.btn-main {
    position: relative;
    overflow: hidden;

    font-family: 'Poppins', sans-serif;
    font-size: 14px;
    font-weight: 600;
    letter-spacing: -0.14px;

    height: 40px;
    padding: 12px;
    border-radius: 6px;
    border: none;

    color: #fff;
    background: linear-gradient(180deg, #3593D0 0%, #1A7EBE 100%);

    box-shadow: 0 0 7px rgba(0, 0, 0, 0.25);

    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 6px;

    transition:
        box-shadow 0.3s ease,
        transform 0.3s ease;
}

/* capa de hover */
.btn-main::before {
    content: "";
    position: absolute;
    inset: 0;
    background: linear-gradient(180deg, #2f86bf 0%, #166da5 100%);
    opacity: 0;
    transition: opacity 0.3s ease;
    z-index: 0;
}

/* eleva TODO el contenido del botón */
.btn-main {
    z-index: 1;
}

/* hover */
.btn-main:hover::before,
.btn-main:focus::before,
.btn-main:active::before {
    opacity: .2;
}

.btn-main:hover,
.btn-main:focus,
.btn-main:active {
    box-shadow: 0 0 7px rgba(0, 0, 0, 0.35);
    transform: translateY(-1px);
}