/* ==========================================================================
   AI Infrastructure Engineering — foglio di stile condiviso
   ========================================================================== */
@import url("https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700;800&family=JetBrains+Mono:wght@400;600&display=swap");

:root {
  color-scheme: light;
  --bg: #f7f7f5;
  --surface: #ffffff;
  --surface-2: #f0efec;
  --surface-3: #e6e5e1;
  --border: #dcdbd6;
  --text: #16161a;
  --text-2: #4a4a52;
  --text-3: #75757e;
  --accent: #2a78d6;
  --accent-2: #6250d6;
  --accent-soft: #e4eefb;
  --good: #0f8a4f;
  --good-soft: #e3f5ec;
  --warn: #b26b00;
  --warn-soft: #fdf2dc;
  --bad: #c83a3a;
  --bad-soft: #fbe7e7;
  --code-bg: #f3f2ef;
  --shadow: 0 1px 2px rgba(0,0,0,.05), 0 8px 24px rgba(0,0,0,.06);
  --s1: #2a78d6; --s2: #eb6834; --s3: #1baf7a; --s4: #eda100;
  --s5: #e87ba4; --s6: #008300; --s7: #6250d6; --s8: #e34948;
  --grid: #e3e2de;
  --radius: 14px;
  --sidebar-w: 300px;
  --top-h: 58px;
  --font: "Inter", system-ui, -apple-system, "Segoe UI", sans-serif;
  --mono: "JetBrains Mono", ui-monospace, "SFMono-Regular", Menlo, monospace;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    color-scheme: dark;
    --bg: #0f1013; --surface: #17181c; --surface-2: #1e2025; --surface-3: #282a31;
    --border: #2d3038; --text: #ecebe8; --text-2: #b9b8b2; --text-3: #8b8a85;
    --accent: #4d9bf0; --accent-2: #9085e9; --accent-soft: #16263b;
    --good: #3ccf8e; --good-soft: #12291f; --warn: #f0b440; --warn-soft: #2d2412;
    --bad: #f07171; --bad-soft: #2e1717; --code-bg: #121317;
    --shadow: 0 1px 2px rgba(0,0,0,.4), 0 8px 24px rgba(0,0,0,.35);
    --s1: #3987e5; --s2: #d95926; --s3: #199e70; --s4: #c98500;
    --s5: #d55181; --s6: #2f9e2f; --s7: #9085e9; --s8: #e66767;
    --grid: #2a2c33;
  }
}
:root[data-theme="dark"] {
  color-scheme: dark;
  --bg: #0f1013; --surface: #17181c; --surface-2: #1e2025; --surface-3: #282a31;
  --border: #2d3038; --text: #ecebe8; --text-2: #b9b8b2; --text-3: #8b8a85;
  --accent: #4d9bf0; --accent-2: #9085e9; --accent-soft: #16263b;
  --good: #3ccf8e; --good-soft: #12291f; --warn: #f0b440; --warn-soft: #2d2412;
  --bad: #f07171; --bad-soft: #2e1717; --code-bg: #121317;
  --shadow: 0 1px 2px rgba(0,0,0,.4), 0 8px 24px rgba(0,0,0,.35);
  --s1: #3987e5; --s2: #d95926; --s3: #199e70; --s4: #c98500;
  --s5: #d55181; --s6: #2f9e2f; --s7: #9085e9; --s8: #e66767;
  --grid: #2a2c33;
}

*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: calc(var(--top-h) + 16px); }
body {
  margin: 0; background: var(--bg); color: var(--text);
  font-family: var(--font); font-size: 17px; line-height: 1.7;
  -webkit-font-smoothing: antialiased; text-rendering: optimizeLegibility;
}
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }
img, svg { max-width: 100%; }
h1, h2, h3, h4 { line-height: 1.25; letter-spacing: -0.015em; }
h1 { font-size: clamp(2rem, 4.5vw, 2.9rem); font-weight: 800; margin: .2em 0 .35em; }
h2 { font-size: 1.65rem; font-weight: 750; margin: 2.4em 0 .6em; padding-top: .2em; }
h3 { font-size: 1.22rem; font-weight: 700; margin: 1.8em 0 .5em; }
h4 { font-size: 1.02rem; font-weight: 700; margin: 1.4em 0 .4em; color: var(--text-2); }
p, ul, ol { margin: 0 0 1.05em; }
li { margin: .25em 0; }
strong { font-weight: 650; }
hr { border: 0; border-top: 1px solid var(--border); margin: 2.5em 0; }
code, kbd, pre { font-family: var(--mono); }
:not(pre) > code {
  font-size: .86em; background: var(--surface-2); border: 1px solid var(--border);
  padding: .08em .38em; border-radius: 6px; white-space: nowrap;
}
kbd { font-size: .82em; border: 1px solid var(--border); border-bottom-width: 2px; padding: 0 .4em; border-radius: 5px; background: var(--surface); }

/* ---------- Topbar ---------- */
.topbar {
  position: fixed; inset: 0 0 auto 0; height: var(--top-h); z-index: 50;
  display: flex; align-items: center; gap: 14px; padding: 0 16px;
  background: color-mix(in srgb, var(--bg) 82%, transparent);
  backdrop-filter: saturate(160%) blur(12px); -webkit-backdrop-filter: saturate(160%) blur(12px);
  border-bottom: 1px solid var(--border);
}
.topbar .brand { display: flex; align-items: center; gap: 10px; color: var(--text); font-weight: 750; letter-spacing: -.01em; white-space: nowrap; }
.topbar .brand:hover { text-decoration: none; }
.topbar .brand img { width: 30px; height: 30px; }
.topbar .brand span small { display: block; font-size: .68rem; font-weight: 500; color: var(--text-3); letter-spacing: .02em; margin-top: -4px; }
.topbar .spacer { flex: 1; }
.icon-btn {
  display: inline-grid; place-items: center; width: 38px; height: 38px; border-radius: 10px;
  background: transparent; color: var(--text-2); border: 1px solid var(--border); cursor: pointer;
}
.icon-btn:hover { background: var(--surface-2); color: var(--text); }
.icon-btn svg { width: 18px; height: 18px; }
.menu-btn { display: none; }
.progress-pill { font-size: .8rem; color: var(--text-2); border: 1px solid var(--border); border-radius: 999px; padding: 4px 12px; white-space: nowrap; }
.progress-pill b { color: var(--accent); }
.read-progress { position: fixed; top: var(--top-h); left: 0; height: 3px; width: 0; z-index: 51; background: linear-gradient(90deg, var(--accent), var(--accent-2)); transition: width .1s linear; }

/* ---------- Sidebar ---------- */
.sidebar {
  position: fixed; top: var(--top-h); bottom: 0; left: 0; width: var(--sidebar-w); z-index: 40;
  overflow-y: auto; padding: 18px 12px 40px; border-right: 1px solid var(--border); background: var(--bg);
  scrollbar-width: thin;
}
.sidebar .side-home { display: flex; gap: 8px; align-items: center; padding: 8px 10px; border-radius: 10px; color: var(--text-2); font-weight: 600; font-size: .9rem; }
.sidebar .side-home:hover { background: var(--surface-2); text-decoration: none; }
.side-stage { margin: 4px 0; }
.side-stage > button {
  width: 100%; display: flex; align-items: center; gap: 10px; text-align: left; cursor: pointer;
  background: none; border: 0; color: var(--text); padding: 8px 10px; border-radius: 10px; font: 600 .88rem/1.3 var(--font);
}
.side-stage > button:hover { background: var(--surface-2); }
.side-stage .num {
  flex: none; width: 26px; height: 26px; border-radius: 8px; display: grid; place-items: center;
  font-size: .75rem; font-weight: 800; color: #fff; background: var(--stage-color, var(--accent));
}
.side-stage .chev { margin-left: auto; transition: transform .2s; color: var(--text-3); }
.side-stage.open .chev { transform: rotate(90deg); }
.side-stage ul { list-style: none; margin: 2px 0 8px 22px; padding: 0 0 0 14px; border-left: 1px solid var(--border); display: none; }
.side-stage.open ul { display: block; }
.side-stage li { margin: 0; }
.side-stage li a {
  display: flex; align-items: flex-start; gap: 8px; padding: 6px 10px; border-radius: 8px;
  color: var(--text-2); font-size: .85rem; line-height: 1.35;
}
.side-stage li a:hover { background: var(--surface-2); color: var(--text); text-decoration: none; }
.side-stage li a.current { background: var(--accent-soft); color: var(--accent); font-weight: 600; }
.side-stage li a .dot { flex: none; width: 14px; height: 14px; margin-top: 2px; border-radius: 50%; border: 1.5px solid var(--text-3); display: grid; place-items: center; }
.side-stage li a.done .dot { background: var(--good); border-color: var(--good); }
.side-stage li a.done .dot::after { content: ""; width: 6px; height: 3px; border: solid #fff; border-width: 0 0 1.5px 1.5px; transform: rotate(-45deg) translate(1px,-1px); }
.side-stage li a .lab-tag { font-size: .62rem; font-weight: 700; letter-spacing: .05em; padding: 1px 5px; border-radius: 4px; background: var(--warn-soft); color: var(--warn); margin-left: auto; flex: none; }

/* ---------- Layout contenuti ---------- */
.page { margin-left: var(--sidebar-w); padding-top: var(--top-h); min-height: 100vh; }
.content { max-width: 860px; margin: 0 auto; padding: 36px 32px 80px; }
.content.wide { max-width: 1140px; }
.breadcrumb { font-size: .82rem; color: var(--text-3); display: flex; flex-wrap: wrap; gap: 6px; align-items: center; }
.breadcrumb a { color: var(--text-3); }
.eyebrow { display: inline-flex; align-items: center; gap: 8px; font-size: .78rem; font-weight: 700; letter-spacing: .08em; text-transform: uppercase; color: var(--stage-color, var(--accent)); margin-top: 18px; }
.eyebrow::before { content: ""; width: 18px; height: 3px; border-radius: 2px; background: currentColor; }
.lead { font-size: 1.18rem; color: var(--text-2); line-height: 1.6; }
.meta-row { display: flex; flex-wrap: wrap; gap: 8px; margin: 14px 0 6px; }
.chip { display: inline-flex; align-items: center; gap: 6px; font-size: .78rem; font-weight: 600; color: var(--text-2); background: var(--surface); border: 1px solid var(--border); padding: 4px 10px; border-radius: 999px; }
.chip.lab { color: var(--warn); background: var(--warn-soft); border-color: transparent; }

.toc { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 16px 20px; margin: 26px 0; font-size: .92rem; }
.toc strong { display: block; font-size: .75rem; letter-spacing: .08em; text-transform: uppercase; color: var(--text-3); margin-bottom: 6px; }
.toc ol { margin: 0; padding-left: 1.2em; columns: 2; column-gap: 28px; }
.toc li { break-inside: avoid; margin: .15em 0; }
.toc a { color: var(--text-2); }

/* ---------- Componenti didattici ---------- */
.callout { position: relative; border-radius: 12px; padding: 16px 18px 16px 52px; margin: 1.6em 0; background: var(--accent-soft); border: 1px solid color-mix(in srgb, var(--accent) 25%, transparent); }
.callout::before { position: absolute; left: 16px; top: 15px; width: 24px; height: 24px; border-radius: 7px; display: grid; place-items: center; font-weight: 800; font-size: .85rem; color: #fff; background: var(--accent); content: "i"; font-family: var(--mono); }
.callout > :last-child { margin-bottom: 0; }
.callout .title { display: block; font-weight: 700; margin-bottom: 4px; }
.callout.tip { background: var(--good-soft); border-color: color-mix(in srgb, var(--good) 30%, transparent); }
.callout.tip::before { content: "✓"; background: var(--good); }
.callout.warn { background: var(--warn-soft); border-color: color-mix(in srgb, var(--warn) 30%, transparent); }
.callout.warn::before { content: "!"; background: var(--warn); }
.callout.danger { background: var(--bad-soft); border-color: color-mix(in srgb, var(--bad) 30%, transparent); }
.callout.danger::before { content: "×"; background: var(--bad); }
.callout.why { background: linear-gradient(135deg, color-mix(in srgb, var(--accent) 12%, var(--surface)), color-mix(in srgb, var(--accent-2) 12%, var(--surface))); }
.callout.why::before { content: "?"; background: linear-gradient(135deg, var(--accent), var(--accent-2)); }

.formula {
  font-family: var(--mono); font-size: .98rem; text-align: center; padding: 18px 16px; margin: 1.4em 0;
  border-radius: 12px; background: var(--surface); border: 1px dashed var(--border); overflow-x: auto; line-height: 1.9;
}
.formula .lbl { display: block; font-family: var(--font); font-size: .78rem; color: var(--text-3); margin-top: 4px; }
.formula var { font-style: italic; color: var(--accent); }

.cards { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 14px; margin: 1.4em 0; }
.card { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 16px 18px; box-shadow: var(--shadow); }
.card h4 { margin: 0 0 6px; color: var(--text); font-size: 1rem; }
.card p { font-size: .92rem; color: var(--text-2); margin: 0; }
.card .big { font-size: 1.8rem; font-weight: 800; letter-spacing: -.02em; color: var(--accent); line-height: 1.1; display: block; margin-bottom: 4px; font-variant-numeric: tabular-nums; }

.stats { display: grid; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); gap: 12px; margin: 1.4em 0; }
.stat { background: var(--surface); border: 1px solid var(--border); border-radius: 12px; padding: 14px 16px; }
.stat .v { font-size: 1.6rem; font-weight: 800; letter-spacing: -.02em; font-variant-numeric: tabular-nums; }
.stat .k { font-size: .8rem; color: var(--text-3); }

.two-col { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; align-items: start; }

table.data { width: 100%; border-collapse: collapse; margin: 1.4em 0; font-size: .9rem; display: block; overflow-x: auto; }
table.data th, table.data td { padding: 9px 12px; border-bottom: 1px solid var(--border); text-align: left; vertical-align: top; }
table.data th { font-size: .76rem; text-transform: uppercase; letter-spacing: .06em; color: var(--text-3); font-weight: 700; background: var(--surface-2); white-space: nowrap; }
table.data td.num, table.data th.num { text-align: right; font-variant-numeric: tabular-nums; }
table.data tr:hover td { background: color-mix(in srgb, var(--surface-2) 60%, transparent); }

/* ---------- Codice ---------- */
.code-wrap { position: relative; margin: 1.3em 0; }
.code-wrap .code-label { position: absolute; top: 0; left: 14px; transform: translateY(-50%); font: 600 .7rem/1 var(--font); letter-spacing: .06em; text-transform: uppercase; color: var(--text-3); background: var(--bg); border: 1px solid var(--border); padding: 4px 8px; border-radius: 6px; }
pre { background: var(--code-bg); border: 1px solid var(--border); border-radius: 12px; padding: 20px 18px 16px; overflow-x: auto; font-size: .84rem; line-height: 1.6; margin: 1.3em 0; tab-size: 4; }
pre code { background: none; border: 0; padding: 0; white-space: pre; }
.copy-btn { position: absolute; top: 8px; right: 8px; font: 600 .72rem var(--font); padding: 4px 9px; border-radius: 7px; border: 1px solid var(--border); background: var(--surface); color: var(--text-2); cursor: pointer; opacity: 0; transition: opacity .15s; }
.code-wrap:hover .copy-btn, .copy-btn:focus { opacity: 1; }
.hljs-comment, .hljs-quote { color: #7d7d86; font-style: italic; }
.hljs-keyword, .hljs-selector-tag, .hljs-built_in, .hljs-meta .hljs-keyword { color: #7a3ec8; }
.hljs-string, .hljs-attr .hljs-string, .hljs-regexp { color: #0b7a3e; }
.hljs-number, .hljs-literal { color: #b4520a; }
.hljs-title, .hljs-title.function_, .hljs-section { color: #1f63c4; }
.hljs-type, .hljs-title.class_ { color: #a1307a; }
.hljs-meta, .hljs-meta .hljs-string { color: #8a6200; }
.hljs-attr, .hljs-variable, .hljs-template-variable, .hljs-params { color: #2b4a8a; }
:root[data-theme="dark"] .hljs-keyword, :root[data-theme="dark"] .hljs-built_in { color: #c792ea; }
:root[data-theme="dark"] .hljs-string { color: #a5d6a7; }
:root[data-theme="dark"] .hljs-number, :root[data-theme="dark"] .hljs-literal { color: #f7a76c; }
:root[data-theme="dark"] .hljs-title, :root[data-theme="dark"] .hljs-title.function_ { color: #82aaff; }
:root[data-theme="dark"] .hljs-type, :root[data-theme="dark"] .hljs-title.class_ { color: #f48fb1; }
:root[data-theme="dark"] .hljs-meta { color: #ffcb6b; }
:root[data-theme="dark"] .hljs-attr, :root[data-theme="dark"] .hljs-variable, :root[data-theme="dark"] .hljs-params { color: #9ccfe8; }
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .hljs-keyword, :root:not([data-theme="light"]) .hljs-built_in { color: #c792ea; }
  :root:not([data-theme="light"]) .hljs-string { color: #a5d6a7; }
  :root:not([data-theme="light"]) .hljs-number, :root:not([data-theme="light"]) .hljs-literal { color: #f7a76c; }
  :root:not([data-theme="light"]) .hljs-title, :root:not([data-theme="light"]) .hljs-title.function_ { color: #82aaff; }
  :root:not([data-theme="light"]) .hljs-type, :root:not([data-theme="light"]) .hljs-title.class_ { color: #f48fb1; }
  :root:not([data-theme="light"]) .hljs-meta { color: #ffcb6b; }
  :root:not([data-theme="light"]) .hljs-attr, :root:not([data-theme="light"]) .hljs-variable, :root:not([data-theme="light"]) .hljs-params { color: #9ccfe8; }
}

/* ---------- Figure e diagrammi ---------- */
figure.diagram { margin: 1.8em 0; background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 18px; box-shadow: var(--shadow); }
figure.diagram svg { display: block; width: 100%; height: auto; margin: 0 auto; font-family: var(--font); }
figure.diagram figcaption { font-size: .85rem; color: var(--text-3); margin-top: 12px; text-align: center; line-height: 1.5; }
/* Token di colore utilizzabili dentro gli SVG inline */
svg .t { fill: var(--text); } svg .t2 { fill: var(--text-2); } svg .t3 { fill: var(--text-3); }
svg .bg { fill: var(--surface); } svg .bg2 { fill: var(--surface-2); } svg .bg3 { fill: var(--surface-3); }
svg .ln { stroke: var(--border); } svg .ln2 { stroke: var(--text-3); }
svg .f1 { fill: var(--s1); } svg .f2 { fill: var(--s2); } svg .f3 { fill: var(--s3); } svg .f4 { fill: var(--s4); }
svg .f5 { fill: var(--s5); } svg .f6 { fill: var(--s6); } svg .f7 { fill: var(--s7); } svg .f8 { fill: var(--s8); }
svg .st1 { stroke: var(--s1); } svg .st2 { stroke: var(--s2); } svg .st3 { stroke: var(--s3); } svg .st4 { stroke: var(--s4); }
svg .st5 { stroke: var(--s5); } svg .st6 { stroke: var(--s6); } svg .st7 { stroke: var(--s7); } svg .st8 { stroke: var(--s8); }
svg .sacc { stroke: var(--accent); } svg .facc { fill: var(--accent); }
svg text { font-family: var(--font); }
svg .mono { font-family: var(--mono); }
svg .lbl { font-size: 13px; fill: var(--text-2); }
svg .lbl-s { font-size: 11px; fill: var(--text-3); }
svg .lbl-b { font-size: 14px; font-weight: 700; fill: var(--text); }
svg .on-color { fill: #fff; font-weight: 700; }
svg .soft1 { fill: color-mix(in srgb, var(--s1) 18%, var(--surface)); }
svg .soft2 { fill: color-mix(in srgb, var(--s2) 18%, var(--surface)); }
svg .soft3 { fill: color-mix(in srgb, var(--s3) 18%, var(--surface)); }
svg .soft4 { fill: color-mix(in srgb, var(--s4) 18%, var(--surface)); }
svg .soft5 { fill: color-mix(in srgb, var(--s5) 18%, var(--surface)); }
svg .soft7 { fill: color-mix(in srgb, var(--s7) 18%, var(--surface)); }
svg .soft8 { fill: color-mix(in srgb, var(--s8) 18%, var(--surface)); }

/* Animazioni riutilizzabili */
@keyframes flow { to { stroke-dashoffset: -40; } }
@keyframes flow-rev { to { stroke-dashoffset: 40; } }
@keyframes pulse { 0%,100% { opacity: .35; } 50% { opacity: 1; } }
@keyframes pop { 0% { transform: scale(.6); opacity: 0; } 60% { transform: scale(1.08); opacity: 1; } 100% { transform: scale(1); opacity: 1; } }
@keyframes slide-x { from { transform: translateX(0); } to { transform: translateX(var(--dx, 100px)); } }
@keyframes blink { 0%,100% { opacity: 1; } 50% { opacity: .2; } }
@keyframes grow-w { from { transform: scaleX(0); } to { transform: scaleX(1); } }
@keyframes float { 0%,100% { transform: translateY(0); } 50% { transform: translateY(-6px); } }
@keyframes spin { to { transform: rotate(360deg); } }
.anim-flow { stroke-dasharray: 8 12; animation: flow 1.2s linear infinite; }
.anim-flow.fast { animation-duration: .5s; }
.anim-flow.slow { animation-duration: 2.6s; }
.anim-flow-rev { stroke-dasharray: 8 12; animation: flow-rev 1.2s linear infinite; }
.anim-pulse { animation: pulse 2s ease-in-out infinite; }
.anim-blink { animation: blink 1s steps(2) infinite; }
.anim-float { animation: float 3s ease-in-out infinite; transform-box: fill-box; }
.anim-spin { animation: spin 6s linear infinite; transform-box: fill-box; transform-origin: center; }
.d1 { animation-delay: .2s; } .d2 { animation-delay: .4s; } .d3 { animation-delay: .6s; } .d4 { animation-delay: .8s; }
.d5 { animation-delay: 1s; } .d6 { animation-delay: 1.2s; } .d7 { animation-delay: 1.4s; } .d8 { animation-delay: 1.6s; }
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation-duration: .001ms !important; animation-iteration-count: 1 !important; transition-duration: .001ms !important; }
}

/* Comparsa allo scroll */
.reveal { opacity: 0; transform: translateY(14px); transition: opacity .6s ease, transform .6s ease; }
.reveal.in { opacity: 1; transform: none; }

/* ---------- Widget interattivi ---------- */
.widget { margin: 1.8em 0; background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); box-shadow: var(--shadow); overflow: hidden; }
.widget-head { display: flex; align-items: center; gap: 10px; padding: 12px 18px; border-bottom: 1px solid var(--border); background: var(--surface-2); font-weight: 700; font-size: .92rem; }
.widget-head .badge { font-size: .66rem; letter-spacing: .08em; text-transform: uppercase; padding: 2px 7px; border-radius: 5px; background: var(--accent); color: #fff; }
.widget-body { padding: 18px; }
.controls { display: grid; grid-template-columns: repeat(auto-fit, minmax(190px, 1fr)); gap: 12px 18px; margin-bottom: 16px; }
.ctl label { display: flex; justify-content: space-between; font-size: .8rem; font-weight: 600; color: var(--text-2); margin-bottom: 4px; }
.ctl label output { font-family: var(--mono); color: var(--accent); font-weight: 600; }
.ctl input[type=range] { width: 100%; accent-color: var(--accent); }
.ctl select, .ctl input[type=number] { width: 100%; padding: 7px 10px; border-radius: 8px; border: 1px solid var(--border); background: var(--surface); color: var(--text); font: 500 .88rem var(--font); }
.btn { display: inline-flex; align-items: center; gap: 6px; font: 600 .85rem var(--font); padding: 8px 14px; border-radius: 9px; border: 1px solid var(--border); background: var(--surface); color: var(--text); cursor: pointer; }
.btn:hover { background: var(--surface-2); }
.btn.primary { background: var(--accent); color: #fff; border-color: transparent; }
.btn.primary:hover { filter: brightness(1.08); }
.btn-row { display: flex; flex-wrap: wrap; gap: 8px; margin: 10px 0; }
.result-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); gap: 10px; }
.result { background: var(--surface-2); border-radius: 10px; padding: 10px 14px; }
.result .k { font-size: .78rem; color: var(--text-3); font-weight: 600; letter-spacing: .01em; }
.result .v { font-size: 1.3rem; font-weight: 800; font-variant-numeric: tabular-nums; letter-spacing: -.01em; }
.result .v small { font-size: .75rem; font-weight: 600; color: var(--text-3); margin-left: 3px; }
.result.good .v { color: var(--good); } .result.bad .v { color: var(--bad); } .result.warn .v { color: var(--warn); }
.bar-track { height: 14px; border-radius: 7px; background: var(--surface-3); overflow: hidden; display: flex; gap: 2px; }
.bar-track > span { display: block; height: 100%; transition: width .4s ease; border-radius: 4px; }
.legend { display: flex; flex-wrap: wrap; gap: 14px; font-size: .8rem; color: var(--text-2); margin-top: 8px; }
.legend i { display: inline-block; width: 10px; height: 10px; border-radius: 3px; margin-right: 6px; vertical-align: -1px; }
.viz-tip { position: fixed; pointer-events: none; z-index: 100; background: var(--surface); border: 1px solid var(--border); box-shadow: var(--shadow); border-radius: 8px; padding: 6px 10px; font-size: .8rem; color: var(--text); opacity: 0; transition: opacity .12s; }
.viz-tip.on { opacity: 1; }

/* ---------- Quiz ---------- */
.quiz { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 18px 20px; margin: 1.4em 0; }
.quiz .q { font-weight: 650; margin-bottom: 12px; }
.quiz .q::before { content: "Verifica"; display: block; font-size: .7rem; letter-spacing: .1em; text-transform: uppercase; color: var(--accent-2); font-weight: 800; margin-bottom: 4px; }
.quiz .opts { display: grid; gap: 8px; }
.quiz button.opt { text-align: left; font: 500 .93rem/1.45 var(--font); color: var(--text); background: var(--surface-2); border: 1.5px solid transparent; border-radius: 10px; padding: 10px 14px; cursor: pointer; transition: border-color .15s, background .15s; }
.quiz button.opt:hover { border-color: var(--border); }
.quiz button.opt.right { border-color: var(--good); background: var(--good-soft); }
.quiz button.opt.wrong { border-color: var(--bad); background: var(--bad-soft); }
.quiz .explain { display: none; margin-top: 12px; font-size: .92rem; color: var(--text-2); border-left: 3px solid var(--accent-2); padding-left: 12px; }
.quiz.answered .explain { display: block; animation: pop .35s ease; }

/* ---------- Lab ---------- */
.objectives { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 16px 20px; }
.objectives h4 { margin-top: 0; }
ol.steps { counter-reset: step; list-style: none; padding: 0; }
ol.steps > li { counter-increment: step; position: relative; padding: 0 0 18px 50px; margin: 0; border-left: 2px solid var(--border); margin-left: 16px; padding-left: 34px; }
ol.steps > li:last-child { border-left-color: transparent; }
ol.steps > li::before { content: counter(step); position: absolute; left: -17px; top: -2px; width: 32px; height: 32px; border-radius: 50%; background: var(--accent); color: #fff; font-weight: 800; font-size: .85rem; display: grid; place-items: center; box-shadow: 0 0 0 4px var(--bg); }
ol.steps > li > strong:first-child { display: block; font-size: 1.04rem; margin-bottom: 4px; }
.checklist { list-style: none; padding: 0; }
.checklist li { display: flex; gap: 10px; align-items: flex-start; padding: 8px 12px; border-radius: 10px; cursor: pointer; }
.checklist li:hover { background: var(--surface-2); }
.checklist li::before { content: ""; flex: none; width: 18px; height: 18px; margin-top: 4px; border-radius: 5px; border: 2px solid var(--text-3); transition: all .15s; }
.checklist li.checked::before { background: var(--good); border-color: var(--good); box-shadow: inset 0 0 0 3px var(--surface); }
.checklist li.checked { color: var(--text-3); text-decoration: line-through; }
details.solution { background: var(--surface); border: 1px solid var(--border); border-radius: 12px; padding: 0 16px; margin: 1.2em 0; }
details.solution summary { cursor: pointer; padding: 12px 0; font-weight: 650; color: var(--accent); list-style: none; }
details.solution summary::-webkit-details-marker { display: none; }
details.solution summary::before { content: "▸ "; display: inline-block; transition: transform .2s; }
details.solution[open] summary::before { transform: rotate(90deg); }
details.solution[open] { padding-bottom: 6px; }

.takeaways { background: linear-gradient(135deg, color-mix(in srgb, var(--accent) 10%, var(--surface)), color-mix(in srgb, var(--accent-2) 10%, var(--surface))); border: 1px solid var(--border); border-radius: var(--radius); padding: 18px 22px; margin: 2.5em 0 1.5em; }
.takeaways h3 { margin-top: 0; }
.takeaways ul { margin-bottom: 0; }
.refs { font-size: .9rem; color: var(--text-2); }
.refs li { margin: .3em 0; }

/* ---------- Footer lezione ---------- */
.lesson-footer { margin-top: 3em; display: grid; gap: 14px; }
.complete-btn { justify-self: center; display: inline-flex; align-items: center; gap: 8px; font: 700 .95rem var(--font); padding: 12px 22px; border-radius: 12px; border: 1.5px solid var(--good); background: transparent; color: var(--good); cursor: pointer; }
.complete-btn.done { background: var(--good); color: #fff; }
.pager { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
.pager a { display: block; padding: 14px 18px; border: 1px solid var(--border); border-radius: 12px; background: var(--surface); color: var(--text); }
.pager a:hover { border-color: var(--accent); text-decoration: none; }
.pager a small { display: block; font-size: .75rem; color: var(--text-3); text-transform: uppercase; letter-spacing: .06em; font-weight: 700; }
.pager a.next { text-align: right; grid-column: 2; }
.site-footer { margin-left: var(--sidebar-w); border-top: 1px solid var(--border); padding: 24px 32px; color: var(--text-3); font-size: .82rem; text-align: center; }

/* ---------- Home & indici di stage ---------- */
.home-hero { position: relative; overflow: hidden; border-radius: 22px; padding: 46px 40px; margin-bottom: 30px; background: radial-gradient(1200px 400px at 10% -20%, color-mix(in srgb, var(--accent) 28%, transparent), transparent), radial-gradient(800px 400px at 110% 120%, color-mix(in srgb, var(--accent-2) 30%, transparent), transparent), var(--surface); border: 1px solid var(--border); }
.home-hero h1 { font-size: clamp(2.2rem, 5vw, 3.5rem); max-width: 14em; }
.home-hero .lead { max-width: 40em; }
.home-hero svg.hero-art { position: absolute; right: 12px; top: 50%; transform: translateY(-50%); width: 300px; opacity: .95; pointer-events: none; }
.home-hero > :not(svg) { position: relative; max-width: 600px; }
@media (max-width: 1360px) { .home-hero svg.hero-art { opacity: .16; right: -30px; } .home-hero > :not(svg) { max-width: none; } }
.stage-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(300px, 1fr)); gap: 16px; }
.stage-card { position: relative; display: flex; flex-direction: column; gap: 6px; padding: 20px; border-radius: var(--radius); background: var(--surface); border: 1px solid var(--border); color: var(--text); box-shadow: var(--shadow); transition: transform .2s, border-color .2s; overflow: hidden; }
.stage-card::after { content: ""; position: absolute; inset: 0 0 auto 0; height: 4px; background: var(--stage-color); }
.stage-card:hover { transform: translateY(-3px); border-color: var(--stage-color); text-decoration: none; }
.stage-card .n { font: 800 .75rem var(--mono); color: var(--stage-color); letter-spacing: .08em; }
.stage-card h3 { margin: 0; font-size: 1.12rem; }
.stage-card p { margin: 0; font-size: .88rem; color: var(--text-2); }
.stage-card .why { font-style: italic; color: var(--text-3); font-size: .84rem; }
.stage-card .bar { margin-top: auto; height: 6px; border-radius: 3px; background: var(--surface-3); overflow: hidden; }
.stage-card .bar span { display: block; height: 100%; background: var(--stage-color); }
.stage-card .foot { display: flex; justify-content: space-between; font-size: .76rem; color: var(--text-3); margin-top: 8px; }
.topic-list { list-style: none; padding: 0; display: grid; gap: 10px; }
.topic-list a { display: flex; gap: 16px; align-items: center; padding: 16px 18px; border-radius: 12px; border: 1px solid var(--border); background: var(--surface); color: var(--text); }
.topic-list a:hover { border-color: var(--stage-color, var(--accent)); text-decoration: none; }
.topic-list .idx { flex: none; width: 40px; height: 40px; display: grid; place-items: center; border-radius: 10px; background: var(--surface-2); font: 800 .9rem var(--mono); color: var(--stage-color, var(--accent)); }
.topic-list .done .idx { background: var(--good); color: #fff; }
.topic-list .t { font-weight: 650; }
.topic-list .d { font-size: .86rem; color: var(--text-2); }
.topic-list .m { margin-left: auto; font-size: .78rem; color: var(--text-3); white-space: nowrap; text-align: right; }
.roadmap { display: flex; gap: 0; overflow-x: auto; padding: 10px 0 18px; margin: 10px 0 30px; }

/* ---------- Responsive ---------- */
@media (max-width: 1020px) {
  .sidebar { transform: translateX(-100%); transition: transform .25s ease; box-shadow: var(--shadow); width: min(86vw, 320px); }
  body.nav-open .sidebar { transform: none; }
  body.nav-open::after { content: ""; position: fixed; inset: var(--top-h) 0 0 0; background: rgba(0,0,0,.35); z-index: 30; }
  .menu-btn { display: inline-grid; }
  .page, .site-footer { margin-left: 0; }
  .home-hero svg.hero-art { opacity: .25; }
}
@media (max-width: 680px) {
  body { font-size: 16px; }
  .content { padding: 24px 16px 60px; }
  .two-col { grid-template-columns: 1fr; }
  .toc ol { columns: 1; }
  .pager { grid-template-columns: 1fr; }
  .pager a.next { grid-column: 1; }
  .home-hero { padding: 30px 20px; }
  .topbar .brand span small, .progress-pill { display: none; }
  figure.diagram { padding: 10px; }
  .topic-list .m { display: none; }
}
@media print {
  .topbar, .sidebar, .lesson-footer, .read-progress, .site-footer { display: none !important; }
  .page { margin: 0; padding: 0; }
  .reveal { opacity: 1; transform: none; }
}