.topbar {
    background-image: linear-gradient(to left, #3B424A,#624283) !important;
}

#select {
    border: 2px solid #624283 !important;
}

.swagger-ui img {
    content: url(WHI_Logo_Horizontal_White.png);
    width: 100%; /* width of your logo */
    height: 100%; /* height of your logo */
}