/* Botón “Regresar” con estilo pill */
.btn-back {
    display: inline-flex;
    align-items: center;
    gap: .5rem;
    padding: .45rem 1rem;
    border-radius: 999px;
    font-weight: 600;
    border: 1px solid rgba(0,188,212,.45);
    background: rgba(0,188,212,.10);
    color: #00bcd4;
    transition: background-color .15s ease, color .15s ease, box-shadow .15s ease, transform .15s ease;
}

    .btn-back i {
        line-height: 1;
    }

    .btn-back:hover {
        background: rgba(0,188,212,.18);
        color: #00d2e1;
        box-shadow: 0 4px 12px rgba(0,188,212,.20);
        transform: translateY(-1px);
    }

    .btn-back:active {
        transform: translateY(0);
    }

/* Header del modal sin borde para que luzca limpio */
.modal-header {
    border-bottom: 0;
    padding: .75rem 1rem .25rem 1rem;
}
/* Haz visible el botón sobre el modal */
.modal-content {
    position: relative;
}

/* Base */
.btn-back {
    display: inline-flex;
    align-items: center;
    gap: .55rem;
    border-radius: 999px;
    font-weight: 700;
    letter-spacing: .02em;
    transition: transform .15s ease, box-shadow .15s ease, background-color .15s ease, color .15s ease;
}

/* Versión FAB (flotante) y XL */
.btn-back--fab {
    position: absolute;
    top: 12px;
    left: 12px;
    z-index: 5;
    background: #00bcd4;
    color: #03222c;
    border: none;
    padding: .6rem 1.15rem;
    font-size: 1rem;
    box-shadow: 0 8px 22px rgba(0,188,212,.35), 0 2px 6px rgba(0,0,0,.2);
}

    .btn-back--fab:hover {
        background: #00d2e1;
        transform: translateY(-2px);
        box-shadow: 0 10px 26px rgba(0,188,212,.42), 0 3px 8px rgba(0,0,0,.25);
    }

    .btn-back--fab:active {
        transform: translateY(0);
    }

/* Icono un poquito más grande */
.btn-back i {
    font-size: 1.1em;
    line-height: 1;
}

/* Sutile animación para llamar la atención */
@keyframes pulseRing {
    0% {
        box-shadow: 0 0 0 0 rgba(0,188,212,.50);
    }

    70% {
        box-shadow: 0 0 0 14px rgba(0,188,212,0);
    }

    100% {
        box-shadow: 0 0 0 0 rgba(0,188,212,0);
    }
}

.btn-back--pulse {
    animation: pulseRing 2.6s infinite;
}

/* Ajustes en pantallas chicas */
@media (max-width:576px) {
    .btn-back--fab {
        top: 10px;
        left: 10px;
        padding: .58rem 1.05rem;
        font-size: .95rem;
    }
}