Refactor spacing of WebIDE containers

app/assets/stylesheets/pages/repo.scss

@@ -19,7 +19,7 @@
 .ide-view {
   display: flex;
   height: calc(100vh - #{$header-height});
-  margin-top: 40px;
+  margin-top: 0;
   border-top: 1px solid $white-dark;
   border-bottom: 1px solid $white-dark;
 
@@ -456,6 +456,8 @@
   display: flex;
   flex-direction: column;
   flex: 1;
+  max-height: 100%;
+  overflow: auto;
 }
 
 .multi-file-commit-empty-state-container {
@@ -466,7 +468,7 @@
 .multi-file-commit-panel-header {
   display: flex;
   align-items: center;
-  margin-bottom: 12px;
+  margin-bottom: 0;
   border-bottom: 1px solid $white-dark;
   padding: $gl-btn-padding 0;
 
@@ -673,8 +675,14 @@
   overflow: hidden;
 
   &.nav-only {
+    padding-top: $header-height;
+
+    .with-performance-bar & {
+      padding-top: $header-height + $performance-bar-height;
+    }
+
     .flash-container {
-      margin-top: $header-height;
+      margin-top: 0;
       margin-bottom: 0;
     }
 
@@ -684,7 +692,7 @@
     }
 
     .content-wrapper {
-      margin-top: $header-height;
+      margin-top: 0;
       padding-bottom: 0;
     }
 
@@ -708,11 +716,11 @@
 
 .with-performance-bar .ide.nav-only {
   .flash-container {
-    margin-top: #{$header-height + $performance-bar-height};
+    margin-top: 0;
   }
 
   .content-wrapper {
-    margin-top: #{$header-height + $performance-bar-height};
+    margin-top: 0;
     padding-bottom: 0;
   }
 
@@ -721,10 +729,6 @@
   }
 
   &.flash-shown {
-    .content-wrapper {
-      margin-top: 0;
-    }
-
     .ide-view {
       height: calc(100vh - #{$header-height + $performance-bar-height + $flash-height});
     }