/* Shared course stylesheet — every lesson and reference doc links this. */

:root {
  --bg: #fffdf8;
  --ink: #1a1a1a;
  --muted: #6b6b6b;
  --accent: #b3541e;      /* warm rust — links, highlights */
  --accent-soft: #f6e3d3;
  --rule: #e2ddd2;
  --code-bg: #f4f1ea;
  --good: #2e7d32;
  --bad: #b23b3b;
  --card: #ffffff;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #191713;
    --ink: #e8e4dc;
    --muted: #9a958b;
    --accent: #e08a4e;
    --accent-soft: #3a2a1c;
    --rule: #35312a;
    --code-bg: #232019;
    --good: #7cc47f;
    --bad: #e08585;
    --card: #201d18;
  }
}

* { box-sizing: border-box; }

body {
  background: var(--bg);
  color: var(--ink);
  font-family: Charter, Georgia, 'Times New Roman', serif;
  font-size: 1.06rem;
  line-height: 1.65;
  max-width: 44rem;
  margin: 0 auto;
  padding: 3rem 1.5rem 6rem;
}

h1, h2, h3 {
  font-weight: 600;
  line-height: 1.25;
  margin: 2.2em 0 0.6em;
}
h1 { font-size: 2rem; margin-top: 0; }
h1 .lesson-number { display: block; font-size: 0.8rem; letter-spacing: 0.18em; text-transform: uppercase; color: var(--muted); margin-bottom: 0.6em; }
h2 { font-size: 1.35rem; }
h3 { font-size: 1.1rem; }

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

p, ul, ol { margin: 0 0 1.1em; }
li { margin-bottom: 0.35em; }

hr { border: none; border-top: 1px solid var(--rule); margin: 2.5rem 0; }

code, pre {
  font-family: ui-monospace, 'SF Mono', Menlo, Consolas, monospace;
  font-size: 0.86em;
  background: var(--code-bg);
  border-radius: 4px;
}
code { padding: 0.12em 0.35em; }
pre {
  padding: 1rem 1.2rem;
  overflow-x: auto;
  line-height: 1.5;
  border: 1px solid var(--rule);
}
pre code { background: none; padding: 0; }

table {
  border-collapse: collapse;
  width: 100%;
  margin: 1.2em 0;
  font-size: 0.95em;
}
th, td { text-align: left; padding: 0.45em 0.8em; border-bottom: 1px solid var(--rule); vertical-align: top; }
th { font-family: system-ui, sans-serif; font-size: 0.8em; text-transform: uppercase; letter-spacing: 0.06em; color: var(--muted); }
.table-scroll { overflow-x: auto; }

/* Callouts */
.note, .win, .warn {
  border-left: 3px solid var(--accent);
  background: var(--accent-soft);
  padding: 0.8rem 1.1rem;
  border-radius: 0 6px 6px 0;
  margin: 1.4em 0;
}
.win { border-left-color: var(--good); }
.warn { border-left-color: var(--bad); }
.note > :last-child, .win > :last-child, .warn > :last-child { margin-bottom: 0; }

/* Simple flow diagram built from divs */
.flow {
  display: flex;
  flex-wrap: wrap;
  align-items: stretch;
  gap: 0.5rem;
  margin: 1.6em 0;
  font-family: system-ui, sans-serif;
  font-size: 0.85rem;
}
.flow .step {
  flex: 1 1 9rem;
  background: var(--card);
  border: 1px solid var(--rule);
  border-radius: 8px;
  padding: 0.7rem 0.9rem;
}
.flow .step b { display: block; margin-bottom: 0.25rem; color: var(--accent); }
.flow .arrow { align-self: center; color: var(--muted); font-size: 1.2rem; }

/* Footer nav present in every lesson */
.lesson-footer {
  margin-top: 3.5rem;
  padding-top: 1.2rem;
  border-top: 1px solid var(--rule);
  font-family: system-ui, sans-serif;
  font-size: 0.88rem;
  color: var(--muted);
}

/* Two-party protocol view (wallet | wire | mint) — used by BDHKE and flow lessons */
.protocol {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.6rem;
  font-family: system-ui, sans-serif;
  font-size: 0.85rem;
  margin: 1.4em 0;
}
.protocol .party {
  background: var(--card);
  border: 1px solid var(--rule);
  border-radius: 8px;
  padding: 0.7rem 0.9rem;
  min-height: 8rem;
}
.protocol .party h4 { margin: 0 0 0.6rem; font-size: 0.8rem; text-transform: uppercase; letter-spacing: 0.08em; color: var(--muted); }
.protocol .val {
  border: 1px solid var(--rule);
  border-left: 3px solid var(--accent);
  border-radius: 4px;
  padding: 0.35rem 0.6rem;
  margin-bottom: 0.4rem;
  background: var(--bg);
  overflow-wrap: anywhere;
}
.protocol .val.secret { border-left-color: var(--bad); }
.protocol .val.public { border-left-color: var(--good); }
.protocol .val b { font-family: ui-monospace, Menlo, monospace; }
.protocol .val code { font-size: 0.8em; }
.protocol .wire {
  grid-column: 1 / -1;
  text-align: center;
  color: var(--muted);
  font-size: 0.8rem;
  padding: 0.1rem 0;
}
.controls { display: flex; flex-wrap: wrap; gap: 0.5rem; margin: 1em 0; font-family: system-ui, sans-serif; }
.controls button {
  font: inherit;
  font-size: 0.9rem;
  color: var(--ink);
  background: var(--card);
  border: 1px solid var(--rule);
  border-radius: 6px;
  padding: 0.45em 0.9em;
  cursor: pointer;
}
.controls button.primary { border-color: var(--accent); color: var(--accent); font-weight: 600; }
.controls button:disabled { opacity: 0.4; cursor: default; }
.status-line { font-family: system-ui, sans-serif; font-size: 0.9rem; min-height: 1.5em; margin: 0.6em 0; }
.status-line.ok { color: var(--good); }
.status-line.err { color: var(--bad); }

/* Quiz (rendered by quiz.js) */
.quiz { margin: 1.6em 0; font-family: system-ui, sans-serif; }
.quiz .q {
  background: var(--card);
  border: 1px solid var(--rule);
  border-radius: 8px;
  padding: 1rem 1.2rem;
  margin-bottom: 1rem;
}
.quiz .q p.question { font-weight: 600; margin-bottom: 0.7em; }
.quiz button.opt {
  display: block;
  width: 100%;
  text-align: left;
  font: inherit;
  color: inherit;
  background: var(--bg);
  border: 1px solid var(--rule);
  border-radius: 6px;
  padding: 0.5em 0.8em;
  margin-bottom: 0.45em;
  cursor: pointer;
}
.quiz button.opt:hover:not(:disabled) { border-color: var(--accent); }
.quiz button.opt.correct { border-color: var(--good); background: color-mix(in srgb, var(--good) 12%, var(--bg)); }
.quiz button.opt.wrong { border-color: var(--bad); background: color-mix(in srgb, var(--bad) 12%, var(--bg)); }
.quiz .explain { font-size: 0.92em; color: var(--muted); margin-top: 0.6em; display: none; }
.quiz .q.answered .explain { display: block; }