/* ==========================================================================
   哈狗游戏CN — 共享外壳样式 /assets/site.css
   ========================================================================== */

*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

:root {
  --ink-950: #07040e;
  --ink-900: #100a1c;
  --ink-800: #1a1230;
  --violet-500: #7b2bff;
  --violet-300: #b18cff;
  --cyan-400: #22e6ff;
  --orange-500: #ff7a1a;
  --paper-100: #f4efe6;
  --paper-400: #c9c0ae;
  --magenta-500: #ff2ea6;
  --text-hi: #f3f0ff;
  --text-mid: #b6aecb;

  --font-display: "Noto Sans SC", "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
  --font-body: "Noto Sans SC", "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
  --font-mono: ui-monospace, "JetBrains Mono", "SFMono-Regular", Menlo, Consolas, monospace;

  --wrap: 1240px;
  --gutter: clamp(16px, 4vw, 48px);
  --header-h: 76px;
  --header-h-sm: 62px;
  --radius-lg: 28px;
  --radius-md: 18px;
  --radius-sm: 10px;
  --ease: cubic-bezier(0.22, 0.61, 0.36, 1);
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-h) + 16px);
  -webkit-text-size-adjust: 100%;
}

body {
  min-height: 100vh;
  background-color: var(--ink-950);
  color: var(--text-hi);
  font-family: var(--font-body);
  font-size: 16px;
  font-weight: 400;
  line-height: 1.85;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

/* 全站颗粒噪点覆盖层 */
body::after {
  content: "";
  position: fixed;
  inset: -20%;
  z-index: 900;
  pointer-events: none;
  opacity: 0.055;
  background-image:
    repeating-linear-gradient(0deg, rgba(255, 255, 255, 0.9) 0 1px, transparent 1px 3px),
    repeating-linear-gradient(90deg, rgba(255, 255, 255, 0.5) 0 1px, transparent 1px 4px);
  background-size: 3px 3px, 5px 5px;
  animation: grain-drift 24s linear infinite;
  will-change: transform;
}

@keyframes grain-drift {
  0% { transform: translate3d(0, 0, 0); }
  100% { transform: translate3d(-3%, 2%, 0); }
}

h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: 900;
  letter-spacing: -0.02em;
  line-height: 1.15;
  color: var(--text-hi);
}

p { text-wrap: pretty; }

ul, ol { list-style: none; }

a {
  color: var(--cyan-400);
  text-decoration: none;
  transition: color 0.12s ease;
}

a:hover { color: var(--orange-500); }

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

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

:focus-visible {
  outline: 2px solid var(--cyan-400);
  outline-offset: 3px;
  border-radius: 4px;
}

::selection {
  background: var(--violet-500);
  color: var(--paper-100);
}

/* ---------- 布局与工具 ---------- */

.wrap {
  position: relative;
  z-index: 1;
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.mono {
  font-family: var(--font-mono);
  letter-spacing: 0.06em;
  font-variant-numeric: tabular-nums;
}

.grid {
  display: grid;
  gap: clamp(20px, 3vw, 40px);
}

.grid--3-9 { grid-template-columns: 3fr 9fr; }
.grid--4-8 { grid-template-columns: 4fr 8fr; }
.grid--5-7 { grid-template-columns: 5fr 7fr; }

.rule {
  height: 1px;
  border: 0;
  background: linear-gradient(90deg, rgba(34, 230, 255, 0.5), rgba(123, 43, 255, 0.28), transparent);
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 0.6em;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.16em;
  color: var(--cyan-400);
}

.eyebrow::before {
  content: "";
  width: 22px;
  height: 2px;
  background: var(--violet-500);
  transform: skewX(-24deg);
}

.section-title {
  font-size: clamp(1.4rem, 2.4vw, 2.1rem);
  line-height: 1.25;
}

.lede {
  max-width: 56ch;
  font-size: clamp(1rem, 1.3vw, 1.15rem);
  line-height: 1.8;
  color: var(--text-mid);
}

.chapter {
  position: relative;
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 0.4em 1em;
}

.chapter-num {
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: clamp(2rem, 5vw, 4.5rem);
  line-height: 1;
  letter-spacing: 0.04em;
  color: var(--violet-500);
  text-shadow: 0 0 24px rgba(123, 43, 255, 0.55);
  transform: translateY(8px);
}

/* ---------- 按钮 ---------- */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5em;
  padding: 0.85em 1.5em;
  border: 1px solid transparent;
  border-radius: 999px;
  font-family: var(--font-body);
  font-size: 0.95rem;
  font-weight: 700;
  line-height: 1;
  white-space: nowrap;
  cursor: pointer;
  transition:
    background-color 0.12s ease,
    color 0.12s ease,
    border-color 0.12s ease,
    box-shadow 0.16s ease,
    transform 0.12s var(--ease);
}

.btn--cta {
  background: var(--orange-500);
  color: var(--ink-950);
}

.btn--cta:hover {
  background: #ff9140;
  color: var(--ink-950);
  box-shadow: 0 0 22px -4px rgba(255, 122, 26, 0.75);
  transform: translateY(-1px);
}

.btn--ghost {
  background: transparent;
  border-color: rgba(34, 230, 255, 0.5);
  color: var(--cyan-400);
}

.btn--ghost:hover {
  border-color: var(--orange-500);
  color: var(--orange-500);
  transform: translateY(-1px);
}

.btn--quiet {
  background: var(--ink-800);
  color: var(--text-hi);
}

.btn--quiet:hover {
  background: var(--violet-500);
  color: var(--paper-100);
}

.btn--sm {
  padding: 0.55em 1.05em;
  font-size: 0.82rem;
}

/* ---------- 卡片 / 徽章 / 媒体 ---------- */

.card {
  position: relative;
  padding: clamp(18px, 2.4vw, 28px);
  background: var(--ink-800);
  border: 1px solid rgba(34, 230, 255, 0.35);
  border-radius: var(--radius-md);
  box-shadow: 0 18px 40px -32px rgba(0, 0, 0, 0.9);
  transition:
    border-color 0.16s ease,
    box-shadow 0.16s ease,
    transform 0.16s var(--ease);
}

.card:hover,
.card:focus-within {
  border-color: var(--orange-500);
  box-shadow: 0 0 12px rgba(255, 122, 26, 0.28), 0 22px 44px -32px rgba(0, 0, 0, 0.9);
  transform: translateY(-2px);
}

.badge {
  display: inline-flex;
  align-items: center;
  gap: 0.45em;
  padding: 0.28em 0.7em;
  border: 1px solid rgba(34, 230, 255, 0.4);
  border-radius: 999px;
  background: rgba(26, 18, 48, 0.7);
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.06em;
  color: var(--text-mid);
  white-space: nowrap;
}

.badge::before {
  content: "";
  flex: none;
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: currentColor;
  box-shadow: 0 0 8px currentColor;
}

.badge--new { color: var(--cyan-400); border-color: rgba(34, 230, 255, 0.55); }
.badge--update { color: var(--violet-300); border-color: rgba(177, 140, 255, 0.55); }
.badge--season { color: var(--magenta-500); border-color: rgba(255, 46, 166, 0.5); }
.badge--open { color: var(--orange-500); border-color: rgba(255, 122, 26, 0.55); }
.badge--event { color: var(--paper-100); border-color: rgba(244, 239, 230, 0.45); }
.badge--fix { color: var(--paper-400); border-color: rgba(201, 192, 174, 0.45); }

.media-frame {
  position: relative;
  display: block;
  overflow: hidden;
  aspect-ratio: 16 / 9;
  border: 1px solid rgba(34, 230, 255, 0.55);
  border-radius: var(--radius-md);
  background: linear-gradient(160deg, var(--ink-800), var(--ink-950));
  box-shadow: 0 0 12px rgba(34, 230, 255, 0.22);
}

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

.media-frame::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  opacity: 0.5;
  background: repeating-linear-gradient(0deg, rgba(7, 4, 14, 0.32) 0 1px, transparent 1px 3px);
}

.media-frame--wide { aspect-ratio: 21 / 9; }
.media-frame--tall { aspect-ratio: 3 / 4; }
.media-frame--square { aspect-ratio: 1 / 1; }

.paper-insert {
  padding: clamp(24px, 4vw, 56px);
  background: var(--paper-100);
  color: var(--ink-900);
  border-radius: var(--radius-lg);
}

.paper-insert h2,
.paper-insert h3,
.paper-insert h4 { color: var(--ink-900); }

.paper-insert .mono,
.paper-insert .lede { color: var(--ink-900); }

.paper-insert a { color: var(--violet-500); }
.paper-insert a:hover { color: var(--orange-500); }

.marginalia {
  padding-left: 0.9em;
  border-left: 2px solid var(--violet-500);
  font-family: var(--font-mono);
  font-size: 0.72rem;
  line-height: 1.7;
  letter-spacing: 0.06em;
  color: var(--text-mid);
}

.breadcrumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.5em;
  padding-top: clamp(20px, 3vw, 36px);
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.08em;
  color: var(--text-mid);
}

.breadcrumbs li {
  display: flex;
  align-items: center;
  gap: 0.5em;
}

.breadcrumbs li + li::before {
  content: "/";
  color: rgba(34, 230, 255, 0.6);
}

.breadcrumbs a { color: var(--text-mid); }
.breadcrumbs a:hover { color: var(--orange-500); }
.breadcrumbs [aria-current="page"] { color: var(--cyan-400); }

/* ---------- 头部 ---------- */

.skip-link {
  position: fixed;
  top: 10px;
  left: 10px;
  z-index: 1000;
  padding: 0.6em 1.1em;
  border-radius: 999px;
  background: var(--orange-500);
  color: var(--ink-950);
  font-weight: 700;
  font-size: 0.9rem;
  transform: translateY(-180%);
  transition: transform 0.18s var(--ease);
}

.skip-link:focus-visible {
  transform: translateY(0);
  outline-color: var(--paper-100);
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 200;
  background: linear-gradient(
    180deg,
    rgba(7, 4, 14, 0.94) 0%,
    rgba(7, 4, 14, 0.58) 62%,
    rgba(7, 4, 14, 0) 100%
  );
  border-bottom: 1px solid rgba(34, 230, 255, 0.14);
  backdrop-filter: blur(10px) saturate(1.15);
  -webkit-backdrop-filter: blur(10px) saturate(1.15);
  transition:
    background-color 0.26s var(--ease),
    border-color 0.26s var(--ease),
    box-shadow 0.26s var(--ease);
}

.site-header.is-scrolled {
  background: var(--ink-900);
  border-bottom-color: rgba(255, 122, 26, 0.34);
  box-shadow: 0 18px 40px -30px rgba(0, 0, 0, 0.95);
}

.header-inner {
  display: flex;
  align-items: center;
  gap: clamp(12px, 2vw, 32px);
  width: 100%;
  max-width: var(--wrap);
  min-height: var(--header-h);
  margin-inline: auto;
  padding-inline: var(--gutter);
  transition: min-height 0.26s var(--ease);
}

.site-header.is-scrolled .header-inner {
  min-height: var(--header-h-sm);
}

.brand {
  display: inline-flex;
  align-items: baseline;
  gap: 0.4em;
  flex: none;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(1.05rem, 1.6vw, 1.35rem);
  line-height: 1;
  letter-spacing: -0.03em;
  color: var(--text-hi);
}

.brand:hover { color: var(--text-hi); }

.brand-mark {
  position: relative;
  padding-bottom: 3px;
}

.brand-mark::after {
  content: "";
  position: absolute;
  left: 0;
  right: -6%;
  bottom: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--violet-500), var(--cyan-400));
  transform: skewX(-9deg);
}

.brand-tag {
  padding: 0.16em 0.4em;
  border: 1px solid rgba(34, 230, 255, 0.45);
  border-radius: 4px;
  font-family: var(--font-mono);
  font-size: 0.6em;
  font-weight: 500;
  letter-spacing: 0.14em;
  color: var(--cyan-400);
  transform: translateY(-0.16em);
}

.site-nav { margin-left: auto; }

.nav-list {
  display: flex;
  align-items: center;
  gap: clamp(10px, 1.5vw, 26px);
}

.nav-item { flex: none; }

.nav-link {
  position: relative;
  display: inline-flex;
  align-items: baseline;
  gap: 0.35em;
  padding: 0.4em 0;
  font-size: 0.95rem;
  font-weight: 500;
  letter-spacing: 0.01em;
  color: var(--text-mid);
  transition: color 0.12s ease;
}

.nav-link::before {
  content: "";
  position: absolute;
  left: -3px;
  top: 50%;
  width: 2px;
  height: 0;
  background: var(--cyan-400);
  transform: translateY(-50%) skewY(-9deg);
  transition: height 0.16s var(--ease), background-color 0.16s ease;
}

.nav-link::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: 0;
  height: 2px;
  background: var(--cyan-400);
  transition: width 0.14s var(--ease), background-color 0.14s ease;
}

.nav-link:hover,
.nav-link[aria-current="page"] { color: var(--text-hi); }

.nav-link:hover::before,
.nav-link[aria-current="page"]::before { height: 15px; }

.nav-link:hover::after,
.nav-link[aria-current="page"]::after { width: 100%; }

.nav-link:hover::after { background: var(--orange-500); }

.nav-link:hover::before { background: var(--orange-500); }

.nav-idx {
  font-family: var(--font-mono);
  font-size: 0.66em;
  letter-spacing: 0.08em;
  color: rgba(34, 230, 255, 0.55);
  transition: color 0.12s ease;
}

.nav-link:hover .nav-idx,
.nav-link[aria-current="page"] .nav-idx { color: var(--orange-500); }

.header-actions {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  flex: none;
}

.version-chip {
  padding: 0.28em 0.75em;
  border: 1px solid rgba(177, 140, 255, 0.4);
  border-radius: 999px;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.1em;
  color: var(--violet-300);
  white-space: nowrap;
  opacity: 0;
  transform: translateX(6px);
  transition: opacity 0.24s ease, transform 0.24s var(--ease);
}

.site-header.is-scrolled .version-chip {
  opacity: 1;
  transform: none;
}

.header-cta { letter-spacing: 0.02em; }

.nav-toggle {
  display: none;
  align-items: center;
  gap: 0.5em;
  padding: 0.45em 0.9em;
  border: 1px solid rgba(34, 230, 255, 0.45);
  border-radius: 999px;
  color: var(--cyan-400);
  cursor: pointer;
  transition: color 0.12s ease, border-color 0.12s ease;
}

.nav-toggle:hover {
  color: var(--orange-500);
  border-color: var(--orange-500);
}

.nav-toggle-bars {
  position: relative;
  display: block;
  width: 16px;
  height: 2px;
  background: currentColor;
}

.nav-toggle-bars::before,
.nav-toggle-bars::after {
  content: "";
  position: absolute;
  left: 0;
  width: 16px;
  height: 2px;
  background: currentColor;
  transition: transform 0.2s var(--ease), opacity 0.2s 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-label {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.14em;
}

.scroll-progress {
  position: absolute;
  left: 0;
  right: 0;
  bottom: -1px;
  height: 2px;
  overflow: hidden;
  pointer-events: none;
}

.scroll-progress__bar {
  display: block;
  width: 100%;
  height: 100%;
  transform: scaleX(0);
  transform-origin: 0 50%;
  background: linear-gradient(90deg, var(--violet-500), var(--cyan-400) 55%, var(--orange-500));
  box-shadow: 0 0 10px rgba(34, 230, 255, 0.6);
}

/* ---------- 页脚 ---------- */

.site-footer {
  position: relative;
  margin-top: clamp(64px, 10vw, 140px);
  background: var(--ink-900);
  color: var(--text-mid);
  border-top: 1px solid rgba(34, 230, 255, 0.18);
  isolation: isolate;
}

.site-footer::before {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  top: -1px;
  height: 6px;
  background: linear-gradient(
    90deg,
    var(--violet-500),
    var(--cyan-400) 45%,
    var(--orange-500) 78%,
    var(--magenta-500)
  );
  clip-path: polygon(0 0, 100% 0, 100% 38%, 0 100%);
}

.site-footer::after {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  background:
    radial-gradient(80% 60% at 8% 0%, rgba(123, 43, 255, 0.22), transparent 65%),
    radial-gradient(60% 50% at 100% 100%, rgba(34, 230, 255, 0.12), transparent 70%);
}

.brand--footer {
  font-size: clamp(1.15rem, 1.8vw, 1.4rem);
}

.footer-brand {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 14px 28px;
  padding: clamp(28px, 4vw, 44px) 0 clamp(20px, 3vw, 28px);
  border-bottom: 1px solid rgba(201, 192, 174, 0.16);
}

.footer-line {
  font-family: var(--font-mono);
  font-size: 0.74rem;
  letter-spacing: 0.12em;
  color: var(--paper-400);
}

.footer-top-link {
  display: inline-flex;
  align-items: center;
  gap: 0.4em;
  margin-left: auto;
  padding: 0.35em 0.95em;
  border: 1px solid rgba(34, 230, 255, 0.4);
  border-radius: 999px;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  color: var(--cyan-400);
  transition: color 0.12s ease, border-color 0.12s ease, background-color 0.12s ease;
}

.footer-top-link:hover {
  background: var(--orange-500);
  border-color: var(--orange-500);
  color: var(--ink-950);
}

.footer-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: clamp(24px, 3vw, 48px);
  padding: clamp(32px, 4vw, 56px) 0;
}

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

.footer-title {
  display: flex;
  align-items: center;
  gap: 0.6em;
  margin-bottom: 1em;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  font-weight: 400;
  letter-spacing: 0.16em;
  color: var(--cyan-400);
}

.footer-title::before {
  content: "";
  flex: none;
  width: 14px;
  height: 2px;
  background: var(--violet-500);
  transform: skewX(-24deg);
}

.footer-list {
  display: grid;
  gap: 0.55em;
}

.footer-list--2 {
  grid-template-columns: repeat(2, minmax(0, 1fr));
  column-gap: 1.2em;
}

.footer-link {
  position: relative;
  display: inline-block;
  padding-right: 0.2em;
  font-size: 0.94rem;
  color: var(--text-mid);
}

.footer-link::after {
  content: "";
  position: absolute;
  left: 0;
  right: 100%;
  bottom: 1px;
  height: 1px;
  background: var(--orange-500);
  transition: right 0.16s var(--ease);
}

.footer-link:hover { color: var(--text-hi); }
.footer-link:hover::after { right: 0; }

.legend {
  display: grid;
  gap: 0.5em;
}

.legend li {
  display: flex;
  align-items: center;
  gap: 0.55em;
  font-size: 0.9rem;
  color: var(--text-mid);
}

.dot {
  flex: none;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  box-shadow: 0 0 8px currentColor;
}

.dot--new { background: var(--cyan-400); color: var(--cyan-400); }
.dot--update { background: var(--violet-300); color: var(--violet-300); }
.dot--season { background: var(--magenta-500); color: var(--magenta-500); }
.dot--open { background: var(--orange-500); color: var(--orange-500); }
.dot--event { background: var(--paper-100); color: var(--paper-100); }
.dot--fix { background: var(--paper-400); color: var(--paper-400); }

.footer-note {
  margin-top: 1.1em;
  font-size: 0.8rem;
  line-height: 1.7;
  color: rgba(182, 174, 203, 0.85);
}

.footer-contact {
  display: grid;
  gap: 0.55em;
  margin-top: 1.1em;
  font-size: 0.82rem;
  line-height: 1.7;
  color: var(--text-mid);
}

.footer-contact p {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.5em;
}

.footer-contact .mono {
  font-size: 0.78rem;
  color: var(--paper-100);
}

.copy-btn {
  padding: 0.2em 0.65em;
  border: 1px solid rgba(34, 230, 255, 0.35);
  border-radius: 999px;
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.08em;
  color: var(--cyan-400);
  cursor: pointer;
  transition: color 0.12s ease, border-color 0.12s ease, background-color 0.12s ease;
}

.copy-btn:hover {
  border-color: var(--orange-500);
  color: var(--orange-500);
}

.copy-btn[data-copied="true"] {
  background: var(--orange-500);
  border-color: var(--orange-500);
  color: var(--ink-950);
}

.footer-bottom {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 10px 28px;
  padding: clamp(20px, 3vw, 32px) 0;
  border-top: 1px solid rgba(201, 192, 174, 0.16);
}

.footer-mono {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  line-height: 1.7;
  letter-spacing: 0.06em;
  color: var(--paper-400);
}

/* ---------- 响应式 ---------- */

@media (max-width: 1120px) {
  .nav-list { gap: 0.7rem; }
  .nav-link { font-size: 0.88rem; }
  .nav-idx { display: none; }
}

@media (max-width: 1080px) {
  .footer-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (max-width: 920px) {
  :root {
    --header-h: 64px;
    --header-h-sm: 58px;
  }

  .site-header {
    backdrop-filter: none;
    -webkit-backdrop-filter: none;
    background: rgba(10, 6, 20, 0.9);
  }

  .site-header.is-scrolled {
    background: var(--ink-900);
  }

  .version-chip { display: none; }

  .nav-toggle { display: inline-flex; }

  .site-nav {
    position: fixed;
    inset: 0;
    z-index: 150;
    display: flex;
    flex-direction: column;
    justify-content: flex-start;
    padding: calc(var(--header-h) + 36px) var(--gutter) 48px;
    overflow-y: auto;
    overscroll-behavior: contain;
    background:
      radial-gradient(90% 60% at 100% 0%, rgba(123, 43, 255, 0.38), transparent 62%),
      radial-gradient(70% 50% at 0% 100%, rgba(34, 230, 255, 0.16), transparent 70%),
      var(--ink-950);
    transform: translateX(102%);
    visibility: hidden;
    opacity: 0;
    transition:
      transform 0.32s var(--ease),
      opacity 0.24s var(--ease),
      visibility 0.32s linear;
  }

  .site-nav[data-open="true"] {
    transform: translateX(0);
    visibility: visible;
    opacity: 1;
  }

  .nav-list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    width: 100%;
    max-width: 520px;
    margin-inline: auto;
  }

  .nav-item { border-bottom: 1px solid rgba(34, 230, 255, 0.16); }
  .nav-item:first-child { border-top: 1px solid rgba(34, 230, 255, 0.16); }

  .nav-link {
    display: flex;
    align-items: baseline;
    gap: 0.9em;
    padding: 1em 0.2em;
    font-size: 1.18rem;
    font-weight: 700;
    color: var(--text-hi);
  }

  .nav-link::before { display: none; }

  .nav-link::after {
    left: 0.2em;
    bottom: 0.72em;
    width: 0;
  }

  .nav-link:hover::after,
  .nav-link[aria-current="page"]::after { width: calc(100% - 0.4em); }

  .nav-idx {
    display: inline;
    font-size: 0.78em;
    color: var(--violet-300);
  }

  .header-actions { gap: 0.5rem; }

  .grid--3-9,
  .grid--4-8,
  .grid--5-7 {
    grid-template-columns: minmax(0, 1fr);
  }

  .chapter-num { transform: none; }
}

@media (max-width: 640px) {
  body { font-size: 15.5px; }

  .footer-brand {
    align-items: flex-start;
    flex-direction: column;
    gap: 12px;
  }

  .footer-top-link {
    margin-left: 0;
  }

  .footer-grid {
    grid-template-columns: minmax(0, 1fr);
    gap: 32px;
  }

  .footer-bottom {
    flex-direction: column;
    align-items: flex-start;
  }

  .header-cta {
    padding: 0.5em 0.85em;
    font-size: 0.76rem;
  }
}

@media (max-width: 400px) {
  .nav-toggle-label { display: none; }
  .nav-toggle { padding: 0.5em 0.6em; }
}

@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;
  }

  body::after { animation: none; }

  .card:hover,
  .card:focus-within,
  .btn--cta:hover,
  .btn--ghost:hover {
    transform: none;
  }

  .scroll-progress__bar {
    transform: scaleX(0);
  }
}