/* =========================================================
   太阳鑫游艺 · 共享样式 /assets/site.css
   主轴：太阳金橙 × 深空蓝；鑫铜色描边；霓虹青交互
   ========================================================= */

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

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

body,
h1, h2, h3, h4, h5, h6,
p, ul, ol, li, figure, blockquote, dl, dd { margin: 0; padding: 0; }

ul, ol { list-style: none; }

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

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

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

/* ---------- 2. 设计变量 ---------- */
:root {
  --sun: #F5A524;
  --sun-soft: #FFD27A;
  --deep: #0B1C3A;
  --deep-2: #132A52;
  --copper: #B87333;
  --cyan: #35E0D0;
  --indigo: #3F3D8F;
  --teal: #0E3B36;
  --stardust: #E8EDF6;
  --ink: #1B2A41;
  --orbit: #6B7C99;

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

  --rail-w: 232px;
  --top-h: 66px;
  --shell-max: 1180px;

  --radius-s: 6px;
  --radius-m: 14px;
  --radius-l: 22px;

  --glass: rgba(232, 237, 246, 0.07);
  --glass-line: rgba(232, 237, 246, 0.16);

  --ease: cubic-bezier(0.22, 0.61, 0.36, 1);
  --dur: 0.2s;
}

/* ---------- 3. 基础排版（中文优先） ---------- */
body {
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.95;
  font-weight: 400;
  color: var(--stardust);
  background-color: var(--deep);
  background-image:
    radial-gradient(1200px 620px at 88% -12%, rgba(63, 61, 143, 0.45), transparent 68%),
    radial-gradient(900px 520px at -8% 6%, rgba(245, 165, 36, 0.14), transparent 62%);
  background-repeat: no-repeat;
  min-height: 100vh;
  padding-top: var(--top-h);
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4 {
  font-family: var(--font-head);
  font-weight: 900;
  letter-spacing: -0.02em;
  line-height: 1.16;
}

h1 { font-size: clamp(2rem, 5.2vw, 3.9rem); }
h2 { font-size: clamp(1.5rem, 2.7vw, 2.15rem); }
h3 { font-size: clamp(1.15rem, 1.8vw, 1.4rem); }

p { text-wrap: pretty; }

#main-content {
  display: block;
  scroll-margin-top: calc(var(--top-h) + 18px);
}

/* ---------- 4. 文本工具 ---------- */
.prose { max-width: 68ch; }
.prose p { margin-bottom: 1.05em; }
.prose p:last-child { margin-bottom: 0; }
.prose strong { color: var(--sun-soft); font-weight: 800; }
.prose a {
  color: var(--cyan);
  border-bottom: 1px solid rgba(53, 224, 208, 0.45);
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}
.prose a:hover { color: var(--sun-soft); border-bottom-color: var(--sun); }

.lede {
  font-size: clamp(1.02rem, 1.4vw, 1.16rem);
  line-height: 1.95;
  color: rgba(232, 237, 246, 0.86);
  max-width: 62ch;
}

.mono { font-family: var(--font-mono); font-size: 0.86em; letter-spacing: 0.06em; }

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.28em;
  text-transform: uppercase;
  color: var(--sun);
}
.eyebrow::before {
  content: "";
  width: 22px;
  height: 1px;
  background: var(--copper);
}

.chip {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 11px;
  border-radius: 999px;
  border: 1px solid var(--glass-line);
  background: var(--glass);
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.08em;
  color: var(--stardust);
}

.visually-hidden {
  position: absolute !important;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  clip-path: inset(50%);
  white-space: nowrap;
  border: 0;
}

/* ---------- 5. 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 10px 18px;
  border-radius: 999px;
  border: 1px solid transparent;
  font-family: var(--font-body);
  font-weight: 800;
  font-size: 14px;
  letter-spacing: 0.02em;
  white-space: nowrap;
  transition: transform var(--dur) var(--ease), background var(--dur) var(--ease),
              color var(--dur) var(--ease), border-color var(--dur) var(--ease),
              box-shadow var(--dur) var(--ease);
}

.btn--sun {
  background: linear-gradient(135deg, var(--sun), var(--sun-soft));
  color: #241503;
  box-shadow: 0 10px 24px rgba(245, 165, 36, 0.28);
}
.btn--sun:hover { transform: translateY(-2px); box-shadow: 0 14px 30px rgba(245, 165, 36, 0.36); }

.btn--ghost {
  border-color: rgba(232, 237, 246, 0.28);
  background: rgba(232, 237, 246, 0.05);
  color: var(--stardust);
}
.btn--ghost:hover { border-color: var(--cyan); color: #fff; background: rgba(53, 224, 208, 0.12); }

.btn--line {
  border-color: var(--copper);
  color: var(--sun-soft);
  background: transparent;
}
.btn--line:hover { border-color: var(--sun); color: #fff; background: rgba(245, 165, 36, 0.12); }

/* ---------- 6. 头部：顶部横向条 ---------- */
.site-header { position: relative; z-index: 60; }

.skip-link {
  position: fixed;
  top: 8px;
  left: 50%;
  z-index: 200;
  padding: 10px 18px;
  border-radius: 999px;
  background: var(--sun);
  color: #241503;
  font-weight: 800;
  font-size: 14px;
  transform: translate(-50%, -180%);
  transition: transform var(--dur) var(--ease);
}
.skip-link:focus { transform: translate(-50%, 0); }

.topbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 60;
  height: var(--top-h);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 0 20px;
  background: rgba(11, 28, 58, 0.88);
  border-bottom: 1px solid rgba(184, 115, 51, 0.4);
  backdrop-filter: blur(10px) saturate(140%);
  color: var(--stardust);
}

.topbar__brand {
  display: flex;
  align-items: center;
  gap: 12px;
  min-width: 0;
}

.brandmark {
  position: relative;
  flex: 0 0 30px;
  width: 30px;
  height: 30px;
  border-radius: 50%;
  background: radial-gradient(circle at 50% 50%,
              var(--sun-soft) 0 18%, var(--sun) 20% 44%, rgba(245, 165, 36, 0.12) 46% 100%);
  box-shadow: 0 0 0 1px rgba(184, 115, 51, 0.6), inset 0 0 16px rgba(245, 165, 36, 0.35);
}
.brandmark::after {
  content: "";
  position: absolute;
  inset: -6px;
  border-radius: 50%;
  border: 1px solid rgba(53, 224, 208, 0.5);
  border-left-color: transparent;
  border-right-color: transparent;
  transform: rotate(-18deg);
}

.topbar__title {
  display: flex;
  flex-direction: column;
  line-height: 1.15;
  min-width: 0;
}

.topbar__name {
  font-family: var(--font-head);
  font-weight: 900;
  font-size: 17px;
  letter-spacing: 0.02em;
  color: #fff;
}

.topbar__tag {
  font-size: 11.5px;
  letter-spacing: 0.16em;
  color: var(--orbit);
}

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

.version-chip {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.12em;
  padding: 4px 9px;
  border-radius: 999px;
  color: var(--sun-soft);
  border: 1px solid rgba(245, 165, 36, 0.45);
  background: rgba(245, 165, 36, 0.1);
}

.topbar__link { padding: 9px 16px; font-size: 13.5px; }

.nav-toggle {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  padding: 9px 13px;
  border-radius: 999px;
  border: 1px solid rgba(232, 237, 246, 0.24);
  background: rgba(232, 237, 246, 0.06);
  font-size: 13px;
  font-weight: 800;
  color: var(--stardust);
}
.nav-toggle:hover { border-color: var(--cyan); }

.nav-toggle__bars {
  position: relative;
  width: 16px;
  height: 2px;
  border-radius: 2px;
  background: var(--sun);
}
.nav-toggle__bars::before,
.nav-toggle__bars::after {
  content: "";
  position: absolute;
  left: 0;
  width: 16px;
  height: 2px;
  border-radius: 2px;
  background: var(--sun);
  transition: transform var(--dur) var(--ease), background var(--dur) var(--ease);
}
.nav-toggle__bars::before { top: -5px; }
.nav-toggle__bars::after { top: 5px; }

.nav-toggle[aria-expanded="true"] .nav-toggle__bars { background: transparent; }
.nav-toggle[aria-expanded="true"] .nav-toggle__bars::before { transform: translateY(5px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle__bars::after { transform: translateY(-5px) rotate(-45deg); }

.nav-toggle__text { line-height: 1; }

.topbar__progress {
  position: absolute;
  left: 0;
  right: 0;
  bottom: -1px;
  height: 2px;
  background: rgba(107, 124, 153, 0.2);
}

.topbar__progress-bar {
  display: block;
  width: 0;
  height: 100%;
  background: linear-gradient(90deg, var(--sun), var(--sun-soft) 55%, var(--cyan));
  transition: width 0.1s linear;
}

/* ---------- 7. 头部：侧边轨道导航 ---------- */
.rail {
  position: fixed;
  top: var(--top-h);
  left: 0;
  bottom: 0;
  z-index: 40;
  width: var(--rail-w);
  display: flex;
  flex-direction: column;
  gap: 14px;
  padding: 26px 18px 22px 30px;
  overflow-y: auto;
  background:
    radial-gradient(150% 62% at 0% 0%, rgba(245, 165, 36, 0.2), transparent 62%),
    linear-gradient(180deg, var(--deep-2), var(--deep) 72%);
  border-right: 1px solid rgba(184, 115, 51, 0.35);
}

.rail::before {
  content: "";
  position: absolute;
  top: 18px;
  bottom: 18px;
  left: 20px;
  width: 1px;
  background: linear-gradient(180deg,
              transparent,
              rgba(184, 115, 51, 0.6) 12%,
              rgba(184, 115, 51, 0.6) 88%,
              transparent);
  pointer-events: none;
}

.rail::after {
  content: "";
  position: absolute;
  top: -84px;
  right: -66px;
  width: 180px;
  height: 180px;
  border-radius: 50%;
  background: radial-gradient(circle,
              rgba(255, 210, 122, 0.32), rgba(245, 165, 36, 0.08) 45%, transparent 70%);
  pointer-events: none;
}

.rail__caption {
  position: relative;
  z-index: 1;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.28em;
  color: var(--orbit);
}

.rail__list {
  position: relative;
  z-index: 1;
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.rail__item { display: block; }

.rail__link {
  display: grid;
  grid-template-columns: 34px 1fr;
  align-items: center;
  gap: 10px;
  padding: 11px 10px;
  border-left: 2px solid transparent;
  border-radius: var(--radius-s);
  color: var(--stardust);
  transition: transform var(--dur) var(--ease), background var(--dur) var(--ease),
              border-color var(--dur) var(--ease), color var(--dur) var(--ease);
}

.rail__num {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--orbit);
  transition: color var(--dur) var(--ease);
}

.rail__label {
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.01em;
}

.rail__link:hover {
  background: var(--glass);
  border-left-color: var(--copper);
  transform: translateX(3px);
}

.rail__link[aria-current="page"] {
  background: linear-gradient(90deg, rgba(245, 165, 36, 0.2), transparent);
  border-left-color: var(--sun);
  color: #fff;
}
.rail__link[aria-current="page"] .rail__num { color: var(--sun-soft); }

.rail__meter {
  position: relative;
  z-index: 1;
  flex: 1 1 auto;
  min-height: 36px;
  width: 2px;
  margin: 6px 0 6px 16px;
  background: rgba(107, 124, 153, 0.3);
  overflow: hidden;
}

.rail__meter-fill {
  display: block;
  width: 100%;
  height: 0;
  background: linear-gradient(180deg, var(--sun-soft), var(--sun));
  transition: height 0.1s linear;
}

.rail__note {
  position: relative;
  z-index: 1;
  padding-top: 12px;
  border-top: 1px dashed rgba(184, 115, 51, 0.45);
  font-size: 12px;
  line-height: 1.7;
  color: var(--orbit);
}

/* ---------- 8. 移动端遮罩 ---------- */
.nav-scrim {
  position: fixed;
  inset: 0;
  z-index: 70;
  background: rgba(4, 10, 24, 0.68);
  backdrop-filter: blur(2px);
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--dur) var(--ease), visibility var(--dur) var(--ease);
}
.nav-scrim[data-open] { opacity: 1; visibility: visible; }

/* ---------- 9. 页脚 ---------- */
.site-footer {
  position: relative;
  z-index: 20;
  background:
    radial-gradient(120% 92% at 12% 0%, rgba(63, 61, 143, 0.55), transparent 60%),
    linear-gradient(180deg, var(--deep-2), #071127 78%);
  border-top: 1px solid rgba(184, 115, 51, 0.45);
  color: var(--stardust);
}

.footer-inner {
  width: 100%;
  max-width: var(--shell-max);
  margin: 0 auto;
  padding: 56px 20px 36px;
  display: grid;
  gap: 34px;
  grid-template-columns: 1.5fr 1fr 1fr 1.5fr;
}

.footer-brand { min-width: 0; }

.footer-brand__mark {
  position: relative;
  display: block;
  width: 44px;
  height: 44px;
  margin-bottom: 16px;
  border-radius: 12px;
  background: linear-gradient(140deg, rgba(245, 165, 36, 0.92), rgba(184, 115, 51, 0.85));
  box-shadow: 0 0 0 1px rgba(255, 210, 122, 0.6), 0 12px 30px rgba(245, 165, 36, 0.22);
}
.footer-brand__mark::after {
  content: "";
  position: absolute;
  inset: 9px;
  border-radius: 50%;
  border: 2px solid rgba(11, 28, 58, 0.85);
  border-top-color: rgba(53, 224, 208, 0.9);
  transform: rotate(20deg);
}

.footer-brand__name {
  font-family: var(--font-head);
  font-size: 20px;
  font-weight: 900;
  letter-spacing: 0.02em;
  color: #fff;
}

.footer-brand__line {
  margin-top: 10px;
  max-width: 36ch;
  font-size: 14px;
  line-height: 1.9;
  color: rgba(232, 237, 246, 0.76);
}

.footer-brand__meta {
  margin-top: 14px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.04em;
  line-height: 1.8;
  color: var(--orbit);
}

.footer-col { min-width: 0; }

.footer-col__title {
  margin-bottom: 14px;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.24em;
  color: var(--sun-soft);
}

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

.footer-links a {
  display: inline-block;
  font-size: 14.5px;
  color: rgba(232, 237, 246, 0.8);
  border-bottom: 1px solid transparent;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}
.footer-links a:hover { color: #fff; border-bottom-color: var(--cyan); }
.footer-links a[aria-current="page"] { color: var(--sun-soft); }

.footer-contact {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.footer-contact__item {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.footer-contact__key {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.18em;
  color: var(--orbit);
}

.footer-contact__val {
  font-size: 14.5px;
  line-height: 1.85;
  color: rgba(232, 237, 246, 0.9);
  overflow-wrap: anywhere;
}

.footer-bottom {
  width: 100%;
  max-width: var(--shell-max);
  margin: 0 auto;
  padding: 18px 20px 26px;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 10px 24px;
  border-top: 1px solid rgba(107, 124, 153, 0.28);
  font-size: 12.5px;
  color: var(--orbit);
}

.footer-copy { line-height: 1.8; }

.footer-icp {
  font-family: var(--font-mono);
  letter-spacing: 0.06em;
  line-height: 1.8;
}

/* ---------- 10. 浮动操作 ---------- */
.totop {
  position: fixed;
  right: 24px;
  bottom: 26px;
  z-index: 64;
  padding: 11px 16px;
  border-radius: 999px;
  border: 1px solid rgba(53, 224, 208, 0.45);
  background: rgba(19, 42, 82, 0.9);
  backdrop-filter: blur(8px);
  color: var(--stardust);
  font-size: 13px;
  font-weight: 800;
  opacity: 0;
  visibility: hidden;
  transform: translateY(10px);
  transition: opacity var(--dur) var(--ease), transform var(--dur) var(--ease),
              visibility var(--dur) var(--ease), border-color var(--dur) var(--ease),
              color var(--dur) var(--ease);
}
.totop[data-visible] { opacity: 1; visibility: visible; transform: none; }
.totop:hover { border-color: var(--sun); color: #fff; }

.dock {
  position: fixed;
  left: 0;
  right: 0;
  bottom: 0;
  z-index: 65;
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 10px;
  padding: 10px 14px calc(10px + env(safe-area-inset-bottom, 0px));
  background: rgba(7, 17, 39, 0.94);
  border-top: 1px solid rgba(184, 115, 51, 0.4);
  backdrop-filter: blur(10px);
}

.dock__cta {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 13px;
  border-radius: 999px;
  background: linear-gradient(135deg, var(--sun), var(--sun-soft));
  color: #241503;
  font-weight: 900;
  font-size: 15px;
}

.dock__top {
  padding: 13px 16px;
  border-radius: 999px;
  border: 1px solid rgba(53, 224, 208, 0.4);
  background: rgba(53, 224, 208, 0.08);
  color: var(--cyan);
  font-weight: 800;
  font-size: 13px;
  opacity: 0.62;
  transition: opacity var(--dur) var(--ease), border-color var(--dur) var(--ease),
              box-shadow var(--dur) var(--ease);
}
.dock__top[data-visible] {
  opacity: 1;
  border-color: var(--cyan);
  box-shadow: 0 0 18px rgba(53, 224, 208, 0.26);
}

/* ---------- 11. 布局容器与网格 ---------- */
.page-shell {
  width: 100%;
  max-width: var(--shell-max);
  margin: 0 auto;
  padding: 40px 20px 72px;
}

.section {
  padding: 60px 0;
  background-color: transparent;
  color: var(--stardust);
}

.section-inner {
  width: 100%;
  max-width: var(--shell-max);
  margin: 0 auto;
  padding: 0 20px;
}

.section--indigo {
  background-color: var(--indigo);
  border-top: 1px solid rgba(255, 210, 122, 0.18);
  border-bottom: 1px solid rgba(255, 210, 122, 0.18);
}

.section--teal {
  background-color: var(--teal);
  border-top: 1px solid rgba(255, 210, 122, 0.18);
  border-bottom: 1px solid rgba(255, 210, 122, 0.18);
}

.section--light {
  background-color: var(--stardust);
  color: var(--ink);
}
.section--light .lede { color: rgba(27, 42, 65, 0.78); }
.section--light .prose a { color: #0a6b63; border-bottom-color: rgba(10, 107, 99, 0.4); }
.section--light .prose strong { color: #8a5406; }
.section--light .note-card {
  background: rgba(11, 28, 58, 0.05);
  border-color: rgba(11, 28, 58, 0.12);
  backdrop-filter: none;
}
.section--light .breadcrumb,
.section--light .breadcrumb a { color: #5b6b85; }
.section--light .breadcrumb [aria-current="page"] { color: var(--ink); }

.grid { display: grid; gap: 26px; }
.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, 3fr) minmax(0, 9fr); }

/* ---------- 12. 内容组件 ---------- */
.rule-box {
  padding: 20px 22px;
  border: 1px solid rgba(245, 165, 36, 0.55);
  border-radius: var(--radius-m);
  background: linear-gradient(135deg, rgba(245, 165, 36, 0.14), rgba(245, 165, 36, 0.03));
  box-shadow: inset 3px 0 0 var(--sun);
}

.rule-box__title {
  margin-bottom: 8px;
  font-family: var(--font-head);
  font-weight: 900;
  font-size: 1.02rem;
  color: var(--sun-soft);
}

.note-card {
  padding: 18px 20px;
  border: 1px solid var(--glass-line);
  border-radius: var(--radius-m);
  background: var(--glass);
  backdrop-filter: blur(8px);
}

.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.04em;
  line-height: 1.9;
  color: var(--orbit);
}
.breadcrumb a {
  color: var(--orbit);
  transition: color var(--dur) var(--ease);
}
.breadcrumb a:hover { color: var(--cyan); }
.breadcrumb [aria-current="page"] { color: var(--stardust); }

.breadcrumb__sep { color: rgba(107, 124, 153, 0.6); }

.toc { display: block; }

.toc__title {
  margin-bottom: 12px;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.24em;
  color: var(--orbit);
}

.toc__list {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.toc__link {
  display: block;
  padding: 8px 10px;
  border-left: 2px solid rgba(107, 124, 153, 0.3);
  font-size: 14px;
  line-height: 1.8;
  color: var(--orbit);
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease),
              background var(--dur) var(--ease), padding var(--dur) var(--ease);
}
.toc__link:hover { color: var(--stardust); border-left-color: var(--copper); padding-left: 14px; }
.toc__link[aria-current="true"] {
  color: var(--sun);
  border-left-color: var(--sun);
  background: linear-gradient(90deg, rgba(245, 165, 36, 0.14), transparent);
}

.media { display: block; }

.media__frame {
  position: relative;
  overflow: hidden;
  aspect-ratio: 16 / 9;
  border-radius: var(--radius-m);
  border: 1px solid var(--glass-line);
  background:
    radial-gradient(120% 120% at 20% 0%, rgba(245, 165, 36, 0.22), transparent 58%),
    linear-gradient(135deg, var(--deep-2), var(--indigo));
}

.media--square .media__frame { aspect-ratio: 1 / 1; }
.media--wide .media__frame { aspect-ratio: 21 / 9; }

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

.media__caption {
  margin-top: 10px;
  font-size: 12.5px;
  line-height: 1.8;
  color: var(--orbit);
}

/* ---------- 13. 显现与状态 ---------- */
[data-reveal] {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity 0.5s var(--ease), transform 0.5s var(--ease);
}
[data-reveal].is-visible { opacity: 1; transform: none; }

body.nav-open { overflow: hidden; }

/* ---------- 14. 焦点 ---------- */
:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 3px;
  border-radius: 4px;
}
.section--light :focus-visible { outline-color: #0a6b63; }

/* ---------- 15. 响应式 ---------- */
@media (min-width: 1024px) {
  body { padding-left: var(--rail-w); }
  .nav-toggle { display: none; }
  .nav-scrim { display: none; }
  body.nav-open { overflow: auto; }
}

@media (max-width: 1023px) {
  .rail {
    top: 0;
    bottom: 0;
    width: min(320px, 84vw);
    padding: 26px 18px 26px 30px;
    transform: translateX(-102%);
    transition: transform 0.28s var(--ease);
    box-shadow: 18px 0 48px rgba(3, 9, 22, 0.5);
    z-index: 80;
  }
  .rail[data-open] { transform: translateX(0); }
  .grid--3 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .footer-inner { grid-template-columns: 1fr 1fr; }
  .footer-brand { grid-column: 1 / -1; }
}

@media (max-width: 720px) {
  body { padding-bottom: 82px; }
  .grid--2,
  .grid--3,
  .grid--split { grid-template-columns: 1fr; }
  .footer-inner { grid-template-columns: 1fr; padding: 44px 20px 26px; gap: 28px; }
  .footer-bottom { padding: 16px 20px 24px; }
  .section { padding: 44px 0; }
  .page-shell { padding: 28px 20px 56px; }
  .totop { display: none; }
}

@media (min-width: 721px) {
  .dock { display: none; }
}

@media (max-width: 560px) {
  .topbar__link { display: none; }
  .topbar__tag { display: none; }
  .topbar { padding: 0 14px; }
}

/* ---------- 16. 减少动效 ---------- */
@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;
  }

  [data-reveal] {
    opacity: 1 !important;
    transform: none !important;
  }

  .rail__link:hover { transform: none; }
  .totop { transform: none; }
}