/* cram: shared look for every page (same tokens as the semester skill). */
:root {
  --paper: #F4F3EF; --paper-2: #EBE9E3; --card: #FBFAF7;
  --ink: #45403C; --ink-soft: #6C6661; --muted: #9A948D; --rule: #DCD8D0; --grid: rgba(110,100,90,.06);
  --sage: #D4E2D0; --sage-ink: #4F7A4A; --slate: #4E7184; --slate-soft: #E2EAEE;
  --brown: #7A3D1C; --brown-soft: #F1E6DF; --blue: #1668B8; --blue-soft: #E3EEF9;
  --code-bg: #EFEDE7; --on-accent: #FFFFFF;
  --font: "Jost", "IBM Plex Sans Thai", system-ui, sans-serif;
  --hand: "Mali", "Jost", "IBM Plex Sans Thai", cursive;
  --mono: "IBM Plex Mono", ui-monospace, Menlo, monospace;
  --measure: 44rem;
  color-scheme: light;
}
/* Light is the default. Dark mode is opt-in: set data-theme="dark" on the root html element. */
:root[data-theme="dark"] {
  --paper: #1A1917; --paper-2: #23211E; --card: #211F1C;
  --ink: #E6E0D8; --ink-soft: #B9B1A8; --muted: #8C857D; --rule: #3A3631; --grid: rgba(255,250,240,.035);
  --sage: #2E3B2B; --sage-ink: #9CC394; --slate: #93B6C9; --slate-soft: #233039;
  --brown: #A8603A; --brown-soft: #3A2A20; --blue: #74AAF0; --blue-soft: #1D2A3B;
  --code-bg: #26241F; --on-accent: #12161C; color-scheme: dark; }

* { box-sizing: border-box; }
body { background-color: var(--paper); color: var(--ink); font: 17px/1.85 var(--font);
  background-image: linear-gradient(var(--grid) 1px, transparent 1px), linear-gradient(90deg, var(--grid) 1px, transparent 1px);
  background-size: 28px 28px; }
body::after { content: ""; position: fixed; inset: 0; border: 6px solid var(--brown); pointer-events: none; z-index: 50; }
a { color: var(--slate); text-underline-offset: 3px; }
a:hover { color: var(--brown); }
:focus-visible { outline: 2px solid var(--blue); outline-offset: 2px; }
.topbar { max-width: 60rem; margin: 0 auto; padding-block: 24px 0;
  padding-left: max(24px, env(safe-area-inset-left, 0px)); padding-right: max(24px, env(safe-area-inset-right, 0px));
  display: flex; flex-wrap: wrap; gap: 4px 18px; align-items: baseline; font-size: 13px; letter-spacing: .06em; text-transform: uppercase; }
.topbar .course { font-weight: 600; color: var(--ink); margin-right: auto; text-decoration: none; }
.topbar a { color: var(--ink-soft); text-decoration: none; }
main { max-width: var(--measure); margin: 0 auto; padding-block: 8px 96px;
  padding-left: max(24px, env(safe-area-inset-left, 0px)); padding-right: max(24px, env(safe-area-inset-right, 0px)); }
@media (max-width: 520px) { .topbar, main { padding-left: max(18px, env(safe-area-inset-left, 0px)); padding-right: max(18px, env(safe-area-inset-right, 0px)); } body { font-size: 16px; } }

.kicker { margin: 34px 0 6px; font-size: 13px; letter-spacing: .12em; text-transform: uppercase; color: var(--ink-soft); }
h1 { margin: 0 0 8px; padding: 14px 18px; background: var(--sage); font-weight: 500; font-size: clamp(1.55rem, 4.2vw, 2rem); line-height: 1.38; text-wrap: balance; }
h2 { margin: 56px 0 10px; font-weight: 500; font-size: 1.3rem; letter-spacing: .03em; border-bottom: 1px solid var(--rule); padding-bottom: 4px; text-wrap: balance; }
h2 .num { font-family: var(--hand); color: var(--blue); margin-right: 8px; }
h3 { margin: 30px 0 4px; font-weight: 600; font-size: 1.06rem; }
p, li { hyphens: auto; }
.meta { color: var(--ink-soft); font-size: 15px; }
strong { font-weight: 600; }
.goal { border-left: 4px solid var(--sage-ink); background: var(--card); padding: 12px 18px; margin: 20px 0; }
.goal b, .goal strong { color: var(--sage-ink); }
.def { background: var(--card); border-top: 28px solid var(--slate); position: relative; padding: 12px 18px; margin: 26px 0; }
.def::before { content: attr(data-label); position: absolute; top: -25px; left: 14px; color: var(--on-accent); font-size: 12px; letter-spacing: .1em; text-transform: uppercase; }
.note { background: var(--slate-soft); padding: 10px 16px; margin: 20px 0; font-size: 15.5px; }
.warn { background: var(--brown-soft); border-left: 4px solid var(--brown); padding: 10px 16px; margin: 20px 0; font-size: 15.5px; }
.link-infer { border-left: 4px solid var(--blue); background: var(--blue-soft); padding: 10px 16px; margin: 20px 0; font-size: 15.5px; }
.link-infer::before { content: "ใช้ตรงไหน"; display: block; font-family: var(--hand); font-size: 13px; color: var(--blue); }
details.predict { background: var(--card); border: 1px dashed var(--muted); padding: 10px 16px; margin: 20px 0; }
details.predict summary { cursor: pointer; font-weight: 500; }
details.predict summary::before { content: "ทายก่อน · "; font-family: var(--hand); color: var(--blue); }
details.predict[open] summary { margin-bottom: 6px; }
code { font-family: var(--mono); font-size: .86em; background: var(--code-bg); padding: 1px 5px; }
.code { position: relative; margin: 16px 0; }
.code pre { margin: 0; background: var(--code-bg); border: 1px solid var(--rule); padding: 12px 14px; overflow-x: auto; font: 14px/1.6 var(--mono); }
.code pre code { background: none; padding: 0; font-size: inherit; }
.code .lang { position: absolute; top: -10px; left: 10px; font: 11px/1.6 var(--mono); background: var(--paper); padding: 0 6px; color: var(--muted); }
.code button { position: absolute; top: 6px; right: 6px; font: 12px var(--font); background: var(--card); color: var(--ink-soft); border: 1px solid var(--rule); padding: 1px 8px; cursor: pointer; }
.code button:hover { color: var(--slate); border-color: var(--slate); }
table { border-collapse: collapse; width: 100%; font-size: 15px; margin: 16px 0; }
.tbl { overflow-x: auto; }
th, td { border-bottom: 1px solid var(--rule); padding: 6px 10px; text-align: left; vertical-align: top; }
th { font-weight: 500; color: var(--ink-soft); font-size: 13px; letter-spacing: .05em; text-transform: uppercase; }
td code { white-space: nowrap; }
.exercise { background: var(--card); border: 2px solid var(--ink); border-radius: 14px 6px 12px 5px / 6px 12px 5px 14px; padding: 14px 18px; margin: 28px 0; }
.exercise .tag { font-family: var(--hand); color: var(--blue); font-size: 14px; }
.exercise h4 { margin: 0 0 4px; font-size: 1.05rem; font-weight: 600; }
.exercise ul { margin: 6px 0; padding-left: 1.2em; }
.checklist { list-style: none; padding-left: 0; }
.checklist li::before { content: "☐ "; color: var(--sage-ink); }
.paper-ref { background: var(--card); border: 1px solid var(--rule); padding: 10px 16px; margin: 16px 0; font-size: 15.5px; }
.paper-ref .lbl { font-size: 12px; letter-spacing: .12em; text-transform: uppercase; color: var(--brown); }
.pager { display: flex; justify-content: space-between; gap: 16px; margin-top: 48px; font-size: 16px; border-top: 1px solid var(--rule); padding-top: 14px; }
.index-list { list-style: none; padding: 0; display: grid; gap: 12px; }
.index-list a { display: grid; grid-template-columns: 64px minmax(0,1fr); gap: 12px; text-decoration: none; color: var(--ink); background: var(--card); border: 1px solid var(--rule); padding: 12px 16px; }
.index-list a:hover { border-color: var(--slate); }
.index-list .w { font-family: var(--hand); font-size: 1.2rem; font-weight: 600; color: var(--blue); }
.index-list .t { font-weight: 500; line-height: 1.5; }
.index-list .s { display: block; font-size: 14px; color: var(--ink-soft); }
article[hidden], section[hidden] { display: none; }

/* ---- cram additions ------------------------------------------------- */
:root { --ok: #4F7A4A; --bad: #A3472A; }
:root[data-theme="dark"] { --ok: #9CC394; --bad: #E58C70; }
.wide { margin-inline: -6rem; }
@media (max-width: 1000px) { .wide { margin-inline: 0; } }

/* slide image taken from the lecture PDF */
figure.slide { margin: 24px 0; }
figure.slide img { width: 100%; display: block; border: 1px solid var(--rule); background: #fff; }
figure.slide figcaption { font-size: 14px; color: var(--ink-soft); margin-top: 6px; }
figure.slide figcaption b { font-family: var(--hand); color: var(--brown); font-weight: 600; margin-right: 6px; }

/* what the lecturer said, with a jump to that moment */
.lecture { background: var(--card); border-left: 4px solid var(--sage-ink); padding: 10px 16px; margin: 20px 0; font-size: 15.5px; }
.lecture::before { content: "จากคาบเรียน"; display: block; font-size: 12px; letter-spacing: .08em; color: var(--sage-ink); font-weight: 600; }
.lecture[data-t]::before { content: "จากคาบเรียน · " attr(data-t); }
.jump { font: 13px var(--mono); background: var(--paper); color: var(--ink); border: 1px solid var(--rule); padding: 1px 8px; cursor: pointer; margin-top: 6px; }
.jump:hover { border-color: var(--sage-ink); color: var(--sage-ink); }

/* list of clips for this lesson */
.clips { background: var(--card); border: 1px solid var(--rule); padding: 10px 16px 6px; margin: 20px 0; font-size: 15px; }
.clips ul { list-style: none; padding: 0; margin: 6px 0 0; }
.clips li { display: flex; gap: 10px; align-items: baseline; padding: 4px 0; border-top: 1px solid var(--rule); }
.clips li:first-child { border-top: 0; }

/* web sources that back up the lesson */
.sources { border: 1px solid var(--rule); background: var(--card); padding: 12px 18px; margin: 28px 0; font-size: 15.5px; }
.sources .lbl { font-size: 12px; letter-spacing: .12em; text-transform: uppercase; color: var(--brown); }
.sources ul { margin: 6px 0 0; padding-left: 1.2em; display: grid; gap: 4px; }

/* self-check questions (quiz.js) */
.q { background: var(--card); border: 1px solid var(--rule); padding: 14px 18px; margin: 16px 0; }
.q-head { font-size: 12px; letter-spacing: .1em; text-transform: uppercase; color: var(--muted); }
.q-head .tag { color: var(--slate); }
.q-body { margin: 4px 0 10px; }
.q-row { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; }
.q-row input { font: inherit; font-size: 16px; padding: 3px 10px; border: 1px solid var(--rule); background: var(--paper); color: var(--ink); width: 12em; }
.q button, .q .btn { font: inherit; font-size: 15px; background: var(--paper); color: var(--ink); border: 1px solid var(--rule); padding: 3px 12px; cursor: pointer; }
.q button:hover { border-color: var(--slate); color: var(--slate); }
.q button.primary { background: var(--slate); color: var(--on-accent); border-color: var(--slate); }
.choices { display: grid; gap: 6px; }
.choices button { text-align: left; padding: 6px 12px; }
.choices button.right { border-color: var(--ok); background: var(--sage); color: var(--ok); }
.choices button.wrong { border-color: var(--bad); background: var(--brown-soft); color: var(--bad); }
.q .fb { margin-top: 8px; font-size: 15.5px; background: none; border: 0; padding: 0; }
.q .fb.ok { color: var(--ok); } .q .fb.no { color: var(--bad); }
.q-hint, .q-sol { margin-top: 10px; padding: 8px 14px; font-size: 15.5px; background: var(--paper); border-left: 3px solid var(--muted); }
.q-sol { border-left-color: var(--sage-ink); }
.q.done { border-color: var(--sage-ink); }

/* index */
.lesson-list { list-style: none; padding: 0; margin: 12px 0; }
.lesson-list li { display: grid; grid-template-columns: 3rem minmax(0,1fr) auto; gap: 12px; align-items: baseline; padding: 10px 0; border-bottom: 1px solid var(--rule); }
.lesson-list .n { font-family: var(--hand); font-size: 1.3rem; color: var(--blue); font-weight: 600; }
.lesson-list .t a { font-weight: 500; text-decoration: none; color: var(--ink); }
.lesson-list .t a:hover { color: var(--brown); }
.lesson-list .d { display: block; font-size: 14.5px; color: var(--ink-soft); }
.lesson-list .s { font-family: var(--hand); font-size: 13px; color: var(--muted); white-space: nowrap; }
.lesson-list .s.done { color: var(--sage-ink); }

/* floating video dock (video.js) */
#dock { position: fixed; right: max(18px, env(safe-area-inset-right, 0px)); bottom: max(18px, env(safe-area-inset-bottom, 0px)); z-index: 70;
  width: min(460px, calc(100vw - 32px)); background: var(--card); border: 1px solid var(--rule); box-shadow: 0 6px 24px rgba(0,0,0,.14); }
#dock[hidden] { display: none; }
#dock .bar { display: flex; align-items: center; gap: 6px; padding: 4px 6px 4px 12px; font-size: 13px; }
#dock .bar span { flex: 1; font-weight: 600; }
#dock .bar button { background: none; border: 0; color: var(--ink-soft); font-size: 16px; cursor: pointer; }
#dock video { width: 100%; display: block; background: #000; }
@media (prefers-reduced-motion: reduce) { * { scroll-behavior: auto !important; } }

/* quotes in lessons */
blockquote { margin: 16px 0; padding: 6px 16px; border-left: 4px solid var(--rule); color: var(--ink-soft); }
blockquote p { margin: 4px 0; }

/* interactive widgets (widgets.js) */
.widget { background: var(--card); border: 1px solid var(--rule); padding: 14px 16px; margin: 24px 0; }
.widget .kit-plot { width: 100%; height: auto; display: block; touch-action: pan-y; }
.kit-axes line { stroke: var(--muted); stroke-width: 1; }
.kit-axes text, .kit-label { font: 12px var(--mono); fill: var(--ink-soft); }
.kit-slider { display: flex; align-items: center; gap: 10px; margin: 10px 0 4px; font-size: 15px; }
.kit-slider input { flex: 1; accent-color: var(--blue); }
.kit-slider output { font-family: var(--mono); min-width: 4em; text-align: right; }
.widget .readout { font-size: 15.5px; margin-top: 6px; }
.widget .legend { display: flex; flex-wrap: wrap; gap: 14px; font-size: 14px; color: var(--ink-soft); margin: 4px 0 8px; }
.widget .legend i { display: inline-block; width: 18px; height: 3px; vertical-align: middle; margin-right: 6px; }
.widget button { font: inherit; font-size: 15px; background: var(--paper); color: var(--ink); border: 1px solid var(--rule); padding: 3px 12px; cursor: pointer; }
.widget button:hover { border-color: var(--slate); color: var(--slate); }

/* boxes written in Markdown wrap their text in <p>: no extra space at the edges */
:is(.def, .warn, .note, .goal, .lecture, .link-infer, .exercise, details.predict, .sources) > p:first-child,
details.predict > summary + p { margin-top: 0; }
:is(.def, .warn, .note, .goal, .lecture, .link-infer, .exercise, details.predict, .sources) > p:last-child { margin-bottom: 0; }
.tbl { margin: 16px 0; } .tbl > table { margin: 0; }