Fix button border color

- Remove bottom borders on links and use text-decoration: underline instead
- Use sans-serif font for button text

_sass/elements.scss

@@ -51,11 +51,14 @@ svg:not(:root) {
   margin-bottom: 20px;
   padding: 8px 20px;
   @include font-rem(14);
+  font-family: $heading-font;
+  font-weight: 700;
   background-color: $primary;
   color: $white;
   border-width: 2px !important;
   border-style: solid !important;
   border-color: $primary;
+  text-decoration: none !important;
   @include rounded(3px);
   &:visited {
     color: $white;