; }
.prose a { color: #0B5D66; text-decoration: underline; text-underline-offset: 3px; }

/* ---------- 4. 布局工具 ---------- */
.section { padding-block: 72px; }
.section--tight { padding-block: 44px; }

.layout-rail {
  display: grid;
  grid-template-columns: var(--rail) minmax(0, 1fr);
  gap: 48px;
  align-items: start;
}

.grid { display: grid; gap: var(--gutter); }
.grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid--4 { grid-template-columns: repeat(4, minmax(0, 1fr)); }

.divider {
  border: 0;
  border-top: 1px solid var(--line-print);
  margin-block: 40px;
}

.print-frame {
  border: 1px solid var(--line-print);
  background: linear-gradient(180deg, rgba(15, 36, 48, .72), rgba(8, 19, 31, .3));
  border-radius: var(--radius-sm);
  padding: 26px;
}

.paper-zone {
  background: var(--paper);
  color: var(--ink-text);
  border: 1px solid var(--paper-dim);
  border-radius: var(--radius-sm);
  padding: clamp(24px, 4vw, 52px);
}

/* ---------- 5. 面包屑 ---------- */
.breadcrumb { margin-block: 20px 0; }

.breadcrumb__list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .06em;
  color: var(--muted);
}

.breadcrumb__list li { display: inline-flex; align-items: center; gap: 6px; }
.breadcrumb__list li + li::before { content: "/"; color: rgba(159, 178, 192, .5); }
.breadcrumb__list a { text-decoration: none; color: var(--muted); transition: color var(--dur) var(--ease); }
.breadcrumb__list a:hover { color: var(--accent-cyan); }
.breadcrumb__list [aria-current="page"] { color: #DCE6EE; }

/* ---------- 6. 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 10px 18px;
  font-family: var(--font-body);
  font-size: 13px;
  font-weight: 600;
  letter-spacing: .04em;
  line-height: 1.1;
  text-decoration: none;
  white-space: nowrap;
  border: 1px solid transparent;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: background var(--dur) var(--ease), color var(--dur) var(--ease),
              border-color var(--dur) var(--ease), transform var(--dur) var(--ease);
}

.btn--sm { padding: 7px 13px; font-size: 12px; }

.btn--amber {
  background: var(--accent-amber);
  border-color: var(--accent-amber);
  color: #1A0E00;
}
.btn--amber:hover { background: var(--accent-amber-soft); border-color: var(--accent-amber-soft); }

.btn--cyan {
  background: transparent;
  border-color: var(--line-cyan);
  color: var(--accent-cyan);
}
.btn--cyan:hover { background: rgba(47, 224, 200, .12); }

.btn--ghost {
  background: transparent;
  border-color: var(--line-print);
  color: var(--muted);
}
.btn--ghost:hover { color: var(--white); border-color: rgba(255, 255, 255, .5); }

.btn--paper {
  background: var(--paper);
  border-color: var(--paper);
  color: var(--ink-text);
}
.btn--paper:hover { background: #FFF8EA; }

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

/* ---------- 7. 标记与卡片 ---------- */
.ring-mark {
  position: relative;
  display: block;
  flex: none;
  width: 34px;
  height: 34px;
  border-radius: 50%;
  border: 1px solid var(--line-cyan);
  background: repeating-radial-gradient(circle at 50% 50%,
              rgba(47, 224, 200, .45) 0 1px, transparent 1px 6px);
}

.ring-mark::after {
  content: "";
  position: absolute;
  left: 50%;
  top: 50%;
  width: 6px;
  height: 6px;
  margin: -3px 0 0 -3px;
  border-radius: 50%;
  background: var(--accent-amber);
}

.ring-mark--sm { width: 26px; height: 26px; }
.ring-mark--sm::after { width: 5px; height: 5px; margin: -2.5px 0 0 -2.5px; }

.label-strip {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 5px 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--muted);
  border: 1px solid var(--line-print);
  border-radius: var(--radius-sm);
}

.label-strip--amber { border-color: var(--line-amber); color: var(--accent-amber); }
.label-strip--cyan { border-color: var(--line-cyan); color: var(--accent-cyan); }

.card {
  position: relative;
  padding: 22px;
  background: var(--panel-800);
  border: 1px solid var(--line-print);
  border-radius: var(--radius-sm);
  transition: background var(--dur) var(--ease), border-color var(--dur) var(--ease),
              transform var(--dur) var(--ease);
}

.card--amber { border-left: 2px solid var(--accent-amber); }
.card--cyan { border-left: 2px solid var(--accent-cyan); }
.card--wine { border-left: 2px solid var(--wine-700); }

.card:hover { background: var(--panel-750); border-color: rgba(255, 255, 255, .26); }

/* ---------- 8. 图片容器 ---------- */
.figure {
  position: relative;
  width: 100%;
  aspect-ratio: 16 / 9;
  overflow: hidden;
  border: 1px solid var(--line-print);
  border-radius: var(--radius-sm);
  background:
    radial-gradient(circle at 50% 50%, rgba(47, 224, 200, .12), transparent 62%),
    radial-gradient(circle at 78% 22%, rgba(255, 162, 58, .12), transparent 55%),
    var(--panel-800);
}

.figure__media,
.figure > img,
.figure > svg {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  display: block;
  object-fit: cover;
}

.figure--wide { aspect-ratio: 21 / 9; }
.figure--square { aspect-ratio: 1 / 1; }
.figure--tall { aspect-ratio: 3 / 4; }
.figure--paper { background: var(--paper); border-color: var(--paper-dim); }

/* ---------- 9. 页头 ---------- */
.skip-link {
  position: absolute;
  left: 16px;
  top: -120px;
  z-index: 200;
  padding: 10px 16px;
  font-size: 13px;
  font-weight: 700;
  letter-spacing: .04em;
  text-decoration: none;
  color: #1A0E00;
  background: var(--accent-amber);
  border-radius: var(--radius-sm);
  transition: top var(--dur) var(--ease);
}

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

.site-header {
  position: sticky;
  top: 0;
  z-index: 80;
  background: var(--ink-900);
  border-bottom: 1px solid var(--line-print);
}

.reading-progress {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: rgba(255, 255, 255, .06);
  pointer-events: none;
  z-index: 6;
}

.reading-progress__bar {
  display: block;
  height: 100%;
  width: 0;
  background: linear-gradient(90deg, var(--accent-cyan), var(--accent-amber));
  transition: width 80ms linear;
}

.header-top {
  background:
    radial-gradient(1100px 220px at 10% -60%, rgba(42, 46, 92, .9), transparent 72%),
    var(--ink-900);
  border-bottom: 1px solid var(--line-soft);
}

.header-top__inner {
  display: flex;
  align-items: center;
  gap: 20px;
  min-height: 68px;
  padding-block: 10px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  color: var(--white);
}

.brand__text { display: block; }

.brand__name {
  display: block;
  font-family: var(--font-display);
  font-weight: 800;
  font-stretch: condensed;
  font-size: 21px;
  line-height: 1.1;
  letter-spacing: .04em;
  color: var(--white);
}

.brand__sub {
  display: block;
  margin-top: 2px;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: .12em;
  color: var(--muted);
}

.header-meta {
  display: flex;
  align-items: center;
  gap: 9px;
  margin-left: auto;
  font-size: 12px;
  letter-spacing: .04em;
  color: var(--muted);
  white-space: nowrap;
}

.header-meta__dot {
  width: 6px;
  height: 6px;
  flex: none;
  border-radius: 50%;
  background: var(--accent-cyan);
  box-shadow: 0 0 0 3px rgba(47, 224, 200, .16);
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 10px;
}

/* 第二层栏目导航 */
.header-nav {
  background: var(--panel-800);
  border-bottom: 1px solid var(--line-print);
}

.header-nav__inner {
  display: flex;
  align-items: center;
  gap: 18px;
  min-height: 54px;
  padding-block: 6px;
}

.header-nav__index {
  flex: none;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--muted);
  white-space: nowrap;
}

.nav-list {
  display: flex;
  align-items: center;
  gap: 4px;
}

.nav-list a {
  display: block;
  padding: 9px 12px;
  font-size: 14px;
  letter-spacing: .03em;
  text-decoration: none;
  color: #C9D6E0;
  border-bottom: 2px solid transparent;
  transition: color var(--dur) var(--ease), background var(--dur) var(--ease),
              border-color var(--dur) var(--ease);
}

.nav-list a:hover { color: var(--white); background: rgba(255, 255, 255, .05); }

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

.header-search {
  margin-left: auto;
  position: relative;
  width: 210px;
  flex: none;
}

.header-search__input {
  width: 100%;
  padding: 8px 12px 8px 30px;
  font-size: 13px;
  line-height: 1.2;
  color: var(--white);
  background: rgba(8, 19, 31, .72);
  border: 1px solid var(--line-print);
  border-radius: var(--radius-sm);
  appearance: none;
  transition: border-color var(--dur) var(--ease), background var(--dur) var(--ease);
}

.header-search__input::placeholder { color: rgba(159, 178, 192, .75); }

.header-search__input:focus {
  outline: none;
  border-color: var(--accent-cyan);
  background: rgba(8, 19, 31, .95);
}

.header-search::before {
  content: "";
  position: absolute;
  left: 11px;
  top: 50%;
  width: 9px;
  height: 9px;
  margin-top: -6px;
  border: 1.5px solid var(--accent-cyan);
  border-radius: 50%;
  pointer-events: none;
}

.header-search::after {
  content: "";
  position: absolute;
  left: 19px;
  top: 50%;
  width: 6px;
  height: 1.5px;
  margin-top: 3px;
  background: var(--accent-cyan);
  transform: rotate(45deg);
  transform-origin: left center;
  pointer-events: none;
}

.nav-toggle {
  display: none;
  align-items: center;
  gap: 10px;
  margin-left: auto;
  padding: 8px 12px;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--white);
  background: transparent;
  border: 1px solid var(--line-print);
  border-radius: var(--radius-sm);
  transition: border-color var(--dur) var(--ease), color var(--dur) var(--ease);
}

.nav-toggle:hover { border-color: rgba(255, 255, 255, .45); }

.nav-toggle__bars {
  position: relative;
  display: block;
  width: 16px;
  height: 10px;
}

.nav-toggle__bars::before,
.nav-toggle__bars::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  height: 1.5px;
  background: currentColor;
  transition: transform var(--dur) var(--ease), opacity var(--dur) var(--ease);
}

.nav-toggle__bars::before { top: 0; }
.nav-toggle__bars::after { bottom: 0; }

[data-nav][data-open] .nav-toggle { color: var(--accent-amber); border-color: var(--line-amber); }
[data-nav][data-open] .nav-toggle__bars::before { transform: translateY(4.25px) rotate(45deg); }
[data-nav][data-open] .nav-toggle__bars::after { transform: translateY(-4.25px) rotate(-45deg); }

/* ---------- 10. 页脚 ---------- */
.site-footer {
  position: relative;
  margin-top: 60px;
  background: var(--ink-900);
  border-top: 1px solid var(--line-print);
  color: var(--muted);
  overflow: hidden;
}

.site-footer::before {
  content: "";
  position: absolute;
  inset: 0;
  background:
    repeating-linear-gradient(90deg, rgba(159, 178, 192, .055) 0 1px, transparent 1px 72px),
    repeating-linear-gradient(0deg, rgba(159, 178, 192, .055) 0 1px, transparent 1px 72px),
    radial-gradient(760px 320px at 88% 8%, rgba(42, 46, 92, .55), transparent 70%);
  pointer-events: none;
}

.site-footer > .shell { position: relative; z-index: 1; }

.site-footer__inner {
  display: grid;
  grid-template-columns: 1.5fr 1fr 1fr 1.3fr;
  gap: 40px;
  padding-block: 56px 40px;
}

.footer-brand__name {
  margin-top: 14px;
  font-family: var(--font-display);
  font-weight: 800;
  font-stretch: condensed;
  font-size: 22px;
  line-height: 1.1;
  letter-spacing: .04em;
  color: var(--white);
}

.footer-brand__desc {
  margin-top: 10px;
  max-width: 30em;
  font-size: 13.5px;
  line-height: 1.75;
  color: var(--muted);
}

.footer-marks {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 16px;
}

.footer-marks li {
  padding: 4px 9px;
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: .1em;
  color: var(--accent-cyan);
  border: 1px solid var(--line-cyan);
  border-radius: var(--radius-sm);
}

.footer-col__title {
  margin-bottom: 14px;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--accent-amber);
}

.footer-links {
  display: flex;
  flex-direction: column;
  gap: 9px;
}

.footer-links a {
  display: inline-block;
  font-size: 14px;
  text-decoration: none;
  color: #C7D3DD;
  transition: color var(--dur) var(--ease), padding-left var(--dur) var(--ease);
}

.footer-links a:hover { color: var(--accent-amber); padding-left: 5px; }

.footer-contact__row {
  display: flex;
  gap: 10px;
  font-size: 13px;
  line-height: 1.7;
}

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

.footer-contact__key {
  flex: none;
  width: 40px;
  padding-top: 2px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .1em;
  color: var(--muted);
}

.footer-contact__val {
  color: #C7D3DD;
  word-break: break-word;
}

.footer-note {
  margin-top: 14px;
  padding-top: 12px;
  font-size: 12px;
  line-height: 1.7;
  color: var(--muted);
  border-top: 1px dashed var(--line-dark);
}

.footer-sitemap {
  padding-block: 16px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .08em;
  color: var(--muted);
  border-top: 1px solid var(--line-soft);
}

.site-footer__legal {
  border-top: 1px solid var(--line-soft);
  padding-block: 18px 28px;
}

.site-footer__legal-inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 10px 28px;
}

.footer-legal-text {
  font-size: 12px;
  letter-spacing: .03em;
  color: var(--muted);
}

/* ---------- 11. 通用动效与状态 ---------- */
[data-reveal] {
  transition: opacity 140ms var(--ease), transform 140ms var(--ease);
}

[data-reveal].reveal-init:not(.is-visible) {
  opacity: 0;
  transform: translateY(12px);
  transition: none;
}

[data-section-link] {
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

[data-section-link][data-current="true"] { color: var(--accent-amber); }

.is-filtered-out { display: none !important; }

/* ---------- 12. 响应式 ---------- */
@media (max-width: 1100px) {
  .header-search { width: 168px; }
  .header-meta { display: none; }
}

@media (max-width: 980px) {
  .layout-rail { grid-template-columns: minmax(0, 1fr); gap: 28px; }
}

@media (max-width: 900px) {
  :root { --gutter: 20px; }

  .header-top__inner { min-height: 60px; gap: 12px; }
  .header-actions .btn--ghost { display: none; }

  .header-nav__inner { flex-wrap: wrap; padding-block: 8px 10px; }
  .header-nav__index { display: none; }
  .nav-toggle { display: inline-flex; order: 2; }
  .header-search { display: none; }

  [data-nav] .nav-list {
    display: none;
    order: 3;
    width: 100%;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    margin-top: 8px;
    padding-top: 6px;
    border-top: 1px solid var(--line-soft);
  }

  [data-nav][data-open] .nav-list { display: flex; }

  [data-nav] .nav-list a {
    padding: 12px 8px;
    font-size: 15px;
    border-bottom: 1px solid var(--line-soft);
    border-left: 2px solid transparent;
  }

  [data-nav] .nav-list a[aria-current="page"] {
    border-bottom-color: var(--line-soft);
    border-left-color: var(--accent-amber);
    padding-left: 14px;
  }

  .site-footer__inner {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 32px;
    padding-block: 44px 32px;
  }

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

@media (max-width: 960px) {
  .grid--3, .grid--4 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (max-width: 768px) {
  .section { padding-block: 48px; }
  .section--tight { padding-block: 32px; }
  .lede { font-size: 16px; }
}

@media (max-width: 620px) {
  .grid--2, .grid--3, .grid--4 { grid-template-columns: minmax(0, 1fr); }
  .site-footer__inner { grid-template-columns: minmax(0, 1fr); gap: 28px; }
  .figure--wide { aspect-ratio: 16 / 9; }
  .figure--tall { aspect-ratio: 4 / 5; }
  .site-footer__legal-inner { flex-direction: column; align-items: flex-start; }
}

@media (max-width: 420px) {
  .brand__name { font-size: 19px; }
  .brand__sub { font-size: 10px; letter-spacing: .08em; }
  .header-actions .btn { padding: 9px 13px; font-size: 12px; }
}

/* ---------- 13. 减弱动效 ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }

  *,
  *::before,
  *::after {
    animation-duration: .001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .001ms !important;
  }

  [data-reveal],
  [data-reveal].reveal-init:not(.is-visible) {
    opacity: 1;
    transform: none;
    transition: none;
  }

  .reading-progress__bar { transition: none; }
}