Snippets: Total QuickStart Module Basic CSS

/* basic styling */
.vcex-quickstart-selector { width: 70%; float: left; }
.vcex-quickstart-selector select { width: 100%; height: 50px; line-height: 50px; background: #fff; padding: 0 20px; font-size: 16px; }
.vcex-quickstart-button-wrap { float: right;
width: 28%; }
.vcex-quickstart-button { width: 100%; font-size: 18px; text-align: center; padding: 0 20px; height: 50px; line-height: 50px; }
.vcex-quickstart-button .fa { padding-left: 20px; }

/* responsive */
@media only screen and (max-width: 767px) { 
    .vcex-quickstart-selector,
    .vcex-quickstart-button-wrap { width: 100%; float: none; }
}

Result:

All CSS snippets should be added via a child theme's style.css file or using the built-in Custom CSS panel.