Updates to download page 3.

Author: economon

download.html

@@ -52,6 +52,7 @@ <h3>Current Release for macOS/Linux: SU2 v6.0.0</h3>
   <br>
 
 <div class="row">
+  <center>
   <div class="col-sm-3 text-center">
     <p><a class="btn btn-success btn-lg" href="{{ "/download/su2-macos-latest.tgz" | prepend: site.baseurl }}" role="button">macOS (.tgz)</a>
     </p>
@@ -64,13 +65,15 @@ <h3>Current Release for macOS/Linux: SU2 v6.0.0</h3>
     <p> <a class="btn btn-warning btn-lg" href="{{ "/download/su2-redhat-latest.tgz" | prepend: site.baseurl }}" role="button">Redhat (.tgz)</a>
     </p>
   </div>
+  </center>
 </div>
 
 <br>
 <h3>Current Release for Windows: SU2 v6.0.0</h3>
 <br>
 
 <div class="row">
+  <center>
   <div class="col-sm-3 text-center">
     <p> <a class="btn btn-primary btn-lg" href="{{ "/download/su2-windows7-latest.zip" | prepend: site.baseurl }}" role="button">Windows 7 (.zip)</a>
     </p>
@@ -79,6 +82,7 @@ <h3>Current Release for Windows: SU2 v6.0.0</h3>
     <p> <a class="btn btn-danger btn-lg" href="{{ "/download/su2-windows10-latest.zip" | prepend: site.baseurl }}" role="button">Windows 10 (.zip)</a>
     </p>
   </div>
+  </center>
 </div>
 
 <br>