/* Code Learning Dojo — shared theme. No framework, no jQuery, no CDN. */

:root {
  --accent: #3b82f6;
  --accent2: #0ea5e9;

  --bg: #ffffff;
  --bg-sunk: #f6f7f9;
  --bg-raised: #ffffff;
  --bg-code: #0f1420;
  --line: #e4e7ec;
  --line-soft: #eef0f4;
  --ink: #14181f;
  --ink-2: #454c59;
  --ink-3: #6b7280;
  --ink-inv: #f7f9fc;

  --t-k: #c792ea;
  --t-s: #a5d6a7;
  --t-c: #6b7a90;
  --t-n: #f8c07a;
  --t-f: #82aaff;
  --t-v: #f78c6c;

  --radius: 10px;
  --radius-lg: 16px;
  --shadow: 0 1px 2px rgb(16 24 40 / 6%), 0 8px 24px -12px rgb(16 24 40 / 14%);
  --font: ui-sans-serif, system-ui, -apple-system, "Segoe UI", Inter, Roboto, Helvetica, Arial, sans-serif;
  --mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, "Liberation Mono", monospace;
  --wrap: 1240px;
}

:root[data-theme="dark"],
html:not([data-theme="light"]) body.auto-dark {
  color-scheme: dark;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #0b0e14;
    --bg-sunk: #0f131b;
    --bg-raised: #121722;
    --bg-code: #0a0d14;
    --line: #222a38;
    --line-soft: #1a212c;
    --ink: #e6eaf2;
    --ink-2: #a8b2c4;
    --ink-3: #7c8799;
    --ink-inv: #0b0e14;
    color-scheme: dark;
  }
}

:root[data-theme="dark"] {
  --bg: #0b0e14;
  --bg-sunk: #0f131b;
  --bg-raised: #121722;
  --bg-code: #0a0d14;
  --line: #222a38;
  --line-soft: #1a212c;
  --ink: #e6eaf2;
  --ink-2: #a8b2c4;
  --ink-3: #7c8799;
  --ink-inv: #0b0e14;
  color-scheme: dark;
}

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

html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; scroll-padding-top: 84px; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font);
  font-size: 16.5px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

img, svg, video { max-width: 100%; height: auto; }
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; border-radius: 4px; }

.wrap { max-width: var(--wrap); margin-inline: auto; padding-inline: 20px; }
.skip { position: absolute; left: -9999px; }
.skip:focus { left: 12px; top: 12px; z-index: 100; background: var(--accent); color: #fff; padding: 10px 16px; border-radius: 8px; }

/* ---------- header ---------- */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: color-mix(in oklab, var(--bg) 88%, transparent);
  backdrop-filter: saturate(160%) blur(12px);
  border-bottom: 1px solid var(--line);
}
.site-header__inner { display: flex; align-items: center; gap: 18px; height: 60px; }
.brand { display: flex; align-items: center; gap: 9px; font-weight: 700; color: var(--ink); letter-spacing: -0.02em; flex: 0 0 auto; }
.brand:hover { text-decoration: none; }
.brand__mark {
  width: 26px; height: 26px; border-radius: 7px; display: grid; place-items: center;
  background: linear-gradient(135deg, var(--accent), var(--accent2));
  color: #fff; font: 700 12px/1 var(--mono);
}
.brand__sub { color: var(--ink-3); font-weight: 500; }

.nav { display: flex; gap: 4px; margin-left: auto; align-items: center; }
.nav a { color: var(--ink-2); padding: 7px 11px; border-radius: 8px; font-size: 14.5px; font-weight: 500; }
.nav a:hover { background: var(--bg-sunk); color: var(--ink); text-decoration: none; }
.nav a[aria-current] { color: var(--ink); background: var(--bg-sunk); }

.iconbtn {
  border: 1px solid var(--line); background: var(--bg-raised); color: var(--ink-2);
  width: 34px; height: 34px; border-radius: 9px; cursor: pointer; display: grid; place-items: center; font-size: 15px;
}
.iconbtn:hover { color: var(--ink); border-color: var(--ink-3); }

.netbar { border-bottom: 1px solid var(--line-soft); background: var(--bg-sunk); font-size: 13px; }
.netbar ul { display: flex; gap: 2px; list-style: none; margin: 0; padding: 6px 0; overflow-x: auto; scrollbar-width: none; }
.netbar ul::-webkit-scrollbar { display: none; }
.netbar a { color: var(--ink-3); padding: 4px 10px; border-radius: 6px; white-space: nowrap; }
.netbar a:hover { color: var(--ink); background: var(--bg-raised); text-decoration: none; }
.netbar a.is-current { color: var(--ink); font-weight: 600; }

/* ---------- layout ---------- */
.layout { display: grid; grid-template-columns: 250px minmax(0, 1fr) 210px; gap: 40px; align-items: start; padding: 34px 0 80px; }
@media (max-width: 1100px) { .layout { grid-template-columns: 230px minmax(0, 1fr); } .toc { display: none; } }
@media (max-width: 860px) { .layout { grid-template-columns: minmax(0, 1fr); gap: 0; } .sidebar { display: none; } }

.sidebar { position: sticky; top: 76px; max-height: calc(100vh - 96px); overflow-y: auto; padding-bottom: 20px; font-size: 14.5px; }
.sidebar h3 {
  font-size: 11px; text-transform: uppercase; letter-spacing: 0.08em; color: var(--ink-3);
  margin: 22px 0 8px; font-weight: 700;
}
.sidebar h3:first-child { margin-top: 0; }
.sidebar ul { list-style: none; margin: 0; padding: 0; }
.sidebar li a {
  display: block; padding: 5px 10px; border-radius: 7px; color: var(--ink-2); line-height: 1.4;
  border-left: 2px solid transparent;
}
.sidebar li a:hover { background: var(--bg-sunk); color: var(--ink); text-decoration: none; }
.sidebar li a[aria-current] { color: var(--accent); background: color-mix(in oklab, var(--accent) 9%, transparent); font-weight: 600; border-left-color: var(--accent); }
.sidebar li a.visited::after { content: "✓"; float: right; color: var(--ink-3); font-size: 11px; }

.toc { position: sticky; top: 76px; font-size: 13.5px; max-height: calc(100vh - 96px); overflow-y: auto; }
.toc p { font-size: 11px; text-transform: uppercase; letter-spacing: 0.08em; color: var(--ink-3); font-weight: 700; margin: 0 0 8px; }
.toc ul { list-style: none; margin: 0; padding: 0; border-left: 1px solid var(--line); }
.toc a { display: block; padding: 4px 0 4px 12px; color: var(--ink-3); margin-left: -1px; border-left: 1px solid transparent; }
.toc a:hover { color: var(--ink); text-decoration: none; }
.toc a.is-active { color: var(--accent); border-left-color: var(--accent); }
.toc li.lvl-3 a { padding-left: 24px; font-size: 13px; }

/* ---------- prose ---------- */
.prose { max-width: 74ch; }
.prose > :first-child { margin-top: 0; }
.prose h1 { font-size: clamp(30px, 4vw, 40px); line-height: 1.15; letter-spacing: -0.025em; margin: 0 0 12px; }
.prose h2 { font-size: 25px; letter-spacing: -0.02em; margin: 46px 0 14px; padding-top: 6px; line-height: 1.25; }
.prose h3 { font-size: 19.5px; letter-spacing: -0.01em; margin: 34px 0 10px; }
.prose h4 { font-size: 16.5px; margin: 26px 0 8px; }
.prose p { margin: 0 0 17px; color: var(--ink-2); }
.prose li { color: var(--ink-2); margin: 5px 0; }
.prose ul, .prose ol { padding-left: 22px; margin: 0 0 18px; }
.prose strong { color: var(--ink); font-weight: 650; }
.prose hr { border: 0; border-top: 1px solid var(--line); margin: 40px 0; }
.prose blockquote {
  margin: 22px 0; padding: 2px 0 2px 18px; border-left: 3px solid var(--line);
  color: var(--ink-3); font-style: italic;
}
.prose blockquote p:last-child { margin-bottom: 0; }
.anchor { margin-left: 8px; color: var(--line); font-weight: 400; opacity: 0; transition: opacity .12s; }
h2:hover .anchor, h3:hover .anchor { opacity: 1; text-decoration: none; }

.prose :not(pre) > code {
  font-family: var(--mono); font-size: 0.875em; padding: 0.14em 0.38em;
  background: var(--bg-sunk); border: 1px solid var(--line-soft); border-radius: 5px; color: var(--ink);
  word-break: break-word;
}

/* ---------- code ---------- */
figure.code { margin: 22px 0; position: relative; border-radius: var(--radius); overflow: hidden; background: var(--bg-code); border: 1px solid #1e2532; }
figure.code figcaption {
  font: 600 11px/1 var(--mono); text-transform: uppercase; letter-spacing: 0.07em;
  color: #7c8799; padding: 10px 14px; border-bottom: 1px solid #1a2029; background: #0d1119;
}
figure.code pre { margin: 0; padding: 15px 16px; overflow-x: auto; }
figure.code code { font-family: var(--mono); font-size: 13.5px; line-height: 1.62; color: #dbe3f0; display: block; }
figure.code .copy {
  position: absolute; top: 7px; right: 8px; border: 1px solid #263041; background: #131a26; color: #8b98ad;
  font: 500 11px/1 var(--font); padding: 6px 9px; border-radius: 6px; cursor: pointer; opacity: 0; transition: opacity .12s;
}
figure.code:hover .copy, figure.code .copy:focus { opacity: 1; }
figure.code .copy:hover { color: #fff; border-color: #3a465c; }
figure.code[data-lang] .copy { top: 6px; }
.t-k { color: var(--t-k); } .t-s { color: var(--t-s); } .t-c { color: var(--t-c); font-style: italic; }
.t-n { color: var(--t-n); } .t-f { color: var(--t-f); } .t-v { color: var(--t-v); }

.table-wrap { overflow-x: auto; margin: 22px 0; border: 1px solid var(--line); border-radius: var(--radius); }
table { border-collapse: collapse; width: 100%; font-size: 14.5px; }
th, td { text-align: left; padding: 10px 14px; border-bottom: 1px solid var(--line-soft); vertical-align: top; }
th { background: var(--bg-sunk); font-weight: 650; font-size: 13px; letter-spacing: 0.01em; color: var(--ink); white-space: nowrap; }
tbody tr:last-child td { border-bottom: 0; }
td { color: var(--ink-2); }

/* ---------- callouts ---------- */
.callout {
  display: flex; gap: 13px; margin: 24px 0; padding: 15px 17px;
  border: 1px solid var(--line); border-left: 3px solid var(--ink-3);
  border-radius: var(--radius); background: var(--bg-sunk);
}
.callout__icon {
  flex: 0 0 auto; font: 700 10px/18px var(--mono); min-width: 20px; height: 18px; text-align: center;
  color: var(--ink-3); border-radius: 5px;
}
.callout__body { min-width: 0; }
.callout__body > :last-child { margin-bottom: 0; }
.callout__title { font-weight: 650; color: var(--ink); margin: 0 0 5px !important; }
.callout--warn { border-left-color: #f59e0b; }
.callout--warn .callout__icon { color: #f59e0b; }
.callout--danger { border-left-color: #ef4444; background: color-mix(in oklab, #ef4444 6%, var(--bg-sunk)); }
.callout--danger .callout__icon { color: #ef4444; }
.callout--tip { border-left-color: #10b981; }
.callout--tip .callout__icon { color: #10b981; }
.callout--ai { border-left-color: var(--accent); background: color-mix(in oklab, var(--accent) 6%, var(--bg-sunk)); }
.callout--ai .callout__icon { color: var(--accent); }

.details { margin: 22px 0; border: 1px solid var(--line); border-radius: var(--radius); background: var(--bg-sunk); }
.details summary { padding: 12px 16px; cursor: pointer; font-weight: 600; font-size: 15px; color: var(--ink); list-style: none; }
.details summary::-webkit-details-marker { display: none; }
.details summary::before { content: "▸"; display: inline-block; width: 16px; color: var(--ink-3); transition: transform .15s; }
.details[open] summary::before { transform: rotate(90deg); }
.details__body { padding: 0 16px 4px; }

.verdict {
  margin: 26px 0; padding: 16px 18px; border-radius: var(--radius);
  border: 1px solid color-mix(in oklab, var(--accent) 30%, var(--line));
  background: color-mix(in oklab, var(--accent) 6%, transparent);
}
.verdict__label { font: 700 11px/1 var(--font); text-transform: uppercase; letter-spacing: 0.09em; color: var(--accent); margin: 0 0 8px; }
.verdict > div > :last-child { margin-bottom: 0; }

/* ---------- monetisation ---------- */
.promo {
  margin: 30px 0; padding: 18px 20px; border-radius: var(--radius-lg);
  border: 1px solid var(--line); background: var(--bg-raised); box-shadow: var(--shadow);
}
.promo__eyebrow { font: 700 10.5px/1 var(--font); text-transform: uppercase; letter-spacing: 0.09em; color: var(--ink-3); margin: 0 0 7px; }
.promo__title { font-weight: 680; font-size: 16.5px; color: var(--ink); margin: 0 0 5px; }
.promo__text { color: var(--ink-2); font-size: 14.5px; margin: 0 0 13px; }
.promo__cta {
  display: inline-block; background: var(--ink); color: var(--bg); font-weight: 600; font-size: 14px;
  padding: 9px 16px; border-radius: 8px;
}
.promo__cta:hover { text-decoration: none; opacity: .88; }
.promo__disc { font-size: 11.5px; color: var(--ink-3); margin: 11px 0 0; }
.ad-slot { margin: 30px 0; min-height: 0; }
.ad-slot:empty { display: none; }

.disclosure {
  font-size: 12.5px; color: var(--ink-3); border-top: 1px solid var(--line-soft);
  padding-top: 14px; margin-top: 40px;
}

.capture {
  margin: 40px 0 0; padding: 22px 24px; border-radius: var(--radius-lg);
  background: linear-gradient(135deg, color-mix(in oklab, var(--accent) 13%, var(--bg-sunk)), var(--bg-sunk));
  border: 1px solid color-mix(in oklab, var(--accent) 22%, var(--line));
}
.capture h3 { margin: 0 0 6px; font-size: 18px; letter-spacing: -0.01em; }
.capture p { margin: 0 0 14px; color: var(--ink-2); font-size: 14.5px; }
.capture form { display: flex; gap: 8px; flex-wrap: wrap; }
.capture input {
  flex: 1 1 220px; padding: 10px 13px; border-radius: 8px; border: 1px solid var(--line);
  background: var(--bg); color: var(--ink); font-size: 14.5px; font-family: inherit;
}
.capture button {
  padding: 10px 18px; border-radius: 8px; border: 0; background: var(--accent); color: #fff;
  font-weight: 650; font-size: 14.5px; cursor: pointer; font-family: inherit;
}
.capture button:hover { opacity: .9; }
.capture small { display: block; margin-top: 9px; color: var(--ink-3); font-size: 12px; }

/* ---------- exercise ---------- */
.exercise { margin: 34px 0; border: 1px solid var(--line); border-radius: var(--radius-lg); overflow: hidden; background: var(--bg-raised); }
.exercise__head { padding: 14px 18px; border-bottom: 1px solid var(--line); background: var(--bg-sunk); display: flex; align-items: center; gap: 10px; }
.exercise__head h2, .exercise__head h3 { margin: 0 !important; font-size: 16px !important; }
.exercise__tag { font: 700 10px/1 var(--mono); letter-spacing: .08em; text-transform: uppercase; color: var(--accent); border: 1px solid color-mix(in oklab, var(--accent) 40%, transparent); padding: 4px 7px; border-radius: 5px; }
.exercise__body { padding: 16px 18px; }
.exercise__body > :first-child { margin-top: 0; }
.editor { border: 1px solid #1e2532; border-radius: var(--radius); overflow: hidden; background: var(--bg-code); }
.editor textarea {
  width: 100%; min-height: 220px; border: 0; resize: vertical; padding: 14px 16px;
  font-family: var(--mono); font-size: 13.5px; line-height: 1.62; background: var(--bg-code); color: #dbe3f0;
  tab-size: 4;
}
.editor textarea:focus { outline: none; }
.editor__bar { display: flex; gap: 8px; align-items: center; padding: 9px 12px; border-top: 1px solid #1a2029; background: #0d1119; }
.btn {
  border: 1px solid var(--line); background: var(--bg-raised); color: var(--ink);
  font: 600 13.5px/1 var(--font); padding: 8px 14px; border-radius: 7px; cursor: pointer;
}
.btn:hover { border-color: var(--ink-3); }
.btn--primary { background: var(--accent); border-color: var(--accent); color: #fff; }
.btn--primary:hover { opacity: .9; }
.btn--ghost { background: transparent; border-color: #263041; color: #8b98ad; }
.editor__status { margin-left: auto; font: 500 12px/1 var(--mono); color: #7c8799; }
.console {
  margin: 0; padding: 13px 16px; background: #060910; color: #cfd8e6; font-family: var(--mono);
  font-size: 13px; line-height: 1.6; max-height: 260px; overflow: auto; white-space: pre-wrap; border-top: 1px solid #1a2029;
}
.console:empty { display: none; }
.console .err { color: #ff8b8b; }
.console .ok { color: #7ee2a8; }

/* ---------- cards / hub ---------- */
.hero { padding: 68px 0 46px; border-bottom: 1px solid var(--line); }
.hero__eyebrow { font: 700 11.5px/1 var(--font); letter-spacing: .1em; text-transform: uppercase; color: var(--accent); margin: 0 0 16px; }
.hero h1 { font-size: clamp(34px, 6vw, 58px); line-height: 1.05; letter-spacing: -0.035em; margin: 0 0 18px; max-width: 17ch; }
.hero p { font-size: clamp(16.5px, 2vw, 19.5px); color: var(--ink-2); max-width: 62ch; margin: 0 0 26px; }
.hero__cta { display: flex; gap: 11px; flex-wrap: wrap; }
.btn-lg { padding: 12px 22px; font-size: 15.5px; border-radius: 9px; display: inline-block; font-weight: 650; }

.grid { display: grid; gap: 16px; }
.grid--3 { grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); }
.grid--2 { grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); }

.card {
  display: block; padding: 20px; border: 1px solid var(--line); border-radius: var(--radius-lg);
  background: var(--bg-raised); color: inherit; transition: border-color .14s, transform .14s;
}
a.card:hover { text-decoration: none; border-color: color-mix(in oklab, var(--accent) 45%, var(--line)); transform: translateY(-2px); }
.card__eyebrow { font: 700 10.5px/1 var(--font); text-transform: uppercase; letter-spacing: .09em; color: var(--ink-3); margin: 0 0 9px; }
.card h3 { margin: 0 0 7px; font-size: 17px; letter-spacing: -0.012em; }
.card p { margin: 0; color: var(--ink-2); font-size: 14.5px; }
.card__meta { margin-top: 12px; font-size: 12.5px; color: var(--ink-3); display: flex; gap: 10px; flex-wrap: wrap; }

.section { padding: 56px 0; }
.section__head { margin-bottom: 26px; }
.section__head h2 { font-size: 27px; letter-spacing: -0.022em; margin: 0 0 7px; }
.section__head p { color: var(--ink-2); margin: 0; max-width: 66ch; }

.pill {
  display: inline-block; font: 600 11px/1 var(--font); letter-spacing: .04em; text-transform: uppercase;
  padding: 5px 9px; border-radius: 999px; border: 1px solid var(--line); color: var(--ink-3); background: var(--bg-sunk);
}
.pill--new { color: var(--accent); border-color: color-mix(in oklab, var(--accent) 40%, transparent); background: color-mix(in oklab, var(--accent) 9%, transparent); }

.track-head { margin: 0 0 24px; padding: 18px 20px; border-radius: var(--radius-lg); background: var(--bg-sunk); border: 1px solid var(--line); }
.track-head p { margin: 6px 0 0; color: var(--ink-2); font-size: 14.5px; }

.pager { display: flex; gap: 12px; justify-content: space-between; margin: 48px 0 0; padding-top: 22px; border-top: 1px solid var(--line); }
.pager a { flex: 1 1 0; padding: 14px 16px; border: 1px solid var(--line); border-radius: var(--radius); color: inherit; }
.pager a:hover { text-decoration: none; border-color: var(--ink-3); }
.pager span { display: block; font-size: 11.5px; color: var(--ink-3); text-transform: uppercase; letter-spacing: .07em; font-weight: 700; margin-bottom: 4px; }
.pager strong { font-weight: 600; font-size: 15px; color: var(--ink); }
.pager .next { text-align: right; }

.meta-bar { display: flex; gap: 14px; flex-wrap: wrap; align-items: center; font-size: 13px; color: var(--ink-3); margin: 0 0 26px; }
.meta-bar a { color: var(--ink-3); }

/* ---------- footer ---------- */
.site-footer { border-top: 1px solid var(--line); background: var(--bg-sunk); padding: 46px 0 34px; margin-top: 0; }
.site-footer .cols { display: grid; grid-template-columns: 1.6fr repeat(3, 1fr); gap: 32px; }
@media (max-width: 800px) { .site-footer .cols { grid-template-columns: 1fr 1fr; } }
.site-footer h4 { font: 700 11px/1 var(--font); text-transform: uppercase; letter-spacing: .09em; color: var(--ink-3); margin: 0 0 12px; }
.site-footer ul { list-style: none; margin: 0; padding: 0; }
.site-footer li { margin: 0 0 7px; }
.site-footer a { color: var(--ink-2); font-size: 14px; }
.site-footer__legal { margin-top: 34px; padding-top: 20px; border-top: 1px solid var(--line); font-size: 12.5px; color: var(--ink-3); display: flex; justify-content: space-between; gap: 16px; flex-wrap: wrap; }

@media print { .sidebar, .toc, .site-header, .netbar, .promo, .capture, .ad-slot { display: none !important; } }
@media (prefers-reduced-motion: reduce) { * { animation: none !important; transition: none !important; scroll-behavior: auto !important; } }

/* ---------- narrow screens ---------- */
@media (max-width: 720px) {
  body { font-size: 16px; }
  .site-header__inner { height: auto; padding-block: 8px; flex-wrap: wrap; gap: 8px 12px; }
  .brand { font-size: 15px; }
  .brand__sub { display: none; }
  .nav {
    order: 3; width: 100%; margin-left: 0; overflow-x: auto; gap: 2px;
    scrollbar-width: none; -webkit-overflow-scrolling: touch;
  }
  .nav::-webkit-scrollbar { display: none; }
  .nav a { white-space: nowrap; padding: 6px 9px; font-size: 14px; }
  #theme-toggle { order: 2; margin-left: auto; }
  .netbar ul { padding: 5px 0; }
  .layout { padding-top: 22px; }
  .prose h1 { font-size: 27px; }
  .prose h2 { font-size: 21px; margin-top: 34px; }
  .prose h3 { font-size: 17.5px; }
  .hero { padding: 40px 0 30px; }
  .hero h1 { font-size: 30px; }
  .hero__cta { flex-direction: column; align-items: stretch; }
  .btn-lg { text-align: center; }
  figure.code pre { padding: 12px; }
  figure.code code { font-size: 12.5px; }
  figure.code .copy { opacity: 1; }
  .capture form { flex-direction: column; }
  .pager { flex-direction: column; }
  .pager .next { text-align: left; }
  .site-footer .cols { grid-template-columns: 1fr; gap: 26px; }
  .editor textarea { font-size: 12.5px; min-height: 180px; }
  .editor__bar { flex-wrap: wrap; }
}