Added search button and menu icon

(cherry picked from commit 468264941d08b00252a4f6f081bc2dff5920bffe)

_sass/layout.scss

@@ -147,16 +147,10 @@
 }
 
 .site-button {
-  appearance: none;
   display: flex;
   height: 100%;
   padding: $gutter-spacing-sm;
   align-items: center;
-  color: $link-color;
-  text-transform: uppercase;
-  background: transparent;
-  border: 0;
-  @include fs-3;
 
   @include mq(md) {
     display: none;
@@ -197,3 +191,9 @@ body {
     justify-self: end;
   }
 }
+
+.icon {
+  width: $sp-5;
+  height: $sp-5;
+  fill: $link-color;
+}