/* ============================================================
   Synavoryx Whitepaper — docs UI
   ============================================================ */

@font-face {
  font-family: 'Sora';
  src: url('/assets/fonts/sora-var.woff2') format('woff2');
  font-weight: 300 800;
  font-style: normal;
  font-display: swap;
}
@font-face {
  font-family: 'Inter';
  src: url('/assets/fonts/inter-var.woff2') format('woff2');
  font-weight: 300 800;
  font-style: normal;
  font-display: swap;
}
@font-face {
  font-family: 'IBM Plex Mono';
  src: url('/assets/fonts/plex-mono-400.woff2') format('woff2');
  font-weight: 400;
  font-style: normal;
  font-display: swap;
}
@font-face {
  font-family: 'IBM Plex Mono';
  src: url('/assets/fonts/plex-mono-500.woff2') format('woff2');
  font-weight: 500;
  font-style: normal;
  font-display: swap;
}

/* Brand theme — mirrors synavoryx.com (dark navy, electric blue, cyan). */
:root {
  --bg: #05080f;
  --bg-soft: #070d1f;
  --bg-elev: #0b142b;
  --bg-hover: rgba(140, 180, 255, 0.07);
  --text: #f2f6fc;
  --text-2: #b9c6dc;
  --muted: #8fa0bc;
  --faint: #6f81a0;
  --line: rgba(199, 210, 228, 0.13);
  --line-soft: rgba(199, 210, 228, 0.08);
  --accent: #56ccf2;
  --accent-2: #3d8bfd;
  --accent-soft: rgba(61, 139, 253, 0.16);
  --active-fg: #cfe6ff;
  --link: #7cc0ff;
  --link-hover: #a7dbff;
  --code-bg: rgba(255, 255, 255, 0.055);
  --shadow: 0 24px 70px -24px rgba(0, 0, 0, 0.8);
  --pill-on-bg: rgba(255, 255, 255, 0.12);
  --pill-on-fg: #ffffff;
  --topbar-bg: rgba(5, 8, 15, 0.82);
  --input-bg: rgba(255, 255, 255, 0.03);
  --mark: rgba(86, 204, 242, 0.2);
  --glow-1: rgba(61, 139, 253, 0.16);
  --glow-2: rgba(86, 204, 242, 0.07);
  --table-head: rgba(255, 255, 255, 0.035);
  --hint-info-bg: rgba(61, 139, 253, 0.1);
  --hint-info-line: rgba(86, 204, 242, 0.22);
  --hint-info-ico: #56ccf2;
  --hint-warning-bg: rgba(214, 158, 46, 0.1);
  --hint-warning-line: rgba(214, 158, 46, 0.28);
  --hint-warning-ico: #e0a54a;
  --hint-danger-bg: rgba(197, 48, 48, 0.12);
  --hint-danger-line: rgba(245, 101, 101, 0.3);
  --hint-danger-ico: #f56565;
  --topbar-h: 64px;
  --sidebar-w: 284px;
  --toc-w: 232px;
  --font-display: 'Sora', 'Segoe UI', system-ui, sans-serif;
  --font-body: 'Inter', 'Segoe UI', system-ui, -apple-system, sans-serif;
  --font-mono: 'IBM Plex Mono', Consolas, monospace;
}

html[data-theme='light'] {
  --bg: #ffffff;
  --bg-soft: #f7f8fb;
  --bg-elev: #ffffff;
  --bg-hover: #eef1f7;
  --text: #162033;
  --text-2: #3f4b61;
  --muted: #6c7890;
  --faint: #96a1b5;
  --line: #e5e9f1;
  --line-soft: #eef1f6;
  --accent: #2f6fe4;
  --accent-2: #0e8fb8;
  --accent-soft: #eaf2ff;
  --active-fg: #1b56c4;
  --link: #2f6fe4;
  --link-hover: #1b56c4;
  --code-bg: #f4f6fa;
  --shadow: 0 12px 40px -18px rgba(18, 32, 60, 0.28);
  --pill-on-bg: #162033;
  --pill-on-fg: #ffffff;
  --topbar-bg: rgba(255, 255, 255, 0.86);
  --input-bg: #f7f8fb;
  --mark: rgba(47, 111, 228, 0.16);
  --glow-1: rgba(61, 139, 253, 0.05);
  --glow-2: rgba(86, 204, 242, 0.03);
  --table-head: #f6f8fb;
  --hint-info-bg: #eef5ff;
  --hint-info-line: #cfe2ff;
  --hint-info-ico: #2f6fe4;
  --hint-warning-bg: #fff8e8;
  --hint-warning-line: #ffe3ad;
  --hint-warning-ico: #b7791f;
  --hint-danger-bg: #fff1f1;
  --hint-danger-line: #ffd2d2;
  --hint-danger-ico: #c53030;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background:
    radial-gradient(900px 520px at 72% -8%, var(--glow-1), transparent 62%),
    radial-gradient(700px 420px at 10% 0%, var(--glow-2), transparent 65%),
    var(--bg);
  background-attachment: fixed;
  color: var(--text);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  transition: background-color 0.25s, color 0.25s;
}
img { max-width: 100%; display: block; }
a { color: var(--link); text-decoration: none; }
a:hover { color: var(--link-hover); text-decoration: underline; text-underline-offset: 3px; }
button { font: inherit; color: inherit; }
h1, h2, h3, h4 { margin: 0; font-weight: 600; color: var(--text); }
p { margin: 0; }
ul, ol { margin: 0; padding: 0; list-style: none; }
::selection { background: rgba(86, 204, 242, 0.28); }

body::after {
  content: '';
  position: fixed;
  inset: 0;
  z-index: 1;
  pointer-events: none;
  opacity: 0.025;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 200 200' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.85' numOctaves='3' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
}

* { scrollbar-width: thin; scrollbar-color: rgba(199, 210, 228, 0.24) transparent; }
::-webkit-scrollbar { width: 10px; height: 10px; }
::-webkit-scrollbar-thumb { background: rgba(199, 210, 228, 0.24); border-radius: 999px; border: 3px solid transparent; background-clip: content-box; }
::-webkit-scrollbar-track { background: transparent; }

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

.skip {
  position: fixed; top: -80px; left: 16px; z-index: 300;
  background: var(--accent); color: #fff; padding: 10px 16px; border-radius: 8px; font-size: 13px;
  transition: top 0.2s;
}
.skip:focus { top: 12px; }

.iconbtn {
  width: 36px; height: 36px; display: grid; place-items: center;
  border: 1px solid transparent; border-radius: 8px; background: transparent;
  cursor: pointer; color: var(--muted); transition: background 0.2s, color 0.2s;
}
.iconbtn:hover { background: var(--bg-hover); color: var(--text); }
.iconbtn svg { width: 18px; height: 18px; }

/* ------------------------------------------------------------- topbar */
.topbar {
  position: sticky; top: 0; z-index: 90;
  height: var(--topbar-h);
  display: flex; align-items: center; gap: 14px;
  padding: 0 20px;
  background: var(--topbar-bg);
  backdrop-filter: blur(18px) saturate(1.5);
  -webkit-backdrop-filter: blur(18px) saturate(1.5);
  border-bottom: 1px solid var(--line);
}
.topbar__menu { display: none; }
.brand { display: inline-flex; align-items: center; gap: 10px; flex: none; color: var(--text); }
.brand:hover { text-decoration: none; }
.brand__mark {
  width: 30px; height: 30px; border-radius: 9px; display: grid; place-items: center;
  background: radial-gradient(120% 120% at 20% 10%, rgba(86, 204, 242, 0.16), rgba(61, 139, 253, 0.06));
  border: 1px solid rgba(86, 204, 242, 0.22);
  box-shadow: 0 0 22px -6px rgba(61, 139, 253, 0.55);
}
.brand__mark svg { width: 23px; height: 23px; }
.brand__name {
  display: flex; flex-direction: column; line-height: 1.1;
  font-family: var(--font-display); font-size: 13px; font-weight: 600;
  letter-spacing: 0.22em; text-transform: uppercase;
}
.brand__name em {
  font-style: normal; font-family: var(--font-mono); font-size: 8.5px; font-weight: 400;
  letter-spacing: 0.18em; text-transform: uppercase; color: var(--muted); margin-top: 3px;
}

.searchbtn {
  margin-inline: auto;
  width: min(460px, 42vw);
  display: flex; align-items: center; gap: 10px;
  padding: 8px 12px;
  border: 1px solid var(--line);
  border-radius: 9px;
  background: var(--input-bg);
  color: var(--muted);
  font-size: 13px;
  cursor: pointer;
  transition: border-color 0.2s, background 0.2s;
}
.searchbtn:hover { border-color: rgba(86, 204, 242, 0.4); background: var(--bg-elev); }
.searchbtn svg { width: 16px; height: 16px; flex: none; }
.searchbtn span { flex: 1; text-align: left; }
.searchbtn kbd {
  font-family: var(--font-mono); font-size: 9.5px; letter-spacing: 0.06em;
  border: 1px solid var(--line); border-radius: 5px; padding: 2px 6px; color: var(--faint);
}

.topbar__actions { display: flex; align-items: center; gap: 8px; flex: none; }
.langswitch {
  display: inline-flex; padding: 3px; border: 1px solid var(--line); border-radius: 999px;
}
.langswitch a {
  padding: 4px 10px; border-radius: 999px;
  font-family: var(--font-mono); font-size: 10px; letter-spacing: 0.08em; color: var(--muted);
}
.langswitch a:hover { text-decoration: none; color: var(--text); }
.langswitch a.is-on { background: var(--pill-on-bg); color: var(--pill-on-fg); }

.pdfbtn {
  display: inline-flex; align-items: center; gap: 6px;
  padding: 7px 14px; border: 1px solid transparent; border-radius: 999px;
  background: linear-gradient(120deg, #4f9bff, #3d8bfd 55%, #2f6fe4);
  color: #fff;
  font-size: 12px; font-weight: 600;
  box-shadow: 0 10px 26px -12px rgba(61, 139, 253, 0.85), inset 0 1px 0 rgba(255, 255, 255, 0.22);
  transition: filter 0.2s, transform 0.2s;
}
.pdfbtn:hover { text-decoration: none; color: #fff; filter: brightness(1.08); transform: translateY(-1px); }
.pdfbtn svg { width: 15px; height: 15px; }

.theme-ico { display: none; }
html[data-theme='light'] .theme-ico--moon { display: block; }
html[data-theme='dark'] .theme-ico--sun { display: block; }

/* --------------------------------------------------------------- shell */
.shell {
  display: grid;
  grid-template-columns: var(--sidebar-w) minmax(0, 1fr) var(--toc-w);
  max-width: 1560px;
  margin: 0 auto;
  min-height: calc(100vh - var(--topbar-h));
  position: relative;
  z-index: 2;
}

/* ------------------------------------------------------------- sidebar */
.sidebar {
  position: sticky; top: var(--topbar-h);
  height: calc(100vh - var(--topbar-h));
  border-right: 1px solid var(--line);
  background: var(--bg-soft);
  overflow: hidden;
}
.sidebar__scroll {
  height: 100%; overflow-y: auto;
  padding: 26px 18px 30px;
  display: flex; flex-direction: column;
}
.sidebar__label {
  font-family: var(--font-mono); font-size: 9.5px; letter-spacing: 0.18em;
  text-transform: uppercase; color: var(--faint);
  padding: 0 10px 12px;
}
.sidenav { display: flex; flex-direction: column; gap: 2px; }
.navlink {
  display: flex; align-items: baseline; gap: 10px;
  padding: 8px 10px;
  border-radius: 7px;
  font-size: 13.5px;
  line-height: 1.45;
  color: var(--text-2);
  transition: background 0.18s, color 0.18s;
}
.navlink:hover { background: var(--bg-hover); color: var(--text); text-decoration: none; }
.navlink__n {
  font-family: var(--font-mono); font-size: 9px; color: var(--faint); width: 16px; flex: none;
}
.navlink.is-active {
  background: linear-gradient(90deg, var(--accent-soft), rgba(61, 139, 253, 0.03));
  color: var(--active-fg);
  font-weight: 600;
  box-shadow: inset 2px 0 0 var(--accent-2);
}
.navlink.is-active .navlink__n { color: var(--accent); }

.sidebar__extra { margin-top: auto; padding: 22px 10px 0; }
.sidebar__extra > a:first-child {
  display: flex; gap: 10px; align-items: flex-start;
  padding: 11px 12px; border: 1px solid var(--line); border-radius: 9px;
  background: var(--bg-elev); color: var(--text);
  transition: border-color 0.2s;
}
.sidebar__extra > a:first-child:hover { border-color: var(--accent); text-decoration: none; }
.sidebar__extra svg { width: 16px; height: 16px; color: var(--accent); margin-top: 2px; flex: none; }
.sidebar__extra span { display: flex; flex-direction: column; font-size: 12.5px; line-height: 1.4; }
.sidebar__extra em { font-style: normal; font-size: 10px; color: var(--faint); margin-top: 3px; font-family: var(--font-mono); }
.sidebar__home {
  display: inline-block; margin-top: 14px; font-family: var(--font-mono);
  font-size: 9.5px; letter-spacing: 0.14em; text-transform: uppercase; color: var(--faint);
}
.sidebar__home:hover { color: var(--accent); text-decoration: none; }

/* ---------------------------------------------------------------- main */
.main {
  min-width: 0;
  padding: 44px 56px 90px;
  max-width: calc(820px + 112px);
  width: 100%;
  justify-self: center;
}
.crumbs {
  display: flex; align-items: center; gap: 8px; flex-wrap: wrap;
  font-size: 12.5px; color: var(--muted);
  margin-bottom: 26px;
}
.crumbs a { color: var(--muted); }
.crumbs a:hover { color: var(--accent); text-decoration: none; }
.crumbs span:last-child { color: var(--text-2); }

/* --------------------------------------------------------------- prose */
.prose { font-size: 16px; line-height: 1.8; color: var(--text-2); }
.prose > *:first-child { margin-top: 0; }
.prose h1 {
  font-family: var(--font-display);
  font-size: clamp(1.9rem, 3vw, 2.5rem);
  line-height: 1.15;
  letter-spacing: -0.035em;
  color: var(--text);
  margin: 0 0 10px;
}
.prose h1 + p { font-size: 1.06rem; color: var(--text-2); }
.prose h2 {
  font-family: var(--font-display);
  font-size: 1.42rem;
  line-height: 1.3;
  letter-spacing: -0.025em;
  margin: 46px 0 14px;
  padding-top: 26px;
  border-top: 1px solid var(--line-soft);
  scroll-margin-top: calc(var(--topbar-h) + 22px);
}
.prose h3 {
  font-size: 1.08rem;
  line-height: 1.4;
  letter-spacing: -0.01em;
  margin: 30px 0 8px;
  scroll-margin-top: calc(var(--topbar-h) + 22px);
}
.prose p { margin: 14px 0; }
.prose strong { color: var(--text); font-weight: 600; }
.prose em { font-style: italic; }
.prose a { font-weight: 500; }
.prose > p > img:only-child { margin: 26px 0; }
.prose img {
  border-radius: 12px;
  border: 1px solid var(--line);
  margin: 26px 0;
  cursor: zoom-in;
  background: var(--bg-soft);
}
.prose ul, .prose ol { margin: 14px 0; padding-left: 24px; }
.prose ul { list-style: disc; }
.prose ol { list-style: decimal; }
.prose li { margin: 7px 0; padding-left: 2px; }
.prose li::marker { color: var(--faint); }
.prose blockquote {
  margin: 22px 0;
  padding: 12px 18px 12px 20px;
  border-left: 2px solid var(--accent);
  border-radius: 0 8px 8px 0;
  background: linear-gradient(90deg, rgba(86, 204, 242, 0.07), transparent 72%);
  color: var(--text);
  font-size: 1.02rem;
}
.prose blockquote p { margin: 6px 0; }
.prose hr { border: 0; height: 1px; background: var(--line); margin: 42px 0; }
.prose code {
  font-family: var(--font-mono); font-size: 0.88em;
  background: var(--code-bg); padding: 2px 6px; border-radius: 5px; color: var(--text);
  overflow-wrap: anywhere;
}
.prose pre {
  background: var(--code-bg); border: 1px solid var(--line); border-radius: 10px;
  padding: 16px; overflow-x: auto; margin: 20px 0;
}
.prose pre code { background: none; padding: 0; }

.codecopy {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  flex-wrap: wrap;
  vertical-align: middle;
}
.copybtn {
  border: 1px solid var(--line);
  background: var(--bg-soft);
  color: var(--muted);
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  padding: 3px 8px;
  border-radius: 6px;
  cursor: pointer;
  transition: border-color 0.2s, color 0.2s, background 0.2s;
}
.copybtn:hover { border-color: var(--accent); color: var(--accent); background: var(--accent-soft); }
.copybtn.is-done { border-color: #2f9e6e; color: #2f9e6e; background: transparent; }
.copybtn.is-fail { border-color: var(--hint-warning-line); color: var(--hint-warning-ico); background: transparent; }

.table-wrap {
  margin: 22px 0;
  overflow-x: auto;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--bg-elev);
}
.prose table { width: 100%; border-collapse: collapse; font-size: 14px; line-height: 1.6; }
.prose thead th {
  text-align: left; font-weight: 600; color: var(--text);
  background: var(--table-head);
  padding: 10px 14px;
  border-bottom: 1px solid var(--line);
  white-space: nowrap;
}
.prose tbody td {
  padding: 10px 14px;
  border-bottom: 1px solid var(--line-soft);
  vertical-align: top;
}
.prose tbody tr:last-child td { border-bottom: 0; }
.prose tbody tr:hover td { background: var(--bg-hover); }
.prose th[style*='right'], .prose td[style*='right'] { text-align: right; }

/* --------------------------------------------------------------- hints */
.hint {
  display: flex; gap: 12px;
  padding: 14px 16px;
  border: 1px solid;
  border-radius: 10px;
  margin: 22px 0;
  font-size: 14.5px;
  line-height: 1.68;
}
.hint__ico { flex: none; margin-top: 2px; }
.hint__ico svg { width: 17px; height: 17px; }
.hint__body { min-width: 0; }
.hint__body p { margin: 0; }
.hint__body p + p { margin-top: 8px; }
.hint--info { background: var(--hint-info-bg); border-color: var(--hint-info-line); color: var(--text-2); }
.hint--info .hint__ico { color: var(--hint-info-ico); }
.hint--warning { background: var(--hint-warning-bg); border-color: var(--hint-warning-line); color: var(--text-2); }
.hint--warning .hint__ico { color: var(--hint-warning-ico); }
.hint--danger { background: var(--hint-danger-bg); border-color: var(--hint-danger-line); color: var(--text-2); }
.hint--danger .hint__ico { color: var(--hint-danger-ico); }

/* ---------------------------------------------------------------- toc */
.toc {
  position: sticky; top: var(--topbar-h);
  align-self: start;
  height: calc(100vh - var(--topbar-h));
  overflow-y: auto;
  padding: 46px 26px 40px 8px;
  font-size: 12.5px;
}
.toc__label {
  font-family: var(--font-mono); font-size: 9.5px; letter-spacing: 0.16em;
  text-transform: uppercase; color: var(--faint); margin-bottom: 14px;
}
.toc nav { display: flex; flex-direction: column; border-left: 1px solid var(--line); }
.toclink {
  display: block; padding: 5px 0 5px 13px; margin-left: -1px;
  border-left: 2px solid transparent;
  color: var(--muted); line-height: 1.45;
  transition: color 0.18s, border-color 0.18s;
}
.toclink:hover { color: var(--text); text-decoration: none; }
.toclink.toc-3 { padding-left: 26px; font-size: 12px; }
.toclink.is-active { color: var(--accent); border-left-color: var(--accent); }

/* -------------------------------------------------------------- pager */
.pager {
  display: grid; grid-template-columns: 1fr 1fr; gap: 12px;
  margin-top: 64px;
}
.pager__item {
  display: flex; flex-direction: column; gap: 8px;
  padding: 14px 16px;
  border: 1px solid var(--line); border-radius: 10px;
  background: var(--bg-elev);
  color: var(--text);
  transition: border-color 0.2s, transform 0.25s ease;
}
.pager__item:hover { text-decoration: none; border-color: var(--accent); transform: translateY(-1px); }
.pager__item > span {
  font-family: var(--font-mono); font-size: 9.5px; letter-spacing: 0.14em;
  text-transform: uppercase; color: var(--faint);
}
.pager__item strong {
  display: flex; align-items: center; gap: 8px;
  font-size: 13.5px; font-weight: 500; line-height: 1.4;
}
.pager__item svg { width: 15px; height: 15px; flex: none; color: var(--accent); }
.pager__item--next { text-align: right; }
.pager__item--next strong { justify-content: flex-end; }

.pagefoot {
  margin-top: 48px; padding-top: 22px;
  border-top: 1px solid var(--line-soft);
  display: flex; justify-content: space-between; gap: 24px;
  font-size: 11.5px; color: var(--faint);
}
.pagefoot p { max-width: 560px; }

/* -------------------------------------------------------------- search */
.search {
  border: 0; padding: 0; background: transparent;
  width: min(640px, 94vw);
  margin: 12vh auto 0;
  color: var(--text);
}
.search::backdrop {
  background: rgba(10, 16, 30, 0.45);
  backdrop-filter: blur(6px);
  -webkit-backdrop-filter: blur(6px);
}
.search__panel {
  background: var(--bg-elev);
  border: 1px solid var(--line);
  border-radius: 14px;
  box-shadow: var(--shadow);
  overflow: hidden;
}
.search__field {
  display: flex; align-items: center; gap: 12px;
  padding: 14px 16px;
  border-bottom: 1px solid var(--line);
}
.search__field > svg { width: 18px; height: 18px; color: var(--muted); flex: none; }
.search__field input {
  flex: 1; min-width: 0;
  border: 0; outline: 0; background: transparent;
  font: inherit; font-size: 16px; color: var(--text);
}
.search__field input::placeholder { color: var(--faint); }
.search__results { max-height: min(58vh, 520px); overflow-y: auto; padding: 8px; }
.search__hint { padding: 26px 16px; text-align: center; color: var(--faint); font-size: 13px; }
.result {
  display: block; padding: 11px 12px; border-radius: 8px; color: var(--text);
}
.result:hover, .result.is-active { background: var(--bg-hover); text-decoration: none; }
.result__top {
  display: flex; align-items: baseline; gap: 8px; flex-wrap: wrap;
  font-size: 10px; font-family: var(--font-mono); letter-spacing: 0.08em; text-transform: uppercase;
  color: var(--faint); margin-bottom: 3px;
}
.result__top b { color: var(--accent); font-weight: 500; }
.result__title { font-size: 14px; font-weight: 600; margin-bottom: 2px; }
.result__snippet {
  font-size: 12.5px; color: var(--muted); line-height: 1.5;
  display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; overflow: hidden;
}
.result__snippet mark, .result__title mark { background: var(--mark); color: var(--text); border-radius: 3px; padding: 0 2px; }
.search__foot {
  border-top: 1px solid var(--line);
  padding: 9px 16px;
  font-size: 10.5px; color: var(--faint); text-align: right;
  font-family: var(--font-mono); letter-spacing: 0.03em;
}

/* ------------------------------------------------------------ lightbox */
.lightbox {
  border: 0; padding: 0; background: transparent;
  max-width: 96vw; max-height: 94vh;
}
.lightbox::backdrop { background: rgba(5, 9, 18, 0.9); }
.lightbox img { max-width: 94vw; max-height: 88vh; border-radius: 10px; box-shadow: 0 30px 80px -20px rgba(0, 0, 0, 0.8); }
.lightbox__close {
  position: fixed; top: 18px; right: 18px;
  background: rgba(255, 255, 255, 0.1); color: #fff; border-radius: 10px;
  width: 42px; height: 42px;
}
.lightbox__close:hover { background: rgba(255, 255, 255, 0.2); color: #fff; }

/* ------------------------------------------------------------ backdrop */
.backdrop {
  position: fixed; inset: 0; z-index: 70;
  background: rgba(8, 13, 25, 0.45);
  backdrop-filter: blur(3px);
}

/* ------------------------------------------------------------- notfound */
.notfound {
  min-height: 100vh; display: grid; place-items: center; text-align: center; padding: 40px 24px;
  position: relative; z-index: 2;
}
.notfound__code {
  font-family: var(--font-display); font-size: clamp(5rem, 16vw, 10rem); line-height: 0.9;
  letter-spacing: -0.06em; color: transparent;
  -webkit-text-stroke: 1px var(--faint); margin: 0 0 10px;
}
.notfound h1 { font-size: clamp(1.4rem, 3vw, 2rem); margin-bottom: 10px; }
.notfound p { color: var(--muted); margin-bottom: 24px; }
.btn {
  display: inline-flex; align-items: center; gap: 8px; padding: 10px 18px; margin: 0 4px;
  border-radius: 9px; color: #fff; font-size: 13.5px; font-weight: 600;
  background: linear-gradient(120deg, #4f9bff, #3d8bfd 55%, #2f6fe4);
  box-shadow: 0 10px 26px -12px rgba(61, 139, 253, 0.85), inset 0 1px 0 rgba(255, 255, 255, 0.22);
}
.btn:hover { text-decoration: none; filter: brightness(1.06); }
.btn--ghost { background: transparent; border: 1px solid var(--line); color: var(--text); }

/* ----------------------------------------------------------- responsive */
@media (max-width: 1280px) {
  .shell { grid-template-columns: var(--sidebar-w) minmax(0, 1fr); }
  .toc { display: none; }
  .main { max-width: 860px; padding-inline: 48px; }
}

@media (max-width: 1024px) {
  .topbar__menu { display: grid; }
  .shell { grid-template-columns: minmax(0, 1fr); }
  .sidebar {
    position: fixed; top: var(--topbar-h); left: 0; bottom: 0;
    width: min(320px, 86vw);
    height: auto;
    z-index: 80;
    transform: translateX(-102%);
    transition: transform 0.32s cubic-bezier(0.22, 1, 0.36, 1);
    box-shadow: 20px 0 50px -30px rgba(0, 0, 0, 0.4);
  }
  .sidebar.is-open { transform: translateX(0); }
  .main { padding: 32px 28px 80px; }
  .searchbtn { width: auto; margin-left: auto; padding: 8px 10px; }
  .searchbtn span, .searchbtn kbd { display: none; }
  .brand__name em { display: none; }
}

@media (max-width: 720px) {
  .topbar { padding: 0 12px; gap: 8px; }
  .brand__name { display: none; }
  .pdfbtn span { display: none; }
  .pdfbtn { padding: 7px 9px; }
  .main { padding: 26px 18px 70px; }
  .prose { font-size: 15.5px; }
  .prose h2 { font-size: 1.28rem; }
  .pager { grid-template-columns: 1fr; }
  .pager__item--next { text-align: left; }
  .pager__item--next strong { justify-content: flex-start; }
  .pagefoot { flex-direction: column; gap: 8px; }
  .search { margin-top: 8vh; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition-duration: 0.001ms !important; animation-duration: 0.001ms !important; }
}

@media print {
  .topbar, .sidebar, .toc, .pager, .pagefoot, .search, .lightbox { display: none !important; }
  .main { max-width: none; padding: 0; }
  body { color: #000; background: #fff; }
  .prose a { color: #000; text-decoration: underline; }
  .prose img { border: 0; }
}