/* style.css — shared look for the playground (index.html) and the handout links.
   Same palette family as Phil's PHYS 230 / multiverse web deck: light surface, navy ink, teal accent. */
:root {
  --bg: #EEF3F8; --surface: #FFFFFF; --ink: #1B2638; --muted: #53637C; --line: #C9D4E2; --chip: #E3EAF3;
  --accent: #0A7F9C; --accent-ink: #FFFFFF; --amber: #B8730C; --green: #2B8A3A; --red: #CC2620;
  --cell-on: #1B2638; --cell-off: #FFFFFF; --cell-grid: rgba(27, 38, 56, 0.14); --cell-text: #7C8AA3; --cell-text-on: #FFFFFF;
  --display: "Bricolage Grotesque", "Segoe UI", system-ui, sans-serif;
  --body: "Atkinson Hyperlegible", "Segoe UI", system-ui, sans-serif;
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #0B1024; --surface: #121936; --ink: #E6ECF5; --muted: #9AA8C2; --line: #2B3762; --chip: #1C2549;
    --accent: #22D3EE; --accent-ink: #0B1024; --amber: #F5B83D; --green: #5BD27A; --red: #FF6B6B;
    --cell-on: #22D3EE; --cell-off: #0B1024; --cell-grid: rgba(230, 236, 245, 0.12); --cell-text: #6E7FA3; --cell-text-on: #0B1024;
    color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --bg: #0B1024; --surface: #121936; --ink: #E6ECF5; --muted: #9AA8C2; --line: #2B3762; --chip: #1C2549;
  --accent: #22D3EE; --accent-ink: #0B1024; --amber: #F5B83D; --green: #5BD27A; --red: #FF6B6B;
  --cell-on: #22D3EE; --cell-off: #0B1024; --cell-grid: rgba(230, 236, 245, 0.12); --cell-text: #6E7FA3; --cell-text-on: #0B1024;
  color-scheme: dark;
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body { margin: 0; background: var(--bg); color: var(--ink); font-family: var(--body); font-size: 17px; line-height: 1.45; }
h1, h2, h3 { font-family: var(--display); line-height: 1.1; margin: 0; text-wrap: balance; }
p { margin: 0; }
a { color: var(--accent); }
[hidden] { display: none !important; }
button, input, select { font: inherit; }
button:focus-visible, input:focus-visible, a:focus-visible, canvas:focus-visible, summary:focus-visible { outline: 3px solid var(--accent); outline-offset: 2px; }

.wrap { max-width: 760px; margin-inline: auto; padding: 12px 16px 48px; display: grid; gap: 14px; }
header.top { display: flex; align-items: baseline; justify-content: space-between; gap: 12px; flex-wrap: wrap; }
header.top h1 { font-size: clamp(1.5rem, 1.2rem + 1.8vw, 2.2rem); font-weight: 800; letter-spacing: -0.01em; }
header.top .sub { color: var(--muted); font-size: 0.95rem; }
header.top nav a { font-size: 0.95rem; text-decoration: none; border: 1px solid var(--line); border-radius: 8px; padding: 6px 10px; color: var(--ink); background: var(--surface); }

.board { background: var(--surface); border: 1px solid var(--line); border-radius: 12px; padding: 10px; display: grid; gap: 10px; }
.board canvas { width: 100%; height: auto; border-radius: 6px; cursor: crosshair; }
.readout { display: flex; gap: 18px; flex-wrap: wrap; font-variant-numeric: tabular-nums; color: var(--muted); font-size: 0.95rem; }
.readout b { color: var(--ink); font-weight: 700; }
.readout .settled { color: var(--green); font-weight: 700; }

.controls { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; }
button.b { font-size: 1rem; padding: 10px 14px; min-height: 44px; border-radius: 10px; border: 1px solid var(--line); background: var(--chip); color: var(--ink); cursor: pointer; }
button.b:hover { border-color: var(--accent); }
button.b.primary { background: var(--accent); border-color: var(--accent); color: var(--accent-ink); font-weight: 700; min-width: 6.5em; }
button.b[aria-pressed="true"] { background: var(--ink); color: var(--surface); border-color: var(--ink); }
button.b.small { font-size: 0.92rem; padding: 7px 11px; min-height: 38px; }
label.r { display: grid; gap: 2px; font-size: 0.9rem; color: var(--muted); flex: 1; min-width: 150px; }
input[type="range"] { accent-color: var(--accent); width: 100%; height: 28px; margin: 0; }
.seg { display: inline-flex; border: 1px solid var(--line); border-radius: 10px; overflow: hidden; }
.seg button { border: 0; border-radius: 0; background: var(--surface); padding: 8px 12px; min-height: 40px; color: var(--ink); cursor: pointer; }
.seg button[aria-pressed="true"] { background: var(--accent); color: var(--accent-ink); font-weight: 700; }

.chips { display: flex; flex-wrap: wrap; gap: 8px; }
.chips .kicker { width: 100%; font-size: 0.78rem; letter-spacing: 0.12em; text-transform: uppercase; color: var(--accent); font-weight: 700; }

details { background: var(--surface); border: 1px solid var(--line); border-radius: 12px; padding: 0; }
details summary { cursor: pointer; padding: 12px 14px; font-family: var(--display); font-weight: 700; font-size: 1.05rem; list-style: none; display: flex; justify-content: space-between; align-items: center; }
details summary::-webkit-details-marker { display: none; }
details summary::after { content: "+"; color: var(--muted); font-weight: 400; font-size: 1.3rem; }
details[open] summary::after { content: "−"; }
details .in { padding: 0 14px 14px; display: grid; gap: 10px; }

.rules { display: grid; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); gap: 10px; }
.rule { border: 1px solid var(--line); border-radius: 10px; padding: 10px; display: grid; gap: 8px; justify-items: start; background: var(--bg); }
.rule h3 { font-size: 1rem; }
.rule p { font-size: 0.92rem; color: var(--muted); }
.mini { display: grid; grid-template-columns: repeat(3, 18px); gap: 2px; }
.mini i { display: block; width: 18px; height: 18px; background: var(--chip); border-radius: 3px; }
.mini i.on { background: var(--cell-on); }
.mini i.c { outline: 2px solid var(--accent); outline-offset: -2px; }
.mini i.c.dead { background: var(--red); opacity: 0.45; }
.mini i.c.born { background: var(--green); }

ol.ch { margin: 0; padding-left: 1.3em; display: grid; gap: 8px; }
ol.ch li::marker { color: var(--accent); font-weight: 700; }
ol.ch .hint { color: var(--muted); font-size: 0.92rem; }

footer.credits { color: var(--muted); font-size: 0.85rem; line-height: 1.5; }
.toast { position: fixed; left: 50%; bottom: 18px; transform: translateX(-50%); background: var(--ink); color: var(--surface); padding: 8px 14px; border-radius: 999px; font-size: 0.92rem; opacity: 0; transition: opacity 0.25s; pointer-events: none; }
.toast.show { opacity: 0.95; }
@media (max-width: 420px) { button.b { padding: 10px 11px; } .readout { gap: 12px; } }
@media (prefers-reduced-motion: reduce) { .toast { transition: none; } }