/* Solitaire Cipher Lab — explainer styles.
   No framework and no build step: this page should still work in five years. */

:root {
  /* Grounded in the subject's materials: card-table baize, card stock, the
     true red and black of pips, and the brass of a gilt card edge. */
  --felt: #14402f;
  --felt-deep: #0d2a1f;
  --bg: #f2f2ee;
  --surface: #fffefb;
  --surface-2: #e8e9e3;
  --ink: #16191a;
  --ink-dim: #53595a;
  --ink-faint: #5f6665;
  --rule: #d8dad2;
  --accent: #1d6146;
  --accent-soft: #e0ebe4;
  --red: #a51f14;
  --black: #1e2120;
  --joker: #6b4c9a;
  --joker-soft: #ece5f6;
  --brass: #8a6a1f;
  --brass-soft: #f2ead3;
  --good: #1d6146;
  --mono: "IBM Plex Mono", ui-monospace, "SF Mono", Menlo, Consolas, monospace;
  --sans: "IBM Plex Sans", ui-sans-serif, system-ui, -apple-system, "Segoe UI", sans-serif;
  --display: "Fraunces", "Iowan Old Style", Palatino, Georgia, serif;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --felt: #0f2a20;
    --felt-deep: #081710;
    --bg: #101413;
    --surface: #181e1c;
    --surface-2: #222927;
    --ink: #e6eae7;
    --ink-dim: #a2aca8;
    --ink-faint: #8a958f;
    --rule: #2c3532;
    --accent: #6fc59a;
    --accent-soft: #17302582;
    --red: #e8776b;
    --black: #d4dad6;
    --joker: #b79ae0;
    --joker-soft: #2c2438;
    --brass: #d8b458;
    --brass-soft: #332c16;
    --good: #6fc59a;
  }
}

:root[data-theme="dark"] {
  --felt: #0f2a20; --felt-deep: #081710;
  --bg: #101413; --surface: #181e1c; --surface-2: #222927;
  --ink: #e6eae7; --ink-dim: #a2aca8; --ink-faint: #8a958f; --rule: #2c3532;
  --accent: #6fc59a; --accent-soft: #17302582; --red: #e8776b; --black: #d4dad6;
  --joker: #b79ae0; --joker-soft: #2c2438; --brass: #d8b458; --brass-soft: #332c16;
  --good: #6fc59a;
}

* { box-sizing: border-box; }

[hidden] { display: none !important; }

html { overflow-x: hidden; }

body {
  margin: 0;
  padding-block: 0 4rem;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 17px;
  line-height: 1.65;
  -webkit-text-size-adjust: 100%;
}

.wrap { max-width: 760px; margin: 0 auto; padding-inline: 20px; }
.wide { max-width: 1000px; margin: 0 auto; padding-inline: 20px; }

header.hero {
  background: var(--felt);
  color: #f4f7f4;
  padding-block: 3.5rem 2.8rem;
  margin-bottom: 2.5rem;
  border-bottom: 3px solid var(--brass);
}
.hero .sub, .hero .byline { color: #bdcfc4; }
.hero .byline a, .hero .sub a { color: #e2cf98; }
.hero h1 {
  font-family: var(--display);
  font-size: clamp(2rem, 6vw, 3.1rem);
  line-height: 1.1;
  margin: 0 0 .6rem;
  letter-spacing: -0.02em;
}
.hero .sub { font-size: 1.1rem; margin: 0 0 1.5rem; max-width: 34em; }
.hero .byline { font-size: .9rem; margin: 0; }


.warn {
  border-left: 3px solid var(--accent);
  background: var(--accent-soft);
  padding: .85rem 1rem;
  border-radius: 0 6px 6px 0;
  font-size: .92rem;
  color: var(--ink);
  margin: 1.5rem 0;
}
.warn strong { color: var(--accent); }

h2 {
  font-family: var(--display);
  font-size: clamp(1.45rem, 3.4vw, 1.95rem);
  font-weight: 600;
  font-variation-settings: "SOFT" 0, "WONK" 1, "opsz" 32;
  margin: 3.5rem 0 .4rem;
  letter-spacing: -0.01em;
  line-height: 1.2;
  text-wrap: balance;
}
h2 .num {
  display: block;
  font-family: var(--mono);
  font-size: .7rem;
  letter-spacing: .18em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: .5rem;
}
h3 { font-size: 1.05rem; margin: 2rem 0 .3rem; }
p { margin: 0 0 1.1rem; }
a { color: var(--accent); text-underline-offset: 2px; }
code { font-family: var(--mono); font-size: .88em; background: var(--surface-2); padding: .1em .35em; border-radius: 3px; }
.lede { font-size: 1.08rem; color: var(--ink-dim); }
.note { font-size: .9rem; color: var(--ink-faint); }

/* ---- cards ---- */
.deck {
  display: flex;
  flex-wrap: wrap;
  gap: 3px;
  font-family: var(--mono);
  margin: 0;
  padding: 10px;
  background: var(--surface-2);
  border-radius: 8px;
  border: 1px solid var(--rule);
}
.card {
  flex: 0 0 auto;
  min-width: 30px;
  padding: 3px 4px;
  text-align: center;
  font-size: 12px;
  line-height: 1.25;
  border-radius: 3px;
  background: var(--surface);
  border: 1px solid var(--rule);
  color: var(--black);
  transition: background .15s, transform .15s, border-color .15s;
}
.card.red { color: var(--red); }
.card.joker { color: var(--joker); background: var(--joker-soft); border-color: var(--joker); font-weight: 700; }
.card.hl { background: var(--brass-soft); border-color: var(--brass); transform: translateY(-3px); box-shadow: 0 2px 0 var(--brass); }
.deck.compact .card { min-width: 26px; font-size: 11px; padding: 2px 3px; }

/* ---- player ---- */
.player {
  background: var(--surface);
  border: 1px solid var(--rule);
  border-radius: 10px;
  padding: 1rem;
  margin: 1.5rem 0;
}
.player-head {
  display: flex; flex-wrap: wrap; gap: .5rem 1rem;
  align-items: baseline; justify-content: space-between;
  margin-bottom: .75rem;
}
.step-name { font-weight: 650; font-size: 1rem; }
.step-name .round { color: var(--ink-faint); font-weight: 400; font-family: var(--mono); font-size: .8rem; }
.explain {
  min-height: 3.4em;
  color: var(--ink-dim);
  font-size: .95rem;
  margin: .75rem 0 0;
}
.controls { display: flex; flex-wrap: wrap; gap: .4rem; align-items: center; margin-top: .9rem; }
button {
  font: inherit; font-size: .85rem;
  padding: .38rem .8rem;
  border-radius: 6px;
  border: 1px solid var(--rule);
  background: var(--surface-2);
  color: var(--ink);
  cursor: pointer;
}
button:hover:not(:disabled) { border-color: var(--accent); color: var(--accent); }
button:disabled { opacity: .4; cursor: not-allowed; }
button.primary { background: var(--accent); border-color: var(--accent); color: var(--bg); font-weight: 600; }
button.primary:hover { opacity: .9; color: var(--bg); }
.progress { flex: 1 1 120px; min-width: 100px; accent-color: var(--accent); }
.counter { font-family: var(--mono); font-size: .78rem; color: var(--ink-faint); white-space: nowrap; }

.phases { display: flex; flex-wrap: wrap; gap: 4px; margin-top: .75rem; }
.phase-chip {
  font-family: var(--mono); font-size: .68rem; letter-spacing: .04em;
  padding: .2rem .45rem; border-radius: 4px;
  background: var(--surface-2); color: var(--ink-faint); border: 1px solid transparent;
}
.phase-chip.on { background: var(--accent-soft); color: var(--accent); border-color: var(--accent); font-weight: 600; }
.phase-chip.done { color: var(--ink-dim); }

.keystream-out { font-family: var(--mono); margin-top: .8rem; font-size: .9rem; }
.keystream-out b { color: var(--good); letter-spacing: .12em; }
.skip { color: var(--joker); font-weight: 600; }

/* ---- tables ---- */
.scroll { overflow-x: auto; margin: 1.2rem 0; }
table.layers { border-collapse: collapse; font-family: var(--mono); font-size: .85rem; font-variant-numeric: tabular-nums; }
table.layers th { text-align: right; padding-right: .9rem; color: var(--ink-faint); font-weight: 400; white-space: nowrap; font-size: .78rem; }
table.layers td { text-align: center; padding: .18rem .32rem; min-width: 1.9em; }
table.layers tr.sum td { border-top: 1px solid var(--rule); }
table.layers .p { color: var(--ink); font-weight: 600; }
table.layers .k { color: var(--good); font-weight: 600; }
table.layers .c { color: var(--brass); font-weight: 700; }
table.layers .v { color: var(--ink-faint); font-size: .78rem; }

.stat-row { display: flex; flex-wrap: wrap; gap: 1rem; margin: 1.4rem 0; }
.stat {
  flex: 1 1 160px; background: var(--surface); border: 1px solid var(--rule);
  border-radius: 8px; padding: .9rem 1rem;
}
.stat .n { font-family: var(--mono); font-size: 1.5rem; font-weight: 600; line-height: 1.1; font-variant-numeric: tabular-nums; }
.stat .n.warnish { color: var(--brass); }
.stat .l { font-size: .78rem; color: var(--ink-faint); margin-top: .25rem; }

.bars { margin: 1.2rem 0; }
.bar-row { display: flex; flex-wrap: wrap; align-items: center; gap: .7rem; margin-bottom: .45rem; font-size: .85rem; }
.bar-row .bar-label { flex: 0 0 8.5em; text-align: right; color: var(--ink-dim); font-size: .8rem; }
.bar-track { flex: 1 1 auto; height: 20px; background: var(--surface-2); border-radius: 4px; overflow: hidden; border: 1px solid var(--rule); }
.bar-fill { display: block; height: 100%; border-radius: 3px 0 0 3px; }
.bar-fill.ideal { background: var(--ink-faint); }
.bar-fill.actual { background: var(--brass); }
.bar-row .val { flex: 0 0 13.5em; font-family: var(--mono); font-size: .8rem; }
.bar-row .range { color: var(--ink-faint); }

pre.block {
  background: var(--surface-2); border: 1px solid var(--rule);
  border-radius: 8px; padding: .9rem 1rem; overflow-x: auto;
  font-family: var(--mono); font-size: .84rem; line-height: 1.6; margin: 1.1rem 0;
}
pre.block .k { color: var(--good); }
pre.block .c { color: var(--brass); }
pre.block .eq { color: var(--accent); font-weight: 700; }

footer { border-top: 1px solid var(--rule); margin-top: 4rem; padding-top: 1.5rem; color: var(--ink-faint); font-size: .88rem; }
.perma { font-size: .78rem; color: var(--ink-faint); font-family: var(--mono); }
.perma button { font-size: .72rem; padding: .2rem .5rem; }

@media (max-width: 560px) {
  body { font-size: 16px; }
  .card { min-width: 26px; font-size: 10.5px; }
  .bar-row .bar-label { flex-basis: 100%; text-align: left; }
  .bar-row .val { flex-basis: auto; }
}

@media (prefers-reduced-motion: reduce) {
  * { transition: none !important; animation: none !important; }
}

:focus-visible { outline: 2px solid var(--brass); outline-offset: 2px; border-radius: 3px; }

/* ---- the live lab (section 04) ---- */
.lab {
  background: var(--surface);
  border: 1px solid var(--rule);
  border-radius: 10px;
  padding: 1.1rem;
  margin: 1.5rem 0;
  display: flex;
  flex-direction: column;
  gap: .9rem;
}
.lab .field { display: flex; flex-direction: column; gap: .35rem; }
.lab .field > label { font-size: .78rem; letter-spacing: .06em; text-transform: uppercase; color: var(--ink-faint); }
.lab .note { margin: 0; }

fieldset.keymode {
  border: 0; padding: 0; margin: 0;
  display: flex; flex-wrap: wrap; gap: .3rem .95rem; align-items: center;
}
fieldset.keymode legend {
  padding: 0; margin-bottom: .45rem;
  font-size: .78rem; letter-spacing: .06em; text-transform: uppercase; color: var(--ink-faint);
}
fieldset.keymode label { font-size: .9rem; display: inline-flex; align-items: center; gap: .35rem; cursor: pointer; }
fieldset.keymode input { accent-color: var(--accent); }

.lab input[type="text"], .lab textarea, .lab select {
  font: inherit;
  font-family: var(--mono);
  font-size: .9rem;
  padding: .5rem .6rem;
  border: 1px solid var(--rule);
  border-radius: 6px;
  background: var(--surface-2);
  color: var(--ink);
  width: 100%;
  max-width: 100%;
}
.lab textarea { resize: vertical; line-height: 1.5; }
.lab input[type="text"]:focus, .lab textarea:focus, .lab select:focus { border-color: var(--accent); outline: none; }

button.linkish {
  background: none; border: 0; padding: 0;
  color: var(--accent); font: inherit; font-size: inherit;
  text-decoration: underline; text-underline-offset: 2px; cursor: pointer;
}
button.linkish:hover { opacity: .8; color: var(--accent); }

.error {
  background: var(--brass-soft);
  border-left: 3px solid var(--brass);
  border-radius: 0 6px 6px 0;
  padding: .6rem .8rem;
  font-size: .88rem;
  margin: 0;
}
.cipher-out {
  font-family: var(--mono);
  font-size: clamp(1rem, 3.4vw, 1.3rem);
  font-weight: 600;
  letter-spacing: .06em;
  color: var(--brass);
  word-break: break-word;
  margin: .2rem 0 .3rem;
}
.verdict {
  font-size: .92rem;
  color: var(--ink-dim);
  border-left: 3px solid var(--good);
  padding-left: .8rem;
  margin: .9rem 0 0;
}