/* visualia.css — the whole visual language of Visualia, on purpose this small.
   Black sans on white. Two sizes, two weights, two inks, three spaces.
   Change a variable below and every page that uses this sheet changes.
   plans/style.md explains why. */

:root {
  --ink: #000;
  --paper: #fff;
  --quiet: 0.5;              /* the second ink: labels, notes, things that don't apply */

  --text: 1rem;              /* everything */
  --large: 2.5rem;           /* the page title, nothing else */

  --bold: 700;               /* the second weight: headings, names, the answer */

  --s: 0.5rem;               /* within a group */
  --m: 1.5rem;               /* between items */
  --l: 4rem;                 /* between sections */

  --measure: 60ch;
  --font: ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  :root { --ink: #fff; --paper: #000; color-scheme: dark; }
}

* { box-sizing: border-box; margin: 0; }

html { background: var(--paper); color: var(--ink); }

body {
  font: 400 var(--text) / 1.5 var(--font);
  padding: var(--l) 1rem;
  -webkit-font-smoothing: antialiased;
}

main { max-width: var(--measure); margin: 0 auto; display: grid; gap: var(--l); }
section, header { display: grid; gap: var(--m); }

h1 { font-size: var(--large); font-weight: var(--bold); line-height: 1.05; letter-spacing: -0.02em; text-wrap: balance; }
h2, h3, b, strong, dt.bold { font-size: var(--text); font-weight: var(--bold); }
p { text-wrap: pretty; }

.quiet { opacity: var(--quiet); }
.bold { font-weight: var(--bold); }

dl { display: grid; grid-template-columns: max-content 1fr; gap: var(--s) var(--m); }
dt { opacity: var(--quiet); }
dd { font-variant-numeric: tabular-nums; }

label { display: grid; gap: var(--s); }
label > span { opacity: var(--quiet); }

/* fields and buttons: one box, square, roomy */
input, select, textarea, button {
  font: inherit; color: inherit; background: transparent;
  border: 1px solid currentColor; border-radius: 0;
  padding: 0.6rem 0.75rem; width: 100%;
}
textarea { resize: vertical; min-height: 6rem; }
select {
  appearance: none; padding-right: 2rem;
  background-image: linear-gradient(45deg, transparent 50%, currentColor 50%), linear-gradient(135deg, currentColor 50%, transparent 50%);
  background-position: calc(100% - 1.1rem) 55%, calc(100% - 0.8rem) 55%;
  background-size: 0.3rem 0.3rem; background-repeat: no-repeat;
}
button { width: auto; padding-inline: 1.5rem; font-weight: var(--bold); cursor: pointer; }
input:focus-visible, select:focus-visible, textarea:focus-visible, button:focus-visible { outline: 2px solid currentColor; outline-offset: 2px; }
button:disabled { opacity: var(--quiet); cursor: default; }

a { color: inherit; text-underline-offset: 0.2em; }