remove some unused sidebar styles

app/assets/stylesheets/framework/header.scss

@@ -269,14 +269,6 @@ header {
   }
 }
-.page-sidebar-pinned.right-sidebar-expanded {
-  @media (max-width: $screen-md-max) {
-    .header-content .title {
-      width: 300px;
-    }
-  }
-}
-
 @media (max-width: $screen-xs-max) {
   header .container-fluid {
     font-size: 18px;

app/assets/stylesheets/pages/notes.scss

@@ -243,22 +243,6 @@ ul.notes {
   }
 }
-.page-sidebar-pinned.right-sidebar-expanded {
-  @media (max-width: $screen-md-max) {
-    .note-header {
-      .note-headline-light {
-        display: block;
-      }
-
-      .note-actions {
-        position: absolute;
-        right: 0;
-        top: 0;
-      }
-    }
-  }
-}
-
 // Diff code in discussion view
 .discussion-body .diff-file {
   .file-title {

app/assets/stylesheets/pages/projects.scss

@@ -477,20 +477,6 @@ a.deploy-project-label {
   }
 }
-.page-sidebar-pinned {
-  .project-stats .nav > li.right {
-    @media (min-width: $screen-lg-min) {
-      float: none;
-    }
-  }
-
-  .download-button {
-    @media (min-width: $screen-lg-min) {
-      margin-left: 0;
-    }
-  }
-}
-
 .project-stats {
   font-size: 0;
   text-align: center;