body {
  font-family: 'Segoe UI', sans-serif;
  background: #111827;
  color: #f9fafb;
  margin: 0;
  padding: 0;
}

main {
  max-width: 600px;
  margin: 40px auto;
  padding: 0 20px;
}

h1 {
  font-size: 28px;
  margin-bottom: 20px;
  color: #facc15;
  text-align: center;
}

/* Formulario */
form {
  display: flex;
  flex-direction: column;
  gap: 14px;
  background: #1f2937;
  padding: 20px;
  border-radius: 12px;
  box-shadow: 0 4px 12px rgba(0,0,0,0.3);
  border: 1px solid #374151;
}

form input[type="text"],
form input[type="file"] {
  padding: 12px 16px;
  font-size: 16px;
  border: 2px solid #374151;
  border-radius: 8px;
  background: #111827;
  color: #f9fafb;
}

form button {
  padding: 14px 20px;
  background: #10b981;
  color: white;
  border: none;
  border-radius: 8px;
  font-weight: bold;
  cursor: pointer;
  transition: background 0.2s;
}

form button:hover {
  background: #059669;
}

/* Barra de progreso */
#barraProgreso {
  width: 100%;
  height: 12px;
  background: #374151;
  border-radius: 6px;
  overflow: hidden;
  margin-top: 10px;
}

#progreso {
  height: 100%;
  width: 0%;
  background: #3b82f6;
  transition: width 0.3s ease;
}

/* Botón de retorno */
a.btn {
  display: block;
  margin: 40px auto 0;
  padding: 14px 24px;
  background: #3b82f6;
  color: white;
  text-align: center;
  text-decoration: none;
  border-radius: 8px;
  font-weight: bold;
  max-width: 300px;
  transition: background 0.2s;
}

a.btn:hover {
  background: #2563eb;
}