/* ========== Base ========== */
*{box-sizing:border-box}
html,body{margin:0;padding:0;font-family:system-ui,-apple-system,Segoe UI,Roboto,Ubuntu,'Helvetica Neue',Arial,sans-serif}
:root{--ring:#0a0a0a;--muted:#666;--line:#e8e8e8;--bg:#fafafa}

/* ========== Header ========== */
.site-header{
  display:flex;justify-content:space-between;align-items:center;gap:12px;
  padding:14px 16px;border-bottom:1px solid var(--line);background:#fff;
  position:sticky;top:0;z-index:10
}
.brand h1{margin:0;font-size:22px}
.subtitle{margin:2px 0 0;color:var(--muted);font-size:13px}
.right-actions{display:flex;gap:10px;align-items:center;flex-wrap:wrap}
@media (max-width:420px){
  .right-actions{flex-wrap:nowrap;overflow-x:auto;-webkit-overflow-scrolling:touch}
  .right-actions .install-btn{flex:0 0 auto;white-space:nowrap}
}

/* Pulsanti header: IT / Tema / Installa (testo sempre visibile, no tagli) */
.install-btn{
  display:inline-flex;align-items:center;justify-content:center;
  padding:8px 14px;border:1px solid #ccc;border-radius:999px;
  background:#fff;color:#111 !important;font-size:14px;line-height:1;
  white-space:nowrap;overflow:visible;cursor:pointer;
  transition:all .2s ease;box-shadow:0 1px 2px rgba(0,0,0,.05)
}
.install-btn:hover{background:#f6f6f6;border-color:#999;box-shadow:0 2px 4px rgba(0,0,0,.1)}
.install-btn:active{transform:scale(.96)}

/* ========== Layout ========== */
main{padding:12px}

/* Tabs (sempre leggibili + responsive) */
.tabs{
  display:flex;gap:8px;margin-bottom:12px;flex-wrap:wrap;
}
button.tab{
  flex:0 0 auto;display:inline-flex;align-items:center;justify-content:center;
  padding:8px 12px;border:1px solid var(--line);border-radius:999px;
  background:#fff !important;color:#111 !important;cursor:pointer;
  transition:background .2s ease,border-color .2s ease,color .2s ease;
  font-weight:600;white-space:nowrap;line-height:1;overflow:visible;max-width:100%;
}
button.tab:hover{background:#f6f6f6 !important;border-color:#999 !important}
button.tab.active{border-color:#111 !important}

/* Su schermi molto stretti: mantieni una riga con scroll orizzontale */
@media (max-width:640px){
  .tabs{flex-wrap:nowrap;overflow-x:auto;-webkit-overflow-scrolling:touch;scrollbar-width:thin}
  .tabs::-webkit-scrollbar{height:6px}
  .tabs::-webkit-scrollbar-thumb{background:#ccc;border-radius:999px}
}

.tab-panel{display:none}
.tab-panel.active{display:block}

/* Cards & grid */
.grid{display:grid;grid-template-columns:repeat(12,1fr);gap:12px}
.card{grid-column:span 6;background:#fff;border:1px solid var(--line);border-radius:12px;padding:12px}
.card.full{grid-column:1/-1}
.card.actions{display:flex;gap:8px;align-items:center}

/* Form */
label{display:flex;flex-direction:column;gap:6px;margin:6px 0;min-width:0}
input,select,textarea,button{font:inherit}
input,select,textarea{padding:8px;border:1px solid #ccc;border-radius:8px;width:100%;max-width:100%}
textarea{resize:vertical}

/* Pulsanti azione principali (Calcola/Reset/Export) */
button{padding:10px 14px;border:1px solid #ccc;border-radius:8px;background:#111;color:#fff;cursor:pointer;white-space:nowrap;line-height:1}
button.secondary{background:#fff;color:#111}
button.ghost{background:#fff;color:#111;border-style:dashed}

/* Helpers */
.result{margin-top:8px;color:#111;font-weight:600}
.muted{color:#777;font-size:12px}
.site-footer{padding:16px;text-align:center;color:#777;border-top:1px solid var(--line);background:var(--bg)}

/* Row helpers */
.row-2,.row-3,.row-4{min-width:0}
.row-2{display:grid;grid-template-columns:repeat(2,1fr);gap:10px}
.row-3{display:grid;grid-template-columns:repeat(3,1fr);gap:10px}
.row-4{display:grid;grid-template-columns:repeat(4,1fr);gap:10px}

/* ========== Responsive grid ========== */
@media (max-width:960px){
  .card{grid-column:span 12}
  .row-4{grid-template-columns:repeat(2,1fr)}
  .row-3{grid-template-columns:repeat(2,1fr)}
}

/* ========== Dark mode (auto + manuale) ========== */
@media (prefers-color-scheme: dark){
  .install-btn{background:#121212;color:#e6e6e6 !important;border-color:#444;box-shadow:0 1px 2px rgba(255,255,255,.05)}
  .install-btn:hover{background:#1d1d1d;border-color:#888;box-shadow:0 2px 4px rgba(255,255,255,.08)}
  button.tab{background:#121212 !important;color:#e6e6e6 !important;border-color:#444 !important}
  button.tab:hover{background:#1d1d1d !important;border-color:#777 !important}
  button.tab.active{border-color:#e6e6e6 !important}
}
/* Override manuale quando l'utente forza il tema */
:root[data-theme='dark'] .install-btn{background:#121212;color:#e6e6e6 !important;border-color:#444}
:root[data-theme='dark'] button.tab{background:#121212 !important;color:#e6e6e6 !important;border-color:#444 !important}
:root[data-theme='dark'] button.tab.active{border-color:#e6e6e6 !important}

/* ===== DARK THEME COMPLETO (AGGIUNTA) ===== */

/* Preferenza di sistema */
@media (prefers-color-scheme: dark){
  body{ background:#0e0e10; color:#e6e6e6 }
  .site-header{ background:#0e0e10; border-color:#2b2b2b }
  .subtitle{ color:#a0a0a0 }

  .card{ background:#141416; border-color:#2b2b2b }
  .site-footer{ background:#0e0e10; color:#9a9a9a; border-color:#2b2b2b }

  /* campi */
  input, select, textarea{
    background:#0e0e10; color:#e6e6e6; border-color:#3a3a3a;
  }
  input::placeholder, textarea::placeholder{ color:#8a8a8a }

  /* pulsanti azione principali */
  button{ background:#e6e6e6; color:#111; border-color:#e6e6e6 }
  button.secondary, button.ghost{ background:#141416; color:#e6e6e6; border-color:#3a3a3a }
  button.ghost{ border-style:dashed }
}

/* Toggle manuale via <html data-theme="dark"> */
:root[data-theme='dark'] body{ background:#0e0e10; color:#e6e6e6 }
:root[data-theme='dark'] .site-header{ background:#0e0e10; border-color:#2b2b2b }
:root[data-theme='dark'] .subtitle{ color:#a0a0a0 }
:root[data-theme='dark'] .card{ background:#141416; border-color:#2b2b2b }
:root[data-theme='dark'] .site-footer{ background:#0e0e10; color:#9a9a9a; border-color:#2b2b2b }

:root[data-theme='dark'] input,
:root[data-theme='dark'] select,
:root[data-theme='dark'] textarea{
  background:#0e0e10; color:#e6e6e6; border-color:#3a3a3a;
}
:root[data-theme='dark'] input::placeholder,
:root[data-theme='dark'] textarea::placeholder{ color:#8a8a8a }

:root[data-theme='dark'] button{ background:#e6e6e6; color:#111; border-color:#e6e6e6 }
:root[data-theme='dark'] button.secondary,
:root[data-theme='dark'] button.ghost{
  background:#141416; color:#e6e6e6; border-color:#3a3a3a;
}
:root[data-theme='dark'] button.ghost{ border-style:dashed }

/* NB: pulsanti header (.install-btn) e tab (button.tab) in dark
       rimangono gestiti dalle regole che hai già */