:root {
  /* Paleta de colores */
  --bg: #0f141b;
  --card: #131a22;
  --text: #e7edf3;
  --muted: #9fb1c1;
  --accent: #4aa8ff;
  --accent-strong: #1c7ee8;
  --border: #223041;
  --success: #28c16d;
  --focus: #9bd1ff;

  /* Tipografía y espaciado */
  --radius: 12px;
  --radius-sm: 10px;
  --shadow: 0 10px 30px rgba(0, 0, 0, 0.4);
  --font: ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, "Helvetica Neue",
    Arial, "Noto Sans", "Liberation Sans", sans-serif;
  --mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono",
    "Courier New", monospace;
}

*, *::before, *::after {
  box-sizing: border-box;
}

html, body {
  height: 100%;
}

body {
  margin: 0;
  font-family: var(--font);
  color: var(--text);
  background: radial-gradient(1200px 800px at 10% 10%, #12202e, var(--bg));
  display: grid;
  grid-template-rows: auto 1fr auto;
  gap: 24px;
  padding: 24px;
}

/* Header del sitio */
header {
  display: grid;
  place-items: center;
}

header h1 {
  margin: 0;
  font-size: clamp(1.2rem, 2vw, 1.5rem);
  color: var(--muted);
  font-weight: 600;
  letter-spacing: 0.3px;
}

/* Main centrado */
main {
  display: grid;
  place-items: center;
}

/* Contenedor principal del generador */
#generator {
  width: min(680px, 95vw);
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.02), transparent),
    var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 24px;
  display: grid;
  gap: 20px;
  position: relative;
}

#generator-title {
  margin: 0;
  font-size: clamp(1.25rem, 2.4vw, 1.6rem);
  letter-spacing: 0.2px;
}

/* Salida de contraseña */
#output {
  display: grid;
  gap: 10px;
}

#output > label {
  font-size: 0.95rem;
  color: var(--muted);
}

#field {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 12px;
  align-items: center;
}

#passwordOutput {
  width: 100%;
  padding: 14px 16px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
  background: #0b1117;
  color: var(--text);
  font-family: var(--mono);
  font-size: 1rem;
  letter-spacing: 0.4px;
  outline: none;
  transition: border-color 0.2s, box-shadow 0.2s;
}

#passwordOutput::placeholder {
  color: #6f859a;
}

#passwordOutput:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px color-mix(in oklab, var(--focus) 30%, transparent);
}

/* Pista/ayuda */
#passwordHelp {
  margin: 0;
  color: var(--muted);
  font-size: 0.9rem;
}

/* Controles */
#generatorForm {
  display: grid;
  gap: 16px;
}

#lengthControl {
  display: grid;
  gap: 10px;
}

#lengthControl > label {
  font-size: 0.95rem;
  color: var(--muted);
}

#lengthRow {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 12px;
  align-items: center;
}

/* Valor visible de longitud */
#lengthValue {
  display: inline-block;
  min-width: 36px;
  padding: 6px 10px;
  text-align: center;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: #0b1117;
  color: var(--text);
  font-variant-numeric: tabular-nums;
}

/* Slider estilizado */
#lengthRange {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: 10px;
  border-radius: 999px;
  background: linear-gradient(90deg, var(--accent), #7fc7ff);
  outline: none;
  border: 1px solid var(--border);
  position: relative;
}

/* Thumb (control) */
#lengthRange::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 22px;
  height: 22px;
  border-radius: 50%;
  background: var(--accent);
  border: 2px solid #ffffff22;
  box-shadow: 0 2px 10px rgba(74, 168, 255, 0.5);
  cursor: pointer;
  transition: transform 0.12s ease;
}

#lengthRange::-webkit-slider-thumb:active {
  transform: scale(1.05);
}

#lengthRange::-moz-range-thumb {
  width: 22px;
  height: 22px;
  border-radius: 50%;
  background: var(--accent);
  border: 2px solid #ffffff22;
  box-shadow: 0 2px 10px rgba(74, 168, 255, 0.5);
  cursor: pointer;
}

/* Acciones */
#actions {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

/* Botones base */
button {
  --btn-bg: #1a2430;
  --btn-text: var(--text);
  --btn-border: var(--border);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 16px;
  border-radius: 12px;
  border: 1px solid var(--btn-border);
  background: var(--btn-bg);
  color: var(--btn-text);
  font-weight: 600;
  letter-spacing: 0.2px;
  cursor: pointer;
  transition: transform 0.04s ease, background-color 0.2s, border-color 0.2s,
    box-shadow 0.2s;
  user-select: none;
}

button:active {
  transform: translateY(1px);
}

/* Modificadores por ID */
#generateBtn {
  --btn-bg: linear-gradient(180deg, var(--accent), var(--accent-strong));
  --btn-text: #05101a;
  --btn-border: #3f87c7;
  color: #061219;
  box-shadow: 0 8px 18px rgba(74, 168, 255, 0.35);
}

#copyBtn {
  --btn-bg: #0b1117;
  --btn-border: var(--border);
  color: var(--text);
  min-width: 88px;
}

/* Estado deshabilitado */
button[disabled] {
  opacity: 0.55;
  cursor: not-allowed;
  box-shadow: none;
}

/* Toast */
#copyToast {
  position: absolute;
  right: 16px;
  bottom: 16px;
  padding: 10px 14px;
  border-radius: 10px;
  background: color-mix(in oklab, var(--success) 18%, #0b1117);
  border: 1px solid color-mix(in oklab, var(--success) 30%, var(--border));
  color: color-mix(in oklab, var(--success) 92%, #ffffff);
  font-weight: 600;
  letter-spacing: 0.2px;
  opacity: 0;
  transform: translateY(10px);
  pointer-events: none;
  transition: opacity 0.18s ease, transform 0.18s ease;
}

/* Visibilidad del toast mediante atributo de datos */
#copyToast[data-visible="true"] {
  opacity: 1;
  transform: translateY(0);
}

/* Footer del sitio */
footer {
  display: grid;
  place-items: center;
}

#siteNote {
  margin: 0;
  color: var(--muted);
  font-size: 0.9rem;
}

/* Responsividad ligera */
@media (max-width: 480px) {
  #generator {
    padding: 18px;
  }
  #field {
    grid-template-columns: 1fr;
  }
  #copyBtn {
    justify-self: end;
  }
}