/* =========================================================
   THEME TOKENS (warm violet/amber) + DARK OVERRIDES
   - Palette e variabili CSS centralizzate per tema light/dark
   - Facilita coerenza visiva e manutenzione
   ========================================================= */
:root {
  --bg: #fbfaf8;
  --text: #1f2230;
  --muted: #5d627a;

  --card: rgba(255, 255, 255, 0.9);
  --border: #e7e1d8;
  --shadow: 0 14px 36px rgba(31, 34, 48, 0.12);
  --glass-blur: saturate(170%) blur(8px);

  --brand: #7c3aed; /* violet - accento primario */
  --brand-2: #f59e0b; /* amber - accento secondario */
  --ring: #c084fc; /* colore per focus ring accessibile */

  --btn-bg: linear-gradient(135deg, #f59e0b, #f97316);
  --btn-bg-hover: linear-gradient(135deg, #f59e0b, #fb923c);

  --field-bg: color-mix(in srgb, #7c3aed 5%, transparent);
}

body[data-theme="dark"] {
  --bg: #0f1117;
  --text: #e6e7ef;
  --muted: #a6adcb;

  --card: rgba(22, 24, 32, 0.75);
  --border: #252a40;
  --shadow: 0 18px 40px rgba(0, 0, 0, 0.55);

  --brand: #a78bfa;
  --brand-2: #fbbf24;
  --ring: #c084fc;

  --btn-bg: linear-gradient(135deg, #f59e0b, #f97316);
  --btn-bg-hover: linear-gradient(135deg, #f59e0b, #fb923c);

  --field-bg: color-mix(in srgb, #a78bfa 8%, transparent);
}

/* =========================================================
   BASE / RESET
   - Normalizza il box model
   - Imposta tipografia e sfondo con gradiente leggero
   - Transizioni morbide per il cambio tema
   ========================================================= */
*,
*::before,
*::after {
  box-sizing: border-box;
}

html,
body {
  height: 100%;
}

body {
  margin: 0;
  font-family: system-ui, -apple-system, "Segoe UI", Inter, Roboto, Arial,
    sans-serif;
  color: var(--text);
  background: radial-gradient(
      1100px 520px at -10% -20%,
      rgba(124, 58, 237, 0.12),
      transparent 60%
    ),
    radial-gradient(
      900px 520px at 120% 0%,
      rgba(245, 158, 11, 0.1),
      transparent 60%
    ),
    var(--bg);
  transition: background-color 0.25s ease, color 0.25s ease;
}

/* =========================================================
   THEME TOGGLE (icona in alto a destra)
   - Aspetto minimale, feedback hover
   - Focus gestito a livello app (senza outline di default)
   ========================================================= */
.theme-icon {
  position: fixed;
  top: 14px;
  right: 18px;
  font-size: 1.4rem;
  line-height: 1;
  cursor: pointer;
  user-select: none;
  color: var(--text);
  background: transparent;
  border: none;
  box-shadow: none;
  padding: 0;
  transition: transform 0.1s ease, opacity 0.2s ease;
  opacity: 0.8;
}
.theme-icon:hover {
  opacity: 1;
  transform: scale(1.08);
}
.theme-icon:focus {
  outline: none;
}

/* =========================================================
   LAYOUT CENTRATO
   - Centro verticale/orizzontale
   - Ritmo verticale uniforme tra sezioni
   ========================================================= */
.container {
  min-height: 100dvh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 1rem;
  padding: 2rem 1rem;
}

.header {
  text-align: center;
  margin: 0;
}

.title {
  margin: 0 0 0.25rem 0;
  font-size: clamp(1.7rem, 3.4vw, 2.2rem);
  letter-spacing: 0.2px;
  /* Effetto gradiente sul testo con background-clip */
  background: linear-gradient(90deg, var(--brand), var(--brand-2));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.subtitle {
  margin: 0;
  color: var(--muted);
  font-size: 0.95rem;
}

/* =========================================================
   CARD (contenitore form principale)
   - Effetto vetro con blur e ombra soft
   ========================================================= */
.card {
  width: min(700px, 92vw);
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 16px;
  box-shadow: var(--shadow);
  backdrop-filter: var(--glass-blur);
  padding: 1rem 1.25rem;
}

/* =========================================================
   INPUT + BUTTON LAYOUT
   - Mobile: in colonna (bottone sotto)
   - Desktop (>= 720px): in riga (bottone accanto)
   ========================================================= */
.row {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

@media (min-width: 720px) {
  .row {
    flex-direction: row;
    align-items: stretch;
  }

  .row .input {
    flex: 1; /* l’input occupa lo spazio residuo */
  }

  .row .btn {
    min-width: 160px; /* dimensione minima per gerarchia visiva */
  }
}

/* =========================================================
   INPUT (numero)
   - Contrasto elevato, focus ring visibile
   ========================================================= */
.input {
  padding: 0.9rem 1rem;
  border-radius: 12px;
  border: 1px solid var(--border);
  background: var(--field-bg);
  color: var(--text);
  font-size: 1rem;
  transition: border-color 0.2s ease, box-shadow 0.2s ease, background 0.2s ease;
}
.input::placeholder {
  color: color-mix(in srgb, var(--muted) 75%, transparent);
}
.input:focus {
  outline: none;
  border-color: var(--ring);
  box-shadow: 0 0 0 4px color-mix(in srgb, var(--ring) 28%, transparent);
  background: color-mix(in srgb, var(--card) 55%, transparent);
}

/* =========================================================
   BUTTON (Convert)
   - Evidenziato con gradiente caldo
   - Stati hover/active/focus curati
   ========================================================= */
.btn {
  padding: 0.9rem 1.1rem;
  border: 0;
  border-radius: 12px;
  font-weight: 800;
  letter-spacing: 0.3px;
  color: #1f1305;
  background: var(--btn-bg);
  cursor: pointer;
  transition: transform 0.06s ease, filter 0.15s ease, box-shadow 0.15s ease,
    background 0.2s ease;
  box-shadow: 0 8px 22px rgba(249, 115, 22, 0.25);
}
.btn:hover {
  filter: brightness(1.06);
  background: var(--btn-bg-hover);
}
.btn:active {
  transform: translateY(1px);
}
.btn:focus {
  outline: 2px solid var(--ring);
  outline-offset: 2px;
}

/* Mobile: bottone full-width quando in colonna */
@media (max-width: 719.98px) {
  .btn {
    width: 100%;
  }
}

/* =========================================================
   OUTPUT (risultato)
   - Spazio minimo per evitare salti layout quando vuoto
   ========================================================= */
.result {
  margin-top: 1rem;
  font-size: 1.2rem;
  min-height: 1.6em;
  text-align: center;
  transition: color 0.25s ease, transform 0.15s ease;
}
.result.ok {
  color: #15803d; /* verde: successo */
  font-weight: 700;
}
.result.err {
  color: #b91c1c; /* rosso: errore/validazione */
  font-weight: 700;
}

/* =========================================================
   BANNER (nota informativa sotto la card)
   - Richiamo visivo coerente con la palette
   ========================================================= */
.banner {
  width: min(700px, 92vw);
  background: color-mix(in srgb, var(--brand) 12%, transparent);
  border: 1px solid color-mix(in srgb, var(--brand) 28%, transparent);
  border-radius: 14px;
  padding: 0.9rem 1.1rem;
  text-align: center;
  box-shadow: var(--shadow);
  backdrop-filter: var(--glass-blur);
  color: var(--text);
  font-size: 0.95rem;
}
.banner em {
  font-style: normal;
  font-weight: 700;
  color: var(--brand);
}

/* =========================================================
   FOOTER / BADGE
   ========================================================= */
.footer {
  margin-top: 0.25rem;
}
.badge {
  display: inline-block;
  font-size: 0.75rem;
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 0.25rem 0.6rem;
  background: color-mix(in srgb, var(--brand-2) 18%, transparent);
  backdrop-filter: var(--glass-blur);
}