/* Shared design tokens for all three hosts. Fonts and brand arrive in Phase 4. */
:root {
  --bg: #ffffff;
  --fg: #16181d;
  --muted: #4b5260;
  --accent: #1f4fd8;
  --border: #d6d9e0;
  --btn-ink: #000000;
  --btn-on-ink: #ed0e86;
  --btn-accent: #ed0e86;
  --btn-accent-ink: #ffffff;
  --max: 42rem;
  --gutter: 1rem;
  --font: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #101216;
    --fg: #eceef2;
    --muted: #a8afbd;
    --accent: #8fb0ff;
    --border: #2b2f38;
    --btn-ink: #ffffff;
    --btn-on-ink: #101216;
  }
}

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

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

body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: var(--font);
  font-size: 1.0625rem;
  line-height: 1.65;
}

a { color: var(--accent); text-underline-offset: 0.15em; }

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

.skip-link {
  position: absolute;
  left: var(--gutter);
  top: -4rem;
  padding: 0.5rem 0.75rem;
  background: var(--bg);
  color: var(--fg);
  border: 2px solid var(--accent);
  z-index: 10;
}
.skip-link:focus { top: var(--gutter); }

.site-header {
  padding: var(--gutter);
  border-bottom: 1px solid var(--border);
}
.brand { font-weight: 700; letter-spacing: 0.01em; }

main { padding: 2rem var(--gutter) 4rem; }
.page { max-width: var(--max); margin: 0 auto; }
h1 { line-height: 1.2; margin: 0 0 1rem; }

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

.narrow { max-width: 24rem; }
.form label { display: block; margin: 1rem 0 0.25rem; font-weight: 600; }
.form input {
  width: 100%;
  padding: 0.6rem 0.7rem;
  font: inherit;
  color: var(--fg);
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 6px;
}

.notice { padding: 0.7rem 0.9rem; border: 1px solid var(--border); border-radius: 6px; }
.notice.error { border-color: #b00020; }

.icon { width: 20px; height: 20px; flex: none; }

/* ---- Button: filled black, white text. On hover the text rolls up and the same text comes in from below. ---- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.8rem 1.6rem;
  margin: 0;
  font: inherit;
  font-size: 1rem;
  font-weight: 600;
  line-height: 1.25;
  color: #ffffff;
  background: var(--btn-ink);
  border: 2px solid var(--btn-ink);
  border-radius: 14px;
  cursor: pointer;
  -webkit-appearance: none;
  appearance: none;
  touch-action: manipulation;
  transition: transform 0.1s ease, opacity 0.2s ease;
}
.btn:active { transform: scale(0.96); }
.btn-icon { display: none; }
.btn--block { display: flex; width: 100%; }

/* The rolling text (made by js/roll.js) */
.roll { position: relative; display: inline-block; overflow: hidden; vertical-align: bottom; white-space: nowrap; }
.roll-a, .roll-b { display: block; transition: transform 0.35s cubic-bezier(0.7, 0, 0.2, 1); }
.roll-b { position: absolute; left: 0; top: 0; color: var(--roll-to, var(--btn-on-ink)); transform: translateY(105%); }
@media (hover: hover) {
  :is(a, button):hover > .roll > .roll-a, :is(a, button):hover > .btn-text > .roll > .roll-a, :is(a, button):focus-visible > .roll > .roll-a, :is(a, button):focus-visible > .btn-text > .roll > .roll-a { transform: translateY(-105%); }
  :is(a, button):hover > .roll > .roll-b, :is(a, button):hover > .btn-text > .roll > .roll-b, :is(a, button):focus-visible > .roll > .roll-b, :is(a, button):focus-visible > .btn-text > .roll > .roll-b { transform: translateY(0); }
}
/* Touch screens cannot hover: the button swaps colours while it is pressed, and goes back the moment the finger lifts. */
@media (hover: none) {
  .roll-b { display: none; }
  .btn { transition: background-color 0.12s ease, color 0.12s ease, transform 0.1s ease; }
  .btn:active { color: var(--btn-ink); background: #ffffff; }
  .btn--light:active { color: #ffffff; background: #000000; border-color: #000000; }
  .btn--ghost:active { color: #ffffff; background: var(--btn-ink); }
}
@media (prefers-reduced-motion: reduce) { .roll-a, .roll-b { transition: none; } }

[hidden] { display: none !important; }
a.btn { text-decoration: none; }
.actions { display: flex; flex-wrap: wrap; gap: 1rem; margin-top: 1.5rem; }
.lead { color: var(--muted); margin-top: 0; }
.page.wide { max-width: 52rem; }

.site-header { display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: 0.5rem 1.5rem; }
.topnav { display: flex; flex-wrap: wrap; align-items: center; gap: 0.25rem 1rem; }
.topnav a, .linkbtn {
  padding: 0.5rem 0.25rem;
  font: inherit;
  font-weight: 500;
  color: var(--fg);
  text-decoration: none;
  background: none;
  border: 0;
  border-bottom: 2px solid transparent;
  cursor: pointer;
}
.topnav a.on { border-bottom-color: var(--btn-ink); }
.topnav a:hover, .linkbtn:hover { border-bottom-color: var(--muted); }
.topnav-out { margin: 0; }