:root {
  color-scheme: light dark;

  --paper: #f4efe6;
  --paper-2: #ebe3d3;
  --paper-3: #e2d9c6;
  --ink: #1b1a1f;
  --ink-soft: #4b4842;
  --ink-faint: #8c877b;
  --line: rgba(27, 26, 31, 0.14);

  --navy: #1f2f5c;
  --red: #a8322d;
  --green: #2f5d3a;
  --black: #1b1b1b;
  --purple: #5b3a86;
  --accent: var(--navy);

  --cover-1: #1f3160;
  --cover-2: #0c1428;
  --foil-1: #e7cf91;
  --foil-2: #cbac61;
  --foil-3: #b0904a;
  --gold: #cdb57c;
  --titanium: #c4c1b8;
  --titanium-2: #8f8c84;
  --bezel: #0b0b0d;

  --font-serif: "Fraunces", ui-serif, "Iowan Old Style", Georgia, serif;
  --font-mono: "JetBrains Mono", ui-monospace, "SF Mono", Menlo, monospace;
  --font-sans: -apple-system, BlinkMacSystemFont, "SF Pro Text", "Helvetica Neue", system-ui, sans-serif;

  --ease-cover: cubic-bezier(0.32, 0, 0.12, 1);
  --ease-thunk: cubic-bezier(0.2, 0.9, 0.25, 1);
  --ease-lift: cubic-bezier(0.2, 0.7, 0, 1);
  --ease-page: cubic-bezier(0.4, 0, 0.2, 1);
  --dur-cover: 1200ms;
  --dur-thunk: 180ms;

  --gutter: clamp(16px, 4vw, 56px);
  --measure: 58ch;

  /* One half of the Duo. Spread = 2 * half + hinge. */
  --half-w: min(19vw, 46vh, 280px);
}
@media (max-width: 860px) {
  :root { --half-w: min(44vw, 36vh, 300px); }
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --paper: #221f1a;
    --paper-2: #2a2620;
    --paper-3: #332e27;
    --ink: #ece6d8;
    --ink-soft: #b8b1a3;
    --ink-faint: #7d776c;
    --line: rgba(236, 230, 216, 0.14);
    --accent: #9fb2e6;
  }
}
:root[data-theme="dark"] {
  --paper: #221f1a;
  --paper-2: #2a2620;
  --paper-3: #332e27;
  --ink: #ece6d8;
  --ink-soft: #b8b1a3;
  --ink-faint: #7d776c;
  --line: rgba(236, 230, 216, 0.14);
  --accent: #9fb2e6;
}