/*
 * Behaving in Public
 * Layout concept: a wayfinding system. Yellow signs and a black directory board carry the
 * structure, the way they do in an airport. Everything between them stays quiet.
 */
:root {
  --signal: #ffc400;
  --on-signal: #14130c;
  --board: #14130c;
  --on-board: #ffc400;
  --on-board-soft: #e9e7d6;
  --board-rule: #3a392c;

  --ground: #f4f6f2;
  --surface: #ffffff;
  --ink: #16150e;
  --muted: #55574c;
  --rule: #cfd2c6;
  --focus: #1257a8;
  --link: #0e4a93;

  /* ISO 7010 safety sign colours, used for verdicts. */
  --sign-green: #0a7a46;
  --sign-blue: #1257a8;
  --sign-yellow: #ffc400;
  --sign-red: #c8201a;
  --sign-mark: #ffffff;
  --sign-ink: #14130c;

  --font-display: "Big Shoulders Display", "Arial Narrow", "Helvetica Neue Condensed", Impact, sans-serif;
  --font-body: "Public Sans", "Helvetica Neue", Helvetica, Arial, sans-serif;

  --gutter-left: max(16px, env(safe-area-inset-left, 0px));
  --gutter-right: max(16px, env(safe-area-inset-right, 0px));
  --wide: 1180px;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --board: #1f1e15;
    --board-rule: #45443a;
    --ground: #101009;
    --surface: #1b1b12;
    --ink: #f3f3e9;
    --muted: #aeb0a2;
    --rule: #36372b;
    --focus: #ffc400;
    --link: #ffd34d;
    --sign-blue: #2a73cf;
    --sign-green: #118a52;
    --sign-red: #dd352e;
    color-scheme: dark;
  }
}

:root[data-theme="dark"] {
  --board: #1f1e15;
  --board-rule: #45443a;
  --ground: #101009;
  --surface: #1b1b12;
  --ink: #f3f3e9;
  --muted: #aeb0a2;
  --rule: #36372b;
  --focus: #ffc400;
  --link: #ffd34d;
  --sign-blue: #2a73cf;
  --sign-green: #118a52;
  --sign-red: #dd352e;
  color-scheme: dark;
}

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

[hidden] { display: none !important; }

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

body {
  margin: 0;
  background: var(--ground);
  color: var(--ink);
  font-family: var(--font-body);
  font-size: 1.0625rem;
  line-height: 1.55;
}

h1, h2, h3, h4 {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 900;
  line-height: 0.95;
  letter-spacing: 0.005em;
  text-transform: uppercase;
  text-wrap: balance;
}

p { margin: 0; }

a { color: var(--link); text-underline-offset: 0.16em; }

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

.on-signal { --focus: var(--on-signal); --link: var(--on-signal); }

.bleed { padding-left: var(--gutter-left); padding-right: var(--gutter-right); }
.wrap { max-width: var(--wide); margin-inline: auto; }

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  overflow: hidden;
  clip-path: inset(50%);
  white-space: nowrap;
}

/* Buttons are small signs: square corners, heavy condensed type. */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5em;
  min-height: 48px;
  padding: 0.55rem 1.15rem;
  border: 3px solid var(--ink);
  border-radius: 4px;
  background: transparent;
  color: var(--ink);
  font-family: var(--font-display);
  font-size: 1.3rem;
  font-weight: 800;
  line-height: 1.05;
  letter-spacing: 0.02em;
  text-align: center;
  text-decoration: none;
  text-transform: uppercase;
  cursor: pointer;
  transition: transform 120ms ease, background-color 120ms ease, color 120ms ease;
}
.btn:hover { background: var(--ink); color: var(--ground); }
.btn:active { transform: translateY(2px); }

.btn-primary { background: var(--signal); border-color: var(--on-signal); color: var(--on-signal); }
.btn-primary:hover { background: var(--on-signal); color: var(--signal); }

.on-signal .btn { border-color: var(--on-signal); color: var(--on-signal); }
.on-signal .btn:hover { background: var(--on-signal); color: var(--signal); }
.on-signal .btn-primary { background: var(--on-signal); color: var(--signal); }
.on-signal .btn-primary:hover { background: transparent; color: var(--on-signal); }

/* Slim black bar shared by both pages. */
.topbar { background: var(--board); color: var(--on-board-soft); }
.topbar-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  min-height: 52px;
}
.topbar a { color: inherit; text-decoration: none; }
.topbar a:hover { color: var(--on-board); }
.topbar :focus-visible { outline-color: var(--on-board); }
.brand {
  font-family: var(--font-display);
  font-size: 1.3rem;
  font-weight: 800;
  letter-spacing: 0.03em;
  text-transform: uppercase;
  white-space: nowrap;
}
.topbar-link {
  font-family: var(--font-display);
  font-size: 1.15rem;
  font-weight: 700;
  letter-spacing: 0.03em;
  text-transform: uppercase;
}

.footer {
  background: var(--board);
  color: var(--on-board-soft);
  padding-block: 2.5rem 3rem;
  font-size: 0.95rem;
}
.footer a { color: var(--on-board); }
.footer :focus-visible { outline-color: var(--on-board); }
.footer-credit { margin-top: 0.75rem; }
.footer-note { margin-top: 0.5rem; font-size: 0.85rem; }

/* The source list appears on both pages. */
.sources { display: grid; gap: 0.7rem; margin: 1rem 0 0; padding: 0; list-style: none; font-size: 0.97rem; }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation-duration: 0.01ms !important; transition-duration: 0.01ms !important; }
}