feature(header): Issue#106 - add a logout button

src/styles/header.scss

@@ -194,7 +194,9 @@ details#user-controls {
 
       button {
         color: $color-text-base;
-        margin: 1.6rem 1.3rem;
+        padding: 1.6rem 1.3rem;
+        text-align: left;
+        width: 100%;
       }
     }
   }

src/styles/main.scss

@@ -4,10 +4,8 @@
   display: none !important;
 }
 
-*,
-*::after,
-*::before {
-  //  box-sizing: inherit;
+* {
+  box-sizing: border-box;
 }
 
 :root {
@@ -16,7 +14,6 @@
   --sib-notifications-theme: #{$color-46-100-50};
   
   body {
-    //box-sizing: border-box;
     background-color: $color-anti-flash-white;
     color: $color-text-base;
     font-size: 1.6rem;