/* ==============================================================
   DARK project page: article layout (v2)
   Research-article structure (centred reading column, numbered figures,
   margin table of contents) with numansaeed.com branding: ink + cobalt blue,
   Source Serif 4 display and prose, Inter interface text, JetBrains Mono labels.
   Fonts are self-hosted by the main site.
   ============================================================== */

@font-face { font-family: 'Inter'; font-style: normal; font-weight: 400; font-display: swap; src: url('/fonts/site/inter-latin-400-normal.woff2') format('woff2'); }
@font-face { font-family: 'Inter'; font-style: normal; font-weight: 500; font-display: swap; src: url('/fonts/site/inter-latin-500-normal.woff2') format('woff2'); }
@font-face { font-family: 'Inter'; font-style: normal; font-weight: 600; font-display: swap; src: url('/fonts/site/inter-latin-600-normal.woff2') format('woff2'); }
@font-face { font-family: 'Inter'; font-style: normal; font-weight: 700; font-display: swap; src: url('/fonts/site/inter-latin-700-normal.woff2') format('woff2'); }
@font-face { font-family: 'Source Serif 4'; font-style: normal; font-weight: 400; font-display: swap; src: url('/fonts/site/source-serif-4-latin-400-normal.woff2') format('woff2'); }
@font-face { font-family: 'Source Serif 4'; font-style: italic; font-weight: 400; font-display: swap; src: url('/fonts/site/source-serif-4-latin-400-italic.woff2') format('woff2'); }
@font-face { font-family: 'Source Serif 4'; font-style: normal; font-weight: 500; font-display: swap; src: url('/fonts/site/source-serif-4-latin-500-normal.woff2') format('woff2'); }
@font-face { font-family: 'Source Serif 4'; font-style: normal; font-weight: 600; font-display: swap; src: url('/fonts/site/source-serif-4-latin-600-normal.woff2') format('woff2'); }
@font-face { font-family: 'JetBrains Mono'; font-style: normal; font-weight: 400; font-display: swap; src: url('/fonts/course/jetbrains-mono-latin-400-normal.woff2') format('woff2'); }
@font-face { font-family: 'JetBrains Mono'; font-style: normal; font-weight: 500; font-display: swap; src: url('/fonts/course/jetbrains-mono-latin-500-normal.woff2') format('woff2'); }

:root {
    --ink: #131a2a;
    --text: #2b3244;
    --muted: #5b6475;
    --faint: #8a93a5;
    --blue: #1d4ed8;
    --blue-wash: #eef3ff;
    --line: #e2e6ee;
    --wash: #f6f8fb;
    --serif: 'Source Serif 4', Georgia, 'Times New Roman', serif;
    --sans: 'Inter', system-ui, -apple-system, sans-serif;
    --mono: 'JetBrains Mono', ui-monospace, SFMono-Regular, Menlo, monospace;
    --measure: 42rem;   /* reading column, ~680px */
    --wide: 60rem;      /* figures and tables, ~960px */
}

*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 5rem; }
body {
    margin: 0;
    background: #ffffff;
    color: var(--text);
    font-family: var(--sans);
    font-size: 16px;
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    text-rendering: optimizeLegibility;
}
img, video { display: block; max-width: 100%; }
a { color: var(--blue); text-decoration: none; }
a:hover { text-decoration: underline; text-underline-offset: 3px; }
a:focus-visible, button:focus-visible { outline: 2px solid var(--blue); outline-offset: 3px; border-radius: 4px; }
sup { font-size: 0.7em; line-height: 0; }

.skip-link {
    position: absolute; left: 1rem; top: -3rem; z-index: 100;
    background: #fff; color: var(--ink); padding: 0.5rem 0.9rem;
    border: 1.5px solid var(--ink); border-radius: 6px;
}
.skip-link:focus { top: 1rem; }

/* ─── Top bar ─── */
.topbar {
    position: sticky; top: 0; z-index: 50;
    background: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(10px); -webkit-backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--line);
}
.topbar-inner {
    max-width: 72rem; margin: 0 auto; padding: 0.85rem 1.25rem;
    display: flex; align-items: center; justify-content: space-between; gap: 1rem;
}
.brand { display: flex; align-items: center; gap: 0.55rem; color: var(--ink); font-family: var(--serif); font-size: 1.15rem; font-weight: 500; }
.brand:hover { text-decoration: none; }
.brand-mark { width: 0.6rem; height: 0.6rem; border-radius: 3px; background: var(--blue); }
.brand-sub { font-family: var(--mono); font-size: 0.68rem; letter-spacing: 0.06em; text-transform: uppercase; color: var(--muted); }
.topbar-links { display: flex; align-items: center; gap: 1.25rem; font-size: 0.9rem; }
.topbar-links a { color: var(--text); }
.topbar-links a:hover { color: var(--blue); text-decoration: none; }
.home-link { font-family: var(--mono); font-size: 0.75rem !important; border: 1px solid var(--line); border-radius: 6px; padding: 0.3rem 0.6rem; }
.home-link:hover { border-color: var(--ink); }
@media (max-width: 640px) {
    .brand-sub, .topbar-links .hide-sm { display: none; }
}

/* ─── Article column ─── */
.article { padding: 0 1.25rem 6rem; }
.col { max-width: var(--measure); margin: 0 auto; }
.wide { max-width: var(--wide); margin-left: auto; margin-right: auto; }

/* ─── Title block ─── */
.title-block { text-align: center; padding: 4.5rem 0 2.5rem; }
.eyebrow {
    font-family: var(--mono); font-size: 0.75rem; font-weight: 500;
    letter-spacing: 0.08em; text-transform: uppercase; color: var(--blue);
    margin: 0;
}
.title-block h1 {
    font-family: var(--serif); font-weight: 500; color: var(--ink);
    font-size: clamp(2.1rem, 1.4rem + 3vw, 3.25rem); line-height: 1.12; letter-spacing: -0.015em;
    margin: 1rem auto 0; max-width: 46rem; text-wrap: balance;
}
.title-block .subtitle {
    font-family: var(--serif); font-style: italic; font-size: clamp(1.15rem, 1rem + 0.6vw, 1.4rem);
    color: var(--text); margin: 0.75rem 0 0;
}
.authors { margin: 1.75rem auto 0; max-width: 40rem; font-size: 1rem; color: var(--ink); line-height: 1.9; }
.authors span { white-space: nowrap; }
.authors .sep { color: var(--faint); margin: 0 0.35rem; }
.affil { margin-top: 0.5rem; font-size: 0.875rem; color: var(--muted); }
.pills { display: flex; flex-wrap: wrap; justify-content: center; gap: 0.6rem; margin-top: 1.75rem; }
.pill {
    display: inline-flex; align-items: center; gap: 0.45rem;
    padding: 0.5rem 1rem; border-radius: 999px;
    border: 1px solid var(--line); background: #fff; color: var(--ink);
    font-size: 0.92rem; font-weight: 500;
    transition: border-color 0.15s ease, background 0.15s ease;
}
.pill:hover { border-color: var(--ink); text-decoration: none; }
.pill-primary { background: var(--ink); border-color: var(--ink); color: #fff; }
.pill-primary:hover { background: var(--blue); border-color: var(--blue); }
.pill svg { flex-shrink: 0; }

/* ─── Figures ─── */
figure { margin: 2.5rem auto; }
figcaption, .caption {
    margin-top: 0.9rem; font-size: 0.875rem; line-height: 1.55; color: var(--muted);
    max-width: var(--measure);
}
figcaption b, .caption b { color: var(--ink); font-weight: 600; }
.fig-frame { border: 1px solid var(--line); border-radius: 12px; padding: 1.5rem; background: #fff; }
.fig-frame img { margin: 0 auto; border-radius: 6px; }

/* Lead chart (Figure 1) */
.chart-head { display: flex; align-items: baseline; justify-content: space-between; gap: 1rem; margin-bottom: 1.25rem; }
.chart-title { font-weight: 600; color: var(--ink); font-size: 1rem; margin: 0; }
.chart-axis { font-family: var(--mono); font-size: 0.7rem; color: var(--faint); letter-spacing: 0.04em; }
.bars { position: relative; display: grid; gap: 0.9rem; }
.bar-row { display: grid; grid-template-columns: 13.5rem 1fr 3.5rem; align-items: center; gap: 1rem; }
.bar-name { font-size: 0.92rem; color: var(--ink); line-height: 1.3; }
.bar-name small { display: block; font-family: var(--mono); font-size: 0.68rem; color: var(--faint); letter-spacing: 0.03em; }
.bar-name.ours { color: var(--blue); font-weight: 600; }
.bar-track { position: relative; height: 0.85rem; background: var(--wash); border-radius: 3px; }
.bar-fill { position: absolute; inset: 0 auto 0 0; border-radius: 3px; background: #c3c9d4; }
.bar-fill.ours { background: var(--blue); }
.bar-fill.teacher { background: var(--ink); }
.bar-fill.baseline { background: #8a93a5; }
.bar-val { font-family: var(--mono); font-size: 0.85rem; color: var(--ink); text-align: right; font-variant-numeric: tabular-nums; }
.bar-val.ours { color: var(--blue); font-weight: 500; }
.ref-line {
    position: absolute; top: -0.4rem; bottom: -0.4rem; width: 0;
    border-left: 1.5px dashed rgba(29, 78, 216, 0.6); pointer-events: none;
}
.ref-label {
    position: absolute; top: -1.6rem; transform: translateX(-50%); white-space: nowrap;
    font-family: var(--mono); font-size: 0.66rem; letter-spacing: 0.05em; text-transform: uppercase; color: var(--blue);
}
.bars-area { position: relative; margin-top: 1.75rem; }
/* The track column starts after the 13.5rem name column + 1rem gap and ends before the value column. */
.ref-wrap { position: absolute; inset: 0 4.5rem 0 14.5rem; pointer-events: none; }
@media (max-width: 640px) {
    .bar-row { grid-template-columns: 1fr 3rem; }
    .bar-row .bar-name { grid-column: 1 / -1; }
    .bar-row .bar-track { grid-column: 1; }
    .ref-wrap { display: none; }
}

/* Key numbers strip */
.numbers {
    display: grid; grid-template-columns: repeat(4, 1fr); gap: 1px;
    background: var(--line); border: 1px solid var(--line); border-radius: 12px; overflow: hidden;
    margin: 2rem auto 0;
}
.numbers div { background: #fff; padding: 1rem 1.15rem; }
.numbers dt { font-family: var(--mono); font-size: 0.66rem; letter-spacing: 0.06em; text-transform: uppercase; color: var(--muted); }
.numbers dd { margin: 0.2rem 0 0; font-family: var(--serif); font-size: 1.85rem; color: var(--ink); line-height: 1.15; }
.numbers dd small { display: block; font-family: var(--sans); font-size: 0.78rem; color: var(--blue); margin-top: 0.2rem; }
@media (max-width: 720px) { .numbers { grid-template-columns: repeat(2, 1fr); } }

/* ─── Prose ─── */
.section { margin-top: 4.5rem; }
.section h2 {
    font-family: var(--serif); font-weight: 500; color: var(--ink);
    font-size: clamp(1.6rem, 1.3rem + 1vw, 2rem); line-height: 1.2; letter-spacing: -0.01em;
    margin: 0.6rem 0 1.25rem; text-wrap: balance;
}
.section h3 {
    font-family: var(--serif); font-style: italic; font-weight: 400; color: var(--ink);
    font-size: 1.25rem; margin: 2.25rem 0 0.6rem;
}
.prose p, .prose li { font-family: var(--serif); font-size: 1.125rem; line-height: 1.72; color: var(--text); }
.prose p { margin: 0 0 1.15rem; }
.prose strong { color: var(--ink); font-weight: 600; }
.prose ol, .prose ul { padding-left: 1.4rem; margin: 0 0 1.25rem; }
.prose li { margin-bottom: 0.6rem; }
.prose li::marker { font-family: var(--mono); font-size: 0.85rem; color: var(--blue); }

/* Training phases (compact three-step row) */
.phases { display: grid; grid-template-columns: repeat(3, 1fr); gap: 0; margin: 1.75rem 0 0.5rem; border: 1px solid var(--line); border-radius: 12px; overflow: hidden; }
.phase { padding: 1rem 1.1rem; border-right: 1px solid var(--line); background: #fff; }
.phase:last-child { border-right: 0; }
.phase-step { font-family: var(--mono); font-size: 0.66rem; letter-spacing: 0.06em; text-transform: uppercase; color: var(--muted); }
.phase-name { font-weight: 600; color: var(--ink); margin-top: 0.25rem; }
.phase-beta { display: inline-block; margin-top: 0.4rem; font-family: var(--mono); font-size: 0.75rem; padding: 0.1rem 0.45rem; border-radius: 4px; background: var(--wash); color: var(--ink); }
.phase-beta.neg { background: var(--blue-wash); color: var(--blue); }
.phase p { font-size: 0.85rem; color: var(--muted); margin: 0.5rem 0 0; line-height: 1.5; }
@media (max-width: 640px) {
    .phases { grid-template-columns: 1fr; }
    .phase { border-right: 0; border-bottom: 1px solid var(--line); }
    .phase:last-child { border-bottom: 0; }
}

/* ─── App demo: the one bold element ─── */
.demo {
    display: grid; grid-template-columns: 1.05fr 1fr; gap: 2rem; align-items: center;
    border: 1.5px solid var(--ink); border-radius: 14px; box-shadow: 6px 6px 0 var(--ink);
    padding: 1.75rem; background: #fff;
}
.demo-head { display: flex; align-items: center; gap: 0.75rem; }
.demo-head img { width: 2.75rem; height: 2.75rem; border-radius: 10px; border: 1px solid var(--line); }
.demo-head strong { display: block; font-size: 1.1rem; color: var(--ink); }
.demo-head span { font-family: var(--mono); font-size: 0.68rem; letter-spacing: 0.06em; text-transform: uppercase; color: var(--muted); }
.demo p { font-size: 0.95rem; color: var(--text); margin: 1rem 0 0.75rem; }
.demo ul { margin: 0; padding-left: 1.1rem; font-size: 0.9rem; color: var(--muted); }
.demo li { margin-bottom: 0.35rem; }
.demo li::marker { color: var(--blue); }
.demo video { width: 100%; border-radius: 10px; border: 1px solid var(--line); background: var(--wash); }
@media (max-width: 760px) { .demo { grid-template-columns: 1fr; } }

/* ─── Tables ─── */
.table-wrap { overflow-x: auto; -webkit-overflow-scrolling: touch; border-top: 1.5px solid var(--ink); border-bottom: 1.5px solid var(--ink); }
table { width: 100%; border-collapse: collapse; font-size: 0.9rem; font-variant-numeric: tabular-nums; }
th, td { padding: 0.6rem 0.75rem; text-align: right; white-space: nowrap; }
th:first-child, td:first-child { text-align: left; }
thead th { font-weight: 600; color: var(--ink); border-bottom: 1px solid var(--ink); font-size: 0.82rem; }
tbody td { border-bottom: 1px solid var(--line); color: var(--text); }
tbody tr:last-child td { border-bottom: 0; }
tr.group td { font-family: var(--mono); font-size: 0.68rem; letter-spacing: 0.06em; text-transform: uppercase; color: var(--muted); background: var(--wash); padding-top: 0.45rem; padding-bottom: 0.45rem; }
tr.ours td { background: var(--blue-wash); color: var(--ink); }
tr.ours td:first-child { box-shadow: inset 3px 0 0 var(--blue); }
tr.teacher td { color: var(--ink); }
.tag { font-family: var(--mono); font-size: 0.62rem; letter-spacing: 0.06em; text-transform: uppercase; padding: 0.1rem 0.35rem; border-radius: 3px; margin-right: 0.4rem; vertical-align: 1px; }
.tag-ours { background: var(--blue); color: #fff; }
.tag-teacher { background: var(--ink); color: #fff; }
.oom { font-family: var(--mono); font-size: 0.7rem; color: #b42318; letter-spacing: 0.04em; }
.keep { font-family: var(--mono); font-size: 0.7rem; color: var(--blue); margin-left: 0.3rem; }
.table-title { font-weight: 600; color: var(--ink); font-size: 0.95rem; margin: 0 0 0.75rem; }

/* Latency comparison (Figure 4) */
.latency { display: grid; gap: 1.25rem; }
.lat-device { font-family: var(--mono); font-size: 0.7rem; letter-spacing: 0.06em; text-transform: uppercase; color: var(--muted); margin-bottom: 0.5rem; }
.lat-row { display: grid; grid-template-columns: 10rem 1fr 6.5rem; gap: 1rem; align-items: center; margin-bottom: 0.45rem; font-size: 0.9rem; }
.lat-row .bar-track { height: 0.7rem; }
.lat-val { font-family: var(--mono); font-size: 0.85rem; text-align: right; color: var(--ink); }
.lat-val.ours { color: var(--blue); font-weight: 500; }
@media (max-width: 640px) { .lat-row { grid-template-columns: 1fr 5.5rem; } .lat-row .bar-track { display: none; } }

/* ─── Citation ─── */
.bibtex { position: relative; border: 1px solid var(--line); border-radius: 12px; background: var(--wash); }
.bibtex pre { margin: 0; padding: 1.25rem 1.25rem; overflow-x: auto; font-family: var(--mono); font-size: 0.82rem; line-height: 1.6; color: var(--ink); }
.copy-btn {
    position: absolute; top: 0.75rem; right: 0.75rem;
    font-family: var(--mono); font-size: 0.72rem; letter-spacing: 0.04em;
    background: #fff; color: var(--ink); border: 1.5px solid var(--ink); border-radius: 6px;
    padding: 0.3rem 0.6rem; cursor: pointer; box-shadow: 2px 2px 0 var(--ink);
    transition: transform 0.12s ease, box-shadow 0.12s ease;
}
.copy-btn:active { transform: translate(2px, 2px); box-shadow: 0 0 0 var(--ink); }

/* ─── Margin table of contents ─── */
.toc {
    position: fixed; top: 7rem; width: 11rem;
    left: calc(50% - (var(--measure) / 2) - 14rem);
    font-size: 0.85rem; display: none;
}
.toc p { margin: 0 0 0.75rem; }
.toc ol { list-style: none; margin: 0; padding: 0; border-left: 1px solid var(--line); }
.toc a { display: block; padding: 0.3rem 0 0.3rem 0.9rem; margin-left: -1px; color: var(--muted); border-left: 2px solid transparent; }
.toc a:hover { color: var(--ink); text-decoration: none; }
.toc a.active { color: var(--blue); border-left-color: var(--blue); }
@media (min-width: 1280px) { .toc { display: block; } }

/* ─── Footer ─── */
.footer { background: #0f1524; color: rgba(255, 255, 255, 0.7); padding: 3rem 1.25rem; }
.footer-inner { max-width: var(--wide); margin: 0 auto; display: flex; flex-wrap: wrap; gap: 1.5rem; justify-content: space-between; align-items: flex-start; }
.footer .brand { color: #fff; }
.footer p { margin: 0.6rem 0 0; font-size: 0.875rem; max-width: 28rem; }
.footer-links { display: flex; gap: 1.25rem; font-size: 0.9rem; }
.footer-links a { color: rgba(255, 255, 255, 0.8); }
.footer-links a:hover { color: #fff; }
.footer-copy { width: 100%; border-top: 1px solid rgba(255, 255, 255, 0.1); padding-top: 1.25rem; font-family: var(--mono); font-size: 0.7rem; letter-spacing: 0.06em; text-transform: uppercase; color: rgba(255, 255, 255, 0.45); }

@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }

.sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0, 0, 0, 0); white-space: nowrap; border: 0; }

/* Captions align with the figure's left edge (not re-centred like the prose column) */
figure figcaption, figure .caption { margin-left: 0; margin-right: 0; }
.chart-axis { white-space: nowrap; }

/* Margin contents sits beside the WIDE column (figures), not the reading column,
   so figures never slide underneath it. Shown only when both fit side by side. */
:root { --wide: 56rem; }
.toc { width: 10rem; left: calc(50% - (var(--wide) / 2) - 12rem); }
@media (min-width: 1280px) { .toc { display: none; } }
@media (min-width: 1400px) { .toc { display: block; } }