ISTWCMS-6010: Fix the multiple field button in webform

src/patterns/01-core/elements/_form.scss

@@ -181,3 +181,26 @@ button {
     }
   }
 }
+.webform-multiple-add {
+  > .button{
+    @include button-reset();
+    @include svg-background-color(var(--gray-4), plus);
+    background-position: center center;
+    background-repeat: no-repeat;
+    background-size: contain;
+    display: inline-block;
+    height: var(--size-105);
+    position: relative;
+    text-indent: -9999px;
+    vertical-align: middle;
+    width: var(--size-105);
+    &:hover,
+    &:focus{
+      @include svg-background-color(var(--uw-black), plus);
+      background-position: center center;
+      background-repeat: no-repeat;
+      background-size: contain;
+      border: var(--size-xs) solid transparent;
+    }
+  }
+}