a.descargar::before {
    content: "";
    display: inline-block;
    width: 28px;
    height: 28px;
    border:3px;
    /* color: rgb(255, 255, 255); */
    background-image: url('data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" fill="%23fff" viewBox="0 0 24 24"><path d="M5,20H19V18H5V20M9,4H15V14H19L12,21L5,14H9V4Z"/></svg>');
    background-repeat: no-repeat;
    background-size: contain;
    margin-right: 6px;
    vertical-align: middle;
}

.descargar {
    display: inline-flex;
    justify-content: center;
    align-items: center;
    padding: 8px 12px;
    font-size: 13px;
    font-weight: 400;
    background-color: #156296;
    color: white;
    border: 1px solid #156296;
    text-align: center;
    white-space: normal;
    line-height: 1.2;
    border-radius: 4px;
    text-decoration: none;
    max-width: 100%; 
}