/* worksheet.css -- the Guiding Questions companion site.
 *
 * Deliberately shares NOTHING with shared/css/style.css (the light Bootswatch
 * Lumen theme used by the interactive lessons). The two sites sit side by side
 * in a student's browser tabs, so they are styled to be unmistakable at a
 * glance: the interactive site is light and app-like, this one is dark and
 * document-like. No Bootstrap -- these pages are worksheets, not app screens.
 */

:root {
  color-scheme: dark;

  --bg:          #0e1218;
  --bg-soft:     #131923;
  --surface:     #182029;
  --surface-2:   #1e2833;
  --border:      #2a3542;
  --border-soft: #222c37;

  --text:        #d6dee9;
  --text-strong: #f2f6fb;
  --muted:       #8b9aac;

  --link:        #74b9f0;

  /* One accent per task type -- see .task--* below. */
  --recommended: #4fc3ad;
  --coding:      #a78bfa;
  --extension:   #f0a35e;
  --accent:      var(--recommended);

  --radius: 10px;
  --measure: 74ch;   /* comfortable reading width for prose */
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  font-size: 17px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--link); text-decoration-thickness: 1px; text-underline-offset: 2px; }
a:hover { color: #a5d4f7; }

code, pre, kbd { font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, "Liberation Mono", monospace; }

/* ------------------------------------------------------------------ layout */

.page {
  max-width: 940px;
  margin: 0 auto;
  padding: 0 24px;
}

.page > p,
.page > ul,
.page > ol { max-width: var(--measure); }

main.page { padding-bottom: 72px; }

/* ------------------------------------------------------------------ topbar */
/* Injected by js/worksheet.js so every page stays in sync. */

.topbar {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(14, 18, 24, 0.86);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border-soft);
}

.topbar-inner {
  max-width: 940px;
  margin: 0 auto;
  padding: 10px 24px;
  display: flex;
  align-items: center;
  gap: 16px;
}

.brand {
  font-weight: 650;
  color: var(--text-strong);
  text-decoration: none;
  letter-spacing: -0.01em;
  white-space: nowrap;
}

.topbar-links {
  margin-left: auto;
  display: flex;
  align-items: center;
  gap: 18px;
  font-size: 0.9rem;
}
.topbar-links a { color: var(--muted); text-decoration: none; }
.topbar-links a:hover { color: var(--text-strong); }

.topbar-links a.live {
  color: var(--text-strong);
  border: 1px solid var(--border);
  background: var(--surface);
  padding: 5px 12px;
  border-radius: 999px;
}
.topbar-links a.live:hover { border-color: var(--accent); }

/* -------------------------------------------------------------- page header */

.page-head {
  background: var(--bg-soft);
  border-bottom: 1px solid var(--border-soft);
  padding: 40px 0 32px;
  margin-bottom: 40px;
}

.eyebrow {
  margin: 0 0 8px;
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.09em;
  text-transform: uppercase;
  color: var(--accent);
}

.page-title {
  margin: 0;
  font-size: clamp(1.7rem, 3.4vw, 2.3rem);
  line-height: 1.2;
  letter-spacing: -0.02em;
  color: var(--text-strong);
  max-width: 22ch;
}

.lede {
  font-size: 1.06rem;
  color: var(--muted);
  max-width: var(--measure);
}

/* --------------------------------------------------------- launch the site */

.launch {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  margin-top: 22px;
  padding: 12px 18px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-left: 3px solid var(--accent);
  border-radius: var(--radius);
  text-decoration: none;
  color: var(--text-strong);
  transition: border-color 0.15s, transform 0.15s;
}
.launch:hover { border-color: var(--accent); transform: translateY(-1px); color: var(--text-strong); }
.launch-label { font-weight: 600; }
.launch-label::after { content: " \2197"; color: var(--accent); }
.launch-path {
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 0.8rem;
  color: var(--muted);
  border-left: 1px solid var(--border);
  padding-left: 12px;
}

/* ------------------------------------------------------------- task blocks */

.task {
  --task-accent: var(--recommended);
  background: var(--surface);
  border: 1px solid var(--border);
  border-top: 3px solid var(--task-accent);
  border-radius: var(--radius);
  margin: 0 0 28px;
  overflow: hidden;
}

.task--recommended { --task-accent: var(--recommended); }
.task--coding      { --task-accent: var(--coding); }
.task--extension   { --task-accent: var(--extension); }

.task-head {
  display: flex;
  align-items: flex-start;
  gap: 14px;
  padding: 18px 22px;
  border-bottom: 1px solid var(--border-soft);
  background: linear-gradient(180deg, rgba(255,255,255,0.022), transparent);
}

.task-badge {
  flex: none;
  margin-top: 3px;
  padding: 3px 10px;
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.07em;
  text-transform: uppercase;
  color: var(--task-accent);
  border: 1px solid color-mix(in srgb, var(--task-accent) 42%, transparent);
  background: color-mix(in srgb, var(--task-accent) 11%, transparent);
  border-radius: 999px;
  white-space: nowrap;
}

.task-title {
  margin: 0;
  font-size: 1.16rem;
  font-weight: 620;
  line-height: 1.35;
  color: var(--text-strong);
}

.task-body { padding: 20px 22px 4px; }
.task-body > *:first-child { margin-top: 0; }

/* Sub-headings within a long task -- e.g. the numbered steps of a coding task. */
.task-body h3 {
  margin: 32px 0 10px;
  font-size: 1rem;
  font-weight: 650;
  letter-spacing: 0.01em;
  color: var(--text-strong);
  padding-bottom: 6px;
  border-bottom: 1px solid var(--border-soft);
  max-width: var(--measure);
}

.task-body p,
.task-body ul,
.task-body ol { max-width: var(--measure); }

/* ------------------------------------------------------------------- steps */

ol.steps {
  list-style: none;
  counter-reset: step;
  padding: 0;
  margin: 20px 0;
}
ol.steps > li {
  counter-increment: step;
  position: relative;
  padding: 0 0 0 44px;
  margin-bottom: 22px;
}
ol.steps > li::before {
  content: counter(step);
  position: absolute;
  left: 0;
  top: 0;
  width: 28px;
  height: 28px;
  display: grid;
  place-items: center;
  font-size: 0.85rem;
  font-weight: 650;
  color: var(--task-accent, var(--accent));
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: 50%;
}
ol.steps > li > *:first-child { margin-top: 0; }

/* ---------------------------------------------------------------- callouts */

.note, .tip, .warn {
  margin: 18px 0;
  padding: 12px 16px;
  border-radius: 8px;
  border-left: 3px solid var(--muted);
  background: var(--surface-2);
  font-size: 0.95rem;
  max-width: var(--measure);
}
.note > *:first-child, .tip > *:first-child, .warn > *:first-child { margin-top: 0; }
.note > *:last-child,  .tip > *:last-child,  .warn > *:last-child  { margin-bottom: 0; }

.tip  { border-left-color: var(--recommended); }
.warn { border-left-color: var(--extension); }

.note-label {
  display: block;
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 4px;
}
.tip  .note-label { color: var(--recommended); }
.warn .note-label { color: var(--extension); }

/* ------------------------------------------------------- reveal-the-answer */

details.answer {
  margin: 18px 0;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--surface-2);
  max-width: var(--measure);
}
details.answer > summary {
  padding: 10px 16px;
  cursor: pointer;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-strong);
  list-style: none;
}
details.answer > summary::-webkit-details-marker { display: none; }
details.answer > summary::before {
  content: "\25B8";
  display: inline-block;
  margin-right: 9px;
  color: var(--accent);
  transition: transform 0.15s;
}
details.answer[open] > summary::before { transform: rotate(90deg); }
details.answer > summary:hover { color: var(--link); }
.answer-body { padding: 0 16px 14px; border-top: 1px solid var(--border-soft); }
.answer-body > *:first-child { margin-top: 12px; }

/* ------------------------------------------------------------ screenshots */

figure.shot {
  margin: 20px 0;
  padding: 0;
}
figure.shot img {
  display: block;
  max-width: 100%;
  height: auto;
  border: 1px solid var(--border);
  border-radius: 8px;
  /* Lesson screenshots are light-on-white; a hairline keeps them from
     bleeding into the dark page. */
  background: #fff;
}
figure.shot figcaption {
  margin-top: 8px;
  font-size: 0.84rem;
  color: var(--muted);
}

/* Placeholder used until the real screenshot is dropped in. */
.shot--todo .shot-frame {
  display: grid;
  place-items: center;
  min-height: 150px;
  padding: 24px;
  text-align: center;
  border: 1px dashed var(--border);
  border-radius: 8px;
  background: repeating-linear-gradient(
    45deg, transparent, transparent 9px,
    rgba(255,255,255,0.017) 9px, rgba(255,255,255,0.017) 18px);
  color: var(--muted);
  font-size: 0.87rem;
}
.shot--todo .shot-frame b { color: var(--text); font-weight: 600; }

/* ---------------------------------------------------------------- R code */

pre.code {
  position: relative;
  margin: 18px 0;
  padding: 16px 18px;
  background: #0b0f14;
  border: 1px solid var(--border);
  border-radius: 8px;
  overflow-x: auto;
  font-size: 0.87rem;
  line-height: 1.55;
  color: #cfe3d8;
}
pre.code[data-lang]::before {
  content: attr(data-lang);
  position: absolute;
  top: 0;
  right: 0;
  padding: 2px 9px;
  font-size: 0.68rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  color: var(--muted);
  background: var(--surface-2);
  border-left: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
  border-radius: 0 8px 0 8px;
}
pre.code.output {
  color: var(--muted);
  background: #0a0d11;
}

:not(pre) > code {
  padding: 1px 5px;
  font-size: 0.87em;
  background: var(--surface-2);
  border: 1px solid var(--border-soft);
  border-radius: 4px;
  color: #e3d9b8;
}

kbd {
  padding: 1px 6px;
  font-size: 0.82em;
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-bottom-width: 2px;
  border-radius: 4px;
}

/* ---------------------------------------------- skeleton / TODO scaffolding */
/* Everything below is temporary: it marks the not-yet-written parts of the
   site so the shape is visible. Delete .todo blocks as pages get filled in. */

.todo {
  margin: 16px 0;
  padding: 12px 16px;
  border: 1px dashed color-mix(in srgb, var(--extension) 45%, transparent);
  border-radius: 8px;
  background: color-mix(in srgb, var(--extension) 7%, transparent);
  color: var(--muted);
  font-size: 0.9rem;
  max-width: var(--measure);
}
.todo::before {
  content: "TO WRITE";
  display: block;
  font-size: 0.68rem;
  font-weight: 700;
  letter-spacing: 0.09em;
  color: var(--extension);
  margin-bottom: 4px;
}

.tag-skeleton {
  display: inline-block;
  padding: 1px 8px;
  font-size: 0.68rem;
  font-weight: 700;
  letter-spacing: 0.07em;
  text-transform: uppercase;
  color: var(--extension);
  border: 1px solid color-mix(in srgb, var(--extension) 40%, transparent);
  border-radius: 999px;
  vertical-align: middle;
}

/* ------------------------------------------------------------ home page */

.home-hero { padding: 56px 0 40px; }
.home-hero .page-title { max-width: 18ch; }

.home-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 14px;
  margin: 0 0 40px;
}

.ws-card {
  display: block;
  padding: 16px 18px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  text-decoration: none;
  color: var(--text);
  transition: border-color 0.15s, transform 0.15s;
}
.ws-card:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
  color: var(--text);
}
.ws-card-title {
  display: block;
  font-weight: 600;
  color: var(--text-strong);
  line-height: 1.35;
}

.cat-head {
  display: flex;
  align-items: baseline;
  gap: 12px;
  margin: 36px 0 14px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--border-soft);
}
.cat-head h2 {
  margin: 0;
  font-size: 1.15rem;
  letter-spacing: -0.01em;
  color: var(--text-strong);
}
.cat-head .count { font-size: 0.8rem; color: var(--muted); }

/* -------------------------------------------------------- prev / next pager */

.pager {
  display: flex;
  gap: 12px;
  margin-top: 48px;
  padding-top: 24px;
  border-top: 1px solid var(--border-soft);
}
.pager a {
  flex: 1 1 0;
  padding: 12px 16px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  text-decoration: none;
  color: var(--text-strong);
  font-size: 0.92rem;
  line-height: 1.35;
}
.pager a:hover { border-color: var(--accent); }
.pager .dir {
  display: block;
  font-size: 0.72rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 3px;
}
.pager .next { text-align: right; }

/* -------------------------------------------------------------- site footer */

.site-foot {
  border-top: 1px solid var(--border-soft);
  margin-top: 64px;
  padding: 28px 0 48px;
  font-size: 0.85rem;
  color: var(--muted);
}
.site-foot .page { display: flex; gap: 18px; flex-wrap: wrap; }

/* ------------------------------------------------------------------ small */

@media (max-width: 620px) {
  body { font-size: 16px; }
  .page, .topbar-inner { padding-left: 18px; padding-right: 18px; }
  .task-head { flex-wrap: wrap; }
  .pager { flex-direction: column; }
  .pager .next { text-align: left; }
  .launch { flex-wrap: wrap; gap: 6px; }
  .launch-path { border-left: 0; padding-left: 0; }
}

/* Worksheets get printed and handed out -- make that not look terrible. */
@media print {
  :root { --text:#000; --text-strong:#000; --muted:#444; }
  body { background: #fff; color: #000; }
  .topbar, .pager, .site-foot { display: none; }
  .page-head { background: none; border-bottom: 1px solid #ccc; }
  .task { border: 1px solid #bbb; break-inside: avoid; }
  pre.code { background: #f6f6f6; color: #000; }
  details.answer[open] > summary { color: #000; }
}