Move .container .content CSS for mobile to the specific CSS

Signed-off-by: Takuya Noguchi <takninnovationresearch@gmail.com>

app/assets/stylesheets/framework/layout.scss

@@ -40,6 +40,8 @@ body {
 
   .content {
     margin: 0;
+
+    @include media-breakpoint-down(xs) { margin-top: 20px; }
   }
 }
 

app/assets/stylesheets/framework/mobile.scss

 /** Common mobile (screen XS, SM) styles **/
 @include media-breakpoint-down(xs) {
-  .container .content {
-    margin-top: 20px;
-  }
-
   .container .title {
     padding-left: 15px !important;
   }