* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: #111827;
    color: #f9fafb;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    padding: 20px;
}

.container {
    background: #1f2937;
    padding: 32px;
    border-radius: 16px;
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.4);
    width: 100%;
    max-width: 460px;
}

h1 {
    font-size: 1.5rem;
    margin-bottom: 8px;
    text-align: center;
}

.description {
    font-size: 0.95rem;
    color: #9ca3af;
    text-align: center;
    margin-bottom: 24px;
    line-height: 1.4;
}

.form {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.programa-selector {
    display: flex;
    gap: 12px;
}

.opcion {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 12px;
    border: 1px solid #374151;
    border-radius: 8px;
    background: #111827;
    cursor: pointer;
    transition: border-color 0.2s, background 0.2s;
}

.opcion:hover {
    border-color: #3b82f6;
}

.opcion input[type="radio"] {
    accent-color: #3b82f6;
    cursor: pointer;
}

.opcion:has(input:checked) {
    border-color: #3b82f6;
    background: #1e3a8a;
}

label {
    font-size: 0.9rem;
    color: #d1d5db;
    margin-bottom: -10px;
}

input[type="number"] {
    padding: 12px;
    border: 1px solid #374151;
    border-radius: 8px;
    background: #111827;
    color: #f9fafb;
    font-size: 1rem;
    outline: none;
    transition: border-color 0.2s;
}

input[type="number"]:focus {
    border-color: #3b82f6;
}

button {
    padding: 14px;
    border: none;
    border-radius: 8px;
    background: #3b82f6;
    color: white;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.2s;
}

button:hover {
    background: #2563eb;
}

button:active {
    background: #1d4ed8;
}

.resultado {
    margin-top: 24px;
    padding: 16px;
    border-radius: 8px;
    text-align: center;
    font-size: 1.1rem;
    font-weight: 600;
    min-height: 56px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.resultado.exito {
    background: #064e3b;
    color: #34d399;
}

.resultado.error {
    background: #450a0a;
    color: #f87171;
}

.resultado.vacio {
    background: #374151;
    color: #9ca3af;
}

.instrucciones {
    margin-top: 16px;
    padding: 16px;
    border-radius: 8px;
    background: #111827;
    border: 1px solid #374151;
    display: none;
}

.instrucciones.visible {
    display: block;
}

.instrucciones h3 {
    font-size: 1rem;
    margin-bottom: 10px;
    color: #f9fafb;
}

.instrucciones ol {
    padding-left: 20px;
    color: #d1d5db;
    font-size: 0.95rem;
    line-height: 1.5;
}

.instrucciones li {
    margin-bottom: 6px;
}

.nota {
    margin-top: 10px;
    font-size: 0.85rem;
    color: #9ca3af;
    font-style: italic;
}