/* =========================================================
   BMW740 PLAY · Site Kit / assets/site.css
   共享外壳：reset、变量、排版、页头、控制台、页脚、基础组件
   ========================================================= */

/* ---------- 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, blockquote, dl, dd, table, blockquote {
  margin: 0;
}

ul, ol { padding: 0; list-style: none; }
img, svg, video { display: block; max-width: 100%; }
button { font: inherit; color: inherit; }
a { color: inherit; }
[hidden] { display: none !important; }

:where(button, a, input, textarea, select, summary) {
  -webkit-tap-highlight-color: transparent;
}

/* ---------- 2. Tokens ---------- */
:root {
  --night: #081A2F;
  --pit: #0B0F14;
  --steel: #123A66;
  --slate: #1E2A38;
  --silver: #C7D0D9;
  --fog: #F2F6FA;
  --cyan: #00E5FF;
  --orange: #FF6B1A;
  --green: #35D07F;
  --amber: #FFC857;

  --shell: 1240px;
  --gutter: clamp(18px, 4vw, 56px);
  --radius-lg: 26px;
  --radius-md: 16px;
  --radius-pill: 999px;

  --line-soft: rgba(199, 208, 217, 0.16);
  --line-cyan: rgba(0, 229, 255, 0.28);

  --font-display: "Oswald", "Barlow Condensed", "Noto Sans SC", "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
  --font-body: "Noto Sans SC", "Source Han Sans SC", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", system-ui, sans-serif;
  --font-mono: "JetBrains Mono", "IBM Plex Mono", "SFMono-Regular", Consolas, "Liberation Mono", monospace;

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

/* ---------- 3. Base typography ---------- */
body {
  background-color: var(--night);
  background-image:
    radial-gradient(1100px 520px at 80% -10%, rgba(18, 58, 102, 0.6), transparent 70%),
    radial-gradient(760px 460px at 4% 10%, rgba(0, 229, 255, 0.07), transparent 72%),
    radial-gradient(900px 520px at 50% 112%, rgba(255, 107, 26, 0.05), transparent 70%);
  background-repeat: no-repeat;
  color: var(--silver);
  font-family: var(--font-body);
  font-size: 17px;
  line-height: 1.75;
  letter-spacing: 0.005em;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 1.06;
  color: var(--fog);
  text-wrap: balance;
}

h1 { font-size: clamp(38px, 6.2vw, 88px); }
h2 { font-size: clamp(28px, 4vw, 52px); }
h3 { font-size: clamp(21px, 2.4vw, 32px); }
h4 { font-size: clamp(18px, 1.8vw, 22px); }

p { text-wrap: pretty; }

strong { color: var(--fog); font-weight: 700; }

::selection {
  background: rgba(0, 229, 255, 0.28);
  color: var(--fog);
}

:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 3px;
  border-radius: 6px;
}

.skip-link {
  position: fixed;
  top: 10px;
  left: 10px;
  z-index: 999;
  padding: 12px 22px;
  border-radius: var(--radius-pill);
  background: var(--cyan);
  color: #04121F;
  font-weight: 700;
  font-size: 15px;
  text-decoration: none;
  transform: translateY(-180%);
  transition: transform 0.18s var(--ease);
}
.skip-link:focus-visible { transform: translateY(0); }

/* ---------- 4. Layout tools ---------- */
.shell {
  width: min(calc(100% - (var(--gutter) * 2)), var(--shell));
  margin-inline: auto;
}

.sk-grid {
  display: grid;
  gap: clamp(16px, 2.4vw, 28px);
}
.sk-grid--two { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.sk-grid--three { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.sk-grid--split { grid-template-columns: minmax(0, 0.85fr) minmax(0, 1.15fr); }

.sk-prose {
  max-width: 66ch;
  font-size: 17px;
  line-height: 1.8;
  color: var(--silver);
}
.sk-prose > * + * { margin-top: 1.05em; }
.sk-prose h2,
.sk-prose h3 { margin-top: 1.6em; }
.sk-prose a {
  color: var(--cyan);
  text-decoration: underline;
  text-underline-offset: 4px;
}
.sk-prose ul,
.sk-prose ol { padding-left: 1.2em; }
.sk-prose li { list-style: disc; }
.sk-prose strong { color: var(--fog); }

/* ---------- 5. Shared components ---------- */
.mono {
  font-family: var(--font-mono);
  letter-spacing: 0.08em;
}

.sk-eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--cyan);
}
.sk-eyebrow::before {
  content: "";
  width: 26px;
  height: 1px;
  background: linear-gradient(90deg, var(--cyan), transparent);
}

.sk-num {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(48px, 7vw, 92px);
  line-height: 0.92;
  letter-spacing: -0.04em;
  color: var(--orange);
  font-variant-numeric: tabular-nums;
}
.sk-num--ghost {
  color: transparent;
  -webkit-text-stroke: 1.4px rgba(199, 208, 217, 0.55);
}

.sk-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 14px 26px;
  border: 1px solid transparent;
  border-radius: var(--radius-pill);
  background: var(--orange);
  color: #0A1522;
  font-family: var(--font-body);
  font-size: 15.5px;
  font-weight: 700;
  letter-spacing: 0.01em;
  text-decoration: none;
  cursor: pointer;
  transition: transform 0.18s var(--ease), box-shadow 0.18s var(--ease), background 0.18s var(--ease), color 0.18s var(--ease), border-color 0.18s var(--ease);
}
.sk-btn:hover {
  transform: translateY(-2px);
  background: #FF7E36;
  box-shadow: 0 16px 34px -18px rgba(255, 107, 26, 0.9);
}
.sk-btn--ghost {
  background: transparent;
  border-color: rgba(0, 229, 255, 0.6);
  color: var(--cyan);
}
.sk-btn--ghost:hover {
  background: rgba(0, 229, 255, 0.12);
  border-color: var(--cyan);
  color: var(--fog);
  box-shadow: none;
}
.sk-btn--quiet {
  background: rgba(199, 208, 217, 0.1);
  border-color: rgba(199, 208, 217, 0.24);
  color: var(--fog);
}
.sk-btn--quiet:hover {
  background: rgba(199, 208, 217, 0.18);
  box-shadow: none;
}

.sk-chip {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 16px;
  border: 1px solid rgba(199, 208, 217, 0.26);
  border-radius: var(--radius-pill);
  background: rgba(30, 42, 56, 0.6);
  color: var(--silver);
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.06em;
  cursor: pointer;
  transition: background 0.18s var(--ease), border-color 0.18s var(--ease), color 0.18s var(--ease);
}
.sk-chip:hover {
  border-color: rgba(0, 229, 255, 0.6);
  color: var(--fog);
}
.sk-chip[aria-pressed="true"] {
  background: rgba(0, 229, 255, 0.14);
  border-color: var(--cyan);
  color: var(--fog);
  box-shadow: inset 0 0 0 1px rgba(0, 229, 255, 0.35);
}
.sk-chip[aria-pressed="true"]::before {
  content: "";
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--orange);
}

.sk-card {
  position: relative;
  padding: clamp(18px, 2.4vw, 28px);
  border: 1px solid var(--line-soft);
  border-radius: var(--radius-lg);
  background: linear-gradient(160deg, rgba(30, 42, 56, 0.94), rgba(11, 15, 20, 0.94));
  box-shadow: 0 26px 60px -44px #000;
  overflow: hidden;
  transition: transform 0.22s var(--ease), border-color 0.22s var(--ease);
}
.sk-card::after {
  content: "";
  position: absolute;
  top: 0;
  right: 0;
  width: 66px;
  height: 66px;
  background: linear-gradient(225deg, rgba(0, 229, 255, 0.24), transparent 62%);
  clip-path: polygon(100% 0, 100% 100%, 0 0);
  pointer-events: none;
}
.sk-card:hover {
  transform: translateY(-3px);
  border-color: var(--line-cyan);
}
.sk-card__title {
  font-family: var(--font-display);
  font-size: clamp(20px, 2.2vw, 26px);
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--fog);
  margin-bottom: 8px;
}

.sk-panel {
  position: relative;
  padding: clamp(20px, 3.4vw, 44px);
  border: 1px solid var(--line-cyan);
  border-radius: clamp(20px, 3vw, 36px);
  background:
    radial-gradient(120% 140% at 88% -20%, rgba(0, 229, 255, 0.14), transparent 58%),
    linear-gradient(150deg, rgba(18, 58, 102, 0.6), rgba(8, 26, 47, 0.92));
  overflow: hidden;
}

.chapter-band {
  display: flex;
  align-items: center;
  gap: clamp(14px, 3vw, 32px);
  margin-block: clamp(36px, 6vw, 80px);
  padding: clamp(14px, 2.4vw, 26px) clamp(4px, 1vw, 16px);
  border-top: 1px solid var(--line-soft);
  border-bottom: 1px solid var(--line-soft);
  background: linear-gradient(90deg, rgba(0, 229, 255, 0.09), transparent 62%);
}
.chapter-band__num {
  flex: none;
  font-family: var(--font-display);
  font-size: clamp(36px, 6vw, 72px);
  font-weight: 800;
  line-height: 1;
  letter-spacing: -0.05em;
  color: transparent;
  -webkit-text-stroke: 1.4px rgba(0, 229, 255, 0.7);
}
.chapter-band__title {
  font-family: var(--font-display);
  font-size: clamp(20px, 3vw, 32px);
  font-weight: 800;
  letter-spacing: -0.02em;
  color: var(--fog);
}

.media-frame {
  position: relative;
  overflow: hidden;
  border: 1px solid var(--line-soft);
  border-radius: var(--radius-lg);
  aspect-ratio: 16 / 9;
  background:
    radial-gradient(120% 120% at 22% 8%, rgba(0, 229, 255, 0.16), transparent 58%),
    linear-gradient(140deg, #0B0F14, #123A66 62%, #081A2F);
}
.media-frame img,
.media-frame video {
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.media-frame--wide { aspect-ratio: 21 / 9; }
.media-frame--square { aspect-ratio: 1 / 1; }
.media-frame--tall { aspect-ratio: 3 / 4; }
.media-frame--angled {
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 42px), calc(100% - 42px) 100%, 0 100%);
}

.sk-crumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  padding-block: 18px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.1em;
  color: rgba(199, 208, 217, 0.7);
}
.sk-crumbs a {
  text-decoration: none;
  color: var(--silver);
}
.sk-crumbs a:hover {
  color: var(--cyan);
  text-decoration: underline;
  text-underline-offset: 3px;
}
.sk-crumbs__sep { color: rgba(0, 229, 255, 0.65); }
.sk-crumbs [aria-current="page"] { color: var(--fog); }

.sk-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 15px;
  line-height: 1.65;
}
.sk-table th,
.sk-table td {
  padding: 12px 14px;
  border-bottom: 1px solid var(--line-soft);
  text-align: left;
  vertical-align: top;
}
.sk-table th {
  font-family: var(--font-mono);
  font-size: 11.5px;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--cyan);
}
.sk-table tbody tr:nth-child(even) { background: rgba(30, 42, 56, 0.42); }

.sk-empty {
  padding: 24px;
  border: 1px dashed rgba(199, 208, 217, 0.3);
  border-radius: var(--radius-md);
  color: rgba(199, 208, 217, 0.78);
  font-size: 14.5px;
  text-align: center;
}

.is-flash { animation: sk-flash 1.6s var(--ease); }
@keyframes sk-flash {
  0%, 100% { box-shadow: 0 0 0 0 rgba(0, 229, 255, 0); }
  32% { box-shadow: 0 0 0 3px rgba(0, 229, 255, 0.55); }
}

/* ---------- 6. Header ---------- */
.site-head {
  position: relative;
  z-index: 60;
  isolation: isolate;
}

.head-scale {
  height: 6px;
  background:
    repeating-linear-gradient(90deg, rgba(0, 229, 255, 0.5) 0 1px, transparent 1px 24px),
    linear-gradient(90deg, rgba(255, 107, 26, 0.9) 0 88px, rgba(18, 58, 102, 0.92) 88px 100%);
}

.tier--upper {
  background:
    repeating-linear-gradient(135deg, rgba(255, 255, 255, 0.022) 0 2px, transparent 2px 5px),
    linear-gradient(100deg, #081A2F 0%, #0C2138 48%, #14375E 100%);
  border-bottom: 1px solid rgba(199, 208, 217, 0.16);
}

.tier--nav {
  position: relative;
  background: linear-gradient(180deg, #0B0F14 0%, #0C1520 100%);
  border-bottom: 1px solid rgba(0, 229, 255, 0.2);
  box-shadow: 0 18px 42px -34px #000;
}

.tier__inner {
  display: flex;
  align-items: center;
  gap: clamp(16px, 3vw, 40px);
  width: min(calc(100% - (var(--gutter) * 2)), var(--shell));
  margin-inline: auto;
  padding-block: 13px;
}
.tier__inner--nav {
  justify-content: space-between;
  padding-block: 10px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  color: var(--fog);
}
.brand__glyph {
  position: relative;
  display: grid;
  place-items: center;
  width: 36px;
  height: 36px;
  flex: none;
  border: 1px solid rgba(0, 229, 255, 0.5);
  border-radius: 11px;
  background: linear-gradient(140deg, var(--steel), var(--night));
  box-shadow: inset 0 1px 0 rgba(242, 246, 250, 0.14);
}
.brand__glyph-core {
  width: 12px;
  height: 12px;
  border-radius: 3px;
  background: var(--orange);
  transform: skewX(-12deg);
  box-shadow: 0 0 0 3px rgba(0, 229, 255, 0.18);
}
.brand__text { display: block; min-width: 0; }
.brand__name {
  display: block;
  font-family: var(--font-display);
  font-size: 19px;
  font-weight: 800;
  line-height: 1.1;
  letter-spacing: -0.02em;
  color: var(--fog);
}
.brand__sub {
  display: block;
  margin-top: 3px;
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.16em;
  color: var(--cyan);
  text-transform: uppercase;
}

.tier__note {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--silver);
  white-space: nowrap;
}
.tier__note::before {
  content: "";
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--green);
  box-shadow: 0 0 10px rgba(53, 208, 127, 0.8);
}

.tier__shortcut {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 8px 15px 8px 9px;
  border: 1px solid rgba(0, 229, 255, 0.42);
  border-radius: var(--radius-pill);
  background: rgba(8, 26, 47, 0.62);
  color: var(--fog);
  font-size: 13.5px;
  font-weight: 600;
  text-decoration: none;
  white-space: nowrap;
  transition: background 0.18s var(--ease), border-color 0.18s var(--ease);
}
.tier__shortcut:hover {
  background: rgba(0, 229, 255, 0.14);
  border-color: var(--cyan);
}
.tier__shortcut-idx {
  padding: 2px 7px;
  border-radius: 5px;
  background: var(--cyan);
  color: #04121F;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.06em;
}

.pill-nav { flex: 1 1 auto; }
.pill-nav__list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px;
  counter-reset: nav-item;
}
.pill-nav__item { counter-increment: nav-item; }

.pill {
  position: relative;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 9px 15px;
  border: 1px solid var(--line-soft);
  border-radius: var(--radius-pill);
  color: var(--silver);
  font-size: 14.5px;
  font-weight: 500;
  text-decoration: none;
  transition: background 0.18s var(--ease), color 0.18s var(--ease), border-color 0.18s var(--ease), transform 0.18s var(--ease);
}
.pill::before {
  content: "";
  width: 4px;
  height: 4px;
  border-radius: 50%;
  background: rgba(199, 208, 217, 0.5);
  transition: background 0.18s var(--ease), width 0.18s var(--ease), height 0.18s var(--ease);
}
.pill:hover {
  background: rgba(18, 58, 102, 0.78);
  border-color: rgba(0, 229, 255, 0.5);
  color: var(--fog);
  transform: translateY(-1px);
}
.pill:hover::before { background: var(--cyan); }
.pill[aria-current="page"] {
  background: linear-gradient(120deg, var(--cyan), #56ECFF);
  border-color: rgba(0, 229, 255, 0.9);
  color: #04121F;
  font-weight: 700;
  box-shadow: 0 6px 24px -12px rgba(0, 229, 255, 0.9);
}
.pill[aria-current="page"]::before {
  width: 6px;
  height: 6px;
  background: var(--orange);
  box-shadow: 0 0 0 2px rgba(4, 18, 31, 0.32);
}

.nav-toggle {
  display: none;
  align-items: center;
  gap: 10px;
  padding: 10px 16px;
  border: 1px solid rgba(0, 229, 255, 0.45);
  border-radius: var(--radius-pill);
  background: rgba(18, 58, 102, 0.65);
  color: var(--fog);
  font-size: 14px;
  font-weight: 700;
  cursor: pointer;
}
.nav-toggle__bars {
  display: grid;
  gap: 3px;
  width: 16px;
}
.nav-toggle__bars span {
  display: block;
  height: 2px;
  border-radius: 2px;
  background: var(--cyan);
  transition: transform 0.2s var(--ease), opacity 0.2s var(--ease);
}
.site-head[data-open="true"] .nav-toggle__bars span:nth-child(1) { transform: translateY(5px) rotate(45deg); }
.site-head[data-open="true"] .nav-toggle__bars span:nth-child(2) { opacity: 0; }
.site-head[data-open="true"] .nav-toggle__bars span:nth-child(3) { transform: translateY(-5px) rotate(-45deg); }
.nav-toggle__label { letter-spacing: 0.02em; }

/* ---------- 7. Console dock ---------- */
.console-dock {
  position: fixed;
  left: clamp(10px, 2vw, 28px);
  top: 50%;
  z-index: 50;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
  width: 58px;
  padding: 14px 8px 16px;
  border: 1px solid rgba(0, 229, 255, 0.24);
  border-radius: 30px;
  background: linear-gradient(180deg, rgba(11, 15, 20, 0.92), rgba(18, 42, 64, 0.92));
  box-shadow: 0 24px 60px -34px #000, inset 0 1px 0 rgba(242, 246, 250, 0.08);
  transform: translateY(-50%);
}
.console-dock__tick {
  position: relative;
  width: 24px;
  height: 24px;
  border: 1px dashed rgba(0, 229, 255, 0.5);
  border-radius: 50%;
}
.console-dock__tick::after {
  content: "";
  position: absolute;
  inset: 7px;
  border-radius: 50%;
  background: var(--orange);
}
.console-dock__readout {
  max-height: 118px;
  overflow: hidden;
  margin: 0;
  writing-mode: vertical-rl;
  text-orientation: mixed;
  font-family: var(--font-mono);
  font-size: 10.5px;
  line-height: 1.4;
  letter-spacing: 0.16em;
  color: var(--cyan);
}
.console-dock__meter {
  display: flex;
  align-items: flex-end;
  width: 4px;
  height: 92px;
  border-radius: 2px;
  background: rgba(199, 208, 217, 0.18);
  overflow: hidden;
}
.console-dock__meter-bar {
  display: block;
  width: 100%;
  height: 0;
  border-radius: 2px;
  background: linear-gradient(180deg, var(--cyan), var(--orange));
  transition: height 0.12s linear;
}
.console-dock__btn {
  display: grid;
  place-items: center;
  gap: 1px;
  width: 40px;
  height: 40px;
  padding: 0;
  border: 1px solid rgba(199, 208, 217, 0.28);
  border-radius: 50%;
  background: rgba(8, 26, 47, 0.9);
  color: var(--fog);
  cursor: pointer;
  transition: border-color 0.18s var(--ease), background 0.18s var(--ease);
}
.console-dock__btn span:first-child {
  font-size: 13px;
  line-height: 1;
  color: var(--cyan);
}
.console-dock__btn-text {
  font-family: var(--font-mono);
  font-size: 8.5px;
  letter-spacing: 0.08em;
}
.console-dock__btn:hover {
  border-color: var(--cyan);
  background: rgba(0, 229, 255, 0.14);
}

/* ---------- 8. Footer ---------- */
.site-foot {
  position: relative;
  margin-top: clamp(48px, 8vw, 120px);
  border-top: 1px solid rgba(0, 229, 255, 0.22);
  background: linear-gradient(180deg, #0B0F14 0%, #081A2F 58%, #061523 100%);
  color: var(--silver);
  overflow: hidden;
}
.foot-band {
  height: 8px;
  background:
    repeating-linear-gradient(90deg,
      var(--cyan) 0 56px,
      transparent 56px 66px,
      var(--orange) 66px 96px,
      transparent 96px 106px);
  opacity: 0.85;
}
.foot-grid {
  display: grid;
  grid-template-columns: 1.35fr 0.8fr 0.85fr 1.25fr;
  gap: clamp(20px, 3vw, 48px);
  padding-block: clamp(34px, 5vw, 64px) clamp(22px, 3vw, 40px);
}
.foot-col { min-width: 0; }
.foot-col--brand { align-self: start; }

.brand--foot .brand__name { font-size: 20px; }
.brand--foot .brand__glyph { width: 40px; height: 40px; }

.foot-lede {
  margin-top: 18px;
  max-width: 32ch;
  font-size: 15.5px;
  line-height: 1.78;
  color: var(--silver);
}
.foot-note {
  margin-top: 14px;
  max-width: 40ch;
  font-size: 12.8px;
  line-height: 1.75;
  color: rgba(199, 208, 217, 0.72);
}
.foot-title {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 16px;
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--cyan);
}
.foot-title::before {
  content: "";
  width: 14px;
  height: 1px;
  background: var(--orange);
}
.foot-list { display: grid; gap: 10px; }
.foot-list a {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 15px;
  color: var(--silver);
  text-decoration: none;
  transition: color 0.18s var(--ease);
}
.foot-list a::before {
  content: "";
  width: 4px;
  height: 4px;
  border-radius: 50%;
  background: rgba(199, 208, 217, 0.4);
  transition: background 0.18s var(--ease);
}
.foot-list a:hover {
  color: var(--fog);
  text-decoration: underline;
  text-underline-offset: 4px;
}
.foot-list a:hover::before { background: var(--orange); }

.foot-contact { display: grid; gap: 12px; }
.foot-contact li {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px 10px;
}
.foot-label {
  min-width: 42px;
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: rgba(199, 208, 217, 0.66);
}
.foot-value {
  font-family: var(--font-mono);
  font-size: 13.5px;
  letter-spacing: 0.02em;
  color: var(--fog);
  overflow-wrap: anywhere;
}
.foot-value--text {
  font-family: var(--font-body);
  font-size: 14.5px;
}

.copy-btn {
  display: inline-flex;
  align-items: center;
  padding: 3px 10px;
  border: 1px solid rgba(0, 229, 255, 0.35);
  border-radius: var(--radius-pill);
  background: transparent;
  color: var(--cyan);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.06em;
  cursor: pointer;
  transition: background 0.18s var(--ease), border-color 0.18s var(--ease), color 0.18s var(--ease);
}
.copy-btn:hover {
  background: rgba(0, 229, 255, 0.14);
  border-color: var(--cyan);
}
.copy-btn[data-state="ok"] {
  border-color: var(--green);
  color: var(--green);
  background: rgba(53, 208, 127, 0.12);
}
.copy-btn[data-state="warn"] {
  border-color: var(--amber);
  color: var(--amber);
  background: rgba(255, 200, 87, 0.12);
}

.foot-base {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px 24px;
  width: min(calc(100% - (var(--gutter) * 2)), var(--shell));
  margin-inline: auto;
  padding-block: 18px 28px;
  border-top: 1px solid rgba(199, 208, 217, 0.14);
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.06em;
  color: rgba(199, 208, 217, 0.75);
}
.foot-base > span:last-child {
  margin-left: auto;
  color: rgba(199, 208, 217, 0.6);
}

/* ---------- 9. Responsive ---------- */
@media (max-width: 1300px) {
  .console-dock { display: none; }
}

@media (max-width: 1140px) {
  .foot-grid { grid-template-columns: 1.2fr 1fr 1fr; }
  .foot-col--brand { grid-column: 1 / -1; }
  .foot-lede { max-width: 52ch; }
}

@media (max-width: 960px) {
  .nav-toggle { display: inline-flex; }

  .pill-nav {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    z-index: 70;
    max-height: calc(100vh - 96px);
    overflow-y: auto;
    padding: 16px var(--gutter) 24px;
    border-bottom: 1px solid rgba(0, 229, 255, 0.28);
    background: linear-gradient(180deg, #0B0F14, #0A1523);
    box-shadow: 0 40px 70px -34px #000;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: opacity 0.22s var(--ease), transform 0.22s var(--ease), visibility 0.22s var(--ease);
  }
  .site-head[data-open="true"] .pill-nav {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
  }
  .pill-nav__list { display: grid; gap: 8px; }
  .pill {
    justify-content: space-between;
    padding: 14px 18px;
    border-radius: 14px;
    font-size: 16px;
    background: rgba(30, 42, 56, 0.55);
  }
  .pill::after {
    content: counter(nav-item, decimal-leading-zero);
    font-family: var(--font-mono);
    font-size: 11px;
    letter-spacing: 0.1em;
    color: rgba(199, 208, 217, 0.6);
  }
  .pill[aria-current="page"]::after { color: rgba(4, 18, 31, 0.62); }

  html[data-nav="open"] { overflow: hidden; }
}

@media (max-width: 900px) {
  .sk-grid--two,
  .sk-grid--three,
  .sk-grid--split { grid-template-columns: minmax(0, 1fr); }
}

@media (max-width: 780px) {
  body { font-size: 16px; }
  .tier__inner { flex-wrap: wrap; gap: 12px; }
  .tier__note { display: none; }
  .tier__shortcut { margin-left: auto; }
  .brand__name { font-size: 17px; }
  .brand__sub { font-size: 10px; letter-spacing: 0.13em; }
  .tier__inner--nav { padding-block: 9px; }
  .chapter-band { flex-wrap: wrap; gap: 10px 18px; }
}

@media (max-width: 680px) {
  .foot-grid { grid-template-columns: minmax(0, 1fr); gap: 28px; }
  .foot-base { font-size: 11px; gap: 8px 16px; }
  .foot-base > span:last-child { margin-left: 0; }
  .sk-btn { width: 100%; }
}

/* ---------- 10. Accessibility / motion ---------- */
@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;
    scroll-behavior: auto !important;
  }
}