:root {
    --principal-color: #169aff;
    --black-color: #000;
}
.btn, .btn:hover, .btn-principal {
    background-color: var(--principal-color);
    color: white;
    border: var(--principal-color);
}
@media only screen and (min-width: 310px) and (max-width: 400px){
    .panel-logo {max-width: 150px !important;}}