Hello,
Very strange but we don’t see that problem https://gyazo.com/bafaca03ede5eb764ff8c3906a447c2d
What browser do you use and what version?
1) Try this one
.single_add_to_cart_button:after {
content: "\e916";
font-family: 'xstore-icons';
transition: inherit;
padding-left: 7px;
}
2) This is Massive Addons element and can be used as the individual button only. To install button preset go to Massive Panel > Style Presets > WC Add to cart http://prntscr.com/kg3tix and find “Full Bright Red To Dark Red” style. Install it and then you can use it http://prntscr.com/kg3vbn then just change colors.
3) Go to Theme Options > General > Header Settings > Cart icon > choose the icon that is most suitable for you. If you want to change the icon to your custom icon then some additional customization is required.
Regards