Adjust styling of language selection

Adjustments as recommended in
#301 (comment)

And also made buttons round independent of used letters.

Author: sroertgen

src/components/header.jsx

@@ -66,17 +66,17 @@ const Header = ({ siteTitle }) => {
       padding: 0;
       list-style: none;
       display: inline-block;
-      width: 80px;
       text-align: right;
 
       li {
-        margin: 0 0 0 5px;
         display: inline;
 
         button {
           background: none;
+          width: 2rem;
+          height: 2rem;
           display: inline-block;
-          padding: 5px;
+          margin: 2px;
           color: ${config.colors.skoHubMiddleGrey};
           border: 1px solid ${config.colors.skoHubMiddleGrey};
           border-radius: 30px;
@@ -91,7 +91,6 @@ const Header = ({ siteTitle }) => {
           color: black;
           font-weight: bold;
           display: inline-block;
-          padding: 5px;
           border: 1px solid ${config.colors.skoHubLightColor};
           border-radius: 30px;
         }