python-gallery/gallery/user/themes/default/buttons/btn.scss

.btn {    
    padding: 0.5rem 1rem;
    border-radius: 0.25rem;

    border: 1px solid rgba($white100, 0.3);
    background-color: rgba($white100, 0);
    color: $white100;

    transition: background-color 0.3s ease-in-out, border-color 0.3s ease-in-out, color 0.3s ease-in-out;

    &:active {
        border-color: rgba($white100, 1);
        color: $white100;
    }
}