If you ever find you need to add a sticky CTA as a side tab, just follow the steps below!
After that, you should be set :)
Adding the HTML
In Settings –> Header and Footer, add the necessary code to the BEFORE THE </BODY> CLOSING TAG (FOOTER) section.
Adding the CSS
Add the following CSS as normal, swapping/omitting as necessary for your site:
#fs-side-button { position: fixed; z-index: 999999; -webkit-transform: rotate(-90deg); -moz-transform: rotate(-90deg); -o-transform: rotate(-90deg); -ms-transform: rotate(-90deg); transform: rotate(-90deg); left: -70px; top: 235px; } #fs-side-button a { color: black; background-color: #fac01f; display: block; width: 200px; height: 60px; text-align: center; line-height: 60px; white-space: nowrap; padding: 0; text-transform: uppercase; font-weight: bold; font-size: 18px; letter-spacing: 2px; transition: all 0.3s ease; box-shadow: 1px 1px 5px 0 rgba(0,0,0,0.05); }
Variations
From here you can adapt as needed!