/* ==========================================================================
   Shared lesson stylesheet.
   Every lesson and reference document links this file so the workspace reads
   as one course rather than a pile of one-offs.
   Tufte-influenced: generous measure, serif prose, quiet rules, real margins.
   ========================================================================== */

:root {
  --ink: #16150f;
  --ink-soft: #55524a;
  --ink-faint: #8b8779;
  --paper: #fffef9;
  --paper-sunk: #f4f1e6;
  --rule: #ddd8c6;
  --accent: #9c3610;
  --accent-soft: #f4e6df;
  --safe: #2f6b45;
  --danger: #a32020;
  --measure: 38rem;

  --serif: "Iowan Old Style", "Palatino Linotype", Palatino, "Book Antiqua",
    Georgia, serif;
  --mono: "SF Mono", "JetBrains Mono", Menlo, Consolas, monospace;
}

@media (prefers-color-scheme: dark) {
  :root {
    --ink: #e8e4d9;
    --ink-soft: #a8a397;
    --ink-faint: #74705f;
    --paper: #14140f;
    --paper-sunk: #1e1e17;
    --rule: #33322a;
    --accent: #e0864f;
    --accent-soft: #2b1d15;
    --safe: #6ab883;
    --danger: #e07070;
  }
}

* { box-sizing: border-box; }

body {
  margin: 0 auto;
  padding: 4rem 1.5rem 8rem;
  max-width: var(--measure);
  background: var(--paper);
  color: var(--ink);
  font-family: var(--serif);
  font-size: 1.0625rem;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

/* --- Masthead ------------------------------------------------------------ */

.masthead {
  border-bottom: 1px solid var(--rule);
  padding-bottom: 1.25rem;
  margin-bottom: 2.5rem;
}

.eyebrow {
  font-family: var(--mono);
  font-size: 0.7rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--ink-faint);
  margin: 0 0 0.75rem;
}

.eyebrow a { color: inherit; }

h1 {
  font-size: 2rem;
  line-height: 1.15;
  font-weight: 600;
  letter-spacing: -0.01em;
  margin: 0 0 0.6rem;
}

.standfirst {
  margin: 0;
  color: var(--ink-soft);
  font-size: 1.075rem;
  font-style: italic;
}

h2 {
  font-size: 1.3rem;
  font-weight: 600;
  margin: 3rem 0 0.85rem;
  letter-spacing: -0.005em;
}

h3 {
  font-size: 1.02rem;
  font-weight: 600;
  margin: 2rem 0 0.6rem;
}

p { margin: 0 0 1.15rem; }

a { color: var(--accent); text-decoration-thickness: 1px; text-underline-offset: 2px; }

strong { font-weight: 600; }

/* --- Code ---------------------------------------------------------------- */

code {
  font-family: var(--mono);
  font-size: 0.86em;
  background: var(--paper-sunk);
  padding: 0.12em 0.34em;
  border-radius: 3px;
}

pre {
  font-family: var(--mono);
  font-size: 0.82rem;
  line-height: 1.6;
  background: var(--paper-sunk);
  border: 1px solid var(--rule);
  border-radius: 5px;
  padding: 1rem 1.1rem;
  overflow-x: auto;
  margin: 0 0 1.15rem;
}

pre code { background: none; padding: 0; font-size: inherit; }

/* A terminal transcript. .prompt marks what you type, .out what comes back. */
.term .prompt::before {
  content: "$ ";
  color: var(--ink-faint);
}
.term .out { color: var(--ink-soft); }
.term .cmt { color: var(--ink-faint); font-style: italic; }

/* --- Command anatomy diagram --------------------------------------------- */

.anatomy {
  margin: 1.75rem 0;
  padding: 1.25rem 1.1rem 0.9rem;
  background: var(--paper-sunk);
  border: 1px solid var(--rule);
  border-radius: 5px;
  overflow-x: auto;
}

.anatomy-line {
  font-family: var(--mono);
  font-size: 1rem;
  display: flex;
  gap: 0.7rem;
  white-space: nowrap;
}

.part { display: flex; flex-direction: column; align-items: flex-start; }

.part .tok { color: var(--ink); }

.part .bar {
  width: 100%;
  height: 5px;
  border: 1px solid var(--accent);
  border-top: none;
  margin-top: 3px;
}

.part .lbl {
  font-family: var(--mono);
  font-size: 0.63rem;
  letter-spacing: 0.09em;
  text-transform: uppercase;
  color: var(--accent);
  margin-top: 4px;
  white-space: normal;
  max-width: 9rem;
}

/* --- Callouts ------------------------------------------------------------ */

.callout {
  margin: 1.75rem 0;
  padding: 0.95rem 1.1rem;
  border-left: 3px solid var(--accent);
  background: var(--accent-soft);
  border-radius: 0 4px 4px 0;
  font-size: 0.95rem;
}

.callout p:last-child { margin-bottom: 0; }

.callout .tag {
  display: block;
  font-family: var(--mono);
  font-size: 0.65rem;
  letter-spacing: 0.13em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 0.45rem;
}

.callout.danger { border-left-color: var(--danger); }
.callout.danger .tag { color: var(--danger); }

/* --- Quiz ---------------------------------------------------------------- */

.quiz {
  margin: 1.5rem 0;
  padding: 1.15rem 1.2rem;
  border: 1px solid var(--rule);
  border-radius: 5px;
  background: var(--paper-sunk);
}

.quiz .q {
  font-weight: 600;
  margin: 0 0 0.9rem;
}

.quiz .q code { background: var(--paper); }

.quiz button.opt {
  display: block;
  width: 100%;
  text-align: left;
  font-family: var(--mono);
  font-size: 0.82rem;
  line-height: 1.45;
  padding: 0.6rem 0.75rem;
  margin-bottom: 0.45rem;
  background: var(--paper);
  color: var(--ink);
  border: 1px solid var(--rule);
  border-radius: 4px;
  cursor: pointer;
  transition: border-color 0.12s, background 0.12s;
}

.quiz button.opt:hover:not(:disabled) { border-color: var(--accent); }
.quiz button.opt:disabled { cursor: default; opacity: 0.55; }

.quiz button.opt.right {
  border-color: var(--safe);
  background: color-mix(in srgb, var(--safe) 12%, var(--paper));
  opacity: 1;
}

.quiz button.opt.wrong {
  border-color: var(--danger);
  background: color-mix(in srgb, var(--danger) 12%, var(--paper));
  opacity: 1;
}

.quiz .fb {
  display: none;
  margin-top: 0.75rem;
  padding-top: 0.75rem;
  border-top: 1px solid var(--rule);
  font-size: 0.92rem;
  color: var(--ink-soft);
}

.quiz .fb.show { display: block; }
.quiz .fb p:last-child { margin-bottom: 0; }

/* --- Task list (real-world steps) ---------------------------------------- */

.task { counter-reset: step; list-style: none; padding: 0; margin: 1.5rem 0; }

.task li {
  counter-increment: step;
  position: relative;
  padding-left: 2.1rem;
  margin-bottom: 1.1rem;
}

.task li::before {
  content: counter(step);
  position: absolute;
  left: 0;
  top: 0.1em;
  width: 1.45rem;
  height: 1.45rem;
  border: 1px solid var(--accent);
  border-radius: 50%;
  color: var(--accent);
  font-family: var(--mono);
  font-size: 0.72rem;
  display: flex;
  align-items: center;
  justify-content: center;
}

/* --- Source / footer ----------------------------------------------------- */

.source {
  margin: 2.5rem 0;
  padding: 1.1rem 1.2rem;
  border: 1px solid var(--rule);
  border-radius: 5px;
}

.source .tag {
  display: block;
  font-family: var(--mono);
  font-size: 0.65rem;
  letter-spacing: 0.13em;
  text-transform: uppercase;
  color: var(--ink-faint);
  margin-bottom: 0.5rem;
}

.source p:last-child { margin-bottom: 0; }

.ask {
  margin-top: 3.5rem;
  padding-top: 1.25rem;
  border-top: 1px solid var(--rule);
  font-size: 0.95rem;
  color: var(--ink-soft);
  font-style: italic;
}

.next { margin-top: 2rem; font-size: 0.95rem; }

footer {
  margin-top: 3rem;
  padding-top: 1.25rem;
  border-top: 1px solid var(--rule);
  font-family: var(--mono);
  font-size: 0.7rem;
  letter-spacing: 0.06em;
  color: var(--ink-faint);
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
}

footer a { color: inherit; }

/* --- Reference-document variant ------------------------------------------ */

.ref-table { width: 100%; border-collapse: collapse; margin: 1.25rem 0; font-size: 0.9rem; }
.ref-table th, .ref-table td { text-align: left; padding: 0.5rem 0.6rem; border-bottom: 1px solid var(--rule); vertical-align: top; }
.ref-table th { font-family: var(--mono); font-size: 0.66rem; letter-spacing: 0.1em; text-transform: uppercase; color: var(--ink-faint); font-weight: 400; }
.ref-table td:first-child { font-family: var(--mono); font-size: 0.84em; white-space: nowrap; }

/* --- Print --------------------------------------------------------------- */

@media print {
  :root {
    --ink: #000; --ink-soft: #333; --ink-faint: #666;
    --paper: #fff; --paper-sunk: #f6f6f6; --rule: #ccc;
    --accent: #8a2f0d; --accent-soft: #f7f0ec;
  }
  body { padding: 0; max-width: 100%; font-size: 11pt; }
  h1, h2, h3 { break-after: avoid; }
  pre, .anatomy, .callout, .quiz, .source { break-inside: avoid; }
  .quiz button.opt { opacity: 1; }
  .quiz .fb { display: block; }
  .ask, .next { break-inside: avoid; }
}