/* Reset minimo, tipografia, layout di base */
*,
*::before,
*::after {
  box-sizing: border-box;
}

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

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font-body);
  font-size: var(--fs-body);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

main {
  flex: 1;
}

h1,
h2,
h3 {
  font-family: var(--font-display);
  font-weight: 600;
  line-height: 1.2;
  margin: 0 0 var(--space-4);
  text-wrap: balance;
}
h1 { font-size: var(--fs-h1); }
h2 { font-size: var(--fs-h2); margin-top: var(--space-12); }
h3 { font-size: var(--fs-h3); margin-top: var(--space-8); }
h4 { font-size: 1.1em; margin: var(--space-6) 0 var(--space-2); }

p,
ul,
ol,
dl {
  margin: 0 0 var(--space-4);
  max-width: var(--measure);
}

a {
  color: var(--accent);
  text-decoration-thickness: 0.08em;
  text-underline-offset: 0.18em;
}
a:hover {
  text-decoration-thickness: 0.15em;
}

/* Link esterni: indicati con una freccia (il testo per gli screen reader è nel markup) */
a[rel~="external"]::after {
  content: " ↗";
  content: " ↗" / ""; /* testo alternativo vuoto: gli screen reader leggono già "(sito esterno)" */
}

img,
svg,
canvas {
  max-width: 100%;
  display: block;
}

:focus-visible {
  outline: 3px solid var(--focus);
  outline-offset: 3px;
  border-radius: 4px;
}

[hidden] {
  display: none !important;
}

.visually-hidden {
  position: absolute !important;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
  border: 0;
}

.skip-link {
  position: absolute;
  left: var(--space-4);
  top: -100px;
  z-index: 100;
  background: var(--accent);
  color: var(--on-accent);
  padding: var(--space-3) var(--space-4);
  border-radius: var(--radius-s);
  font-weight: 700;
}
.skip-link:focus {
  top: var(--space-4);
}

.container {
  width: 100%;
  max-width: var(--max-width);
  margin-inline: auto;
  padding-inline: var(--space-4);
}
@media (min-width: 768px) {
  .container { padding-inline: var(--space-8); }
}

.prose > * + * {
  margin-top: 0;
}

code,
.formula {
  font-family: ui-monospace, "SFMono-Regular", Menlo, Consolas, monospace;
  font-size: 0.95em;
}

table {
  border-collapse: collapse;
  width: 100%;
  font-size: var(--fs-small);
  font-variant-numeric: tabular-nums;
}
th,
td {
  text-align: left;
  padding: var(--space-2) var(--space-3);
  border-bottom: 1px solid var(--line);
}
th {
  font-weight: 700;
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    scroll-behavior: auto !important;
    transition-property: opacity !important;
  }
}