/* ==========================================================================
   华体网登录 · 夜训场访问支持 — /assets/site.css
   共享外壳：reset / 变量 / 头部 / 页脚 / 基础组件 / 动效
   ========================================================================== */

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

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

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

ul, ol { list-style: none; }

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

button, input, select, textarea { font: inherit; color: inherit; }

button { background: none; border: 0; cursor: pointer; }

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

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

/* 2. Tokens --------------------------------------------------------------- */
:root {
  --ink-950: #0B1633;
  --ink-900: #0F1D3D;
  --ink-800: #152A52;
  --cyan: #22D3EE;
  --orange: #FF6B2C;
  --green: #3DF08A;
  --amber: #FFC53D;
  --paper: #F4F7FB;
  --steel: #8FA3C4;

  --line: rgba(244, 247, 251, 0.10);
  --line-2: rgba(143, 163, 196, 0.24);
  --cyan-line: rgba(34, 211, 238, 0.34);

  --r-xl: 28px;
  --r-lg: 20px;
  --r-md: 14px;
  --r-pill: 999px;

  --rail-w: 248px;
  --topbar-h: 66px;
  --content-max: 1180px;

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

  --shadow-soft: 0 18px 40px rgba(3, 8, 20, 0.36);
}

@media (max-width: 1023px) {
  :root { --topbar-h: 58px; }
}

/* 3. Base ----------------------------------------------------------------- */
body {
  min-height: 100vh;
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.75;
  letter-spacing: 0.005em;
  color: var(--paper);
  background-color: var(--ink-950);
  background-image:
    radial-gradient(760px 420px at 88% -6%, rgba(34, 211, 238, 0.16), transparent 68%),
    radial-gradient(620px 380px at 4% 6%, rgba(255, 107, 44, 0.13), transparent 70%),
    linear-gradient(180deg, #0B1633 0%, #081127 58%, #0B1633 100%);
  background-attachment: fixed;
  padding-top: var(--topbar-h);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

@media (min-width: 1024px) {
  body { padding-left: var(--rail-w); }
}

body.is-nav-open { overflow: hidden; }

::selection { background: rgba(34, 211, 238, 0.35); color: #FFFFFF; }

:focus-visible { outline: 2px solid var(--cyan); outline-offset: 3px; }

.rail:focus { outline: none; }

h1, h2, h3, h4 { font-weight: 800; line-height: 1.25; letter-spacing: -0.01em; }

.shell {
  width: 100%;
  max-width: var(--content-max);
  margin-inline: auto;
  padding-inline: 20px;
}

@media (min-width: 768px) {
  .shell { padding-inline: 32px; }
}

@media (min-width: 1024px) {
  .shell { max-width: calc(var(--content-max) + 88px); padding-inline: 44px; }
}

.page { padding: 36px 0 84px; }

/* 4. Header --------------------------------------------------------------- */
.skip-link {
  position: fixed;
  top: 10px;
  left: 10px;
  z-index: 200;
  padding: 10px 18px;
  border-radius: var(--r-pill);
  background: var(--cyan);
  color: var(--ink-950);
  font-weight: 800;
  font-size: 14px;
  transform: translateY(-180%);
  transition: transform 0.2s ease;
}

.skip-link:focus { transform: translateY(0); }

/* 顶栏 */
.topbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 65;
  display: flex;
  align-items: center;
  gap: 14px;
  height: var(--topbar-h);
  padding: 0 16px;
  background: rgba(9, 18, 42, 0.88);
  border-bottom: 1px solid var(--line);
  -webkit-backdrop-filter: blur(16px) saturate(140%);
  backdrop-filter: blur(16px) saturate(140%);
}

@media (min-width: 1024px) {
  .topbar { padding: 0 26px 0 22px; gap: 22px; }
}

/* 品牌 */
.brand {
  display: flex;
  align-items: center;
  gap: 11px;
  min-width: 0;
  padding: 4px 0;
}

.brand__sigil { display: flex; align-items: flex-end; gap: 3px; flex: none; }

.brand__sigil i {
  display: block;
  width: 4px;
  height: 15px;
  border-radius: 2px;
  background: var(--cyan);
  transform: skewX(-12deg);
}

.brand__sigil i:nth-child(2) { height: 21px; background: var(--orange); }

.brand__sigil i:nth-child(3) { height: 11px; background: var(--green); }

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

.brand__mark {
  font-family: var(--font-display);
  font-size: 16.5px;
  font-weight: 900;
  line-height: 1.1;
  letter-spacing: -0.01em;
  color: var(--paper);
  white-space: nowrap;
}

.brand__sub {
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.18em;
  color: var(--steel);
  white-space: nowrap;
}

@media (min-width: 1024px) {
  .topbar .brand { min-width: calc(var(--rail-w) - 22px); }
  .brand__mark { font-size: 18px; }
}

/* 顶栏中段说明 */
.topbar__track {
  display: none;
  padding-left: 22px;
  border-left: 1px solid var(--line-2);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--steel);
  white-space: nowrap;
}

@media (min-width: 1200px) {
  .topbar__track { display: block; }
}

/* 顶栏快捷入口 */
.topbar__utility {
  display: none;
  align-items: center;
  gap: 4px;
  margin-left: auto;
}

@media (min-width: 1024px) {
  .topbar__utility { display: flex; }
}

.topbar__link {
  padding: 8px 13px;
  border-radius: var(--r-pill);
  font-size: 13.5px;
  font-weight: 600;
  color: rgba(244, 247, 251, 0.74);
  transition: background-color 0.2s ease, color 0.2s ease;
}

.topbar__link:hover { background: rgba(34, 211, 238, 0.12); color: var(--paper); }

/* 抽屉按钮 */
.nav-toggle {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  margin-left: auto;
  padding: 9px 14px;
  border-radius: var(--r-pill);
  border: 1px solid var(--cyan-line);
  background: rgba(34, 211, 238, 0.09);
  color: var(--paper);
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.14em;
  transition: background-color 0.2s ease, border-color 0.2s ease;
}

.nav-toggle:hover { background: rgba(34, 211, 238, 0.18); }

.nav-toggle__bars { display: inline-flex; flex-direction: column; gap: 4px; }

.nav-toggle__bars i {
  display: block;
  width: 18px;
  height: 2px;
  border-radius: 2px;
  background: var(--cyan);
  transition: transform 0.24s ease, opacity 0.24s ease;
}

.nav-toggle[aria-expanded="true"] .nav-toggle__bars i:nth-child(1) { transform: translateY(6px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle__bars i:nth-child(2) { opacity: 0; }
.nav-toggle[aria-expanded="true"] .nav-toggle__bars i:nth-child(3) { transform: translateY(-6px) rotate(-45deg); }

@media (min-width: 1024px) {
  .nav-toggle { display: none; }
}

/* 阅读进度 */
.read-progress {
  position: fixed;
  top: calc(var(--topbar-h) - 3px);
  left: 0;
  right: 0;
  z-index: 66;
  height: 3px;
  background: rgba(143, 163, 196, 0.18);
  pointer-events: none;
}

.read-progress__bar {
  display: block;
  width: 100%;
  height: 100%;
  transform: scaleX(0);
  transform-origin: 0 50%;
  background: linear-gradient(90deg, var(--cyan) 0%, #5AD6FF 42%, var(--orange) 100%);
}

/* 侧边轨道导航 */
.rail {
  position: fixed;
  top: var(--topbar-h);
  bottom: 0;
  left: 0;
  z-index: 60;
  width: var(--rail-w);
  display: flex;
  flex-direction: column;
  gap: 20px;
  padding: 26px 22px;
  border-right: 1px solid var(--line);
  overflow-y: auto;
  overscroll-behavior: contain;
  background:
    linear-gradient(180deg, rgba(34, 211, 238, 0.85), rgba(34, 211, 238, 0) 46%, rgba(255, 107, 44, 0.85)) right / 3px 100% no-repeat,
    linear-gradient(180deg, rgba(21, 42, 82, 0.94), rgba(11, 22, 51, 0.98) 55%, rgba(9, 17, 40, 0.99));
}

.rail__index {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.24em;
  text-transform: uppercase;
  color: var(--steel);
}

.rail__tracks { display: flex; flex-direction: column; gap: 18px; }

.track {
  padding-left: 12px;
  border-left: 2px solid var(--line-2);
  transition: border-color 0.25s ease;
}

.track:hover { border-left-color: var(--cyan-line); }

.track__head { display: flex; align-items: center; gap: 8px; margin-bottom: 6px; }

.track__no {
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.12em;
  color: var(--orange);
}

.track__name { font-size: 12.5px; letter-spacing: 0.04em; color: var(--steel); }

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

.track__link {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-left: -2px;
  padding: 9px 12px;
  border-left: 2px solid transparent;
  border-radius: 12px;
  font-size: 14.5px;
  font-weight: 600;
  color: rgba(244, 247, 251, 0.8);
  transition: background-color 0.2s ease, color 0.2s ease, border-color 0.2s ease;
}

.track__link::before {
  content: "";
  flex: none;
  width: 6px;
  height: 6px;
  border-radius: 1px;
  background: var(--line-2);
  transform: skewX(-12deg);
  transition: background-color 0.2s ease;
}

.track__link:hover { background: rgba(34, 211, 238, 0.10); color: var(--paper); }

.track__link[aria-current="page"] {
  color: #FFFFFF;
  border-left-color: var(--orange);
  background: linear-gradient(90deg, rgba(255, 107, 44, 0.22), rgba(255, 107, 44, 0));
}

.track__link[aria-current="page"]::before { background: var(--orange); }

.rail__foot {
  margin-top: auto;
  display: flex;
  flex-direction: column;
  gap: 9px;
  padding-top: 16px;
  border-top: 1px dashed var(--line-2);
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.05em;
  color: var(--steel);
}

.rail__status { display: flex; align-items: center; gap: 8px; color: var(--green); letter-spacing: 0.08em; }

.rail__meta { line-height: 1.5; }

.status-dot {
  flex: none;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--green);
  box-shadow: 0 0 0 4px rgba(61, 240, 138, 0.14);
  animation: signal-pulse 2.4s ease-in-out infinite;
}

@keyframes signal-pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.88; }
}

/* 移动端抽屉 */
@media (max-width: 1023px) {
  .rail {
    left: 0;
    right: 0;
    width: 100%;
    z-index: 62;
    padding: 24px 20px 40px;
    border-right: 0;
    background: linear-gradient(180deg, rgba(15, 29, 61, 0.99), rgba(9, 17, 40, 1));
    transform: translateX(-100%);
    visibility: hidden;
    transition: transform 0.32s cubic-bezier(0.22, 0.8, 0.24, 1), visibility 0.32s ease;
  }

  .rail[data-open] { transform: translateX(0); visibility: visible; }
}

/* 5. Footer --------------------------------------------------------------- */
.site-footer {
  margin-top: 72px;
  padding: 56px 0 32px;
  border-top: 1px solid var(--line);
  background: linear-gradient(180deg, rgba(15, 29, 61, 0.55), rgba(8, 17, 42, 0.98));
}

.footer__grid { display: grid; grid-template-columns: 1fr; gap: 34px; }

@media (min-width: 768px) {
  .footer__grid { grid-template-columns: repeat(2, 1fr); gap: 34px 28px; }
}

@media (min-width: 1024px) {
  .footer__grid { grid-template-columns: 1.35fr repeat(3, 0.72fr); gap: 40px; }
}

.footer__stripes { display: flex; align-items: flex-end; gap: 6px; margin-bottom: 18px; }

.footer__stripes i {
  display: block;
  width: 6px;
  height: 26px;
  border-radius: 3px;
  background: var(--cyan);
  transform: skewX(-12deg);
  opacity: 0.85;
}

.footer__stripes i:nth-child(2) { height: 38px; background: var(--orange); opacity: 1; }

.footer__stripes i:nth-child(3) { height: 20px; background: var(--green); opacity: 0.7; }

.footer__blurb {
  margin-top: 14px;
  max-width: 34ch;
  font-size: 14.5px;
  line-height: 1.75;
  color: rgba(244, 247, 251, 0.7);
}

.footer__cta { margin-top: 18px; }

.footer__contact {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-top: 20px;
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.04em;
  line-height: 1.6;
  color: var(--steel);
  overflow-wrap: anywhere;
}

.footer__col-head {
  margin-bottom: 14px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.18em;
  color: var(--cyan);
}

.footer__list li + li { margin-top: 10px; }

.footer__link {
  font-size: 14.5px;
  color: rgba(244, 247, 251, 0.76);
  transition: color 0.2s ease, padding-left 0.2s ease;
}

.footer__link:hover { color: var(--cyan); padding-left: 4px; }

.footer__bottom {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 12px 26px;
  margin-top: 46px;
  padding-top: 22px;
  border-top: 1px solid var(--line);
  font-size: 13px;
  color: var(--steel);
}

.footer__closing { font-size: 15px; color: rgba(244, 247, 251, 0.74); }

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

.footer__copy { font-family: var(--font-mono); font-size: 12.5px; letter-spacing: 0.04em; }

/* 6. Components ----------------------------------------------------------- */

/* 索引字与标题 */
.eyebrow {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--cyan);
}

.display {
  font-family: var(--font-display);
  font-size: clamp(38px, 7vw, 72px);
  font-weight: 900;
  line-height: 1.02;
  letter-spacing: -0.02em;
}

.headline {
  font-size: clamp(22px, 3vw, 30px);
  font-weight: 800;
  line-height: 1.25;
  letter-spacing: -0.01em;
}

.lede {
  max-width: 62ch;
  font-size: 17px;
  line-height: 1.75;
  color: rgba(244, 247, 251, 0.78);
}

.mono {
  font-family: var(--font-mono);
  font-size: 14px;
  letter-spacing: 0.06em;
}

.note {
  padding-left: 14px;
  border-left: 2px solid var(--cyan-line);
  font-size: 14px;
  line-height: 1.7;
  color: var(--steel);
}

.rule { height: 1px; margin: 40px 0; border: 0; background: var(--line); }

.band {
  height: 10px;
  border-radius: var(--r-pill);
  background: linear-gradient(90deg, var(--cyan), var(--orange));
}

.band--cyan { background: var(--cyan); }
.band--orange { background: var(--orange); }

/* 章节 */
.chapter { position: relative; padding: 54px 0; }

.chapter + .chapter { border-top: 1px solid var(--line); }

.chapter__band {
  width: 88px;
  height: 10px;
  margin-bottom: 20px;
  border-radius: 2px;
  background: var(--cyan);
  transform: skewX(-12deg);
}

.chapter:nth-of-type(even) .chapter__band { background: var(--orange); }

.chapter__head {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-end;
  gap: 10px 16px;
  margin-bottom: 18px;
}

.chapter__no {
  font-family: var(--font-mono);
  font-size: clamp(30px, 5vw, 52px);
  font-weight: 700;
  line-height: 1;
  color: transparent;
  -webkit-text-stroke: 1.5px rgba(34, 211, 238, 0.65);
}

/* 按钮 */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 13px 24px;
  border: 1px solid transparent;
  border-radius: var(--r-pill);
  font-size: 15px;
  font-weight: 700;
  line-height: 1;
  transition: transform 0.18s ease, box-shadow 0.18s ease, background-color 0.18s ease, color 0.18s ease;
}

.btn--primary {
  background: linear-gradient(120deg, var(--orange), #FF8A4C);
  color: #1B0D04;
  box-shadow: 0 10px 24px rgba(255, 107, 44, 0.24);
}

.btn--primary:hover { transform: translateY(-2px); box-shadow: 0 14px 30px rgba(255, 107, 44, 0.32); }

.btn--ghost {
  border-color: var(--cyan-line);
  background: rgba(34, 211, 238, 0.07);
  color: var(--cyan);
}

.btn--ghost:hover { background: rgba(34, 211, 238, 0.16); color: #FFFFFF; }

.btn--sm { padding: 10px 18px; font-size: 13.5px; }

/* 胶囊标签 */
.chip {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 5px 12px;
  border: 1px solid var(--cyan-line);
  border-radius: var(--r-pill);
  background: rgba(34, 211, 238, 0.12);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--cyan);
}

.chip--amber { background: rgba(255, 197, 61, 0.12); border-color: rgba(255, 197, 61, 0.32); color: var(--amber); }
.chip--green { background: rgba(61, 240, 138, 0.12); border-color: rgba(61, 240, 138, 0.32); color: var(--green); }
.chip--orange { background: rgba(255, 107, 44, 0.14); border-color: rgba(255, 107, 44, 0.32); color: #FFB08A; }

/* 容器 */
.card {
  position: relative;
  padding: 26px 24px;
  border: 1px solid var(--line);
  border-radius: var(--r-xl);
  background: linear-gradient(160deg, rgba(21, 42, 82, 0.85), rgba(15, 29, 61, 0.7));
}

.card--slab { border-top-left-radius: 8px; }

.card--slab::after {
  content: "";
  position: absolute;
  top: -1px;
  left: 24px;
  width: 64px;
  height: 6px;
  border-radius: 0 0 6px 6px;
  background: var(--cyan);
}

.panel {
  padding: 20px;
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  background: rgba(15, 29, 61, 0.72);
}

.grid { display: grid; gap: 20px; }
.grid--2, .grid--3, .grid--stag { grid-template-columns: 1fr; }

@media (min-width: 768px) {
  .grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .grid--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 24px; }
  .grid--stag { grid-template-columns: 1.15fr 0.85fr; align-items: start; }
}

.stat { display: flex; flex-direction: column; gap: 6px; }

.stat__no {
  font-family: var(--font-mono);
  font-size: clamp(28px, 4vw, 40px);
  font-weight: 700;
  line-height: 1;
  color: var(--cyan);
}

.stat__label { font-size: 13px; letter-spacing: 0.06em; color: var(--steel); }

/* 面包屑 */
.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin-bottom: 22px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--steel);
}

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

.breadcrumb li + li::before { content: "/"; color: rgba(143, 163, 196, 0.5); }

.breadcrumb a:hover { color: var(--cyan); }

.breadcrumb [aria-current="page"] { color: var(--paper); }

/* 长正文 */
.prose { max-width: 70ch; font-size: 16.5px; line-height: 1.8; color: rgba(244, 247, 251, 0.86); }

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

.prose h2 { margin-top: 1.8em; font-size: 24px; }

.prose h3 { margin-top: 1.5em; font-size: 19px; }

.prose ul { padding-left: 1.1em; }

.prose ul li { position: relative; padding-left: 14px; }

.prose ul li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.72em;
  width: 6px;
  height: 2px;
  background: var(--cyan);
}

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

.prose strong { color: #FFFFFF; font-weight: 700; }

/* 折叠面板 */
.accordion { display: flex; flex-direction: column; gap: 10px; }

.accordion__item {
  border: 1px solid var(--line);
  border-radius: 18px;
  background: rgba(15, 29, 61, 0.6);
  overflow: hidden;
}

.accordion__trigger {
  width: 100%;
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 16px 18px;
  font-size: 16px;
  font-weight: 700;
  text-align: left;
  color: var(--paper);
}

.accordion__trigger:hover { background: rgba(34, 211, 238, 0.08); }

.accordion__trigger .mono { margin-left: auto; font-size: 12px; color: var(--steel); }

.accordion__sign {
  flex: none;
  display: grid;
  place-items: center;
  width: 22px;
  height: 22px;
  border: 1px solid var(--cyan-line);
  border-radius: 50%;
  font-size: 15px;
  line-height: 1;
  color: var(--cyan);
  transition: transform 0.22s ease, background-color 0.22s ease;
}

.accordion__trigger[aria-expanded="true"] .accordion__sign {
  transform: rotate(45deg);
  background: rgba(34, 211, 238, 0.16);
}

.accordion__panel {
  padding: 0 18px 18px;
  border-top: 1px solid var(--line);
  font-size: 15.5px;
  color: rgba(244, 247, 251, 0.78);
}

.accordion__panel[hidden] { display: none; }

/* 步骤条 */
.steps { display: flex; flex-direction: column; gap: 14px; }

.step {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 14px;
  align-items: start;
  padding: 16px 18px;
  border: 1px solid var(--line);
  border-radius: 18px;
  background: rgba(21, 42, 82, 0.5);
}

.step__no {
  padding: 4px 9px;
  border-radius: 8px;
  background: var(--orange);
  color: #1B0D04;
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 700;
  line-height: 1.25;
}

.step__title { margin-bottom: 4px; font-weight: 700; }

.step__body { font-size: 15px; line-height: 1.7; color: rgba(244, 247, 251, 0.76); }

/* 设备三联胶囊 */
.device-switch {
  display: inline-flex;
  gap: 4px;
  padding: 5px;
  border: 1px solid var(--line);
  border-radius: var(--r-pill);
  background: rgba(21, 42, 82, 0.8);
}

.device-switch__btn {
  padding: 9px 20px;
  border-radius: var(--r-pill);
  font-size: 14px;
  font-weight: 700;
  color: var(--steel);
  transition: background-color 0.2s ease, color 0.2s ease;
}

.device-switch__btn:hover { color: #FFFFFF; }

.device-switch__btn[aria-selected="true"] { background: var(--cyan); color: var(--ink-950); }

.device-panel[hidden] { display: none; }

/* 图片容器 */
.media {
  position: relative;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: var(--r-xl);
  background: linear-gradient(140deg, rgba(21, 42, 82, 0.9), rgba(11, 22, 51, 0.9));
}

.media img, .media svg { width: 100%; height: 100%; object-fit: cover; }

.media--16x9 { aspect-ratio: 16 / 9; }
.media--4x3 { aspect-ratio: 4 / 3; }
.media--wide { aspect-ratio: 21 / 9; }
.media--slab { border-top-right-radius: 8px; }

.media__placeholder {
  position: absolute;
  inset: 0;
  display: grid;
  place-items: center;
  padding: 16px;
  text-align: center;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--steel);
  background-image:
    linear-gradient(rgba(34, 211, 238, 0.09) 1px, transparent 1px),
    linear-gradient(90deg, rgba(34, 211, 238, 0.09) 1px, transparent 1px);
  background-size: 40px 40px;
}

.media__caption { margin-top: 10px; font-size: 13px; color: var(--steel); }

/* 7. Motion --------------------------------------------------------------- */
html.js [data-reveal] {
  opacity: 0;
  transform: translateY(12px);
  transition: opacity 0.5s ease, transform 0.5s ease;
}

html.js [data-reveal].is-in { 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; }

  .status-dot { animation: none; opacity: 1; }
}