/* Learn to Code by Hand - shared styles */
:root {
  --paper: #f7f5f0;
  --card: #ffffff;
  --ink: #1c1d21;
  --ink-2: #55575f;
  --line: #e2ded5;
  --accent: #d9822b;
  --accent-ink: #8a4a0c;
  --good: #1f8a4c;
  --bad: #c43b3b;
  --code-bg: #17181c;
  --code-ink: #e6e6e6;
  --mono: "JetBrains Mono", ui-monospace, "Cascadia Code", Consolas, monospace;
  --sans: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --code-inline: #ebe7de;
  --panel: #fbfaf7;
  --accent-soft: #fdf0e2;
  --good-soft: #e8f5ec;
  --good-line: #b3dcc1;
  --bad-soft: #fbecec;
  --bad-line: #f0c9c9;
  --chrome: #e9e6df;
  --chrome-bar: #dcd8cf;
  --chrome-dot: #b9b4a8;
  --chrome-url: #f4f2ed;
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --paper: #141519; --card: #1d1e23; --ink: #e9e7e2; --ink-2: #a5a49f; --line: #33343b;
    --accent: #e8913a; --accent-ink: #f2a961; --good: #52c47f; --bad: #ff7a7a;
    --code-bg: #0f1013; --code-inline: #2a2b31; --panel: #191a1e; --accent-soft: #3a2914;
    --good-soft: #142a1c; --good-line: #2b5a3b; --bad-soft: #351a1c; --bad-line: #6a2f33;
    --chrome: #222329; --chrome-bar: #2c2d34; --chrome-dot: #4b4d56; --chrome-url: #18191d;
    color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --paper: #141519; --card: #1d1e23; --ink: #e9e7e2; --ink-2: #a5a49f; --line: #33343b;
  --accent: #e8913a; --accent-ink: #f2a961; --good: #52c47f; --bad: #ff7a7a;
  --code-bg: #0f1013; --code-inline: #2a2b31; --panel: #191a1e; --accent-soft: #3a2914;
  --good-soft: #142a1c; --good-line: #2b5a3b; --bad-soft: #351a1c; --bad-line: #6a2f33;
  --chrome: #222329; --chrome-bar: #2c2d34; --chrome-dot: #4b4d56; --chrome-url: #18191d;
  color-scheme: dark;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
* { font-variant-ligatures: none; }
body { margin: 0; background: var(--paper); color: var(--ink); font: 17px/1.6 var(--sans); padding-inline: 16px; }
a { color: var(--accent-ink); }
code { font-family: var(--mono); font-size: .88em; background: var(--code-inline); padding: .1em .35em; border-radius: 4px; }
pre.code { font-family: var(--mono); font-size: 14px; line-height: 1.55; background: var(--code-bg); color: var(--code-ink); padding: 12px 14px; border-radius: 8px; overflow-x: auto; }
pre.code code { background: none; padding: 0; font-size: inherit; color: inherit; }

/* ---------- reading column ---------- */
.top { max-width: 760px; margin: 0 auto; padding-block: 40px 8px; }
.kicker { font: 600 13px/1 var(--mono); letter-spacing: .08em; text-transform: uppercase; color: var(--accent-ink); margin: 0 0 12px; }
h1 { font-size: clamp(30px, 5vw, 44px); line-height: 1.1; margin: 0 0 14px; letter-spacing: -.02em; }
.lede { font-size: 19px; color: var(--ink-2); margin: 0 0 20px; }
.toc { display: flex; flex-wrap: wrap; gap: 6px; padding: 0; margin: 20px 0 0; list-style: none; }
.toc a { display: inline-block; font: 13px/1 var(--mono); padding: 7px 10px; border: 1px solid var(--line); border-radius: 999px; text-decoration: none; color: var(--ink); background: var(--card); }
.toc a:hover { border-color: var(--accent); }
main > section { max-width: 760px; margin: 0 auto; padding-block: 28px; border-top: 1px solid var(--line); }
h2 { font-size: 26px; line-height: 1.2; margin: 0 0 12px; letter-spacing: -.01em; }
h2 .num { font: 600 14px/1 var(--mono); color: var(--accent-ink); display: block; margin-bottom: 8px; letter-spacing: .06em; }
.callout { background: var(--card); border: 1px solid var(--line); border-left: 4px solid var(--accent); border-radius: 8px; padding: 12px 16px; margin: 16px 0; }
.callout p { margin: .3em 0; }
.compare { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 12px; }
.compare figure { margin: 0; }
.compare figcaption { font: 600 12px/1 var(--mono); color: var(--ink-2); margin-bottom: 6px; text-transform: uppercase; letter-spacing: .06em; }
.compare pre.code { margin: 0; }
details.cpp { margin: 12px 0; }
details.cpp summary { cursor: pointer; font: 600 13px var(--mono); color: var(--ink-2); }

/* ---------- concept snippets ---------- */
.snippet { background: var(--card); border: 1px solid var(--line); border-radius: 10px; padding: 14px; margin: 18px 0; }
.predict-q { margin: 0 0 10px; font-weight: 600; }
.tag { font: 700 11px/1 var(--mono); text-transform: uppercase; letter-spacing: .08em; background: var(--accent); color: #fff; padding: 4px 7px; border-radius: 4px; vertical-align: 2px; }
.predict-opts { display: flex; flex-wrap: wrap; gap: 8px; }
.opt { font: 14px var(--mono); padding: 8px 12px; border: 1px solid var(--line); background: var(--paper); border-radius: 6px; cursor: pointer; color: var(--ink); }
.opt:hover:not(:disabled) { border-color: var(--accent); }
.opt:disabled { cursor: default; opacity: .6; }
.opt.right { opacity: 1; border-color: var(--good); background: var(--good-soft); }
.opt.wrong { opacity: 1; border-color: var(--bad); background: var(--bad-soft); }
.predict-fb { margin: 8px 0 12px; min-height: 1.2em; font-size: 15px; color: var(--ink-2); }
.snippet .CodeMirror { height: auto; border-radius: 8px; font-size: 14.5px; }
.snip-bar { display: flex; align-items: center; gap: 8px; margin: 10px 0 0; flex-wrap: wrap; }
.snip-hint { font-size: 14px; color: var(--ink-2); }
.console { font: 14px/1.5 var(--mono); background: #0f1013; color: #cfe8d5; border-radius: 8px; padding: 10px 12px; margin-top: 8px; min-height: 2.6em; white-space: pre-wrap; }
.console:empty::before { content: "Output appears here."; color: #6b6f78; }
.console .dim { color: #6b6f78; }
.console .err { color: #ff8a8a; }
.console .warn { color: #ffd27a; }
.console .info { color: #8fb8ff; }
.try { margin: 12px 0 0; font-size: 15.5px; }
.try strong { color: var(--accent-ink); }
.why { margin-top: 10px; font-size: 15.5px; border-top: 1px dashed var(--line); padding-top: 10px; }

/* ---------- buttons ---------- */
.btn { font: 700 14px/1 var(--sans); letter-spacing: .03em; padding: 10px 16px; border-radius: 7px; border: 1px solid transparent; cursor: pointer; }
.btn.run { background: var(--accent); color: #fff; }
.btn.run:hover:not(:disabled) { background: #c06f1d; }
.btn.check { background: #1f8a4c; color: #fff; }
.btn.check:hover { background: #18723e; }
.btn.ghost { background: transparent; border-color: var(--line); color: var(--ink); }
.btn.ghost:hover:not(:disabled) { border-color: var(--ink-2); }
.btn:disabled { opacity: .45; cursor: default; }

/* ---------- CodeMirror theme ---------- */
.cm-s-lab.CodeMirror { background: var(--code-bg); color: var(--code-ink); font-family: var(--mono); line-height: 1.55; }
.cm-s-lab .CodeMirror-gutters { background: var(--code-bg); border-right: 1px solid #2a2c33; }
.cm-s-lab .CodeMirror-linenumber { color: #5b5f69; }
.cm-s-lab .CodeMirror-cursor { border-left: 2px solid #ffb35c; }
.cm-s-lab .CodeMirror-selected, .cm-s-lab .CodeMirror-focused .CodeMirror-selected { background: #33405a; }
.cm-s-lab .cm-keyword { color: #ff9e64; }
.cm-s-lab .cm-def { color: #7dcfff; }
.cm-s-lab .cm-variable, .cm-s-lab .cm-variable-2 { color: #e6e6e6; }
.cm-s-lab .cm-property { color: #9ece6a; }
.cm-s-lab .cm-string { color: #e0c46c; }
.cm-s-lab .cm-number, .cm-s-lab .cm-atom { color: #c39bff; }
.cm-s-lab .cm-comment { color: #6f7685; font-style: italic; }
.cm-s-lab .cm-operator { color: #89ddff; }
.cm-s-lab .CodeMirror-matchingbracket { color: #fff !important; background: #3b4252; }
.cm-s-lab .lab-err-line { background: rgba(255, 70, 70, .16); }
.cm-s-lab .lab-err-line .CodeMirror-line span { color: #ff7b7b !important; }
.cm-s-lab .lab-err-line .CodeMirror-linenumber { color: #ff7b7b; font-weight: 700; }
.lab-err-note { font: 13px/1.45 var(--sans); color: #ffd0d0; background: #3a1a1d; border-left: 3px solid #ff5d5d; padding: 6px 10px; margin: 2px 0 4px; }

/* ---------- the build ---------- */
.build { max-width: 1440px; margin: 0 auto; padding-block: 28px 60px; border-top: 1px solid var(--line); }
.build-intro { max-width: 760px; margin: 0 auto 18px; }
.wb { background: var(--card); border: 1px solid var(--line); border-radius: 12px; overflow: hidden; }
.wb.focus { position: fixed; inset: 0; z-index: 50; border-radius: 0; display: flex; flex-direction: column; overflow: auto; padding-top: env(safe-area-inset-top, 0px); }
.wb-steps { padding: 14px 16px; border-bottom: 1px solid var(--line); background: var(--panel); }
.wb-nav { display: flex; align-items: center; gap: 6px; flex-wrap: wrap; }
.wb-tabs { display: flex; gap: 4px; flex-wrap: wrap; }
.wb-tab { font: 700 13px/1 var(--mono); min-width: 34px; padding: 8px 9px; border-radius: 6px; border: 1px solid var(--line); background: var(--card); cursor: pointer; color: var(--ink); }
.wb-tab.cur { border-color: var(--accent); background: var(--accent-soft); }
.wb-tab.done { color: var(--good); border-color: var(--good-line); }
.wb-tab.done.cur { background: var(--good-soft); border-color: var(--good); }
.wb-nav .spacer { flex: 1; }
.wb-step { max-width: 900px; }
.wb-step h3 { margin: 14px 0 6px; font-size: 19px; }
.wb-step p, .wb-step li { font-size: 15.5px; }
.wb-step pre.code { font-size: 13.5px; }
.wb-results { margin-top: 10px; }
.wb-results:empty { display: none; }
.res-win { font-weight: 700; color: var(--good); font-size: 17px; margin: 0 0 8px; }
.res-bad { color: var(--bad); font-weight: 600; margin: 0; }
.res-step { border-radius: 8px; padding: 8px 12px; margin: 6px 0; border: 1px solid var(--line); }
.res-step.ok { background: var(--good-soft); border-color: var(--good-line); }
.res-step.bad { background: var(--bad-soft); border-color: var(--bad-line); }
.res-head { margin: 0; font-weight: 700; font-size: 15px; }
.res-step.ok .res-head { color: var(--good); }
.res-step.bad .res-head { color: var(--bad); }
.res-step ul { margin: 6px 0 2px; padding-left: 18px; list-style: none; }
.res-step li { font-size: 14.5px; margin: 3px 0; }
.res-step li.pass { color: var(--good); }
.res-step li.fail { color: var(--ink); }
.res-hint { display: block; color: var(--ink-2); font-size: 14px; margin-left: 1.2em; }
.wb-results > .btn { margin-bottom: 6px; }

.wb-split { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); min-height: 640px; }
.wb.focus .wb-split { flex: 1; min-height: 0; }
.wb-left { display: flex; flex-direction: column; background: var(--code-bg); min-width: 0; }
.wb-bar { display: flex; gap: 8px; align-items: center; padding: 10px 12px; background: #202127; border-bottom: 1px solid #2a2c33; flex-wrap: wrap; }
.wb-bar .label { font: 600 12px/1 var(--mono); color: #9aa0ab; text-transform: uppercase; letter-spacing: .08em; margin-right: auto; }
.wb-bar .btn.ghost { color: #d5d7dc; border-color: #3a3d46; }
.wb-left .CodeMirror { flex: 1; height: auto; min-height: 560px; font-size: 15px; }
.wb.focus .wb-left .CodeMirror { min-height: 0; }
.wb-right { display: flex; flex-direction: column; min-width: 0; border-left: 1px solid var(--line); }

/* On a desktop the workbench fits the window: the step text scrolls in its own panel above
   the code, so the code to copy and the editor to type it in are on screen together. */
@media (min-width: 900px) and (min-height: 600px) {
  .wb { display: flex; flex-direction: column; height: calc(100vh - 24px); height: calc(100dvh - 24px); scroll-margin-top: 12px; }
  .wb.focus { height: auto; }
  .wb-steps { position: relative; flex: 0 1 auto; max-height: 30%; overflow: auto; padding-top: 0; }
  .wb-nav { position: sticky; top: 0; z-index: 2; background: var(--panel); padding-block: 12px 4px; }
  .wb-split { flex: 1; min-height: 0; }
  /* A fixed height (from flex, not the content) so long code scrolls inside the editor. */
  .wb-left { min-height: 0; overflow: hidden; }
  .wb-left .CodeMirror { flex: 1 1 0; height: 0; min-height: 0; }
  .wb-right { min-height: 0; overflow: auto; }
}

@media (max-width: 899px) {
  .wb-split { grid-template-columns: 1fr; }
  .wb-left .CodeMirror { min-height: 420px; }
  .wb-right { border-left: 0; border-top: 1px solid var(--line); }
}

/* fake browser window around the result */
.browser { display: flex; flex-direction: column; flex: 1; background: var(--chrome); }
.browser-bar { display: flex; align-items: center; gap: 10px; padding: 8px 12px; background: var(--chrome-bar); }
.browser-bar .dots { display: flex; gap: 5px; }
.browser-bar .dots i { width: 10px; height: 10px; border-radius: 50%; background: var(--chrome-dot); display: block; }
.browser-bar .url { flex: 1; font: 12.5px var(--mono); background: var(--chrome-url); border-radius: 6px; padding: 5px 10px; color: var(--ink-2); }
.browser-page { flex: 1; padding: 18px; overflow: auto; }
.wb-console { font-size: 13px; margin: 0; border-radius: 0; min-height: 110px; max-height: 220px; overflow: auto; }
.console-head { font: 600 11px/1 var(--mono); text-transform: uppercase; letter-spacing: .08em; color: #8a8f99; background: #0f1013; padding: 8px 12px 0; }

#lab-toast { position: fixed; left: 50%; bottom: calc(24px + env(safe-area-inset-bottom, 0px)); transform: translateX(-50%) translateY(20px); background: #1c1d21; color: #fff; border: 1px solid #44464f; padding: 10px 16px; border-radius: 8px; font-size: 15px; opacity: 0; pointer-events: none; transition: opacity .2s, transform .2s; z-index: 100; max-width: calc(100% - 32px); }
#lab-toast.on { opacity: 1; transform: translateX(-50%) translateY(0); }

footer.foot { max-width: 760px; margin: 0 auto; padding-block: 24px 48px; color: var(--ink-2); font-size: 14px; border-top: 1px solid var(--line); }

/* ---------- light / dark toggle ---------- */
.theme-toggle { position: absolute; top: calc(12px + env(safe-area-inset-top, 0px)); right: 12px; z-index: 40; font: 600 13px/1 var(--sans); padding: 8px 12px; border-radius: 999px; border: 1px solid var(--line); background: var(--card); color: var(--ink); cursor: pointer; }
.theme-toggle:hover { border-color: var(--accent); }
.wb.focus ~ .theme-toggle, body:has(.wb.focus) .theme-toggle { display: none; }

/* ---------- course images ---------- */
.ai-cap { display: block; font-size: 10px; line-height: 1.4; color: #777; text-align: right; padding: 4px 10px 0; }
.splash { margin: 0 0 22px; }
.splash img { display: block; width: 100%; height: auto; aspect-ratio: 12 / 5; object-fit: cover; object-position: 50% 58%; border-radius: 12px; background: #101116; }
.splash .ai-cap { padding: 4px 0 0; }