:root {
    --texto: #222;
    --suave: #666;
    --borde: #ddd;
    --fondo: #fafafa;
    --acento: #111;
}

* { box-sizing: border-box; }

body {
    margin: 0;
    padding: 2rem 1rem 4rem;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    color: var(--texto);
    background: var(--fondo);
    line-height: 1.5;
}

main {
    max-width: 640px;
    margin: 0 auto;
}

h1 {
    font-size: 1.5rem;
    margin: 0 0 .25rem;
}

h2 {
    font-size: 1rem;
    margin: 2rem 0 .5rem;
    color: var(--suave);
    text-transform: uppercase;
    letter-spacing: .04em;
}

.intro {
    margin: 0 0 2rem;
    color: var(--suave);
}

label {
    display: block;
    margin-top: 1rem;
    margin-bottom: .25rem;
    font-weight: 600;
    font-size: .875rem;
}

.opcional {
    font-weight: 400;
    color: var(--suave);
}

input {
    width: 100%;
    padding: .5rem .625rem;
    font-size: 1rem;
    font-family: inherit;
    color: inherit;
    border: 1px solid var(--borde);
    border-radius: 4px;
    background: #fff;
}

input:focus {
    outline: 2px solid var(--acento);
    outline-offset: 1px;
}

.preview {
    padding: .5rem 1rem;
    background: #fff;
    border: 1px solid var(--borde);
    border-radius: 4px;
    overflow-x: auto;
}

.acciones {
    display: flex;
    align-items: center;
    gap: .5rem;
    flex-wrap: wrap;
    margin: 1.5rem 0 1rem;
}

button {
    padding: .5rem 1rem;
    font-size: .9375rem;
    font-family: inherit;
    border: 1px solid var(--borde);
    border-radius: 4px;
    background: #fff;
    cursor: pointer;
}

button:hover { border-color: var(--suave); }

button.primario {
    background: var(--acento);
    border-color: var(--acento);
    color: #fff;
}

.aviso {
    font-size: .875rem;
    color: var(--suave);
}

summary {
    cursor: pointer;
    font-size: .875rem;
    color: var(--suave);
}

textarea {
    width: 100%;
    margin-top: .5rem;
    padding: .625rem;
    font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
    font-size: .75rem;
    color: var(--texto);
    border: 1px solid var(--borde);
    border-radius: 4px;
    resize: vertical;
}

.error {
    margin: .25rem 0 0;
    min-height: 1.2em;
    font-size: .8125rem;
    color: #b00020;
}

button:disabled {
    opacity: .45;
    cursor: not-allowed;
}

button.primario:disabled:hover,
button:disabled:hover {
    border-color: var(--borde);
}

.grupo {
    margin: 1.25rem 0 0;
    padding: .75rem 1rem 1rem;
    border: 1px solid var(--borde);
    border-radius: 4px;
    background: #fff;
}

.grupo legend {
    padding: 0 .35rem;
    font-weight: 600;
    font-size: .875rem;
}

label.radio {
    display: flex;
    align-items: center;
    gap: .5rem;
    margin: .35rem 0 0;
    font-weight: 400;
}

label.radio input {
    width: auto;
    margin: 0;
}