Revert "Merge branch 'revert-f2421b2b' into 'master'"revert-2f46c3a8

This reverts merge request !14148

33 files changed, 648 insertions, 111 deletions

diff --git a/app/assets/stylesheets/framework.scss b/app/assets/stylesheets/framework.scss
index c0524bf6aa3..35e7a10379f 100644
--- a/app/assets/stylesheets/framework.scss
+++ b/app/assets/stylesheets/framework.scss
@@ -19,6 +19,7 @@
 @import "framework/flash";
 @import "framework/forms";
 @import "framework/gfm";
+@import "framework/gitlab-theme";
 @import "framework/header";
 @import "framework/highlight";
 @import "framework/issue_box";
diff --git a/app/assets/stylesheets/framework/gitlab-theme.scss b/app/assets/stylesheets/framework/gitlab-theme.scss
new file mode 100644
index 00000000000..71f764923ff
--- /dev/null
+++ b/app/assets/stylesheets/framework/gitlab-theme.scss
@@ -0,0 +1,265 @@
+/**
+ * Styles the GitLab application with a specific color theme
+ */
+
+@mixin gitlab-theme($color-100, $color-200, $color-500, $color-700, $color-800, $color-900, $color-alternate) {
+  // Header
+
+  header.navbar-gitlab-new {
+    background: linear-gradient(to right, $color-900, $color-800);
+
+    .navbar-collapse {
+      color: $color-200;
+    }
+
+    .container-fluid {
+      .navbar-toggle {
+        border-left: 1px solid lighten($color-700, 10%);
+      }
+    }
+
+    .navbar-sub-nav,
+    .navbar-nav {
+      > li {
+        > a:hover,
+        > a:focus {
+          background-color: rgba($color-200, .2);
+        }
+
+        &.active > a,
+        &.dropdown.open > a {
+          color: $color-900;
+          background-color: $color-alternate;
+
+          svg {
+            fill: currentColor;
+          }
+        }
+
+        &.line-separator {
+          border-left: 1px solid rgba($color-200, .2);
+        }
+      }
+    }
+
+    .navbar-sub-nav {
+      color: $color-200;
+    }
+
+    .nav {
+      > li {
+        color: $color-200;
+
+        > a {
+          svg {
+            fill: $color-200;
+          }
+
+          &.header-user-dropdown-toggle {
+            .header-user-avatar {
+              border-color: $color-200;
+            }
+          }
+
+          &:hover,
+          &:focus {
+            @media (min-width: $screen-sm-min) {
+              background-color: rgba($color-200, .2);
+            }
+
+            svg {
+              fill: currentColor;
+            }
+          }
+        }
+
+        &.active > a,
+        &.dropdown.open > a {
+          color: $color-900;
+          background-color: $color-alternate;
+
+          &:hover {
+            svg {
+              fill: $color-900;
+            }
+          }
+        }
+
+        .impersonated-user,
+        .impersonated-user:hover {
+          svg {
+            fill: $color-900;
+          }
+        }
+      }
+    }
+  }
+
+  .title {
+    > a {
+      &:hover,
+      &:focus {
+        background-color: rgba($color-200, .2);
+      }
+    }
+  }
+
+  .search {
+    form {
+      background-color: rgba($color-200, .2);
+
+      &:hover {
+        background-color: rgba($color-200, .3);
+      }
+    }
+
+    .location-badge {
+      color: $color-100;
+      background-color: rgba($color-200, .1);
+      border-right: 1px solid $color-800;
+    }
+
+    .search-input::placeholder {
+      color: rgba($color-200, .8);
+    }
+
+    .search-input-wrap {
+      .search-icon,
+      .clear-icon {
+        color: rgba($color-200, .8);
+      }
+    }
+
+    &.search-active {
+      form {
+        background-color: $white-light;
+      }
+
+      .location-badge {
+        color: $gl-text-color;
+      }
+
+      .search-input-wrap {
+        .search-icon {
+          color: rgba($color-200, .8);
+        }
+      }
+    }
+  }
+
+  .btn-sign-in {
+    background-color: $color-100;
+    color: $color-900;
+  }
+
+
+  // Sidebar
+  .nav-sidebar li.active {
+    box-shadow: inset 4px 0 0 $color-700;
+
+    > a {
+      color: $color-900;
+    }
+
+    svg {
+      fill: $color-900;
+    }
+  }
+}
+
+
+body {
+  &.ui_indigo {
+    @include gitlab-theme($indigo-100, $indigo-200, $indigo-500, $indigo-700, $indigo-800, $indigo-900, $white-light);
+  }
+
+  &.ui_dark {
+    @include gitlab-theme($theme-gray-100, $theme-gray-200, $theme-gray-500, $theme-gray-700, $theme-gray-800, $theme-gray-900, $white-light);
+  }
+
+  &.ui_blue {
+    @include gitlab-theme($theme-blue-100, $theme-blue-200, $theme-blue-500, $theme-blue-700, $theme-blue-800, $theme-blue-900, $white-light);
+  }
+
+  &.ui_green {
+    @include gitlab-theme($theme-green-100, $theme-green-200, $theme-green-500, $theme-green-700, $theme-green-800, $theme-green-900, $white-light);
+  }
+
+  &.ui_light {
+    @include gitlab-theme($theme-gray-900, $theme-gray-700, $theme-gray-800, $theme-gray-700, $theme-gray-700, $theme-gray-100, $theme-gray-700);
+
+    header.navbar-gitlab-new {
+      background: $theme-gray-100;
+      box-shadow: 0 2px 0 0 $border-color;
+
+      .logo-text svg {
+        fill: $theme-gray-900;
+      }
+
+      .navbar-sub-nav,
+      .navbar-nav {
+        > li {
+          > a:hover,
+          > a:focus {
+            color: $theme-gray-900;
+          }
+
+          &.active > a {
+            color: $white-light;
+
+            &:hover {
+              color: $white-light;
+            }
+          }
+        }
+      }
+
+      .container-fluid {
+        .navbar-toggle,
+        .navbar-toggle:hover {
+          color: $theme-gray-700;
+          border-left: 1px solid $theme-gray-200;
+        }
+      }
+    }
+
+    .search {
+      form {
+        background-color: $white-light;
+        box-shadow: inset 0 0 0 1px $border-color;
+
+        &:hover {
+          background-color: $white-light;
+          box-shadow: inset 0 0 0 1px $blue-100;
+
+          .location-badge {
+            box-shadow: inset 0 0 0 1px $blue-100;
+          }
+        }
+      }
+
+      .search-input-wrap {
+        .search-icon {
+          color: $theme-gray-200;
+        }
+      }
+
+      .location-badge {
+        color: $theme-gray-700;
+        box-shadow: inset 0 0 0 1px $border-color;
+        background-color: $nav-badge-bg;
+        border-right: 0;
+      }
+    }
+
+    .nav-sidebar li.active {
+      > a {
+        color: $theme-gray-900;
+      }
+
+      svg {
+        fill: $theme-gray-900;
+      }
+    }
+  }
+}
diff --git a/app/assets/stylesheets/framework/header.scss b/app/assets/stylesheets/framework/header.scss
index b00a2d053e2..ab3c34df1fb 100644
--- a/app/assets/stylesheets/framework/header.scss
+++ b/app/assets/stylesheets/framework/header.scss
@@ -111,7 +111,6 @@ header {
         svg {
           height: 16px;
           width: 23px;
-          fill: currentColor;
         }
       }
 
diff --git a/app/assets/stylesheets/framework/variables.scss b/app/assets/stylesheets/framework/variables.scss
index e300b006026..3857226cddb 100644
--- a/app/assets/stylesheets/framework/variables.scss
+++ b/app/assets/stylesheets/framework/variables.scss
@@ -74,6 +74,8 @@ $red-700: #a62d19;
 $red-800: #8b2615;
 $red-900: #711e11;
 
+// GitLab themes
+
 $indigo-50: #f7f7ff;
 $indigo-100: #ebebfa;
 $indigo-200: #d1d1f0;
@@ -86,6 +88,43 @@ $indigo-800: #393982;
 $indigo-900: #292961;
 $indigo-950: #1a1a40;
 
+$theme-gray-50: #fafafa;
+$theme-gray-100: #f2f2f2;
+$theme-gray-200: #dfdfdf;
+$theme-gray-300: #cccccc;
+$theme-gray-400: #bababa;
+$theme-gray-500: #a7a7a7;
+$theme-gray-600: #949494;
+$theme-gray-700: #707070;
+$theme-gray-800: #4f4f4f;
+$theme-gray-900: #2e2e2e;
+$theme-gray-950: #1f1f1f;
+
+$theme-blue-50: #f4f8fc;
+$theme-blue-100: #e6edf5;
+$theme-blue-200: #c8d7e6;
+$theme-blue-300: #97b3cf;
+$theme-blue-400: #648cb4;
+$theme-blue-500: #4a79a8;
+$theme-blue-600: #3e6fa0;
+$theme-blue-700: #305c88;
+$theme-blue-800: #25496e;
+$theme-blue-900: #1a3652;
+$theme-blue-950: #0f2235;
+
+$theme-green-50: #f2faf6;
+$theme-green-100: #e4f3ea;
+$theme-green-200: #c0dfcd;
+$theme-green-300: #8ac2a1;
+$theme-green-400: #52a274;
+$theme-green-500: #35935c;
+$theme-green-600: #288a50;
+$theme-green-700: #1c7441;
+$theme-green-800: #145d33;
+$theme-green-900: #0d4524;
+$theme-green-950: #072d16;
+
+
 $black: #000;
 $black-transparent: rgba(0, 0, 0, 0.3);
 $almost-black: #242424;
diff --git a/app/assets/stylesheets/new_nav.scss b/app/assets/stylesheets/new_nav.scss
index 2b6c0fc015c..8e095cbdd7e 100644
--- a/app/assets/stylesheets/new_nav.scss
+++ b/app/assets/stylesheets/new_nav.scss
@@ -9,10 +9,20 @@
 
 header.navbar-gitlab-new {
   color: $white-light;
-  background: linear-gradient(to right, $indigo-900, $indigo-800);
   border-bottom: 0;
   min-height: $new-navbar-height;
 
+  .logo-text {
+    line-height: initial;
+
+    svg {
+      width: 55px;
+      height: 14px;
+      margin: 0;
+      fill: $white-light;
+    }
+  }
+
   .header-content {
     display: -webkit-flex;
     display: flex;
@@ -38,10 +48,10 @@ header.navbar-gitlab-new {
 
       img {
         height: 28px;
-        margin-right: 10px;
+        margin-right: 8px;
       }
 
-      > a {
+      a {
         display: -webkit-flex;
         display: flex;
         align-items: center;
@@ -54,22 +64,6 @@ header.navbar-gitlab-new {
             margin-right: 8px;
           }
         }
-
-        .logo-text {
-          line-height: initial;
-
-          svg {
-            width: 55px;
-            height: 14px;
-            margin: 0;
-            fill: $white-light;
-          }
-        }
-
-        &:hover,
-        &:focus {
-          background-color: rgba($indigo-200, .2);
-        }
       }
     }
 
@@ -106,7 +100,6 @@ header.navbar-gitlab-new {
 
   .navbar-collapse {
     padding-left: 0;
-    color: $indigo-200;
     box-shadow: 0;
 
     @media (max-width: $screen-xs-max) {
@@ -132,7 +125,6 @@ header.navbar-gitlab-new {
       font-size: 14px;
       text-align: center;
       color: currentColor;
-      border-left: 1px solid lighten($indigo-700, 10%);
 
       &:hover,
       &:focus,
@@ -167,63 +159,49 @@ header.navbar-gitlab-new {
         will-change: color;
         margin: 4px 2px;
         padding: 6px 8px;
-        color: $indigo-200;
         height: 32px;
 
         @media (max-width: $screen-xs-max) {
           padding: 0;
         }
 
-        svg {
-          fill: $indigo-200;
-        }
-
         &.header-user-dropdown-toggle {
           margin-left: 2px;
 
           .header-user-avatar {
-            border-color: $indigo-200;
             margin-right: 0;
           }
         }
-      }
-
-      .header-new-dropdown-toggle {
-        margin-right: 0;
-      }
 
-      > a:hover,
-      > a:focus {
-        text-decoration: none;
-        outline: 0;
-        opacity: 1;
-        color: $white-light;
-
-        @media (min-width: $screen-sm-min) {
-          background-color: rgba($indigo-200, .2);
-        }
+        &:hover,
+        &:focus {
+          text-decoration: none;
+          outline: 0;
+          opacity: 1;
+          color: $white-light;
 
-        svg {
-          fill: currentColor;
-        }
+          svg {
+            fill: currentColor;
+          }
 
-        &.header-user-dropdown-toggle {
-          .header-user-avatar {
-            border-color: $white-light;
+          &.header-user-dropdown-toggle {
+            .header-user-avatar {
+              border-color: $white-light;
+            }
           }
         }
       }
 
+      .header-new-dropdown-toggle {
+        margin-right: 0;
+      }
+
       .impersonated-user,
       .impersonated-user:hover {
         margin-right: 1px;
         background-color: $white-light;
         border-top-right-radius: 0;
         border-bottom-right-radius: 0;
-
-        svg {
-          fill: $indigo-900;
-        }
       }
 
       .impersonation-btn,
@@ -241,8 +219,6 @@ header.navbar-gitlab-new {
 
       &.active > a,
       &.dropdown.open > a {
-        color: $indigo-900;
-        background-color: $white-light;
 
         svg {
           fill: currentColor;
@@ -256,7 +232,6 @@ header.navbar-gitlab-new {
   display: -webkit-flex;
   display: flex;
   margin: 0 0 0 6px;
-  color: $indigo-200;
 
   .dropdown-chevron {
     position: relative;
@@ -274,17 +249,6 @@ header.navbar-gitlab-new {
         text-decoration: none;
         outline: 0;
         color: $white-light;
-        background-color: rgba($indigo-200, .2);
-
-        svg {
-          fill: currentColor;
-        }
-      }
-
-      &.active > a,
-      &.dropdown.open > a {
-        color: $indigo-900;
-        background-color: $white-light;
 
         svg {
           fill: currentColor;
@@ -309,7 +273,6 @@ header.navbar-gitlab-new {
       }
 
       &.line-separator {
-        border-left: 1px solid rgba($indigo-200, .2);
         margin: 8px;
       }
     }
@@ -339,17 +302,14 @@ header.navbar-gitlab-new {
     height: 32px;
     border: 0;
     border-radius: $border-radius-default;
-    background-color: rgba($indigo-200, .2);
     transition: border-color ease-in-out 0.15s, background-color ease-in-out 0.15s;
 
     &:hover {
-      background-color: rgba($indigo-200, .3);
       box-shadow: none;
     }
   }
 
   &.search-active form {
-    background-color: $white-light;
     box-shadow: none;
 
     .search-input {
@@ -377,43 +337,26 @@ header.navbar-gitlab-new {
   }
 
   .search-input::placeholder {
-    color: rgba($indigo-200, .8);
     transition: color ease-in-out 0.15s;
   }
 
   .location-badge {
     font-size: 12px;
-    color: $indigo-100;
-    background-color: rgba($indigo-200, .1);
-    will-change: color;
     margin: -4px 4px -4px -4px;
     line-height: 25px;
     padding: 4px 8px;
     border-radius: 2px 0 0 2px;
-    border-right: 1px solid $indigo-800;
     height: 32px;
     transition: border-color ease-in-out 0.15s;
   }
 
-  .search-input-wrap {
-    .search-icon,
-    .clear-icon {
-      color: rgba($indigo-200, .8);
-    }
-  }
-
   &.search-active {
     .location-badge {
-      color: $gl-text-color;
       background-color: $nav-badge-bg;
       border-color: $border-color;
     }
 
     .search-input-wrap {
-      .search-icon {
-        color: rgba($indigo-200, .8);
-      }
-
       .clear-icon {
         color: $white-light;
       }
@@ -517,8 +460,6 @@ header.navbar-gitlab-new {
 
 .btn-sign-in {
   margin-top: 3px;
-  background-color: $indigo-100;
-  color: $indigo-900;
   font-weight: $gl-font-weight-bold;
 
   &:hover {
diff --git a/app/assets/stylesheets/new_sidebar.scss b/app/assets/stylesheets/new_sidebar.scss
index 378ef8926d5..e4c12e46056 100644
--- a/app/assets/stylesheets/new_sidebar.scss
+++ b/app/assets/stylesheets/new_sidebar.scss
@@ -162,16 +162,9 @@ $new-sidebar-collapsed-width: 50px;
   }
 
   li.active {
-    box-shadow: inset 4px 0 0 $active-border;
-
     > a {
-      color: $active-color;
       font-weight: $gl-font-weight-bold;
     }
-
-    svg {
-      fill: $active-color;
-    }
   }
 
   @media (max-width: $screen-xs-max) {
diff --git a/app/assets/stylesheets/pages/profiles/preferences.scss b/app/assets/stylesheets/pages/profiles/preferences.scss
index 305feaacaa1..c197494b152 100644
--- a/app/assets/stylesheets/pages/profiles/preferences.scss
+++ b/app/assets/stylesheets/pages/profiles/preferences.scss
@@ -1,3 +1,67 @@
+@mixin application-theme-preview($color-1, $color-2, $color-3, $color-4) {
+  .one {
+    background-color: $color-1;
+    border-top-left-radius: $border-radius-default;
+  }
+
+  .two {
+    background-color: $color-2;
+    border-top-right-radius: $border-radius-default;
+  }
+
+  .three {
+    background-color: $color-3;
+    border-bottom-left-radius: $border-radius-default;
+  }
+
+  .four {
+    background-color: $color-4;
+    border-bottom-right-radius: $border-radius-default;
+  }
+}
+
+.application-theme {
+  label {
+    margin-right: 20px;
+    text-align: center;
+  }
+
+  .preview {
+    font-size: 0;
+    margin-bottom: 10px;
+
+    &.indigo {
+      @include application-theme-preview($indigo-900, $indigo-700, $indigo-800, $indigo-500);
+    }
+
+    &.dark {
+      @include application-theme-preview($theme-gray-900, $theme-gray-700, $theme-gray-800, $theme-gray-600);
+    }
+
+    &.light {
+      @include application-theme-preview($theme-gray-600, $theme-gray-200, $theme-gray-400, $theme-gray-100);
+    }
+
+    &.blue {
+      @include application-theme-preview($theme-blue-900, $theme-blue-700, $theme-blue-800, $theme-blue-500);
+    }
+
+    &.green {
+      @include application-theme-preview($theme-green-900, $theme-green-700, $theme-green-800, $theme-green-500);
+    }
+  }
+
+  .preview-row {
+    display: block;
+  }
+
+  .quadrant {
+    display: inline-block;
+    height: 50px;
+    width: 80px;
+  }
+}
+
 .syntax-theme {
   label {
     margin-right: 20px;
diff --git a/app/controllers/admin/users_controller.rb b/app/controllers/admin/users_controller.rb
index 9ec7719fabb..cbcef70e957 100644
--- a/app/controllers/admin/users_controller.rb
+++ b/app/controllers/admin/users_controller.rb
@@ -211,6 +211,7 @@ class Admin::UsersController < Admin::ApplicationController
       :provider,
       :remember_me,
       :skype,
+      :theme_id,
       :twitter,
       :username,
       :website_url
diff --git a/app/controllers/profiles/preferences_controller.rb b/app/controllers/profiles/preferences_controller.rb
index 1e557c47638..cce2a847b53 100644
--- a/app/controllers/profiles/preferences_controller.rb
+++ b/app/controllers/profiles/preferences_controller.rb
@@ -35,7 +35,8 @@ class Profiles::PreferencesController < Profiles::ApplicationController
       :color_scheme_id,
       :layout,
       :dashboard,
-      :project_view
+      :project_view,
+      :theme_id
     )
   end
 end
diff --git a/app/helpers/preferences_helper.rb b/app/helpers/preferences_helper.rb
index d36bb4ab074..0d7347ed30d 100644
--- a/app/helpers/preferences_helper.rb
+++ b/app/helpers/preferences_helper.rb
@@ -40,6 +40,10 @@ module PreferencesHelper
     ]
   end
 
+  def user_application_theme
+    @user_application_theme ||= Gitlab::Themes.for_user(current_user).css_class
+  end
+
   def user_color_scheme
     Gitlab::ColorSchemes.for_user(current_user).css_class
   end
diff --git a/app/models/user.rb b/app/models/user.rb
index 358b04ac71f..09c9b3250eb 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -35,6 +35,7 @@ class User < ActiveRecord::Base
   default_value_for :project_view, :files
   default_value_for :notified_of_own_activity, false
   default_value_for :preferred_language, I18n.default_locale
+  default_value_for :theme_id, gitlab_config.default_theme
 
   attr_encrypted :otp_secret,
     key:       Gitlab::Application.secrets.otp_key_base,
diff --git a/app/views/layouts/application.html.haml b/app/views/layouts/application.html.haml
index 65ac8aaa59b..0ca34b276a7 100644
--- a/app/views/layouts/application.html.haml
+++ b/app/views/layouts/application.html.haml
@@ -1,7 +1,7 @@
 !!! 5
 %html{ lang: I18n.locale, class: page_class }
   = render "layouts/head"
-  %body{ class: @body_class, data: { page: body_data_page, project: "#{@project.path if @project}", group: "#{@group.path if @group}", find_file: find_file_path } }
+  %body{ class: "#{user_application_theme} #{@body_class}", data: { page: body_data_page, project: "#{@project.path if @project}", group: "#{@group.path if @group}", find_file: find_file_path } }
     = render "layouts/init_auto_complete" if @gfm_form
     = render 'peek/bar'
     = render "layouts/header/default"
diff --git a/app/views/profiles/preferences/show.html.haml b/app/views/profiles/preferences/show.html.haml
index 352c2d66bab..69885008ecd 100644
--- a/app/views/profiles/preferences/show.html.haml
+++ b/app/views/profiles/preferences/show.html.haml
@@ -3,6 +3,26 @@
 = render 'profiles/head'
 
 = form_for @user, url: profile_preferences_path, remote: true, method: :put, html: { class: 'row prepend-top-default js-preferences-form' } do |f|
+  .col-lg-4.application-theme
+    %h4.prepend-top-0
+      GitLab navigation theme
+    %p Customize the appearance of the application header and navigation sidebar.
+  .col-lg-8.application-theme
+    - Gitlab::Themes.each do |theme|
+      = label_tag do
+        .preview{ class: theme.name.downcase }
+          .preview-row
+            .quadrant.one
+            .quadrant.two
+          .preview-row
+            .quadrant.three
+            .quadrant.four
+        = f.radio_button :theme_id, theme.id
+        = theme.name
+
+  .col-sm-12
+    %hr
+
   .col-lg-4.profile-settings-sidebar
     %h4.prepend-top-0
       Syntax highlighting theme
diff --git a/app/views/profiles/preferences/update.js.erb b/app/views/profiles/preferences/update.js.erb
index 431ab9d052b..8966dd3fd86 100644
--- a/app/views/profiles/preferences/update.js.erb
+++ b/app/views/profiles/preferences/update.js.erb
@@ -1,3 +1,7 @@
+// Remove body class for any previous theme, re-add current one
+$('body').removeClass('<%= Gitlab::Themes.body_classes %>')
+$('body').addClass('<%= user_application_theme %>')
+
 // Toggle container-fluid class
 if ('<%= current_user.layout %>' === 'fluid') {
   $('.content-wrapper .container-fluid').removeClass('container-limited')
diff --git a/changelogs/unreleased/35012-navigation-add-option-to-change-navigation-color-palette.yml b/changelogs/unreleased/35012-navigation-add-option-to-change-navigation-color-palette.yml
new file mode 100644
index 00000000000..74aa337a18c
--- /dev/null
+++ b/changelogs/unreleased/35012-navigation-add-option-to-change-navigation-color-palette.yml
@@ -0,0 +1,5 @@
+---
+title: Add option in preferences to change navigation theme color
+merge_request:
+author:
+type: added
diff --git a/config/gitlab.yml.example b/config/gitlab.yml.example
index e9661090844..cd44f888d3f 100644
--- a/config/gitlab.yml.example
+++ b/config/gitlab.yml.example
@@ -76,6 +76,13 @@ production: &base
 
     # default_can_create_group: false  # default: true
     # username_changing_enabled: false # default: true - User can change her username/namespace
+    ## Default theme ID
+    ##   1 - Indigo
+    ##   2 - Dark
+    ##   3 - Light
+    ##   4 - Blue
+    ##   5 - Green
+    # default_theme: 1 # default: 1
 
     ## Automatic issue closing
     # If a commit message matches this regular expression, all issues referenced from the matched text will be closed.
diff --git a/config/initializers/1_settings.rb b/config/initializers/1_settings.rb
index 8a560d84f1f..94429ee91a9 100644
--- a/config/initializers/1_settings.rb
+++ b/config/initializers/1_settings.rb
@@ -232,6 +232,7 @@ Settings['gitlab'] ||= Settingslogic.new({})
 Settings.gitlab['default_projects_limit'] ||= 100000
 Settings.gitlab['default_branch_protection'] ||= 2
 Settings.gitlab['default_can_create_group'] = true if Settings.gitlab['default_can_create_group'].nil?
+Settings.gitlab['default_theme'] = Gitlab::Themes::APPLICATION_DEFAULT if Settings.gitlab['default_theme'].nil?
 Settings.gitlab['host']       ||= ENV['GITLAB_HOST'] || 'localhost'
 Settings.gitlab['ssh_host']   ||= Settings.gitlab.host
 Settings.gitlab['https']        = false if Settings.gitlab['https'].nil?
diff --git a/db/migrate/20170816234252_add_theme_id_to_users.rb b/db/migrate/20170816234252_add_theme_id_to_users.rb
new file mode 100644
index 00000000000..5043f9ec591
--- /dev/null
+++ b/db/migrate/20170816234252_add_theme_id_to_users.rb
@@ -0,0 +1,10 @@
+# See http://doc.gitlab.com/ce/development/migration_style_guide.html
+# for more information on how to write migrations for GitLab.
+
+class AddThemeIdToUsers < ActiveRecord::Migration
+  DOWNTIME = false
+
+  def change
+    add_column :users, :theme_id, :integer, limit: 2
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index df941afa7d7..2149f5ad23d 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -1608,6 +1608,7 @@ ActiveRecord::Schema.define(version: 20170905112933) do
     t.boolean "notified_of_own_activity"
     t.string "preferred_language"
     t.string "rss_token"
+    t.integer "theme_id", limit: 2
   end
 
   add_index "users", ["admin"], name: "index_users_on_admin", using: :btree
diff --git a/doc/api/keys.md b/doc/api/keys.md
index 376ac27df3a..ddcf7830621 100644
--- a/doc/api/keys.md
+++ b/doc/api/keys.md
@@ -32,6 +32,7 @@ Parameters:
     "twitter": "",
     "website_url": "",
     "email": "john@example.com",
+    "theme_id": 2,
     "color_scheme_id": 1,
     "projects_limit": 10,
     "current_sign_in_at": null,
diff --git a/doc/api/session.md b/doc/api/session.md
index f79eac11689..b97e26f34a2 100644
--- a/doc/api/session.md
+++ b/doc/api/session.md
@@ -39,6 +39,7 @@ Example response:
   "twitter": "",
   "website_url": "",
   "email": "john@example.com",
+  "theme_id": 1,
   "color_scheme_id": 1,
   "projects_limit": 10,
   "current_sign_in_at": "2015-07-07T07:10:58.392Z",
diff --git a/doc/api/users.md b/doc/api/users.md
index 9f3e4caf2f4..6d5db16b36a 100644
--- a/doc/api/users.md
+++ b/doc/api/users.md
@@ -72,6 +72,7 @@ GET /users
     "organization": "",
     "last_sign_in_at": "2012-06-01T11:41:01Z",
     "confirmed_at": "2012-05-23T09:05:22Z",
+    "theme_id": 1,
     "last_activity_on": "2012-05-23",
     "color_scheme_id": 2,
     "projects_limit": 100,
@@ -105,6 +106,7 @@ GET /users
     "organization": "",
     "last_sign_in_at": null,
     "confirmed_at": "2012-05-30T16:53:06.148Z",
+    "theme_id": 1,
     "last_activity_on": "2012-05-23",
     "color_scheme_id": 3,
     "projects_limit": 100,
@@ -215,6 +217,7 @@ Parameters:
   "organization": "",
   "last_sign_in_at": "2012-06-01T11:41:01Z",
   "confirmed_at": "2012-05-23T09:05:22Z",
+  "theme_id": 1,
   "last_activity_on": "2012-05-23",
   "color_scheme_id": 2,
   "projects_limit": 100,
@@ -341,6 +344,7 @@ GET /user
   "organization": "",
   "last_sign_in_at": "2012-06-01T11:41:01Z",
   "confirmed_at": "2012-05-23T09:05:22Z",
+  "theme_id": 1,
   "last_activity_on": "2012-05-23",
   "color_scheme_id": 2,
   "projects_limit": 100,
@@ -387,6 +391,7 @@ GET /user
   "organization": "",
   "last_sign_in_at": "2012-06-01T11:41:01Z",
   "confirmed_at": "2012-05-23T09:05:22Z",
+  "theme_id": 1,
   "last_activity_on": "2012-05-23",
   "color_scheme_id": 2,
   "projects_limit": 100,
diff --git a/lib/api/entities.rb b/lib/api/entities.rb
index 216408064d1..52c49e5caa9 100644
--- a/lib/api/entities.rb
+++ b/lib/api/entities.rb
@@ -45,7 +45,7 @@ module API
       expose :confirmed_at
       expose :last_activity_on
       expose :email
-      expose :color_scheme_id, :projects_limit, :current_sign_in_at
+      expose :theme_id, :color_scheme_id, :projects_limit, :current_sign_in_at
       expose :identities, using: Entities::Identity
       expose :can_create_group?, as: :can_create_group
       expose :can_create_project?, as: :can_create_project
diff --git a/lib/gitlab/themes.rb b/lib/gitlab/themes.rb
new file mode 100644
index 00000000000..d43eff5ba4a
--- /dev/null
+++ b/lib/gitlab/themes.rb
@@ -0,0 +1,84 @@
+module Gitlab
+  # Module containing GitLab's application theme definitions and helper methods
+  # for accessing them.
+  module Themes
+    extend self
+
+    # Theme ID used when no `default_theme` configuration setting is provided.
+    APPLICATION_DEFAULT = 1
+
+    # Struct class representing a single Theme
+    Theme = Struct.new(:id, :name, :css_class)
+
+    # All available Themes
+    THEMES = [
+      Theme.new(1, 'Indigo', 'ui_indigo'),
+      Theme.new(2, 'Dark', 'ui_dark'),
+      Theme.new(3, 'Light', 'ui_light'),
+      Theme.new(4, 'Blue', 'ui_blue'),
+      Theme.new(5, 'Green', 'ui_green')
+    ].freeze
+
+    # Convenience method to get a space-separated String of all the theme
+    # classes that might be applied to the `body` element
+    #
+    # Returns a String
+    def body_classes
+      THEMES.collect(&:css_class).uniq.join(' ')
+    end
+
+    # Get a Theme by its ID
+    #
+    # If the ID is invalid, returns the default Theme.
+    #
+    # id - Integer ID
+    #
+    # Returns a Theme
+    def by_id(id)
+      THEMES.detect { |t| t.id == id } || default
+    end
+
+    # Returns the number of defined Themes
+    def count
+      THEMES.size
+    end
+
+    # Get the default Theme
+    #
+    # Returns a Theme
+    def default
+      by_id(default_id)
+    end
+
+    # Iterate through each Theme
+    #
+    # Yields the Theme object
+    def each(&block)
+      THEMES.each(&block)
+    end
+
+    # Get the Theme for the specified user, or the default
+    #
+    # user - User record
+    #
+    # Returns a Theme
+    def for_user(user)
+      if user
+        by_id(user.theme_id)
+      else
+        default
+      end
+    end
+
+    private
+
+    def default_id
+      @default_id ||= begin
+        id = Gitlab.config.gitlab.default_theme.to_i
+        theme_ids = THEMES.map(&:id)
+
+        theme_ids.include?(id) ? id : APPLICATION_DEFAULT
+      end
+    end
+  end
+end
diff --git a/spec/controllers/profiles/preferences_controller_spec.rb b/spec/controllers/profiles/preferences_controller_spec.rb
index a5f544b4f92..a66b4ab0902 100644
--- a/spec/controllers/profiles/preferences_controller_spec.rb
+++ b/spec/controllers/profiles/preferences_controller_spec.rb
@@ -25,7 +25,8 @@ describe Profiles::PreferencesController do
     def go(params: {}, format: :js)
       params.reverse_merge!(
         color_scheme_id: '1',
-        dashboard: 'stars'
+        dashboard: 'stars',
+        theme_id: '1'
       )
 
       patch :update, user: params, format: format
@@ -40,7 +41,8 @@ describe Profiles::PreferencesController do
       it "changes the user's preferences" do
         prefs = {
           color_scheme_id: '1',
-          dashboard: 'stars'
+          dashboard: 'stars',
+          theme_id: '2'
         }.with_indifferent_access
 
         expect(user).to receive(:assign_attributes).with(prefs)
diff --git a/spec/fixtures/api/schemas/public_api/v4/user/login.json b/spec/fixtures/api/schemas/public_api/v4/user/login.json
index 6181b3ccc86..e6c1d9c9d84 100644
--- a/spec/fixtures/api/schemas/public_api/v4/user/login.json
+++ b/spec/fixtures/api/schemas/public_api/v4/user/login.json
@@ -19,6 +19,7 @@
     "organization",
     "last_sign_in_at",
     "confirmed_at",
+    "theme_id",
     "color_scheme_id",
     "projects_limit",
     "current_sign_in_at",
diff --git a/spec/helpers/preferences_helper_spec.rb b/spec/helpers/preferences_helper_spec.rb
index a04c87b08eb..8b8080563d3 100644
--- a/spec/helpers/preferences_helper_spec.rb
+++ b/spec/helpers/preferences_helper_spec.rb
@@ -1,7 +1,7 @@
 require 'spec_helper'
 
 describe PreferencesHelper do
-  describe 'dashboard_choices' do
+  describe '#dashboard_choices' do
     it 'raises an exception when defined choices may be missing' do
       expect(User).to receive(:dashboards).and_return(foo: 'foo')
       expect { helper.dashboard_choices }.to raise_error(RuntimeError)
@@ -26,7 +26,33 @@ describe PreferencesHelper do
     end
   end
 
-  describe 'user_color_scheme' do
+  describe '#user_application_theme' do
+    context 'with a user' do
+      it "returns user's theme's css_class" do
+        stub_user(theme_id: 3)
+
+        expect(helper.user_application_theme).to eq 'ui_light'
+      end
+
+      it 'returns the default when id is invalid' do
+        stub_user(theme_id: Gitlab::Themes.count + 5)
+
+        allow(Gitlab.config.gitlab).to receive(:default_theme).and_return(1)
+
+        expect(helper.user_application_theme).to eq 'ui_indigo'
+      end
+    end
+
+    context 'without a user' do
+      it 'returns the default theme' do
+        stub_user
+
+        expect(helper.user_application_theme).to eq Gitlab::Themes.default.css_class
+      end
+    end
+  end
+
+  describe '#user_color_scheme' do
     context 'with a user' do
       it "returns user's scheme's css_class" do
         allow(helper).to receive(:current_user)
diff --git a/spec/lib/gitlab/background_migration/migrate_events_to_push_event_payloads_spec.rb b/spec/lib/gitlab/background_migration/migrate_events_to_push_event_payloads_spec.rb
index b155c20d8d3..cb52d971047 100644
--- a/spec/lib/gitlab/background_migration/migrate_events_to_push_event_payloads_spec.rb
+++ b/spec/lib/gitlab/background_migration/migrate_events_to_push_event_payloads_spec.rb
@@ -215,9 +215,17 @@ end
 # to a specific version of the database where said table is still present.
 #
 describe Gitlab::BackgroundMigration::MigrateEventsToPushEventPayloads, :migration, schema: 20170825154015 do
+  let(:user_class) do
+    Class.new(ActiveRecord::Base) do
+      self.table_name = 'users'
+    end
+  end
+
   let(:migration) { described_class.new }
-  let(:project) { create(:project_empty_repo) }
-  let(:author) { create(:user) }
+  let(:user_class) { table(:users) }
+  let(:author) { build(:user).becomes(user_class).tap(&:save!).becomes(User) }
+  let(:namespace) { create(:namespace, owner: author) }
+  let(:project) { create(:project_empty_repo, namespace: namespace, creator: author) }
 
   # We can not rely on FactoryGirl as the state of Event may change in ways that
   # the background migration does not expect, hence we use the Event class of
diff --git a/spec/lib/gitlab/themes_spec.rb b/spec/lib/gitlab/themes_spec.rb
new file mode 100644
index 00000000000..ecacea6bb35
--- /dev/null
+++ b/spec/lib/gitlab/themes_spec.rb
@@ -0,0 +1,48 @@
+require 'spec_helper'
+
+describe Gitlab::Themes, lib: true do
+  describe '.body_classes' do
+    it 'returns a space-separated list of class names' do
+      css = described_class.body_classes
+
+      expect(css).to include('ui_indigo')
+      expect(css).to include(' ui_dark ')
+      expect(css).to include(' ui_blue')
+    end
+  end
+
+  describe '.by_id' do
+    it 'returns a Theme by its ID' do
+      expect(described_class.by_id(1).name).to eq 'Indigo'
+      expect(described_class.by_id(3).name).to eq 'Light'
+    end
+  end
+
+  describe '.default' do
+    it 'returns the default application theme' do
+      allow(described_class).to receive(:default_id).and_return(2)
+      expect(described_class.default.id).to eq 2
+    end
+
+    it 'prevents an infinite loop when configuration default is invalid' do
+      default = described_class::APPLICATION_DEFAULT
+      themes  = described_class::THEMES
+
+      config = double(default_theme: 0).as_null_object
+      allow(Gitlab).to receive(:config).and_return(config)
+      expect(described_class.default.id).to eq default
+
+      config = double(default_theme: themes.size + 5).as_null_object
+      allow(Gitlab).to receive(:config).and_return(config)
+      expect(described_class.default.id).to eq default
+    end
+  end
+
+  describe '.each' do
+    it 'passes the block to the THEMES Array' do
+      ids = []
+      described_class.each { |theme| ids << theme.id }
+      expect(ids).not_to be_empty
+    end
+  end
+end
diff --git a/spec/migrations/convert_custom_notification_settings_to_columns_spec.rb b/spec/migrations/convert_custom_notification_settings_to_columns_spec.rb
index 1396d12e5a9..759e77ac9db 100644
--- a/spec/migrations/convert_custom_notification_settings_to_columns_spec.rb
+++ b/spec/migrations/convert_custom_notification_settings_to_columns_spec.rb
@@ -2,6 +2,8 @@ require 'spec_helper'
 require Rails.root.join('db', 'post_migrate', '20170607121233_convert_custom_notification_settings_to_columns')
 
 describe ConvertCustomNotificationSettingsToColumns, :migration do
+  let(:user_class) { table(:users) }
+
   let(:settings_params) do
     [
       { level: 0, events: [:new_note] }, # disabled, single event
@@ -19,7 +21,7 @@ describe ConvertCustomNotificationSettingsToColumns, :migration do
         events[event] = true
       end
 
-      user = create(:user)
+      user = build(:user).becomes(user_class).tap(&:save!)
       create_params = { user_id: user.id, level: params[:level], events: events }
       notification_setting = described_class::NotificationSetting.create(create_params)
 
@@ -35,7 +37,7 @@ describe ConvertCustomNotificationSettingsToColumns, :migration do
         events[event] = true
       end
 
-      user = create(:user)
+      user = build(:user).becomes(user_class).tap(&:save!)
       create_params = events.merge(user_id: user.id, level: params[:level])
       notification_setting = described_class::NotificationSetting.create(create_params)
 
diff --git a/spec/models/user_spec.rb b/spec/models/user_spec.rb
index 3ba01313efb..c1affa812aa 100644
--- a/spec/models/user_spec.rb
+++ b/spec/models/user_spec.rb
@@ -716,6 +716,7 @@ describe User do
       it "applies defaults to user" do
         expect(user.projects_limit).to eq(Gitlab.config.gitlab.default_projects_limit)
         expect(user.can_create_group).to eq(Gitlab.config.gitlab.default_can_create_group)
+        expect(user.theme_id).to eq(Gitlab.config.gitlab.default_theme)
         expect(user.external).to be_falsey
       end
     end
@@ -726,6 +727,7 @@ describe User do
       it "applies defaults to user" do
         expect(user.projects_limit).to eq(123)
         expect(user.can_create_group).to be_falsey
+        expect(user.theme_id).to eq(1)
       end
     end
 
diff --git a/spec/support/gitlab_stubs/session.json b/spec/support/gitlab_stubs/session.json
index cd55d63125e..688175369ae 100644
--- a/spec/support/gitlab_stubs/session.json
+++ b/spec/support/gitlab_stubs/session.json
@@ -7,7 +7,7 @@
   "skype":"aertert",
   "linkedin":"",
   "twitter":"",
-  "color_scheme_id":2,
+  "theme_id":2,"color_scheme_id":2,
   "state":"active",
   "created_at":"2012-12-21T13:02:20Z",
   "extern_uid":null,
diff --git a/spec/support/gitlab_stubs/user.json b/spec/support/gitlab_stubs/user.json
index cd55d63125e..ce8dfe5ae75 100644
--- a/spec/support/gitlab_stubs/user.json
+++ b/spec/support/gitlab_stubs/user.json
@@ -7,7 +7,7 @@
   "skype":"aertert",
   "linkedin":"",
   "twitter":"",
-  "color_scheme_id":2,
+  "theme_id":2,"color_scheme_id":2,
   "state":"active",
   "created_at":"2012-12-21T13:02:20Z",
   "extern_uid":null,
@@ -17,4 +17,4 @@
   "can_create_project":false,
   "private_token":"Wvjy2Krpb7y8xi93owUz",
   "access_token":"Wvjy2Krpb7y8xi93owUz"
-}
+}
\ No newline at end of file