Remove scrollbars due to overflow by adding box-sizing: border-box

Requested in Maps4HTML/MapML.js#350.

Author: Malvoz

examples/Section5-1.html

@@ -6,14 +6,16 @@
     <title>Requirements - Section 5.1.html</title>
     <script type="module" src="../dist/mapml-viewer.js"></script>
      <style> 
-       html, 
-       body { 
-         height: 100%; 
-       } 
-       * { 
-         margin: 0; 
-         padding: 0; 
-       } 
+       html,
+       body {
+         height: 100%;
+       }
+       body {
+         margin: 0;
+       }
+       *, ::before, ::after {
+         box-sizing: border-box;
+       }
 
        /* Specifying the `:defined` selector is recommended to style the map 
        element, such that styles don't apply when fallback content is in use