:root {
    --azul: #2b6cb0;
    --azul-osc: #1f4f85;
    --gris: #f5f6f8;
    --gris-borde: #e2e8f0;
    --texto: #1a202c;
}

* { box-sizing: border-box; }

body {
    margin: 0;
    font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
    background: var(--gris);
    color: var(--texto);
    line-height: 1.5;
}

.container {
    max-width: 960px;
    margin: 0 auto;
    padding: 2rem 1rem;
}

.header h1 { margin: 0 0 .25rem; font-size: 1.6rem; }
.subtitle { margin: 0 0 1.5rem; color: #64748b; }

.grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.5rem;
}
@media (max-width: 720px) {
    .grid { grid-template-columns: 1fr; }
}

.card {
    background: #fff;
    border: 1px solid var(--gris-borde);
    border-radius: 12px;
    padding: 1.25rem 1.5rem;
    box-shadow: 0 1px 3px rgba(0,0,0,.05);
}
.card h2 { margin-top: 0; font-size: 1.1rem; }

label {
    display: block;
    margin-bottom: 1rem;
    font-weight: 600;
    font-size: .9rem;
}
label input {
    display: block;
    width: 100%;
    margin-top: .35rem;
    padding: .5rem .6rem;
    border: 1px solid var(--gris-borde);
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 400;
}

.hint { color: #64748b; font-size: .9rem; }

.btn {
    background: var(--azul);
    color: #fff;
    border: 0;
    padding: .6rem 1.2rem;
    border-radius: 8px;
    font-size: 1rem;
    cursor: pointer;
    transition: background .15s;
}
.btn:hover { background: var(--azul-osc); }

.result-block {
    display: flex;
    flex-direction: column;
    gap: .2rem;
    padding: 1rem;
    background: var(--gris);
    border-radius: 8px;
    margin-bottom: 1rem;
}
.result-label { font-size: .85rem; color: #64748b; }
.result-value { font-size: 1.8rem; font-weight: 700; color: var(--azul-osc); }

.chart-wrap { margin-top: 1rem; }

/* Spinner */
.loading {
    display: flex;
    align-items: center;
    gap: .5rem;
    color: #64748b;
    margin-bottom: 1rem;
}
.hidden { display: none; }
.spinner {
    width: 18px;
    height: 18px;
    border: 3px solid var(--gris-borde);
    border-top-color: var(--azul);
    border-radius: 50%;
    animation: spin .7s linear infinite;
    display: inline-block;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* Alertas */
.alert {
    padding: 1rem;
    border-radius: 8px;
    margin-bottom: 1.5rem;
}
.alert-error {
    background: #fef2f2;
    border: 1px solid #fecaca;
    color: #991b1b;
}
.alert pre { white-space: pre-wrap; margin: .5rem 0 0; font-size: .85rem; }