/* =====================================================================
   PTC Class Library — styling.
   ---------------------------------------------------------------------
   Colors, fonts and corner radius come from assets/theme.js; the values
   below are only fallbacks for if that file fails to load. Everything
   else — spacing, layout, the shape of the cards — lives here.
   ===================================================================== */

:root {
  /* Parameters (overridden by assets/theme.js) */
  --heading-light: #660000; --heading-dark: #f0b3b3;
  --accent-light: #8c1d1d;  --accent-dark: #e09a9a;
  --ground-light: #fff4e8;  --ground-dark: #1e1614;
  --panel-light:  #fffcf7;  --panel-dark:  #2a1f1c;
  --ink-light:    #2b211c;  --ink-dark:    #f0e4da;
  --radius: 10px;
  --page: 1500px;
  --serif: "IBM Plex Serif", Georgia, "Times New Roman", serif;
  --sans: "IBM Plex Sans", "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --mono: "IBM Plex Mono", Consolas, "Courier New", monospace;
  --focus: #a33b00;

  /* Light palette, derived from the parameters */
  --heading: var(--heading-light);
  --accent: var(--accent-light);
  --ground: var(--ground-light);
  --panel: var(--panel-light);
  --ink: var(--ink-light);
  --panel-2: color-mix(in srgb, var(--ink) 6%, var(--panel));
  --ink-2: color-mix(in srgb, var(--ink) 72%, var(--panel));
  --ink-3: color-mix(in srgb, var(--ink) 48%, var(--panel));
  --line: color-mix(in srgb, var(--ink) 14%, var(--panel));
  --line-2: color-mix(in srgb, var(--ink) 24%, var(--panel));
  --accent-ink: #ffffff;
  --accent-soft: color-mix(in srgb, var(--accent) 14%, var(--panel));
  --shadow: 0 1px 2px rgba(0, 0, 0, .05), 0 8px 24px -12px rgba(0, 0, 0, .18);
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --heading: var(--heading-dark);
    --accent: var(--accent-dark);
    --ground: var(--ground-dark);
    --panel: var(--panel-dark);
    --ink: var(--ink-dark);
    --panel-2: color-mix(in srgb, var(--ink) 5%, var(--panel));
    --ink-2: color-mix(in srgb, var(--ink) 70%, var(--panel));
    --ink-3: color-mix(in srgb, var(--ink) 45%, var(--panel));
    --line: color-mix(in srgb, var(--ink) 12%, var(--panel));
    --line-2: color-mix(in srgb, var(--ink) 20%, var(--panel));
    --accent-ink: #1e1614;
    --accent-soft: color-mix(in srgb, var(--accent) 18%, var(--panel));
    --shadow: 0 1px 2px rgba(0, 0, 0, .3), 0 8px 24px -12px rgba(0, 0, 0, .5);
  }
}
:root[data-theme="dark"] {
  --heading: var(--heading-dark);
  --accent: var(--accent-dark);
  --ground: var(--ground-dark);
  --panel: var(--panel-dark);
  --ink: var(--ink-dark);
  --panel-2: color-mix(in srgb, var(--ink) 5%, var(--panel));
  --ink-2: color-mix(in srgb, var(--ink) 70%, var(--panel));
  --ink-3: color-mix(in srgb, var(--ink) 45%, var(--panel));
  --line: color-mix(in srgb, var(--ink) 12%, var(--panel));
  --line-2: color-mix(in srgb, var(--ink) 20%, var(--panel));
  --accent-ink: #1e1614;
  --accent-soft: color-mix(in srgb, var(--accent) 18%, var(--panel));
  --shadow: 0 1px 2px rgba(0, 0, 0, .3), 0 8px 24px -12px rgba(0, 0, 0, .5);
}

* { box-sizing: border-box; }
html { color-scheme: light dark; }
body {
  margin: 0;
  background: var(--ground);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.55;
  padding-block: 16px 48px;
  padding-inline: clamp(16px, 4vw, 40px);
  -webkit-font-smoothing: antialiased;
}
a { color: var(--accent); }
:focus-visible { outline: 3px solid var(--focus); outline-offset: 2px; border-radius: 4px; }
@media (prefers-reduced-motion: reduce) { * { transition: none !important; animation: none !important; } }

.wrap { max-width: var(--page); margin: 0 auto; }

/* ---------- toolbar (no page title: the Google Site supplies it) ---------- */
.head { display: flex; justify-content: flex-end; padding-bottom: 14px; }
.tools { display: flex; flex-wrap: wrap; gap: 10px; align-items: center; }
@media (max-width: 560px) { .head { justify-content: stretch; } .tools { width: 100%; } .search { flex: 1 1 100%; } }
.search { position: relative; }
.search input {
  font: inherit; font-size: 15px; color: var(--ink); background: var(--panel);
  border: 1px solid var(--line-2); border-radius: 999px; padding: 9px 14px 9px 38px; width: 260px; max-width: 100%;
}
.search input::placeholder { color: var(--ink-3); }
.search svg { position: absolute; left: 13px; top: 50%; translate: 0 -50%; width: 16px; height: 16px; fill: none; stroke: var(--ink-3); stroke-width: 2; }
.btn {
  font: inherit; font-size: 14px; font-weight: 500; color: var(--ink-2); background: transparent;
  border: 1px solid var(--line-2); border-radius: 999px; padding: 8px 14px; cursor: pointer;
}
.btn:hover { color: var(--ink); border-color: var(--ink-3); }

/* ---------- layout ---------- */
.layout { display: grid; grid-template-columns: 220px 1fr; gap: 36px; margin-top: 4px; }
/* One visible unit needs no sidebar index. */
.layout.solo { grid-template-columns: 1fr; }
.layout.solo .index { display: none; }
@media (max-width: 760px) { .layout { grid-template-columns: 1fr; gap: 20px; } }

.index { position: sticky; top: 16px; align-self: start; }
@media (max-width: 760px) { .index { position: static; } }
.index h2 { font-family: var(--mono); font-size: 12px; letter-spacing: .12em; text-transform: uppercase; color: var(--heading); margin: 0 0 10px; font-weight: 500; opacity: .75; }
.index ol { list-style: none; margin: 0; padding: 0; display: flex; flex-direction: column; gap: 2px; }
.index a {
  display: grid; grid-template-columns: 26px 1fr; gap: 8px; align-items: baseline;
  padding: 6px 8px; border-radius: 6px; color: var(--ink-2); text-decoration: none; font-size: 14px;
}
.index a:hover { background: var(--panel-2); color: var(--ink); }
.index a .n { font-family: var(--mono); font-size: 12px; color: var(--ink-3); }
.index .count { margin-top: 14px; font-size: 13px; color: var(--ink-3); }
@media (max-width: 760px) {
  .index ol { flex-direction: row; flex-wrap: wrap; gap: 6px; }
  .index a { grid-template-columns: auto 1fr; padding: 5px 10px; border: 1px solid var(--line); background: var(--panel); }
}

/* ---------- units ---------- */
.units { display: flex; flex-direction: column; gap: 14px; min-width: 0; }
.unit { background: var(--panel); border: 1px solid var(--line); border-radius: var(--radius); box-shadow: var(--shadow); scroll-margin-top: 16px; }
.unit[open] { border-color: var(--line-2); }
.unit > summary {
  list-style: none; cursor: pointer; display: grid; grid-template-columns: 34px 1fr auto; gap: 14px; align-items: center;
  padding: 16px 18px; border-radius: var(--radius);
}
.unit > summary::-webkit-details-marker { display: none; }
.unit > summary .n {
  font-family: var(--mono); font-size: 13px; font-weight: 500; color: var(--heading);
  background: var(--accent-soft); border-radius: 6px; height: 34px; display: grid; place-items: center;
}
.unit > summary h2 { font-family: var(--serif); font-weight: 600; font-size: 19px; margin: 0; line-height: 1.25; text-wrap: balance; color: var(--heading); }
/* The unit's one-line description, sitting under its title. It gets the
   full width of the header rather than a prose measure, so it can run on
   for a good while before wrapping. */
.unit > summary .sub { font-size: 14.5px; color: var(--ink-2); margin-top: 3px; text-wrap: pretty; }
.chev { width: 20px; height: 20px; color: var(--ink-3); transition: transform .2s ease; }
.unit[open] > summary .chev { transform: rotate(180deg); }
.lesson > summary .chev { width: 17px; height: 17px; }
.lesson[open] > summary .chev { transform: rotate(180deg); }
.lesson > summary:hover .chev { color: var(--ink-2); }
@media (max-width: 560px) {
  .unit > summary { grid-template-columns: 30px 1fr auto; gap: 10px; padding: 14px; }
  .unit > summary .n { height: 30px; }
}

/* ---------- lessons ---------- */
.lessons { list-style: none; margin: 0; padding: 0 0 6px; border-top: 1px solid var(--line); }
.lesson { border-bottom: 1px solid var(--line); }
.lesson:last-child { border-bottom: 0; }
.lesson > summary {
  list-style: none; cursor: pointer; display: grid; grid-template-columns: 1fr auto auto; gap: 12px; align-items: center;
  padding: 12px 18px 12px 66px; font-size: 15px;
}
.lesson > summary::-webkit-details-marker { display: none; }
.lesson > summary:hover { background: var(--panel-2); }
.lesson > summary .t { font-weight: 500; }
.lesson > summary .d { font-size: 13px; color: var(--ink-3); margin-top: 1px; }
.lesson > summary .dur { font-family: var(--mono); font-size: 12px; color: var(--ink-3); font-variant-numeric: tabular-nums; }
.lesson[open] > summary { background: var(--panel-2); }
.lesson .body {
  display: grid; grid-template-columns: minmax(0, 1fr) 260px; gap: 20px 28px; padding: 18px 18px 22px 66px;
}
/* No materials means no sidebar, so the video gets the room instead. */
.lesson .body.solo { grid-template-columns: minmax(0, 1fr); }
/* Prose keeps a readable measure whatever the page width; the video gets
   a little more room, and a grid of cards gets all of it. */
.lesson .body.solo .player,
.lesson .body.solo .watch { max-width: 900px; }
.lesson .body.solo .block.with-shots { max-width: none; }
.lesson .body .main { min-width: 0; }

/* Given room, the notes sit beside the video rather than under it. That
   fills the gap to the video's right and keeps the lesson shorter, which
   matters inside a fixed-height Sites block. Cards stay full width below. */
@media (min-width: 1100px) {
  .lesson .body.solo .main {
    display: grid; grid-template-columns: minmax(0, 900px) minmax(240px, 1fr);
    column-gap: 34px; align-items: start;
  }
  .lesson .body.solo .media { grid-column: 1; }
  .lesson .body.solo .write { grid-column: 2; }
  .lesson .body.solo .blocks { grid-column: 1 / -1; }
  .lesson .body.solo .write .notes:first-child { margin-top: 0; }
}
@media (max-width: 860px) { .lesson .body { grid-template-columns: 1fr; } }
@media (max-width: 560px) { .lesson > summary, .lesson .body { padding-left: 14px; } }

.player { aspect-ratio: 16 / 9; max-width: 100%; background: var(--panel-2); border-radius: 8px; overflow: hidden; border: 1px solid var(--line); }
.player iframe { width: 100%; height: 100%; border: 0; display: block; }

/* Thumbnail stand-in. Clicking it swaps in the real player, so a lesson
   costs one image instead of a full YouTube frame until someone watches. */
.poster {
  display: block; position: relative; width: 100%; height: 100%; padding: 0; margin: 0;
  border: 0; background: var(--panel-2); cursor: pointer; overflow: hidden;
}
.poster img { width: 100%; height: 100%; object-fit: cover; display: block; }
.poster .play {
  position: absolute; inset: 0; display: grid; place-items: center;
  background: linear-gradient(to top, rgba(0, 0, 0, .28), rgba(0, 0, 0, 0) 55%);
}
.poster .play svg { width: 64px; height: 64px; transition: transform .18s ease; filter: drop-shadow(0 2px 8px rgba(0, 0, 0, .35)); }
.poster .play .pb { fill: var(--heading); stroke: var(--panel); }
.poster .play .pt { fill: var(--panel); }
.poster:hover .play svg, .poster:focus-visible .play svg { transform: scale(1.08); }
.watch { margin: 10px 0 0; font-size: 13px; display: flex; flex-wrap: wrap; gap: 4px 18px; }
.watch a { text-decoration: none; }
.watch a:hover { text-decoration: underline; }
.placeholder { height: 100%; display: grid; place-content: center; text-align: center; gap: 6px; padding: 20px; color: var(--ink-2); font-size: 14px; }
.placeholder svg { width: 40px; height: 40px; margin: 0 auto 4px; stroke: var(--ink-3); fill: none; stroke-width: 1.6; }
.placeholder code { font-family: var(--mono); font-size: 12px; color: var(--ink-3); }

/* ---------- notes and bullet points under the video ---------- */
.notes { margin: 14px 0 0; color: var(--ink-2); max-width: 65ch; }
.notes + .notes { margin-top: 8px; }
/* **bold** in a note or bullet, lifted to full contrast so it carries. */
.notes strong, .points strong { color: var(--ink); font-weight: 600; }
.block { margin: 16px 0 0; max-width: 65ch; }
.block-title, .side h3 {
  font-family: var(--mono); font-size: 12px; letter-spacing: .12em; text-transform: uppercase;
  color: var(--heading); margin: 0 0 8px; font-weight: 500; opacity: .75;
}
.points { margin: 0; padding-left: 20px; color: var(--ink-2); }
.points li { margin: 0 0 5px; }
.points li:last-child { margin-bottom: 0; }
.points li::marker { color: var(--accent); }

/* A bullet can carry a still from the clip. Once a list has stills it stops
   being a bullet list and becomes a row of cards: picture on top, note under
   it, wrapping to as many columns as the width allows. */
.block.with-shots { max-width: none; }
.block.with-shots .points {
  list-style: none; padding-left: 0;
  display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 26px 22px;
}
.block.with-shots .points li { margin: 0; }
.points .shot {
  display: block; width: 100%; aspect-ratio: 4 / 3; object-fit: cover; margin-bottom: 9px;
  border: 1px solid var(--line); border-radius: 6px; background: var(--panel-2);
}
@media (max-width: 560px) {
  .block.with-shots .points { gap: 20px; }
}
.materials { list-style: none; margin: 0 0 16px; padding: 0; display: flex; flex-direction: column; gap: 6px; }
.materials a {
  display: grid; grid-template-columns: 18px 1fr; gap: 8px; align-items: center; text-decoration: none; color: var(--ink);
  font-size: 14px; padding: 8px 10px; border: 1px solid var(--line); border-radius: 6px; background: var(--panel);
}
.materials a:hover { border-color: var(--accent); }
.materials svg { width: 16px; height: 16px; stroke: var(--accent); fill: none; stroke-width: 1.8; }
.materials .kind { display: block; font-size: 12px; color: var(--ink-3); }
.empty-side { font-size: 14px; color: var(--ink-3); margin: 0; }
.permalink { font-size: 13px; }

.no-results { color: var(--ink-2); padding: 24px; text-align: center; border: 1px dashed var(--line-2); border-radius: var(--radius); }
[hidden] { display: none !important; }
mark { background: var(--accent-soft); color: inherit; padding: 0 2px; border-radius: 3px; }