/* Jayson Qin: personal site. Hand-written, no framework. */

:root {
  color-scheme: light;
  --bg: #fbfaf7;
  --bg-elev: #ffffff;
  --bg-sunk: #f3f1ea;
  --ink: #14130f;
  --ink-2: #3a3832;
  --muted: #5d5a52;
  --line: #e6e2d8;
  --line-2: #d3cebf;
  --accent: #e8501a;
  --accent-ink: #b23a0a;
  --accent-soft: #fdece3;
  --ok: #146c36;
  --ok-soft: #e3f4ea;
  --bad: #b42318;
  --bad-soft: #fde8e6;
  --warn-soft: #fff3d6;
  --warn: #8a5300;
  --code-bg: #14130f;
  --code-ink: #ece9df;
  --code-dim: #8d897d;
  --shadow: 0 1px 2px rgba(20, 19, 15, 0.04), 0 12px 32px -12px rgba(20, 19, 15, 0.14);
  --radius: 14px;
  --maxw: 1120px;
  --sans: ui-sans-serif, -apple-system, BlinkMacSystemFont, "SF Pro Text", "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --display: ui-sans-serif, -apple-system, BlinkMacSystemFont, "SF Pro Display", "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --serif: "Iowan Old Style", "Charter", "Palatino Linotype", Georgia, serif;
  --mono: ui-monospace, "SF Mono", "JetBrains Mono", Menlo, Consolas, monospace;
}

:root[data-theme="dark"] {
  color-scheme: dark;
  --bg: #0f0f0d;
  --bg-elev: #171714;
  --bg-sunk: #1b1b17;
  --ink: #f3f1ea;
  --ink-2: #d4d1c6;
  --muted: #a29e92;
  --line: #2a2924;
  --line-2: #3b3a33;
  --accent: #ff7a45;
  --accent-ink: #ff9a6e;
  --accent-soft: #2b1a12;
  --ok: #5ed08a;
  --ok-soft: #12261a;
  --bad: #ff8a80;
  --bad-soft: #2d1816;
  --warn-soft: #2b2310;
  --warn: #f0b95a;
  --code-bg: #0a0a09;
  --shadow: 0 1px 2px rgba(0, 0, 0, 0.3), 0 12px 32px -12px rgba(0, 0, 0, 0.6);
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    color-scheme: dark;
    --bg: #0f0f0d;
    --bg-elev: #171714;
    --bg-sunk: #1b1b17;
    --ink: #f3f1ea;
    --ink-2: #d4d1c6;
    --muted: #a29e92;
    --line: #2a2924;
    --line-2: #3b3a33;
    --accent: #ff7a45;
    --accent-ink: #ff9a6e;
    --accent-soft: #2b1a12;
    --ok: #5ed08a;
    --ok-soft: #12261a;
    --bad: #ff8a80;
    --bad-soft: #2d1816;
    --warn-soft: #2b2310;
    --warn: #f0b95a;
    --code-bg: #0a0a09;
    --shadow: 0 1px 2px rgba(0, 0, 0, 0.3), 0 12px 32px -12px rgba(0, 0, 0, 0.6);
  }
}

*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; scroll-padding-top: 88px; }
body {
  margin: 0; background: var(--bg); color: var(--ink); font: 17px/1.62 var(--sans);
  -webkit-font-smoothing: antialiased; text-rendering: optimizeLegibility; font-feature-settings: "ss01", "cv11";
}
img, svg { max-width: 100%; display: block; }
a { color: var(--ink); text-decoration-color: var(--line-2); text-decoration-thickness: 1.5px; text-underline-offset: 3px; transition: text-decoration-color 0.15s, color 0.15s; }
a:hover { text-decoration-color: var(--accent); color: var(--accent-ink); }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 3px; border-radius: 4px; }
::selection { background: var(--accent); color: #fff; }

.wrap { width: 100%; max-width: var(--maxw); margin-inline: auto; padding-inline: clamp(20px, 4vw, 40px); }
.skip { position: absolute; left: 12px; top: -48px; z-index: 100; padding: 10px 16px; background: var(--ink); color: var(--bg); border-radius: 8px; text-decoration: none; }
.skip:focus { top: 12px; }

/* ---------- nav ---------- */
.nav {
  position: sticky; top: 0; z-index: 50; backdrop-filter: saturate(1.6) blur(14px); -webkit-backdrop-filter: saturate(1.6) blur(14px);
  background: color-mix(in srgb, var(--bg) 82%, transparent); border-bottom: 1px solid color-mix(in srgb, var(--line) 70%, transparent);
}
.nav-inner { display: flex; align-items: center; justify-content: space-between; height: 64px; gap: 24px; }
.brand { display: inline-flex; align-items: center; gap: 10px; font-weight: 650; letter-spacing: -0.01em; text-decoration: none; }
.brand-mark { width: 28px; height: 28px; border-radius: 8px; background: var(--ink); color: var(--bg); display: grid; place-items: center; font: 700 14px/1 var(--display); letter-spacing: -0.04em; }
.nav-links { display: flex; align-items: center; gap: 4px; list-style: none; margin: 0; padding: 0; }
.nav-links a { display: inline-block; padding: 8px 12px; border-radius: 8px; text-decoration: none; font-size: 15px; color: var(--ink-2); }
.nav-links a:hover, .nav-links a[aria-current="page"] { color: var(--ink); background: var(--bg-sunk); }
.icon-btn { display: inline-grid; place-items: center; width: 38px; height: 38px; border-radius: 10px; border: 1px solid var(--line); background: transparent; color: var(--ink-2); cursor: pointer; }
.icon-btn:hover { background: var(--bg-sunk); color: var(--ink); }
.icon-btn svg { width: 18px; height: 18px; }
.theme-sun { display: none; }
:root[data-theme="dark"] .theme-sun { display: block; }
:root[data-theme="dark"] .theme-moon { display: none; }
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .theme-sun { display: block; }
  :root:not([data-theme="light"]) .theme-moon { display: none; }
}

/* ---------- type ---------- */
h1, h2, h3, h4 { font-family: var(--display); margin: 0; letter-spacing: -0.025em; text-wrap: balance; }
h1 { font-size: clamp(2.5rem, 1.2rem + 5.2vw, 4.6rem); line-height: 1.04; font-weight: 640; letter-spacing: -0.034em; }
h2 { font-size: clamp(1.75rem, 1.1rem + 2.2vw, 2.6rem); line-height: 1.1; font-weight: 640; letter-spacing: -0.03em; }
h3 { font-size: 1.2rem; line-height: 1.3; font-weight: 640; letter-spacing: -0.015em; }
h4 { font-size: 1rem; font-weight: 640; }
p { margin: 0 0 1em; text-wrap: pretty; }
.serif { font-family: var(--serif); font-style: italic; font-weight: 400; letter-spacing: -0.02em; }
.eyebrow { font: 600 0.78rem/1 var(--sans); letter-spacing: 0.1em; text-transform: uppercase; color: var(--muted); margin: 0 0 18px; }
.lede { font-size: clamp(1.1rem, 1rem + 0.5vw, 1.3rem); line-height: 1.55; color: var(--ink-2); max-width: 46ch; }
.muted { color: var(--muted); }
code, kbd, samp, pre { font-family: var(--mono); font-size: 0.88em; }
:not(pre) > code { background: var(--bg-sunk); border: 1px solid var(--line); padding: 0.1em 0.38em; border-radius: 6px; }

/* ---------- hero ---------- */
.hero { padding: clamp(56px, 9vw, 120px) 0 clamp(40px, 6vw, 72px); position: relative; overflow: clip; }
.hero::before {
  content: ""; position: absolute; inset: -20% -10% auto auto; width: 60vw; height: 60vw; max-width: 760px; max-height: 760px;
  background: radial-gradient(closest-side, color-mix(in srgb, var(--accent) 16%, transparent), transparent 70%); z-index: -1; pointer-events: none;
}
.hero-grid { display: grid; grid-template-columns: minmax(0, 1.25fr) minmax(0, 1fr); gap: clamp(32px, 5vw, 72px); align-items: center; }
.hero h1 em { font-style: normal; color: var(--accent-ink); }
.hero .lede { margin-top: 26px; }
.cta-row { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 34px; }
.btn { display: inline-flex; align-items: center; gap: 8px; padding: 13px 20px; border-radius: 12px; font-weight: 600; font-size: 15.5px; text-decoration: none; border: 1px solid transparent; transition: transform 0.15s, background-color 0.15s, border-color 0.15s, box-shadow 0.2s; }
.btn-primary { background: var(--ink); color: var(--bg); }
.btn-primary:hover { color: var(--bg); transform: translateY(-1px); box-shadow: var(--shadow); }
.btn-ghost { border-color: var(--line-2); color: var(--ink); background: var(--bg-elev); }
.btn-ghost:hover { border-color: var(--ink); color: var(--ink); }
.btn svg { width: 16px; height: 16px; }
.hero-meta { margin-top: 28px; display: flex; flex-wrap: wrap; gap: 8px 20px; font-size: 14.5px; color: var(--muted); }
.hero-meta span::before { content: ""; display: inline-block; width: 6px; height: 6px; border-radius: 50%; background: var(--accent); margin-right: 8px; vertical-align: 2px; }

/* evidence terminal */
.term { background: var(--code-bg); color: var(--code-ink); border-radius: 16px; box-shadow: var(--shadow); border: 1px solid color-mix(in srgb, var(--line-2) 50%, transparent); overflow: hidden; }
.term-bar { display: flex; align-items: center; gap: 7px; padding: 12px 14px; border-bottom: 1px solid rgba(255, 255, 255, 0.07); }
.term-bar i { width: 10px; height: 10px; border-radius: 50%; background: #3a3933; }
.term-bar span { margin-left: 8px; font: 500 12px var(--mono); color: var(--code-dim); }
.term pre { margin: 0; padding: 18px 20px 20px; font-size: 13.5px; line-height: 1.7; overflow-x: auto; white-space: pre; }
.t-dim { color: var(--code-dim); } .t-ok { color: #5ed08a; } .t-bad { color: #ff8a80; } .t-key { color: #f0b95a; } .t-acc { color: #ff9a6e; }
.term-note { padding: 0 20px 16px; font-size: 12.5px; color: var(--code-dim); font-family: var(--sans); }
.term-note a { color: var(--code-ink); }

/* ---------- proof strip ---------- */
.proof { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }
.proof > div { padding: 26px 24px 28px 0; }
.proof > div + div { padding-left: 24px; border-left: 1px solid var(--line); }
.proof b { display: block; font: 650 clamp(1.7rem, 1.2rem + 1.6vw, 2.4rem)/1 var(--display); letter-spacing: -0.04em; }
.proof span { display: block; margin-top: 10px; font-size: 14.5px; line-height: 1.5; color: var(--muted); }

/* ---------- sections ---------- */
.section { padding: clamp(64px, 9vw, 112px) 0 0; }
.section-head { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1.4fr); gap: 32px; align-items: end; margin-bottom: 44px; }
.section-head > p { margin: 0; color: var(--muted); font-size: 1.05rem; max-width: 52ch; }
@media (max-width: 820px) { .section-head { grid-template-columns: 1fr; gap: 14px; } }

/* work cards */
.work-grid { display: grid; grid-template-columns: repeat(6, minmax(0, 1fr)); gap: 18px; }
.card {
  position: relative; background: var(--bg-elev); border: 1px solid var(--line); border-radius: var(--radius); padding: 28px 28px 26px;
  display: flex; flex-direction: column; text-decoration: none; color: inherit; transition: transform 0.2s, box-shadow 0.25s, border-color 0.2s;
}
a.card:hover { transform: translateY(-3px); box-shadow: var(--shadow); border-color: var(--line-2); color: inherit; }
.card .num { font: 600 0.8rem var(--mono); color: var(--muted); letter-spacing: 0.04em; }
.card h3 { margin-top: 14px; font-size: 1.35rem; }
.card p { margin: 12px 0 0; color: var(--ink-2); font-size: 1rem; }
.card .proof-line { margin-top: auto; padding-top: 20px; font-size: 14px; color: var(--muted); border-top: 1px dashed var(--line); margin-top: 22px; }
.card .more { margin-top: 14px; font-weight: 600; font-size: 14.5px; color: var(--accent-ink); display: inline-flex; gap: 6px; align-items: center; }
.card .more svg { width: 15px; height: 15px; transition: transform 0.2s; }
a.card:hover .more svg { transform: translateX(3px); }
.work-grid .c-lead { grid-column: span 6; flex-direction: row; gap: 36px; align-items: stretch; padding: 34px; }
.work-grid .c-lead .lead-body { flex: 1.1; display: flex; flex-direction: column; }
.work-grid .c-lead .lead-aside { flex: 1; align-self: flex-start; background: var(--bg-sunk); border-radius: 12px; padding: 22px 24px 20px; border: 1px solid var(--line); font-size: 14.5px; }
.lead-aside h4 { margin-top: 16px; }
.lead-aside h4:first-child { margin-top: 0; }
.lead-aside p { margin: 6px 0 0 !important; }
.work-grid .c-lead h3 { font-size: clamp(1.5rem, 1.1rem + 1vw, 2rem); letter-spacing: -0.03em; }
.work-grid .c-half { grid-column: span 3; }
.work-grid .c-third { grid-column: span 2; }
@media (max-width: 920px) {
  .work-grid .c-half, .work-grid .c-third { grid-column: span 6; }
  .work-grid .c-lead { flex-direction: column; gap: 22px; padding: 26px; }
}
.tags { display: flex; flex-wrap: wrap; gap: 6px; margin: 18px 0 0; padding: 0; list-style: none; }
.tags li { font: 500 12.5px var(--sans); padding: 4px 10px; border-radius: 999px; background: var(--bg-sunk); border: 1px solid var(--line); color: var(--ink-2); }

/* principles */
.principles { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 0; border-top: 1px solid var(--line); }
.principle { padding: 30px 32px 30px 0; border-bottom: 1px solid var(--line); }
.principle:nth-child(even) { padding-left: 32px; padding-right: 0; border-left: 1px solid var(--line); }
.principle h3 { font-size: 1.15rem; }
.principle p { margin: 10px 0 0; color: var(--muted); font-size: 1rem; }
.principle .ev { display: inline-block; margin-top: 12px; font-size: 14px; font-weight: 600; color: var(--accent-ink); }
@media (max-width: 720px) { .principles { grid-template-columns: 1fr; } .principle, .principle:nth-child(even) { padding: 24px 0; border-left: 0; } }

/* training section */
.split { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1.1fr); gap: clamp(28px, 5vw, 64px); align-items: start; }
@media (max-width: 920px) { .split { grid-template-columns: 1fr; } }
.stat-row { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 20px 28px; margin: 28px 0 10px; }
.stat-row b { display: block; font: 650 2.1rem/1 var(--display); letter-spacing: -0.04em; }
.stat-row span { display: block; margin-top: 8px; font-size: 14px; color: var(--muted); line-height: 1.4; }
@media (max-width: 520px) { .stat-row { grid-template-columns: 1fr; } }
.rules { list-style: none; margin: 0; padding: 0; display: grid; gap: 12px; }
.rules li { background: var(--bg-elev); border: 1px solid var(--line); border-radius: 12px; padding: 16px 18px; font-size: 15.5px; }
.rules li small { display: block; margin-top: 6px; color: var(--muted); font-size: 13.5px; line-height: 1.5; }
.rules li b { font-weight: 640; }
.side-note { margin: 28px 0 0; font-size: 15px; }
.prose ul.rules { padding-left: 0; margin: 22px 0; }
.sample { margin: 24px 0 32px; border: 1px solid var(--line); border-radius: 16px; background: var(--bg-elev); overflow: hidden; }
.sample-q { padding: 14px 20px; background: var(--bg-sunk); border-bottom: 1px solid var(--line); font-weight: 600; }
.sample-q span { display: block; margin-bottom: 4px; font: 600 0.72rem var(--sans); letter-spacing: 0.09em; text-transform: uppercase; color: var(--muted); }
.sample-a { padding: 18px 20px 8px; font-size: 15px; }
.sample-a p { margin: 0 0 10px; }
.sample-a table.t { font-size: 13.5px; margin: 8px 0 16px; }
.sample figcaption { padding: 12px 20px 16px; border-top: 1px solid var(--line); }
.side-note a { color: var(--ink-2); }

/* about */
.about { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); gap: clamp(28px, 5vw, 72px); }
@media (max-width: 820px) { .about { grid-template-columns: 1fr; } }
.facts { list-style: none; margin: 0; padding: 0; border-top: 1px solid var(--line); }
.facts li { display: grid; grid-template-columns: 9.5em 1fr; gap: 16px; padding: 14px 0; border-bottom: 1px solid var(--line); font-size: 15.5px; }
.facts li span:first-child { color: var(--muted); }

/* footer */
.footer { margin-top: clamp(72px, 10vw, 128px); border-top: 1px solid var(--line); padding: 44px 0 56px; }
.footer-grid { display: flex; flex-wrap: wrap; justify-content: space-between; gap: 28px; align-items: flex-start; }
.footer h2 { font-size: clamp(1.6rem, 1.1rem + 1.8vw, 2.4rem); max-width: 18ch; }
.footer ul { list-style: none; margin: 0; padding: 0; display: grid; gap: 10px; font-size: 15.5px; }
.footer small { display: block; margin-top: 36px; color: var(--muted); font-size: 13.5px; }

/* ---------- case study pages ---------- */
.crumb { font-size: 14.5px; color: var(--muted); margin-bottom: 26px; }
.crumb a { color: var(--muted); }
.case-hero { padding: clamp(40px, 6vw, 80px) 0 28px; }
.case-hero h1 { font-size: clamp(2.2rem, 1.1rem + 4vw, 3.8rem); max-width: 18ch; }
.case-hero .lede { margin-top: 22px; max-width: 54ch; }
.meta-row { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 0; margin-top: 40px; border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }
.meta-row div { padding: 18px 20px 18px 0; font-size: 15px; }
.meta-row div + div { padding-left: 20px; border-left: 1px solid var(--line); }
.meta-row dt { font: 600 0.74rem var(--sans); letter-spacing: 0.1em; text-transform: uppercase; color: var(--muted); margin-bottom: 8px; }
.meta-row dd { margin: 0; }
.meta-row { margin-bottom: 0; }
@media (max-width: 820px) { .meta-row { grid-template-columns: 1fr 1fr; } .meta-row div:nth-child(3) { border-left: 0; padding-left: 0; } .meta-row div:nth-child(n+3) { border-top: 1px solid var(--line); } }

.case-body { display: grid; grid-template-columns: 200px minmax(0, 1fr); gap: clamp(28px, 5vw, 72px); padding-top: 48px; }
.toc { position: sticky; top: 92px; align-self: start; font-size: 14.5px; }
.toc p { font: 600 0.74rem var(--sans); letter-spacing: 0.1em; text-transform: uppercase; color: var(--muted); margin-bottom: 12px; }
.toc ol { list-style: none; margin: 0; padding: 0; border-left: 1px solid var(--line); }
.toc a { display: block; padding: 6px 0 6px 14px; margin-left: -1px; border-left: 2px solid transparent; text-decoration: none; color: var(--muted); }
.toc a:hover { color: var(--ink); }
.toc a.on { border-left-color: var(--accent); color: var(--ink); font-weight: 600; }
@media (max-width: 920px) { .case-body { grid-template-columns: minmax(0, 1fr); } .toc { display: none; } }
.prose { max-width: 70ch; min-width: 0; }
.prose code { overflow-wrap: anywhere; }
.prose h2 { font-size: clamp(1.45rem, 1.1rem + 1.1vw, 1.9rem); margin: 64px 0 18px; }
.prose h2:first-child { margin-top: 0; }
.prose h3 { margin: 34px 0 10px; }
.prose ul, .prose ol { padding-left: 1.2em; margin: 0 0 1.2em; }
.prose li { margin-bottom: 0.5em; }
.prose li::marker { color: var(--accent); }
.prose strong { font-weight: 640; }
.callout { margin: 28px 0; padding: 20px 22px; border-radius: 12px; border: 1px solid var(--line); background: var(--bg-sunk); font-size: 16px; }
.callout > :last-child { margin-bottom: 0; }
.callout b.k { display: block; font: 600 0.74rem var(--sans); letter-spacing: 0.1em; text-transform: uppercase; margin-bottom: 8px; color: var(--muted); }
.callout.limits { background: var(--warn-soft); border-color: color-mix(in srgb, var(--warn) 30%, transparent); }
.callout.limits b.k { color: var(--warn); }
.callout.ok { background: var(--ok-soft); border-color: color-mix(in srgb, var(--ok) 30%, transparent); }
.callout.ok b.k { color: var(--ok); }
figure { margin: 32px 0; }
figcaption { margin-top: 12px; font-size: 14px; color: var(--muted); }
.fig-card { background: var(--bg-elev); border: 1px solid var(--line); border-radius: var(--radius); padding: clamp(14px, 3vw, 28px); overflow-x: auto; }
.fig-img { border: 1px solid var(--line); border-radius: var(--radius); overflow: hidden; background: var(--bg-elev); }
.fig-img img { width: 100%; height: auto; }
pre.code { background: var(--code-bg); color: var(--code-ink); border-radius: 12px; padding: 18px 20px; overflow-x: auto; font-size: 13.5px; line-height: 1.7; margin: 22px 0; }
table.t { width: 100%; border-collapse: collapse; font-size: 15px; margin: 22px 0; display: block; overflow-x: auto; }
table.t th, table.t td { text-align: left; padding: 11px 16px 11px 0; border-bottom: 1px solid var(--line); vertical-align: top; }
table.t th { font: 600 0.74rem var(--sans); letter-spacing: 0.09em; text-transform: uppercase; color: var(--muted); }
.next { margin-top: 72px; padding-top: 28px; border-top: 1px solid var(--line); display: flex; flex-wrap: wrap; gap: 14px; justify-content: space-between; }
.link-row { display: flex; flex-wrap: wrap; gap: 10px; margin: 22px 0 0; }

/* architecture diagram */
.diagram text { font-family: var(--sans); fill: var(--ink); }
.diagram .box { fill: var(--bg-elev); stroke: var(--line-2); stroke-width: 1.25; }
.diagram .box.key { stroke: var(--accent); stroke-width: 1.75; }
.diagram .soft { fill: var(--bg-sunk); stroke: var(--line); }
.diagram .arrow { stroke: var(--muted); stroke-width: 1.4; fill: none; marker-end: url(#ah); }
.diagram .dash { stroke-dasharray: 4 4; }
.diagram .sub { fill: var(--muted); font-size: 11.5px; }
.diagram .lbl { font-size: 13px; font-weight: 600; }

/* ---------- lab ---------- */
.lab-head { padding: clamp(40px, 6vw, 72px) 0 12px; }
.lab-head h1 { font-size: clamp(2.2rem, 1.1rem + 3.6vw, 3.4rem); }
.lab-head .lede { margin-top: 18px; }
.panel { background: var(--bg-elev); border: 1px solid var(--line); border-radius: var(--radius); }
.toolbar { display: flex; flex-wrap: wrap; gap: 10px 16px; align-items: center; padding: 14px 18px; border-bottom: 1px solid var(--line); }
.seg { display: inline-flex; border: 1px solid var(--line-2); border-radius: 10px; overflow: hidden; }
.seg button { font: 600 14px var(--sans); padding: 8px 14px; border: 0; background: transparent; color: var(--ink-2); cursor: pointer; }
.seg button + button { border-left: 1px solid var(--line-2); }
.seg button[aria-pressed="true"] { background: var(--ink); color: var(--bg); }
.select { font: 500 14px var(--sans); padding: 8px 10px; border-radius: 10px; border: 1px solid var(--line-2); background: var(--bg-elev); color: var(--ink); }
.score { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); border-bottom: 1px solid var(--line); }
.score > div { padding: 18px 20px; }
.score > div + div { border-left: 1px solid var(--line); }
.score b { display: block; font: 650 1.9rem/1 var(--display); letter-spacing: -0.04em; }
.score span { display: block; margin-top: 8px; font-size: 13.5px; color: var(--muted); }
@media (max-width: 720px) { .score { grid-template-columns: 1fr 1fr; } .score > div:nth-child(3) { border-left: 0; } .score > div:nth-child(n+3) { border-top: 1px solid var(--line); } }
.cases { list-style: none; margin: 0; padding: 0; }
.case { border-bottom: 1px solid var(--line); }
.case:last-child { border-bottom: 0; }
.case summary { display: grid; grid-template-columns: 4.2em 1fr auto; gap: 14px; align-items: center; padding: 14px 18px; cursor: pointer; list-style: none; }
.case summary::-webkit-details-marker { display: none; }
.case summary:hover { background: var(--bg-sunk); }
.case .cid { font: 600 13px var(--mono); color: var(--muted); }
.case .prompt { font-size: 15.5px; }
.case .cat { display: block; font-size: 12.5px; color: var(--muted); margin-top: 2px; }
.chip { display: inline-flex; align-items: center; gap: 6px; font: 600 12.5px var(--sans); padding: 4px 10px; border-radius: 999px; white-space: nowrap; }
.chip.pass { background: var(--ok-soft); color: var(--ok); }
.chip.fail { background: var(--bad-soft); color: var(--bad); }
.chip.reg { background: var(--bad); color: #fff; }
.chip.fix { background: var(--ok); color: #fff; }
.chip.warn { background: var(--warn-soft); color: var(--warn); }
.case .detail { padding: 4px 18px 18px calc(4.2em + 32px); font-size: 14.5px; color: var(--ink-2); }
.case .detail ul { margin: 0; padding: 0; list-style: none; display: grid; gap: 6px; }
.case .detail li { display: flex; gap: 10px; align-items: baseline; }
.case .detail code { font-size: 12.5px; }
@media (max-width: 720px) { .case .detail { padding-left: 18px; } .case summary { grid-template-columns: 3.4em 1fr; } .case summary .chip { grid-column: 2; justify-self: start; } }
.legend { display: flex; flex-wrap: wrap; gap: 8px 18px; font-size: 13.5px; color: var(--muted); padding: 14px 18px; border-top: 1px solid var(--line); }

/* learning loop widget */
.loop { display: grid; grid-template-columns: minmax(0, 0.9fr) minmax(0, 1.1fr); gap: 0; }
@media (max-width: 860px) { .loop { grid-template-columns: 1fr; } }
.loop-list { list-style: none; margin: 0; padding: 8px; border-right: 1px solid var(--line); }
@media (max-width: 860px) { .loop-list { border-right: 0; border-bottom: 1px solid var(--line); } }
.loop-list button { width: 100%; text-align: left; border: 1px solid transparent; background: transparent; padding: 14px 16px; border-radius: 10px; cursor: pointer; font: 500 15px/1.45 var(--sans); color: var(--ink-2); }
.loop-list button:hover { background: var(--bg-sunk); }
.loop-list button[aria-selected="true"] { background: var(--bg-sunk); border-color: var(--line-2); color: var(--ink); }
.loop-list small { display: block; color: var(--muted); font-size: 12.5px; margin-bottom: 4px; font-weight: 600; letter-spacing: 0.03em; }
.loop-out { padding: 26px 28px 28px; }
.quote { font: 400 1.15rem/1.5 var(--serif); font-style: italic; border-left: 3px solid var(--accent); padding-left: 16px; margin: 0 0 22px; color: var(--ink); }
.gates { list-style: none; margin: 0 0 22px; padding: 0; display: grid; gap: 8px; }
.gates li { display: grid; grid-template-columns: 22px 1fr; gap: 10px; font-size: 15px; align-items: start; }
.gates .mk { width: 20px; height: 20px; border-radius: 50%; display: grid; place-items: center; font-size: 12px; font-weight: 700; margin-top: 2px; }
.gates .y .mk { background: var(--ok-soft); color: var(--ok); }
.gates .n .mk { background: var(--bad-soft); color: var(--bad); }
.gates em { font-style: normal; color: var(--muted); display: block; font-size: 13.5px; }
.verdict { display: flex; gap: 12px; align-items: center; padding: 14px 16px; border-radius: 12px; font-weight: 600; margin-bottom: 14px; }
.verdict.cap { background: var(--ok-soft); color: var(--ok); }
.verdict.skip { background: var(--warn-soft); color: var(--warn); }
.rule-out { background: var(--code-bg); color: var(--code-ink); border-radius: 12px; padding: 16px 18px; font: 13.5px/1.65 var(--mono); }
.rule-out .t-dim { color: var(--code-dim); }

/* reveal */
.js .reveal { opacity: 0; transform: translateY(14px); transition: opacity 0.6s cubic-bezier(.2,.7,.2,1), transform 0.6s cubic-bezier(.2,.7,.2,1); }
.js .reveal.in { opacity: 1; transform: none; }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .js .reveal { opacity: 1; transform: none; transition: none; }
  *, *::before, *::after { animation: none !important; transition: none !important; }
}

/* ---------- responsive ---------- */
.nav-short { display: none; }
@media (max-width: 920px) { .hero-grid { grid-template-columns: 1fr; } }
@media (max-width: 760px) {
  .proof { grid-template-columns: 1fr 1fr; }
  .proof > div:nth-child(3) { border-left: 0; padding-left: 0; }
  .proof > div:nth-child(n+3) { border-top: 1px solid var(--line); }
  .nav-links .hide-sm { display: none; }
  .nav-long { display: none; }
  .nav-short { display: inline; }
  .nav-links a { padding: 8px 9px; }
  .nav-inner { gap: 8px; }
  .facts li { grid-template-columns: 1fr; gap: 2px; }
}
@media print { .nav, .skip, .icon-btn, .toc { display: none; } body { background: #fff; color: #000; } }