Hello,
Use this CSS in wp-admin >> appearance >> customize >> custom css.
.block.course7 .block_content a.button:last-of-type {
opacity: 1 !important;
background: linear-gradient(to left TOP, #47e3f3, #8be667) !important;
border: 1px solid #ff000000;
}
refer:
http://prntscr.com/pzy9zp
sign up button cant be added for now. this comes under customization request and we are full of isasues and working on wplms 4.0. the fastest wplms.