/* ============================================================
   base.css — fondamenta condivise (sito + portale Lab)
   Token tema, reset, header/nav, theme toggle, bottoni, footer.
   Caricato PRIMA di styles.css (home) o lab.css (portale).
   ============================================================ */

/* ---------- Tokens ---------- */
:root {
  --bg:        #f4f1ea;
  --bg-elev:   #fbfaf6;
  --bg-sunk:   #ece8de;
  --ink:       #181712;
  --ink-soft:  #58544a;
  --ink-faint: #8c887c;
  --line:      rgba(24, 23, 18, 0.14);
  --line-soft: rgba(24, 23, 18, 0.08);
  --accent:    #2c45ff;
  --accent-ink:#ffffff;
  --accent-wash: rgba(44, 69, 255, 0.08);
  --grain-opacity: 0.035;

  --font-display: "Fraunces", Georgia, "Times New Roman", serif;
  --font-sans: "Inter", system-ui, -apple-system, sans-serif;
  --font-mono: "JetBrains Mono", ui-monospace, "SFMono-Regular", monospace;

  --container: 1140px;
  --pad: clamp(1.25rem, 5vw, 2.5rem);
  --radius: 14px;

  --ease: cubic-bezier(0.22, 1, 0.36, 1);
}

[data-theme="dark"] {
  --bg:        #100f0c;
  --bg-elev:   #18170f;
  --bg-sunk:   #0a0a07;
  --ink:       #f3efe4;
  --ink-soft:  #a6a194;
  --ink-faint: #6f6b60;
  --line:      rgba(243, 239, 228, 0.16);
  --line-soft: rgba(243, 239, 228, 0.08);
  --accent:    #9aa0ff;
  --accent-ink:#0a0a07;
  --accent-wash: rgba(154, 160, 255, 0.12);
  --grain-opacity: 0.05;
}

/* ---------- Reset ---------- */
*, *::before, *::after { box-sizing: border-box; }
* { margin: 0; }
/* l'attributo hidden deve sempre vincere, anche su display:grid/flex */
[hidden] { display: none !important; }

/* overflow-x: clip taglia lo sfondamento orizzontale senza creare un
   contenitore di scroll, così position: sticky continua a funzionare */
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; overflow-x: clip; }

body {
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font-sans);
  font-size: clamp(1rem, 0.96rem + 0.2vw, 1.0625rem);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  overflow-x: clip;
  transition: background-color 0.4s var(--ease), color 0.4s var(--ease);
}

/* JetBrains Mono ha le "legature da codice" (es. != reso come ≠, <= come ≤,
   -> come →): negli operatori confondono e non sono copiabili come si scrivono.
   Le disattiviamo dove appaiono: codice, campi di testo ed editor. */
pre, code, kbd, samp,
input, textarea, select,
[contenteditable], svg text {
  font-variant-ligatures: none;
  font-feature-settings: "liga" 0, "calt" 0;
}

img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }

::selection { background: var(--accent); color: var(--accent-ink); }

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
  border-radius: 3px;
}

/* ---------- Grain overlay ---------- */
.grain {
  position: fixed;
  inset: 0;
  z-index: 1;
  pointer-events: none;
  opacity: var(--grain-opacity);
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='160' height='160'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.8' numOctaves='3'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
  mix-blend-mode: multiply;
}
[data-theme="dark"] .grain { mix-blend-mode: screen; }

/* ---------- Layout primitives ---------- */
.container {
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: var(--pad);
}

.section {
  position: relative;
  z-index: 2;
  padding-block: clamp(3.25rem, 7vw, 5.5rem);
}

.skip-link {
  position: absolute;
  left: -9999px;
  top: 1rem;
  z-index: 100;
  background: var(--ink);
  color: var(--bg);
  padding: 0.6rem 1rem;
  border-radius: 8px;
  font-size: 0.9rem;
}
.skip-link:focus { left: 1rem; }

/* ---------- Header ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: color-mix(in srgb, var(--bg) 78%, transparent);
  backdrop-filter: blur(14px) saturate(1.4);
  -webkit-backdrop-filter: blur(14px) saturate(1.4);
  border-bottom: 1px solid transparent;
  transition: border-color 0.3s var(--ease), background-color 0.3s var(--ease);
}
.site-header.scrolled { border-bottom-color: var(--line-soft); }

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
  height: 68px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  font-weight: 500;
}
.brand-mark {
  display: grid;
  place-items: center;
  width: 32px;
  height: 32px;
  border-radius: 9px;
  background: var(--ink);
  color: var(--bg);
  font-family: var(--font-display);
  font-style: italic;
  font-weight: 600;
  font-size: 0.92rem;
  letter-spacing: -0.02em;
}
.brand-name { font-size: 0.98rem; letter-spacing: -0.01em; }
.brand-sub {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--ink-faint);
  padding-left: 0.55rem;
  margin-left: 0.1rem;
  border-left: 1px solid var(--line);
}

.nav {
  display: flex;
  gap: 1.75rem;
  font-size: 0.92rem;
}
.nav a {
  position: relative;
  color: var(--ink-soft);
  padding-block: 0.4rem;
  transition: color 0.2s var(--ease);
}
.nav a:hover { color: var(--ink); }
.nav a.active { color: var(--ink); }
.nav a::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: 100%;
  height: 1.5px;
  background: var(--accent);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.3s var(--ease);
}
.nav a:hover::after,
.nav a.active::after { transform: scaleX(1); }
.nav-num {
  font-family: var(--font-mono);
  font-size: 0.66rem;
  color: var(--ink-faint);
  margin-right: 0.15rem;
}

.header-actions { display: flex; align-items: center; gap: 0.5rem; }

.theme-toggle,
.nav-toggle {
  display: grid;
  place-items: center;
  width: 40px;
  height: 40px;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: transparent;
  color: var(--ink);
  cursor: pointer;
  transition: border-color 0.2s var(--ease), background-color 0.2s var(--ease), transform 0.2s var(--ease);
}
.theme-toggle:hover,
.nav-toggle:hover { border-color: var(--ink); background: var(--bg-elev); }
.theme-toggle:active { transform: scale(0.92); }

.theme-toggle .icon-moon { display: none; }
[data-theme="dark"] .theme-toggle .icon-sun { display: none; }
[data-theme="dark"] .theme-toggle .icon-moon { display: block; }

.nav-toggle { display: none; flex-direction: column; align-items: center; justify-content: center; gap: 5px; }
.nav-toggle span {
  display: block;
  width: 18px;
  height: 2px;
  flex: 0 0 auto;
  background: var(--ink);
  border-radius: 2px;
  transition: transform 0.3s var(--ease), opacity 0.3s var(--ease);
}
.nav-toggle[aria-expanded="true"] span:nth-child(1) { transform: translateY(3.5px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] span:nth-child(2) { transform: translateY(-3.5px) rotate(-45deg); }

/* ---------- Mobile nav ---------- */
/* overlay a tutta altezza sotto l'header (che resta sempre visibile e cliccabile) */
.nav-mobile {
  position: fixed;
  inset: 68px 0 0 0;
  z-index: 49;
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
  padding: 1.25rem var(--pad) 2rem;
  background: var(--bg-elev);
  border-bottom: 1px solid var(--line);
  overflow-y: auto;
  overscroll-behavior: contain;
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
  transition: opacity 0.25s var(--ease), visibility 0.25s var(--ease);
}
.nav-mobile.open { opacity: 1; visibility: visible; pointer-events: auto; }
.nav-mobile a {
  font-family: var(--font-display);
  font-size: 1.6rem;
  padding-block: 0.5rem;
  border-bottom: 1px solid var(--line-soft);
}
.nav-mobile .nav-num {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--accent);
}

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-family: var(--font-sans);
  font-size: 0.95rem;
  font-weight: 500;
  padding: 0.8rem 1.3rem;
  border-radius: 100px;
  border: 1px solid transparent;
  cursor: pointer;
  transition: transform 0.25s var(--ease), background-color 0.25s var(--ease),
              border-color 0.25s var(--ease), color 0.25s var(--ease);
}
.btn svg { transition: transform 0.25s var(--ease); }
.btn:hover svg { transform: translateX(3px); }

.btn-primary { background: var(--accent); color: var(--accent-ink); }
.btn-primary:hover { transform: translateY(-2px); }

.btn-ghost {
  background: transparent;
  color: var(--ink);
  border-color: var(--line);
}
.btn-ghost:hover { border-color: var(--ink); background: var(--bg-elev); }

/* ---------- Section head ---------- */
.section-head { margin-bottom: clamp(1.75rem, 4vw, 2.6rem); }
.section-num {
  display: block;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--accent);
  letter-spacing: 0.08em;
  margin-bottom: 0.85rem;
}
.section-kicker {
  font-family: var(--font-display);
  font-weight: 500;
  font-size: clamp(2rem, 5.5vw, 3.4rem);
  line-height: 1.02;
  letter-spacing: -0.025em;
}
.section-desc {
  margin-top: 1rem;
  max-width: 52ch;
  color: var(--ink-soft);
  font-size: 1.02rem;
}

/* ---------- Footer ---------- */
.site-footer {
  position: relative;
  z-index: 2;
  border-top: 1px solid var(--line);
  padding-block: 2.25rem;
}
.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
}
.footer-brand { font-family: var(--font-display); font-style: italic; font-size: 1.15rem; }
.footer-meta { font-size: 0.85rem; color: var(--ink-faint); font-family: var(--font-mono); }
.footer-top { font-size: 0.9rem; color: var(--ink-soft); transition: color 0.2s var(--ease); }
.footer-top:hover { color: var(--ink); }

/* ---------- Reveal animation ---------- */
.reveal {
  opacity: 0;
  transform: translateY(22px);
  transition: opacity 0.8s var(--ease), transform 0.8s var(--ease);
}
.reveal.visible { opacity: 1; transform: none; }

/* ---------- Responsive (shared) ---------- */
@media (max-width: 880px) {
  .nav { display: none; }
  .nav-toggle { display: flex; }
}
@media (max-width: 620px) {
  .brand-name { display: none; }
  .brand-sub { display: none; }
}

/* ---------- Reduced motion ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
  }
  .reveal { opacity: 1; transform: none; }
}