/* Penny documentation site.
   Warm copper on a light page, with a dark variant that follows the reader's
   system setting. No framework: one stylesheet, one font request. */

:root {
  --bg: #fdfbf9;
  --surface: #ffffff;
  --surface-2: #f8f2ec;
  --ink: #1b1715;
  --ink-2: #463d37;
  --muted: #796d64;
  --line: #ebe0d5;
  --line-2: #ddcfc1;
  --copper: #a3521d;
  --copper-hover: #8a4315;
  --copper-soft: #c47a44;
  --wash: #fdf2e8;
  --term-bg: #211c19;
  --term-ink: #ece3d9;
  --term-dim: #9d8f83;
  --term-green: #8fbf96;
  --term-amber: #e0b25f;
  --shadow: 0 1px 2px rgba(27, 23, 21, .05), 0 8px 24px -12px rgba(27, 23, 21, .18);
  --radius: 12px;
  --maxw: 64rem;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #15110f;
    --surface: #1d1817;
    --surface-2: #231d1a;
    --ink: #f3ece5;
    --ink-2: #d6cabf;
    --muted: #a2948a;
    --line: #322a25;
    --line-2: #43382f;
    --copper: #e09a63;
    --copper-hover: #eeae7b;
    --copper-soft: #c98a54;
    --wash: #251c15;
    --shadow: 0 1px 2px rgba(0, 0, 0, .4), 0 8px 24px -12px rgba(0, 0, 0, .6);
  }
}

*, *::before, *::after { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

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

h1, h2, h3, .wordmark {
  font-family: Fraunces, Georgia, "Times New Roman", serif;
  font-weight: 600;
  line-height: 1.2;
  letter-spacing: -.01em;
  color: var(--ink);
}

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

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

code {
  font-size: .88em;
  background: var(--surface-2);
  border: 1px solid var(--line);
  border-radius: 5px;
  padding: .1em .35em;
}

pre {
  background: var(--surface-2);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1rem 1.1rem;
  overflow-x: auto;
  font-size: .86rem;
  line-height: 1.6;
}

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

.wrap { max-width: var(--maxw); margin: 0 auto; padding: 0 16px; }

/* ── Navigation ─────────────────────────────────────────────────────────── */

.nav {
  position: sticky;
  top: 0;
  z-index: 10;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: saturate(140%) blur(10px);
  border-bottom: 1px solid var(--line);
}

.nav .wrap {
  display: flex;
  align-items: center;
  gap: 1.25rem;
  min-height: 56px;
}

.nav .wordmark {
  font-size: 1.1rem;
  text-decoration: none;
  color: var(--ink);
  margin-right: auto;
}

.nav .wordmark span { color: var(--copper); }

.nav a:not(.wordmark) {
  color: var(--ink-2);
  text-decoration: none;
  font-size: .94rem;
}

.nav a:not(.wordmark):hover { color: var(--copper); }

/* ── Hero ───────────────────────────────────────────────────────────────── */

.hero {
  position: relative;
  overflow: hidden;
  border-bottom: 1px solid var(--line);
  background:
    radial-gradient(60rem 26rem at 18% -18%, var(--wash), transparent 60%),
    var(--bg);
}

.hero .wrap { padding-top: 4.5rem; padding-bottom: 3.5rem; }

.coin {
  font-size: 2.4rem;
  line-height: 1;
  display: block;
  margin-bottom: 1rem;
}

.hero h1 {
  font-size: clamp(2.3rem, 6vw, 3.6rem);
  margin: 0 0 .75rem;
  max-width: 20ch;
}

.hero h1 em { font-style: normal; color: var(--copper); }

.lede {
  font-size: clamp(1.05rem, 2.2vw, 1.22rem);
  color: var(--ink-2);
  max-width: 54ch;
  margin: 0 0 1.75rem;
}

.actions { display: flex; flex-wrap: wrap; gap: .65rem; margin-bottom: 1.5rem; }

.btn {
  display: inline-block;
  padding: .6rem 1.1rem;
  border-radius: 9px;
  font-size: .95rem;
  font-weight: 500;
  text-decoration: none;
  border: 1px solid var(--line-2);
  color: var(--ink);
  background: var(--surface);
  transition: background .15s ease, border-color .15s ease, color .15s ease;
}

.btn:hover { border-color: var(--copper-soft); color: var(--copper); }

.btn-primary {
  background: var(--copper);
  border-color: var(--copper);
  color: #fff;
}

.btn-primary:hover { background: var(--copper-hover); border-color: var(--copper-hover); color: #fff; }

.meta {
  display: flex;
  flex-wrap: wrap;
  gap: .5rem .9rem;
  font-size: .85rem;
  color: var(--muted);
  margin: 0;
  padding: 0;
  list-style: none;
}

.meta li + li::before { content: "·"; margin-right: .9rem; color: var(--line-2); }

/* ── Terminal ───────────────────────────────────────────────────────────── */

.term-shell {
  background: var(--term-bg);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  overflow: hidden;
  margin: 0;
}

.term-bar {
  display: flex;
  align-items: center;
  gap: .4rem;
  padding: .6rem .85rem;
  background: rgba(255, 255, 255, .05);
  border-bottom: 1px solid rgba(255, 255, 255, .07);
}

.dot { width: 10px; height: 10px; border-radius: 50%; display: inline-block; }
.dot.r { background: #d9705f; }
.dot.y { background: #ddb15c; }
.dot.g { background: #83ab74; }

.term-bar .label {
  margin-left: .5rem;
  font-size: .76rem;
  color: var(--term-dim);
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
}

.term {
  margin: 0;
  padding: 1.1rem 1.2rem 1.3rem;
  background: none;
  border: 0;
  border-radius: 0;
  color: var(--term-ink);
  font-size: .8rem;
  line-height: 1.75;
  overflow-x: auto;
  white-space: pre;
}

.term .prompt { color: var(--term-dim); }
.term .rule   { color: var(--copper-soft); }
.term .key    { color: var(--term-dim); }
.term .num    { color: var(--term-green); }
.term .money  { color: var(--term-amber); }

/* ── Sections ───────────────────────────────────────────────────────────── */

section { padding: 3.75rem 0; border-bottom: 1px solid var(--line); }
section:last-of-type { border-bottom: 0; }

.section-head { max-width: 58ch; margin-bottom: 2rem; }
.section-head h2 { font-size: clamp(1.5rem, 3.6vw, 2rem); margin: 0 0 .5rem; }
.section-head p { color: var(--ink-2); margin: 0; }

.eyebrow {
  display: block;
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: .72rem;
  letter-spacing: .13em;
  text-transform: uppercase;
  color: var(--copper);
  margin-bottom: .6rem;
}

.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 1rem;
}

.card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1.4rem;
}

.card h3 { font-size: 1.1rem; margin: 0 0 .5rem; }
.card p { margin: 0; color: var(--ink-2); font-size: .95rem; }

.steps { counter-reset: step; display: grid; gap: 1.5rem; }

.step { position: relative; padding-left: 2.6rem; }

.step::before {
  counter-increment: step;
  content: counter(step);
  position: absolute;
  left: 0;
  top: .1rem;
  width: 1.8rem;
  height: 1.8rem;
  border-radius: 50%;
  background: var(--wash);
  border: 1px solid var(--line-2);
  color: var(--copper);
  font-size: .85rem;
  font-weight: 600;
  display: grid;
  place-items: center;
}

.step h3 { font-size: 1.02rem; margin: .1rem 0 .55rem; }
.step p  { margin: 0 0 .7rem; color: var(--ink-2); font-size: .95rem; }
.step pre { margin: 0; }

/* ── Tables ─────────────────────────────────────────────────────────────── */

.table-wrap { overflow-x: auto; border: 1px solid var(--line); border-radius: var(--radius); }

table { border-collapse: collapse; width: 100%; font-size: .92rem; min-width: 34rem; }

th, td { text-align: left; padding: .7rem .9rem; border-bottom: 1px solid var(--line); }

thead th {
  background: var(--surface-2);
  font-size: .78rem;
  letter-spacing: .04em;
  text-transform: uppercase;
  color: var(--muted);
  font-weight: 600;
}

tbody tr:last-child td { border-bottom: 0; }
td code { white-space: nowrap; }

/* ── Formula pair ───────────────────────────────────────────────────────── */

.formulas { display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); gap: 1rem; }

.formula {
  background: var(--surface);
  border: 1px solid var(--line);
  border-left: 3px solid var(--copper);
  border-radius: var(--radius);
  padding: 1.25rem 1.4rem;
}

.formula h3 { font-size: 1rem; margin: 0 0 .4rem; }
.formula p { margin: 0 0 .7rem; color: var(--ink-2); font-size: .93rem; }
.formula .expr { font-size: .82rem; color: var(--ink); background: var(--surface-2);
                 border: 1px solid var(--line); border-radius: 7px; padding: .5rem .7rem;
                 display: block; overflow-x: auto; }

.note {
  margin-top: 1.5rem;
  padding: .9rem 1.1rem;
  background: var(--wash);
  border: 1px solid var(--line-2);
  border-radius: var(--radius);
  font-size: .92rem;
  color: var(--ink-2);
}

/* ── Footer ─────────────────────────────────────────────────────────────── */

footer {
  padding: 2.5rem 0 3.5rem;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: .9rem;
}

footer .links { display: flex; flex-wrap: wrap; gap: 1.1rem; margin-bottom: .8rem; }
footer a { text-decoration: none; }
footer a:hover { text-decoration: underline; }

/* ── Prose pages (how-penny-works) ──────────────────────────────────────── */

.prose { padding: 3rem 0 4rem; }
.prose h1 { font-size: clamp(2rem, 5vw, 2.7rem); margin: 0 0 1.25rem; }
.prose h2 { font-size: 1.45rem; margin: 2.5rem 0 .75rem; }
.prose h3 { font-size: 1.12rem; margin: 1.8rem 0 .5rem; }
.prose p, .prose li { color: var(--ink-2); }
.prose > p:first-of-type { font-size: 1.1rem; color: var(--ink); }
.prose ul, .prose ol { padding-left: 1.3rem; }
.prose li { margin-bottom: .35rem; }
.prose table { margin: 1rem 0; }
.prose hr { border: 0; border-top: 1px solid var(--line); margin: 2.5rem 0; }
.prose blockquote { margin: 1.25rem 0; padding-left: 1rem; border-left: 3px solid var(--copper-soft); color: var(--muted); }
.prose .back { display: inline-block; margin-bottom: 1.5rem; font-size: .9rem; text-decoration: none; }
.prose .back:hover { text-decoration: underline; }

@media (max-width: 640px) {
  body { font-size: 16px; }
  .hero .wrap { padding-top: 3rem; padding-bottom: 2.5rem; }
  section { padding: 2.75rem 0; }
  .nav a:not(.wordmark) { font-size: .88rem; }
}