/* ==========================================================================
   买球中心 · 入口指南针 — /assets/site.css
   共享外壳：reset / 变量 / 中文排版 / 头部 / 页脚 / 通用组件
   ========================================================================== */

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

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

body,
h1, h2, h3, h4, p,
figure, dl, dd { margin: 0; }

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

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

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

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

table { border-collapse: collapse; width: 100%; }

/* --- 变量 ----------------------------------------------------------------- */
:root {
  --navy: #0A1F33;
  --navy-deep: #071726;
  --mist: #F5F7F9;
  --indigo: #1C1B3B;
  --steel: #8A94A0;
  --cyan: #16E0C4;
  --cyan-deep: #0B8F7C;
  --orange: #FF8B3D;
  --teal: #0F4A4E;
  --violet: #3A2E6E;
  --wine: #6B1F3C;
  --brass: #B99A5B;
  --white: #FFFFFF;
  --ink-soft: #3D5266;

  --line-steel: rgba(138, 148, 160, 0.38);
  --line-steel-strong: rgba(138, 148, 160, 0.72);

  --font-display: "Barlow Condensed", "Archivo Narrow", "Source Han Sans SC Heavy",
    "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-body: "Source Han Sans SC", "PingFang SC", "Microsoft YaHei",
    "Hiragino Sans GB", sans-serif;
  --font-mono: "JetBrains Mono", "IBM Plex Mono", "SFMono-Regular", ui-monospace,
    "Menlo", "Consolas", monospace;

  --edge: 3px;
  --shadow-hard: 8px 8px 0 rgba(7, 23, 38, 0.85);
  --shell: 1280px;
  --pad: clamp(16px, 4vw, 44px);
  --dur: 160ms;
  --ease: cubic-bezier(0.24, 0.72, 0.28, 1);
}

@media (prefers-reduced-motion: no-preference) {
  html { scroll-behavior: smooth; }
}

/* --- 基础排版 -------------------------------------------------------------- */
body {
  background-color: var(--mist);
  color: var(--navy);
  font-family: var(--font-body);
  font-size: 16px;
  font-weight: 400;
  line-height: 1.75;
  letter-spacing: 0.01em;
  min-height: 100vh;
}

h1, h2 {
  font-family: var(--font-display);
  font-weight: 700;
  line-height: 1.08;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

h3, h4 {
  font-family: var(--font-body);
  font-weight: 700;
  line-height: 1.35;
  letter-spacing: 0.01em;
}

p { line-height: 1.75; }

strong, b { font-weight: 700; }

::selection {
  background: var(--cyan);
  color: var(--navy-deep);
}

:focus-visible {
  outline: 3px solid var(--cyan-deep);
  outline-offset: 3px;
}

main { display: block; }

#main-content { scroll-margin-top: 132px; }

/* --- 工具类 --------------------------------------------------------------- */
.shell {
  width: 100%;
  max-width: var(--shell);
  margin-inline: auto;
  padding-inline: var(--pad);
}

.mono {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.06em;
  line-height: 1.5;
}

.rule {
  border: 0;
  height: 3px;
  background: var(--navy);
  margin: 0;
}

.rule--thin {
  height: 1px;
  background: var(--line-steel);
}

.skip-link {
  position: absolute;
  top: -72px;
  left: clamp(12px, 3vw, 28px);
  z-index: 200;
  padding: 12px 22px;
  background: var(--cyan);
  color: var(--navy);
  font-family: var(--font-display);
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  border: var(--edge) solid var(--navy);
  transition: top var(--dur) var(--ease);
}

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

/* --- 头部 ----------------------------------------------------------------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 60;
  background-color: var(--navy);
  background-image: repeating-linear-gradient(
    90deg,
    rgba(138, 148, 160, 0.11) 0 1px,
    transparent 1px 68px
  );
  color: var(--mist);
  border-bottom: var(--edge) solid var(--brass);
}

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

.site-header__inner {
  display: flex;
  flex-direction: column;
}

/* 品牌行 */
.masthead {
  display: flex;
  align-items: center;
  gap: clamp(14px, 3vw, 40px);
  min-height: 76px;
  padding-block: 12px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 14px;
  flex: 1 1 auto;
  min-width: 0;
}

.brand__mark {
  position: relative;
  flex: 0 0 auto;
  width: 44px;
  height: 44px;
  border: 2px solid var(--brass);
  border-radius: 50%;
  box-shadow: inset 0 0 0 4px rgba(185, 154, 91, 0.12);
  transition: box-shadow var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.brand__mark::before {
  content: "";
  position: absolute;
  inset: 4px;
  border-radius: 50%;
  background: conic-gradient(
    from 0deg,
    var(--brass) 0 1.6deg,
    transparent 1.6deg 30deg
  );
  opacity: 0.5;
}

.brand__mark::after {
  content: "";
  position: absolute;
  left: 50%;
  top: 50%;
  width: 2px;
  height: 14px;
  background: var(--cyan);
  transform: translate(-50%, -100%) rotate(38deg);
  transform-origin: 50% 100%;
  transition: background-color var(--dur) var(--ease);
}

.brand:hover .brand__mark {
  border-color: var(--cyan);
  box-shadow: inset 0 0 0 4px rgba(22, 224, 196, 0.16);
}

.brand:hover .brand__mark::after {
  background: var(--orange);
}

.brand__text {
  display: flex;
  flex-direction: column;
  gap: 3px;
  min-width: 0;
}

.brand__line {
  font-family: var(--font-display);
  font-size: clamp(17px, 2vw, 22px);
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--white);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.brand__tagline {
  font-size: 12.5px;
  letter-spacing: 0.04em;
  color: var(--steel);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

/* 版本 / 索引状态条 */
.status-chip {
  display: flex;
  align-items: center;
  gap: 12px;
  flex: 0 0 auto;
  padding: 8px 14px;
  border: 1px solid var(--line-steel);
  background: rgba(22, 224, 196, 0.06);
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.06em;
  white-space: nowrap;
}

.status-chip__dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--cyan);
  box-shadow: 0 0 0 3px rgba(22, 224, 196, 0.18);
  animation: chipPulse 2.6s ease-in-out infinite;
}

@keyframes chipPulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.42; }
}

.status-chip__ver {
  padding: 0;
  color: var(--orange);
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.06em;
  border-bottom: 1px dashed rgba(255, 139, 61, 0.6);
  cursor: pointer;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.status-chip__ver:hover,
.status-chip__ver:focus-visible {
  color: var(--cyan);
  border-bottom-color: var(--cyan);
}

.status-chip__ver[data-copied="true"] {
  color: var(--cyan);
  border-bottom-style: solid;
  border-bottom-color: var(--cyan);
}

.status-chip__divider {
  width: 1px;
  height: 14px;
  background: var(--line-steel);
}

.status-chip__date {
  color: var(--steel);
}

/* 移动导航按钮 */
.nav-toggle {
  display: none;
  align-items: center;
  gap: 10px;
  flex: 0 0 auto;
  padding: 10px 14px;
  border: 2px solid var(--line-steel-strong);
  color: var(--mist);
  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,
.nav-toggle:focus-visible {
  border-color: var(--cyan);
  color: var(--cyan);
}

.nav-toggle__bars {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 4px;
  width: 18px;
  height: 14px;
}

.nav-toggle__bars span {
  display: block;
  height: 2px;
  width: 100%;
  background: var(--cyan);
  transition: transform var(--dur) var(--ease), opacity var(--dur) 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__label {
  line-height: 1;
}

/* 刻度导航带 */
.site-nav {
  display: flex;
  align-items: stretch;
  justify-content: space-between;
  gap: 0;
  border-top: 1px solid var(--line-steel);
  background: var(--navy-deep);
}

.site-nav__list {
  display: flex;
  flex: 1 1 auto;
  min-width: 0;
}

.site-nav__item {
  display: flex;
  flex: 1 1 0;
  min-width: 0;
}

.site-nav__link {
  position: relative;
  display: flex;
  align-items: baseline;
  gap: 10px;
  width: 100%;
  padding: 14px 16px 14px 20px;
  border-right: 1px solid var(--line-steel);
  color: var(--steel);
  transition: color var(--dur) var(--ease), background-color var(--dur) var(--ease);
}

.site-nav__item:last-child .site-nav__link {
  border-right: 0;
}

.site-nav__link::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  height: 3px;
  width: 100%;
  background: var(--cyan);
  transform: scaleX(0);
  transform-origin: left center;
  transition: transform var(--dur) var(--ease);
}

.site-nav__link:hover,
.site-nav__link:focus-visible {
  color: var(--white);
  background: rgba(22, 224, 196, 0.07);
}

.site-nav__link:hover::after,
.site-nav__link:focus-visible::after,
.site-nav__link[aria-current="page"]::after {
  transform: scaleX(1);
}

.site-nav__link[aria-current="page"] {
  color: var(--white);
}

.site-nav__tick {
  position: absolute;
  left: 0;
  top: 50%;
  width: 3px;
  height: 14px;
  background: var(--steel);
  transform: translateY(-50%);
  transition: background-color var(--dur) var(--ease), height var(--dur) var(--ease);
}

.site-nav__link:hover .site-nav__tick,
.site-nav__link:focus-visible .site-nav__tick,
.site-nav__link[aria-current="page"] .site-nav__tick {
  height: 30px;
  background: var(--cyan);
}

.site-nav__num {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--orange);
  line-height: 1.6;
}

.site-nav__label {
  font-family: var(--font-display);
  font-size: clamp(14px, 1.5vw, 17px);
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  line-height: 1.6;
}

.site-nav__utility {
  display: flex;
  align-items: center;
  gap: 18px;
  flex: 0 0 auto;
  padding: 0 20px;
  border-left: 1px solid var(--line-steel);
}

.site-nav__utility-link {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--steel);
  border-bottom: 1px solid transparent;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.site-nav__utility-link:hover,
.site-nav__utility-link:focus-visible {
  color: var(--cyan);
  border-bottom-color: var(--cyan);
}

/* --- 页脚 ----------------------------------------------------------------- */
.site-footer {
  position: relative;
  overflow: hidden;
  background-color: var(--navy);
  background-image: repeating-linear-gradient(
    90deg,
    rgba(138, 148, 160, 0.09) 0 1px,
    transparent 1px 76px
  );
  color: var(--mist);
  border-top: var(--edge) solid var(--brass);
}

.site-footer__inner {
  display: grid;
  gap: clamp(24px, 4vw, 44px);
  padding-block: clamp(38px, 6vw, 68px) clamp(22px, 3vw, 32px);
}

.footer__top {
  display: grid;
  grid-template-columns: minmax(0, 4fr) minmax(0, 8fr);
  gap: clamp(24px, 4vw, 56px);
}

.footer__mark {
  font-family: var(--font-display);
  font-size: clamp(19px, 2.4vw, 27px);
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--white);
}

.footer__note {
  margin-top: 12px;
  max-width: 38ch;
  font-size: 14px;
  color: var(--steel);
}

.footer__index {
  margin-top: 16px;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.06em;
  color: var(--orange);
}

.footer__nav {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: clamp(16px, 2.4vw, 28px);
}

.footer__title {
  margin-bottom: 12px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--line-steel);
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--cyan);
}

.footer__list {
  display: grid;
  gap: 9px;
}

.footer__list li {
  font-size: 14.5px;
  color: var(--mist);
}

.footer__list a {
  border-bottom: 1px solid transparent;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.footer__list a:hover,
.footer__list a:focus-visible {
  color: var(--cyan);
  border-bottom-color: var(--cyan);
}

.footer__ver {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.05em;
  color: var(--steel);
}

.footer__ver b {
  color: var(--orange);
  font-weight: 500;
}

.footer__contact {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(190px, 1fr));
  gap: clamp(16px, 2.4vw, 28px);
  padding-top: clamp(20px, 3vw, 32px);
  border-top: 1px solid var(--line-steel);
}

.footer__item dt {
  margin-bottom: 6px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--steel);
}

.footer__item dd {
  font-size: 14.5px;
  color: var(--mist);
  word-break: break-word;
}

.footer__river {
  height: 26px;
  background:
    linear-gradient(to right, transparent, rgba(185, 154, 91, 0.55), transparent)
      bottom / 100% 1px no-repeat,
    repeating-linear-gradient(90deg, rgba(138, 148, 160, 0.45) 0 1px, transparent 1px 84px)
      bottom / 100% 13px no-repeat;
}

.footer__legal {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px 26px;
  padding-top: clamp(18px, 3vw, 26px);
  border-top: 1px solid var(--line-steel);
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.05em;
  color: var(--steel);
}

.footer__legal a {
  color: var(--mist);
  border-bottom: 1px solid transparent;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.footer__legal a:hover,
.footer__legal a:focus-visible {
  color: var(--cyan);
  border-bottom-color: var(--cyan);
}

.footer__icp {
  color: var(--brass);
}

/* --- 章节结构 -------------------------------------------------------------- */
.section {
  padding-block: clamp(40px, 7vw, 92px);
}

.section__head {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  align-items: end;
  gap: clamp(16px, 3vw, 34px);
  padding-bottom: 16px;
  margin-bottom: clamp(24px, 4vw, 46px);
  border-bottom: var(--edge) solid var(--navy);
}

.section__num {
  display: block;
  font-family: var(--font-display);
  font-size: clamp(56px, 9vw, 112px);
  font-weight: 700;
  line-height: 0.78;
  letter-spacing: 0.06em;
  color: var(--navy);
}

@supports (-webkit-text-stroke: 1px black) {
  .section__num {
    color: transparent;
    -webkit-text-stroke: 2px var(--navy);
  }
}

.section__title {
  font-family: var(--font-display);
  font-size: clamp(24px, 3.4vw, 40px);
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  line-height: 1.06;
  color: var(--navy);
}

.section__lead {
  max-width: 64ch;
  font-size: clamp(16px, 1.4vw, 18px);
  color: var(--ink-soft);
}

.section__body {
  display: grid;
  gap: clamp(16px, 2.4vw, 28px);
}

/* --- 专题研究板卡片 -------------------------------------------------------- */
.board {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 14px;
  padding: clamp(18px, 2.4vw, 28px);
  background: var(--white);
  border: var(--edge) solid var(--navy);
  box-shadow: var(--shadow-hard);
  transition: transform var(--dur) var(--ease), box-shadow var(--dur) var(--ease),
    border-color var(--dur) var(--ease);
}

.board:hover,
.board:focus-within {
  transform: translate(-2px, -2px);
  box-shadow: 10px 10px 0 rgba(7, 23, 38, 0.28);
  border-color: var(--cyan-deep);
}

.board--teal { border-top: 6px solid var(--teal); }
.board--violet { border-top: 6px solid var(--violet); }
.board--wine { border-top: 6px solid var(--wine); }
.board--navy { border-top: 6px solid var(--navy); }

.board__head {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--line-steel);
}

.board__title {
  font-family: var(--font-body);
  font-size: clamp(18px, 1.8vw, 21px);
  font-weight: 700;
  letter-spacing: 0.02em;
  color: var(--navy);
}

.board__meta {
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.06em;
  color: var(--orange);
}

.board__body {
  font-size: 16px;
  line-height: 1.78;
  color: var(--ink-soft);
}

.board__body p + p {
  margin-top: 0.9em;
}

/* --- 标签与版本 ------------------------------------------------------------ */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 4px 10px;
  border: 1px solid var(--line-steel-strong);
  background: var(--mist);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--navy);
}

.tag--live {
  border-color: var(--cyan-deep);
  color: var(--cyan-deep);
}

.version-badge {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.06em;
  color: var(--orange);
}

/* --- 按钮 ----------------------------------------------------------------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 13px 24px;
  border: var(--edge) solid var(--navy);
  background: var(--navy);
  color: var(--mist);
  font-family: var(--font-display);
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  line-height: 1.2;
  cursor: pointer;
  transition: background-color var(--dur) var(--ease), color var(--dur) var(--ease),
    border-color var(--dur) var(--ease), box-shadow var(--dur) var(--ease),
    transform var(--dur) var(--ease);
}

.btn:hover,
.btn:focus-visible {
  background: var(--cyan);
  border-color: var(--cyan);
  color: var(--navy-deep);
  transform: translate(-2px, -2px);
  box-shadow: 6px 6px 0 rgba(7, 23, 38, 0.45);
}

.btn--ghost {
  background: transparent;
  color: var(--navy);
}

.btn--ghost:hover,
.btn--ghost:focus-visible {
  background: var(--navy);
  border-color: var(--navy);
  color: var(--mist);
}

.btn--accent {
  background: var(--orange);
  border-color: var(--orange);
  color: var(--navy-deep);
}

.btn--accent:hover,
.btn--accent:focus-visible {
  background: var(--cyan);
  border-color: var(--cyan);
  color: var(--navy-deep);
}

/* --- 面包屑 --------------------------------------------------------------- */
.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  padding-block: 14px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--steel);
}

.breadcrumb a {
  color: var(--navy);
  border-bottom: 1px solid transparent;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.breadcrumb a:hover,
.breadcrumb a:focus-visible {
  color: var(--cyan-deep);
  border-bottom-color: var(--cyan-deep);
}

.breadcrumb__sep {
  color: var(--steel);
}

/* --- 正文容器 ------------------------------------------------------------- */
.prose {
  max-width: 720px;
  font-size: 17px;
  line-height: 1.8;
  color: var(--navy);
}

.prose > * + * {
  margin-top: 1em;
}

.prose h3 {
  margin-top: 1.9em;
  margin-bottom: 0.6em;
  font-size: 21px;
  letter-spacing: 0.02em;
}

.prose ul {
  display: grid;
  gap: 0.55em;
}

.prose ul li {
  position: relative;
  padding-left: 1.5em;
}

.prose ul li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.78em;
  width: 12px;
  height: 2px;
  background: var(--cyan-deep);
}

.prose a {
  color: var(--cyan-deep);
  border-bottom: 1px solid currentColor;
}

.prose a:hover,
.prose a:focus-visible {
  color: var(--orange);
}

/* --- 栅格 ----------------------------------------------------------------- */
.grid {
  display: grid;
  gap: clamp(16px, 2.4vw, 30px);
}

.grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid--split { grid-template-columns: minmax(0, 5fr) minmax(0, 7fr); }

/* --- 图片容器（页面阶段放置图片） ------------------------------------------ */
.figure {
  display: grid;
  gap: 12px;
  margin: 0;
}

.figure__frame {
  position: relative;
  overflow: hidden;
  aspect-ratio: 16 / 9;
  border: var(--edge) solid var(--navy);
  box-shadow: var(--shadow-hard);
  background: linear-gradient(158deg, var(--navy) 0%, var(--indigo) 58%, var(--teal) 100%);
}

.figure__frame img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.figure__frame::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background:
    repeating-linear-gradient(
      0deg,
      rgba(255, 255, 255, 0.06) 0 1px,
      transparent 1px 4px
    ),
    radial-gradient(circle at 82% 18%, rgba(22, 224, 196, 0.22), transparent 58%);
}

.figure--wide .figure__frame { aspect-ratio: 21 / 9; }
.figure--tall .figure__frame { aspect-ratio: 4 / 5; }
.figure--square .figure__frame { aspect-ratio: 1 / 1; }

.figure__caption {
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.05em;
  color: var(--steel);
}

/* --- 滚动进度（脚本创建） -------------------------------------------------- */
.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  z-index: 90;
  width: 100%;
  height: 2px;
  background: var(--cyan);
  transform: scaleX(0);
  transform-origin: 0 50%;
  pointer-events: none;
  transition: transform 90ms linear;
}

/* --- 响应式 --------------------------------------------------------------- */
@media (max-width: 1080px) {
  .site-nav__utility { gap: 14px; padding-inline: 14px; }
  .footer__top { grid-template-columns: 1fr; }
}

@media (max-width: 899px) {
  .nav-toggle { display: inline-flex; }

  .masthead { flex-wrap: wrap; gap: 12px; min-height: 0; }

  .brand { order: 1; flex: 1 1 62%; }
  .nav-toggle { order: 2; }
  .status-chip {
    order: 3;
    flex: 1 1 100%;
    padding: 8px 0 2px;
    border: 0;
    border-top: 1px solid var(--line-steel);
    background: transparent;
  }

  .site-nav {
    display: block;
    overflow: hidden;
    max-height: 0;
    transition: max-height 240ms var(--ease);
  }

  .site-nav[data-open] {
    max-height: min(76vh, 560px);
    overflow-y: auto;
  }

  .site-nav__list { flex-direction: column; }

  .site-nav__item { flex: 1 1 auto; width: 100%; }

  .site-nav__link {
    padding: 15px 18px 15px 22px;
    border-right: 0;
    border-bottom: 1px solid var(--line-steel);
  }

  .site-nav__item:last-child .site-nav__link { border-bottom: 0; }

  .site-nav__utility {
    flex-direction: column;
    align-items: flex-start;
    gap: 12px;
    padding: 16px 20px 22px;
    border-left: 0;
    border-top: 1px solid var(--line-steel);
  }

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

  .section__head { grid-template-columns: 1fr; align-items: start; gap: 12px; }

  .grid--2,
  .grid--3,
  .grid--split { grid-template-columns: minmax(0, 1fr); }
}

@media (max-width: 560px) {
  .footer__nav { grid-template-columns: minmax(0, 1fr); }
  .brand__tagline { display: none; }
  .footer__legal { gap: 8px 18px; }
}

/* --- 动效偏好 ------------------------------------------------------------- */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
    scroll-behavior: auto !important;
  }

  .status-chip__dot { animation: none; }
}