/* Copyright (c) 2025-2026 Rafael Fernandes Cunha. SPDX-License-Identifier: MIT */
/* Tutorial pages — shared stylesheet */
:root {
  --bg: #fbfbfa;
  --surface: #ffffff;
  --surface-2: #f4f4f2;
  --ink: #1d1f23;
  --ink-2: #4a4f57;
  --ink-3: #7b818a;
  --line: #e3e3df;
  --accent: #2b59c3;
  --code-bg: #f7f7f5;
  --out-bg: #ffffff;
  --err-bg: #fdf0ef;
  --err-ink: #a3271f;

  --k-explain: #2b59c3;
  --k-reveal: #2b59c3;
  --k-question: #7446c7;
  --k-task: #1f8a5b;
  --k-hint: #b57b00;
  --k-experiment: #d2552b;

  --tok-kw: #7446c7;
  --tok-def: #2b59c3;
  --tok-str: #1f7a4d;
  --tok-num: #b0521d;
  --tok-com: #8a8f97;
  --tok-builtin: #0f7c8c;
  --tok-prop: #3d4a63;

  --mono: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, monospace;
  --sans: "Inter", system-ui, -apple-system, "Segoe UI", sans-serif;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #15171a; --surface: #1c1f23; --surface-2: #23272c; --ink: #e7e8ea; --ink-2: #b9bdc4; --ink-3: #868c95;
    --line: #2f343a; --accent: #7aa2f7; --code-bg: #1a1d21; --out-bg: #1c1f23; --err-bg: #2c1c1b; --err-ink: #f2948c;
    --k-explain: #7aa2f7; --k-reveal: #7aa2f7; --k-question: #b392f0; --k-task: #4fc28f; --k-hint: #e0b04a; --k-experiment: #f08a62;
    --tok-kw: #c4a2f5; --tok-def: #8fb4ff; --tok-str: #8fd19e; --tok-num: #f0a56b; --tok-com: #7b828c; --tok-builtin: #6fd0dc; --tok-prop: #c9d1e0;
  }
}
:root[data-theme="dark"] {
  --bg: #15171a; --surface: #1c1f23; --surface-2: #23272c; --ink: #e7e8ea; --ink-2: #b9bdc4; --ink-3: #868c95;
  --line: #2f343a; --accent: #7aa2f7; --code-bg: #1a1d21; --out-bg: #1c1f23; --err-bg: #2c1c1b; --err-ink: #f2948c;
  --k-explain: #7aa2f7; --k-reveal: #7aa2f7; --k-question: #b392f0; --k-task: #4fc28f; --k-hint: #e0b04a; --k-experiment: #f08a62;
  --tok-kw: #c4a2f5; --tok-def: #8fb4ff; --tok-str: #8fd19e; --tok-num: #f0a56b; --tok-com: #7b828c; --tok-builtin: #6fd0dc; --tok-prop: #c9d1e0;
}

* { box-sizing: border-box; }
html { scroll-padding-top: 72px; }
body {
  margin: 0; background: var(--bg); color: var(--ink);
  font: 16px/1.65 var(--sans); -webkit-font-smoothing: antialiased;
}
a { color: var(--accent); }
code, pre { font-family: var(--mono); font-size: 0.875em; }
:not(pre) > code { background: var(--surface-2); padding: 0.1em 0.35em; border-radius: 4px; }

/* ---------- top bar ---------- */
.topbar {
  position: sticky; top: 0; z-index: 10;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: blur(8px); border-bottom: 1px solid var(--line);
}
.topbar-inner { max-width: 1240px; margin: 0 auto; padding: 10px 16px; display: flex; align-items: center; gap: 10px; flex-wrap: wrap; }
.topbar-title { font-weight: 600; font-size: 0.95rem; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; max-width: 40ch; }
.spacer { flex: 1; }
.status { display: inline-flex; align-items: center; gap: 7px; font-size: 0.8rem; color: var(--ink-2); padding: 3px 10px; border-radius: 99px; background: var(--surface-2); }
.status .dot { width: 8px; height: 8px; border-radius: 50%; background: var(--ink-3); }
.status[data-state="loading"] .dot, .status[data-state="busy"] .dot { background: var(--k-hint); animation: pulse 1.2s ease-in-out infinite; }
.status[data-state="ready"] .dot { background: var(--k-task); }
.status[data-state="error"] .dot { background: var(--err-ink); }
.status[data-state="static"] .dot { background: var(--accent); }
a.btn { text-decoration: none; display: inline-block; }
.cell-lang { font-size: 0.72rem; color: var(--ink-3); font-family: var(--mono); }
.toc a.sub { padding-left: 24px; font-size: 0.8rem; color: var(--ink-3); }
.toc a.sub.active { color: var(--accent); }
@keyframes pulse { 50% { opacity: 0.3; } }
.btn {
  font: 500 0.85rem var(--sans); padding: 6px 12px; border-radius: 7px; cursor: pointer;
  border: 1px solid var(--accent); background: var(--accent); color: #fff;
}
.btn.ghost { background: transparent; color: var(--ink); border-color: var(--line); }
.btn:disabled { opacity: 0.45; cursor: default; }
.btn.icon { padding: 5px 8px; display: inline-flex; align-items: center; }
.btn.icon svg { width: 17px; height: 17px; }
/* show the icon of the mode you would switch TO */
.i-sun { display: none; }
:root[data-theme="dark"] .i-sun { display: block; }
:root[data-theme="dark"] .i-moon { display: none; }
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .i-sun { display: block; }
  :root:not([data-theme="light"]) .i-moon { display: none; }
}
.btn:not(:disabled):hover { filter: brightness(1.08); }

/* ---------- layout ---------- */
/* Main column fits ~120 characters of code; longer lines wrap instead of scrolling. */
.layout { max-width: 1340px; margin: 0 auto; padding: 0 16px; display: grid; grid-template-columns: 200px minmax(0, 1040px); gap: 40px; justify-content: center; }
.toc { position: sticky; top: 64px; align-self: start; padding-top: 40px; font-size: 0.85rem; max-height: calc(100vh - 64px); overflow: auto; }
.toc-title { font-weight: 600; color: var(--ink-3); text-transform: uppercase; letter-spacing: 0.06em; font-size: 0.72rem; margin-bottom: 8px; }
.toc ol { list-style: none; margin: 0; padding: 0; border-left: 1px solid var(--line); }
.toc a { display: block; padding: 5px 0 5px 12px; margin-left: -1px; border-left: 2px solid transparent; color: var(--ink-2); text-decoration: none; line-height: 1.35; }
.toc a:hover { color: var(--ink); }
.toc a.active { color: var(--accent); border-left-color: var(--accent); font-weight: 500; }
main { padding: 32px 0 120px; min-width: 0; }
@media (max-width: 1180px) {
  .layout { grid-template-columns: minmax(0, 1040px); gap: 0; }
  .toc { display: none; }
}

/* ---------- prose ---------- */
.hero { padding: 24px 0 28px; border-bottom: 1px solid var(--line); margin-bottom: 28px; }
.hero h1 { font-size: clamp(1.7rem, 4vw, 2.3rem); line-height: 1.2; margin: 0 0 14px; letter-spacing: -0.02em; }
.hero p { margin: 4px 0; color: var(--ink-2); }
.hero h3 { font-size: 1.1rem; font-weight: 500; color: var(--ink-2); margin: -6px 0 12px; }
.hero .byline { font-size: 1.05rem; font-weight: 500; color: var(--ink); margin-top: 6px; }
.hero-note { margin-top: 18px !important; font-size: 0.9rem; padding: 10px 14px; background: var(--surface-2); border-radius: 8px; }
.hero-note.is-solutions { background: color-mix(in srgb, var(--k-experiment) 12%, var(--surface)); border-left: 4px solid var(--k-experiment); }
.md-cell h1 { font-size: 1.55rem; line-height: 1.25; margin: 56px 0 12px; letter-spacing: -0.015em; padding-top: 8px; }
.md-cell h2 { font-size: 1.2rem; margin: 32px 0 8px; }
.md-cell h2.section-title { font-size: 1.3rem; line-height: 1.3; margin: 44px 0 6px; letter-spacing: -0.01em; }
.md-cell h2.intro-title { font-size: 1.3rem; font-weight: 600; color: var(--ink-2); margin: 8px 0 10px; letter-spacing: -0.01em; }
.md-cell h3 { font-size: 1.05rem; margin: 24px 0 6px; }
.md-cell p, .callout-body p { margin: 0.6em 0; }
.md-cell blockquote { margin: 1em 0; padding: 0 14px; border-left: 3px solid var(--line); color: var(--ink-2); }
ul, ol { padding-left: 1.4em; }
li { margin: 0.2em 0; }
.katex-display { overflow-x: auto; overflow-y: hidden; padding: 4px 0; }

/* ---------- callouts ---------- */
.callout {
  --k: var(--k-explain);
  margin: 18px 0; padding: 12px 18px 12px; border-radius: 10px;
  background: color-mix(in srgb, var(--k) 6%, var(--surface));
  border: 1px solid color-mix(in srgb, var(--k) 22%, var(--line));
  border-left: 4px solid var(--k);
}
.callout.k-question { --k: var(--k-question); }
.callout.k-task { --k: var(--k-task); }
.callout.k-hint { --k: var(--k-hint); }
.callout.k-experiment { --k: var(--k-experiment); }
.callout.k-reveal { --k: var(--k-reveal); }
.callout-label { font-size: 0.72rem; font-weight: 700; text-transform: uppercase; letter-spacing: 0.08em; color: var(--k); margin-bottom: 2px; }
.callout-body > :first-child { margin-top: 0.2em; }
.callout-body > :last-child { margin-bottom: 0.2em; }
.callout-body pre { background: var(--code-bg); padding: 8px 12px; border-radius: 6px; overflow-x: auto; }
.callout details { margin: 0.3em 0; }
.callout summary {
  cursor: pointer; font-weight: 600; color: var(--ink-2); list-style: none; display: inline-flex; align-items: center; gap: 6px;
}
.callout summary::-webkit-details-marker { display: none; }
.callout summary::before { content: ""; width: 0; height: 0; border-left: 6px solid currentColor; border-top: 4.5px solid transparent; border-bottom: 4.5px solid transparent; transition: transform 0.15s; }
.callout details[open] > summary::before { transform: rotate(90deg); }
.callout details > div { border-top: 1px dashed color-mix(in srgb, var(--k) 30%, var(--line)); margin-top: 8px; padding-top: 6px; }

/* ---------- code cells ---------- */
.code-cell {
  margin: 18px 0; border: 1px solid var(--line); border-radius: 10px; background: var(--surface); overflow: hidden;
  transition: border-color 0.15s, box-shadow 0.15s;
}
.code-cell:focus-within { border-color: color-mix(in srgb, var(--accent) 55%, var(--line)); box-shadow: 0 0 0 3px color-mix(in srgb, var(--accent) 12%, transparent); }
.code-cell.is-running { border-color: var(--k-hint); }
.code-cell.has-error { border-color: color-mix(in srgb, var(--err-ink) 50%, var(--line)); }
.cell-bar { display: flex; align-items: center; gap: 8px; padding: 6px 8px; background: var(--surface-2); border-bottom: 1px solid var(--line); font-size: 0.8rem; }
.prompt { font-family: var(--mono); color: var(--ink-3); min-width: 3.2em; }
.is-running .prompt, .is-queued .prompt { color: var(--k-hint); }
.cell-title { font-weight: 600; color: var(--ink-2); }
.edited { display: none; font-size: 0.7rem; color: var(--k-hint); border: 1px solid currentColor; border-radius: 99px; padding: 0 7px; }
.is-edited .edited { display: inline; }
.cell-run {
  display: inline-flex; align-items: center; gap: 5px; font: 600 0.78rem var(--sans); cursor: pointer;
  padding: 4px 10px 4px 8px; border-radius: 6px; border: 0; background: var(--accent); color: #fff;
}
.cell-run svg { width: 11px; height: 11px; }
.cell-run:hover { filter: brightness(1.1); }
.elapsed { font-family: var(--mono); font-size: 0.72rem; color: var(--ink-3); }
.runtime-note {
  display: flex; align-items: center; gap: 7px; padding: 6px 12px; font-size: 0.8rem; color: var(--ink-2);
  background: color-mix(in srgb, var(--k-hint) 9%, var(--surface)); border-bottom: 1px solid var(--line);
}
.runtime-note svg { width: 14px; height: 14px; flex: none; color: var(--k-hint); }
.cell-btn { font: 500 0.75rem var(--sans); cursor: pointer; padding: 3px 8px; border-radius: 6px; border: 1px solid transparent; background: none; color: var(--ink-3); }
.cell-btn:hover { color: var(--ink); border-color: var(--line); }
.editor .CodeMirror {
  height: auto; font-family: var(--mono); font-size: 13px; line-height: 1.55;
  background: var(--code-bg); color: var(--ink); padding: 6px 0;
}
.editor .CodeMirror-gutters { background: var(--code-bg); border-right: 0; }
.editor .CodeMirror-linenumber { color: var(--ink-3); opacity: 0.6; padding-right: 10px; }
.editor .CodeMirror-cursor { border-left-color: var(--ink); }
.editor .CodeMirror-selected { background: color-mix(in srgb, var(--accent) 18%, transparent) !important; }
.editor .CodeMirror-matchingbracket { color: inherit !important; background: color-mix(in srgb, var(--accent) 20%, transparent); }
.cm-s-default .cm-keyword { color: var(--tok-kw); }
.cm-s-default .cm-def { color: var(--tok-def); font-weight: 500; }
.cm-s-default .cm-string { color: var(--tok-str); }
.cm-s-default .cm-number { color: var(--tok-num); }
.cm-s-default .cm-comment { color: var(--tok-com); font-style: italic; }
.cm-s-default .cm-builtin { color: var(--tok-builtin); }
.cm-s-default .cm-variable { color: var(--ink); }
.cm-s-default .cm-variable-2 { color: var(--tok-prop); }
.cm-s-default .cm-property { color: var(--tok-prop); }
.cm-s-default .cm-operator { color: var(--ink-2); }
.cm-s-default .cm-meta { color: var(--tok-builtin); }
.output:empty { display: none; }
.output { border-top: 1px solid var(--line); background: var(--out-bg); padding: 8px 14px; }
.out-text { margin: 4px 0; white-space: pre-wrap; word-break: break-word; font-size: 0.82rem; line-height: 1.5; }
.out-stderr { color: var(--k-hint); }
/* terminal colours in text output */
.ansi-b { font-weight: 700; }
.ansi-fg1 { color: #d1242f; } .ansi-fg2 { color: #1a7f37; } .ansi-fg3 { color: #9a6700; } .ansi-fg4 { color: #0969da; }
.ansi-fg5 { color: #8250df; } .ansi-fg6 { color: #1b7c83; } .ansi-fg7 { color: var(--ink-3); } .ansi-fg0 { color: var(--ink); }
[class*="ansi-bg"] { color: #fff; border-radius: 2px; }
.ansi-bg1 { background: #d1242f; } .ansi-bg2 { background: #1a7f37; } .ansi-bg3 { background: #9a6700; } .ansi-bg4 { background: #0969da; }
.ansi-bg5 { background: #8250df; } .ansi-bg6 { background: #1b7c83; } .ansi-bg7 { background: #8c959f; } .ansi-bg0 { background: #24292f; }
.out-error { background: var(--err-bg); color: var(--err-ink); padding: 8px 10px; border-radius: 6px; }
.out-img { display: block; max-width: 100%; height: auto; margin: 6px auto; border-radius: 4px; background: #fff; }
.out-html { overflow-x: auto; font-size: 0.85rem; }
.out-html table { border-collapse: collapse; }
.out-html th, .out-html td { padding: 3px 10px; border-bottom: 1px solid var(--line); text-align: right; }

/* review builds only: Student | Solutions */
.review-switch { display: inline-flex; border: 1px solid var(--line); border-radius: 8px; overflow: hidden; font-size: 0.8rem; font-weight: 600; }
.review-switch > * { padding: 4px 10px; text-decoration: none; color: var(--ink-2); }
.review-switch > a:hover { background: var(--surface-2); color: var(--ink); }
.review-switch [aria-current] { background: var(--k-experiment); color: #fff; }

/* back link + previous/next */
.back { display: inline-flex; align-items: center; gap: 4px; color: var(--ink-2); text-decoration: none; font-size: 0.85rem; padding: 4px 8px 4px 4px; border-radius: 6px; white-space: nowrap; }
.back svg { width: 15px; height: 15px; }
.back:hover { color: var(--ink); background: var(--surface-2); }
@media (max-width: 600px) { .back span { display: none; } }
.pager { max-width: 1040px; margin: 0 auto 32px; padding: 0 16px; display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.pager a { display: block; padding: 14px 16px; border: 1px solid var(--line); border-radius: 10px; text-decoration: none; color: var(--ink); background: var(--surface); font-weight: 500; }
.pager a:hover { border-color: var(--accent); }
.pager a span { display: block; font-size: 0.75rem; text-transform: uppercase; letter-spacing: 0.06em; color: var(--ink-3); font-weight: 600; margin-bottom: 2px; }
.pager .next { text-align: right; grid-column: 2; }
@media (max-width: 600px) { .pager { grid-template-columns: 1fr; } .pager .next { grid-column: 1; } }

/* footer */
.page-footer { border-top: 1px solid var(--line); padding: 20px 16px 40px; text-align: center; font-size: 0.8rem; color: var(--ink-3); }
.page-footer p { margin: 4px auto; max-width: 900px; }
.page-footer a { color: var(--ink-2); }

/* folded code (helpers) */
.code-fold { margin: 18px 0; border: 1px solid var(--line); border-radius: 10px; background: var(--surface); }
.code-fold > summary { cursor: pointer; padding: 10px 14px; display: flex; gap: 12px; align-items: baseline; font-weight: 600; list-style: none; }
.code-fold > summary::-webkit-details-marker { display: none; }
.code-fold > summary::before { content: "▸"; color: var(--ink-3); transition: transform 0.15s; }
.code-fold[open] > summary::before { transform: rotate(90deg); }
.fold-meta { font-weight: 400; font-size: 0.8rem; color: var(--ink-3); }
.helper-state { margin-left: auto; font: 500 0.75rem var(--sans); color: var(--ink-3); padding: 1px 9px; border-radius: 99px; background: var(--surface-2); }
.helper-state[data-state="loaded"] { color: var(--k-task); }
.helper-state[data-state="failed"] { color: var(--err-ink); }
.helper-state[data-state="[*]"] { color: var(--k-hint); }
.ref-list { border-top: 1px solid var(--line); }
.ref-item { border-bottom: 1px solid var(--line); }
.ref-item > summary {
  list-style: none; cursor: pointer; padding: 8px 14px 8px 30px; display: flex; flex-wrap: wrap; column-gap: 10px; align-items: baseline; position: relative;
}
.ref-item > summary::before { content: "▸"; position: absolute; left: 14px; color: var(--ink-3); font-size: 0.75rem; transition: transform 0.15s; }
.ref-item[open] > summary::before { transform: rotate(90deg); }
.ref-doc { flex-basis: 100%; }
.ref-doc:empty { display: none; }
.ref-item > summary::-webkit-details-marker { display: none; }
.ref-item > summary:hover { background: var(--surface-2); }
.ref-sig { font-size: 0.82rem; font-weight: 500; background: none !important; padding: 0 !important; color: var(--tok-def); white-space: normal; word-break: break-word; }
.ref-doc { font-size: 0.85rem; color: var(--ink-2); line-height: 1.45; }
.ref-tag { font-size: 0.68rem; text-transform: uppercase; letter-spacing: 0.06em; color: var(--ink-3); }
.is-private .ref-sig { color: var(--ink-3); }
.ref-src { margin: 0; padding: 10px 14px 12px; background: var(--code-bg); font-size: 12.5px; line-height: 1.55; white-space: pre-wrap; border-top: 1px dashed var(--line); }
.ref-note { margin: 0; padding: 10px 14px; font-size: 0.8rem; color: var(--ink-3); }
.helper-ref .output { border-top: 1px solid var(--line); }
.code-fold .code-cell { margin: 0; border: 0; border-top: 1px solid var(--line); border-radius: 0 0 10px 10px; }

@media (max-width: 600px) {
  body { font-size: 15px; }
  .topbar-title { max-width: 100%; flex-basis: 100%; }
  .cell-btn { display: none; }
}