/* ===== DSA-friendly base ===== */
@font-face{
  font-family:"Atkinson Hyperlegible";
  src: url("https://fonts.gstatic.com/s/atkinsonhyperlegible/v12/HH7cN5w2qMzzf9Y8KV5x.woff2") format("woff2");
  font-display: swap;
}
@import url("https://fonts.googleapis.com/css2?family=Lexend:wght@300;400;500;700&display=swap");

:root{
  --bg: #ffffff;
  --fg: #0e1116;
  --muted:#5e6370;
  --brand:#0d6efd;
  --callout:#ff7a18;         /* arancione per riquadri callout */
  --panel:#f5f7fb;
  --panel-border:#d8deea;
  --focus:#1c7ed6;
  --kbd-bg:#111;
  --kbd-fg:#fff;
  --code-bg:#f3f4f6;
  --shadow: 0 2px 12px rgba(0,0,0,.06);
  --radius: 16px;
}

html{scroll-behavior:smooth}
*{box-sizing:border-box}
body{
  margin:0;
  background:var(--bg);
  color:var(--fg);
  font-family:"Atkinson Hyperlegible","Lexend",-apple-system,Segoe UI,Roboto,Arial,sans-serif;
  line-height:1.6;
  font-size:18px;
}

a{color:var(--brand);text-decoration:none}
a:hover{text-decoration:underline}

/* ===== Layout ===== */
.container{max-width:980px;margin:0 auto;padding:24px}
.container.narrow{max-width:860px}
.page-header{
  padding:28px 24px 8px;
  border-bottom:1px solid var(--panel-border);
}
h1,h2,h3{letter-spacing:.2px}
h1{font-size:clamp(28px,3.4vw,36px);margin:.1em 0 .2em}
.subtitle{margin:0;color:var(--muted)}
.pill{
  background:rgba(255,255,255,.08);
  padding:3px 8px;
  border-radius:10px;
  color:var(--muted);
}

/* ===== Accessibilità ===== */
.skip-link{
  position:absolute;left:-9999px;top:auto;width:1px;height:1px;overflow:hidden;
}
.skip-link:focus{
  position:fixed;left:16px;top:16px;width:auto;height:auto;padding:8px 12px;
  background:#000;color:#fff;border-radius:8px;z-index:9999;
}
:focus-visible{outline:3px solid var(--focus);outline-offset:2px}

/* ===== Pannelli / Riquadri ===== */
.panel{
  background:var(--panel);
  border:1px solid var(--panel-border);
  border-radius:var(--radius);
  box-shadow:var(--shadow);
  padding:18px 20px;
  margin:20px 0;
}
.panel > h2, .panel > h3{margin-top:4px}

.callout{
  border-left:10px solid var(--callout);
  background:linear-gradient(90deg,#fff7f0, var(--panel) 60%);
}
.callout h2,.callout h3{margin-top:0}
.box{
   background:var(--bg);border:1px dashed #c9cfdb;border-radius:14px;padding:14px 16px;margin:14px 0;
}

/* ===== Elenchi a passaggi ===== */
.steps{counter-reset:step;margin:0;padding:0;list-style:none}
.steps > li{
  counter-increment:step;
  background:var(--bg);
  border:1px solid var(--panel-border);
  border-radius:14px;
  padding:14px 16px;
  margin:12px 0;
  box-shadow:var(--shadow);
  position:relative;
}
.steps > li::before{
  content:counter(step);
  position:absolute;left:-12px;top:-12px;
  background:var(--brand);color:#fff;
  width:32px;height:32px;border-radius:50%;
  display:grid;place-items:center;font-weight:700;
}

/* ===== Tip / Warning ===== */
details.tip summary, details.warning summary{
  cursor:pointer;font-weight:600
}
details.tip{border-left:8px solid #2bb673}
details.warning{border-left:8px solid #d6336c}
details{background:var(--bg);border:1px solid var(--panel-border);border-radius:12px;padding:10px 12px;margin:12px 0}

/* ===== Codice & KBD ===== */
code{background:var(--code-bg);padding:.1em .35em;border-radius:8px}
kbd{
  background:var(--kbd-bg);color:var(--kbd-fg);
  padding:0 .45em;border-radius:6px;font-weight:700;font-family:ui-monospace,Menlo,Consolas,monospace;
  box-shadow:inset 0 -2px 0 rgba(255,255,255,.15)
}

/* ===== Figure / Placeholder risultato ===== */
.figure{
  display:block;background:var(--bg);border:2px dashed #a7b1c5;border-radius:16px;
  padding:16px;text-align:center;color:#566074;margin:16px 0;
}
.figure .caption{margin-top:8px;color:#6b7280;font-size:.95rem}
.figure img{max-width:100%;height:auto;border-radius:12px}

/* ===== Esercizi ===== */
.exercise{border-left:10px solid #2b8a3e}
.exercise h2{margin-top:0}
.exercise ol{padding-left:1.2rem}

/* ===== Footer ===== */
footer.small{font-size:.95rem}
.muted{color:var(--muted)}

/* ===== Responsivo ===== */
@media (max-width:720px){
  .container{padding:18px}
  .steps > li{padding:12px 14px}
}

/* ===== Stampa ===== */
@media print{
  .skip-link, .pill {display:none}
  body{font-size:12pt}
  .panel,.steps > li, details{box-shadow:none}
}
/* === Bottoni accessibili ====================================== */
.btn{
  display:inline-block;
  padding:12px 18px;
  border-radius:14px;
  font-weight:700;
  line-height:1;
  text-decoration:none !important;
  border:1px solid transparent;
  background:var(--brand);
  color:#fff !important;
  box-shadow:var(--shadow);
  transition:transform .06s ease, box-shadow .2s ease, background .2s ease;
}
.btn:hover{ transform:translateY(-1px); }
.btn:active{ transform:translateY(0); box-shadow:none; }
.btn:focus-visible{ outline:3px solid var(--focus); outline-offset:2px; }

/* variante “ghost” (solo bordo) */
.btn-ghost{
  background:#fff; color:var(--brand) !important;
  border-color:var(--brand);
}

/* bottone a tutta larghezza (se lo vuoi) */
.btn-block{ display:block; width:100%; text-align:center; }

/* spaziatura quando il bottone sta dentro un .box */
.box .btn{ margin-top:8px; }
.theme-toggle{
  background:var(--brand);
  color:#fff;
  border:0;
  border-radius:12px;
  padding:8px 12px;
  font-weight:700;
  display:inline-flex;
  align-items:center;
  gap:.5rem;
  cursor:pointer;
  box-shadow:var(--shadow);
}
.theme-toggle:hover{ filter:brightness(1.05); }
.theme-toggle:focus-visible{ outline:3px solid var(--focus); outline-offset:2px; }
/* ===== Personalizzazioni aggiuntive (dark mode) ===== */
html[data-theme="dark"] .panel{
  box-shadow: none;
}
/* Pulsante “Contrasto alto” con stato attivo */
#contrastToggle{ transition: color .2s, border-color .2s, background .2s; }
#contrastToggle.is-active{
  color:#ff8c42 !important;          /* arancione accessibile */
  border-color:#ff8c42 !important;
  background:transparent;
}
html[data-theme="dark"] #contrastToggle.is-active{
  /* in dark lasciamo ghost arancione; in light resta blu quando non attivo */
}