Fix css bug.

assets/stylesheets/template/RWD.scss

@@ -7,9 +7,6 @@
 }
 
 @media(max-width: $screen-xs) {
-    .container > .navbar-header {
-        width: 80%;
-    }
     .buttons-slogan{
         flex-wrap: wrap;
     }

assets/stylesheets/template/layout/header.scss

@@ -356,6 +356,7 @@
     .dropdowns{
       display: flex;
       flex-direction: row-reverse;
+      justify-content: flex-end;
     }
   }
 
@@ -374,6 +375,7 @@
     .navbar-header{
       margin-bottom: 1em;
       width: 100%;
+      width: calc(100% - 2.5em);
     }
   }