diff --git a/Gemfile b/Gemfile
index 50715b048..046c6f72c 100644
--- a/Gemfile
+++ b/Gemfile
@@ -108,6 +108,7 @@ gem "uglifier", "~> 4.2" # Uglifier minifies JavaScript files
 gem "ulid", "~> 1.2" # Universally Unique Lexicographically Sortable Identifier implementation for Ruby
 gem "validate_url", "~> 1.0" # Library for validating urls in Rails
 gem "vault", "~> 0.15" # Used to store secrets
+gem "wcag_color_contrast", "~> 0.1" # Detect contrast of colors to determine readability and a11y.
 gem "webpacker", "~> 5.2.1" # Use webpack to manage app-like JavaScript modules in Rails
 
 group :development do
diff --git a/Gemfile.lock b/Gemfile.lock
index f4c5ee119..a2f6da871 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -815,6 +815,7 @@ GEM
       equalizer (~> 0.0, >= 0.0.9)
     warden (1.2.8)
       rack (>= 2.0.6)
+    wcag_color_contrast (0.1.0)
     web-console (4.0.4)
       actionview (>= 6.0.0)
       activemodel (>= 6.0.0)
@@ -995,6 +996,7 @@ DEPENDENCIES
   validate_url (~> 1.0)
   vault (~> 0.15)
   vcr (~> 6.0)
+  wcag_color_contrast (~> 0.1)
   web-console (~> 4.0)
   webdrivers (~> 4.4)
   webmock (~> 3.8)
diff --git a/app/assets/stylesheets/components/buttons.scss b/app/assets/stylesheets/components/buttons.scss
index e1a2d1699..37f585369 100644
--- a/app/assets/stylesheets/components/buttons.scss
+++ b/app/assets/stylesheets/components/buttons.scss
@@ -12,6 +12,10 @@
   --brand-github-bg: #24292e;
   --brand-github-color: #fff;
   --brand-github-bg-hover: #000;
+
+  --brand-facebook-bg: #4267B2;
+  --brand-facebook-color: #fff;
+  --brand-facebook-bg-hover: #476fbf;
 }
 
 // Basic styling
@@ -261,6 +265,18 @@
   --color-inverted-hover: var(--brand-github-color);
 }
 
+.crayons-btn--brand-facebook {
+  --bg: var(--brand-facebook-bg);
+  --bg-hover: var(--brand-facebook-bg-hover);
+  --color: var(--brand-facebook-color);
+  --color-hover: var(--brand-facebook-color);
+  --bg-inverted: var(--brand-facebook-bg);
+  --bg-inverted-hover: var(--brand-facebook-bg-hover);
+  --color-inverted: var(--brand-facebook-color);
+  --color-inverted-hover: var(--brand-facebook-color);
+}
+
+
 // Icon alone
 .crayons-btn--icon,
 .crayons-btn--icon-rounded {
diff --git a/app/controllers/admin/configs_controller.rb b/app/controllers/admin/configs_controller.rb
index dd9d5fb53..0d8d11a47 100644
--- a/app/controllers/admin/configs_controller.rb
+++ b/app/controllers/admin/configs_controller.rb
@@ -3,6 +3,7 @@ module Admin
     layout "admin"
 
     before_action :extra_authorization_and_confirmation, only: [:create]
+    before_action :validate_inputs, only: [:create]
 
     def show
       @confirmation_text = confirmation_text
@@ -54,6 +55,7 @@ module Admin
         facebook_key
         facebook_secret
         allow_email_password_registration
+        primary_brand_color_hex
       ]
 
       allowed_params = allowed_params |
@@ -87,6 +89,13 @@ module Admin
       raise_confirmation_mismatch_error if params.require(:confirmation) != confirmation_text
     end
 
+    def validate_inputs
+      errors = []
+      errors << "Brand color must be darker for accessibility." if brand_contrast_too_low
+      errors << "Brand color must be be a 6 character hex (starting with #)." if brand_color_not_hex
+      redirect_to admin_config_path, alert: "😭 #{errors.join(',')}" if errors.any?
+    end
+
     def clean_up_params
       config = params[:site_config]
       %i[sidebar_tags suggested_tags suggested_users].each do |param|
@@ -103,6 +112,17 @@ module Admin
       Rails.cache.delete_matched(ApplicationConfig["RELEASE_FOOTPRINT"]) # Delete all caches tied to this key.
     end
 
+    # Validations
+    def brand_contrast_too_low
+      hex = params[:site_config][:primary_brand_color_hex]
+      hex.present? && Color::Accessibility.new(hex).low_contrast?
+    end
+
+    def brand_color_not_hex
+      hex = params[:site_config][:primary_brand_color_hex]
+      hex.present? && !hex.match?(/\A#(\h{6}|\h{3})\z/)
+    end
+
     def campaign_params
       %i[
         campaign_featured_tags
diff --git a/app/lib/constants/site_config.rb b/app/lib/constants/site_config.rb
index a44af0be1..c4448ebef 100644
--- a/app/lib/constants/site_config.rb
+++ b/app/lib/constants/site_config.rb
@@ -101,6 +101,10 @@ module Constants
         description: "Determines which default feed the users sees (rich content, more minimal, etc.)",
         placeholder: "basic, rich, or compact"
       },
+      primary_brand_color_hex: {
+        description: "Determines background/border of buttons etc. Must be dark enough to contrast with white text.",
+        placeholder: "#0a0a0a"
+      },
       github_key: {
         description: "The \"Client ID\" portion of the GitHub Oauth Apps portal",
         placeholder: ""
diff --git a/app/models/site_config.rb b/app/models/site_config.rb
index 764627dd1..dafee7215 100644
--- a/app/models/site_config.rb
+++ b/app/models/site_config.rb
@@ -153,6 +153,7 @@ class SiteConfig < RailsSettings::Base
   field :public, type: :boolean, default: 0
   # The default font for all users that have not chosen a custom font yet
   field :default_font, type: :string, default: "sans_serif"
+  field :primary_brand_color_hex, type: :string, default: "#3b49df"
 
   # Broadcast
   field :welcome_notifications_live_at, type: :date
diff --git a/app/services/color/accessibility.rb b/app/services/color/accessibility.rb
new file mode 100644
index 000000000..a2c381e77
--- /dev/null
+++ b/app/services/color/accessibility.rb
@@ -0,0 +1,11 @@
+module Color
+  class Accessibility
+    def initialize(hex)
+      @hex = hex.delete("#")
+    end
+
+    def low_contrast?(compared_color = "ffffff", min_contrast = 4.5)
+      WCAGColorContrast.ratio(@hex, compared_color.delete("#")) < min_contrast
+    end
+  end
+end
diff --git a/app/views/admin/configs/show.html.erb b/app/views/admin/configs/show.html.erb
index 05f1afd09..ba24a205b 100644
--- a/app/views/admin/configs/show.html.erb
+++ b/app/views/admin/configs/show.html.erb
@@ -931,7 +931,7 @@
         <div class="card mt-3">
           <%= render partial: "card_header",
                      locals: {
-                       header: "User Experience",
+                       header: "User Experience and Brand",
                        state: "collapse",
                        target: "uxBodyContainer",
                        expanded: "false"
@@ -956,6 +956,15 @@
                              class: "form-control selectpicker" %>
               <div class="alert alert-info"><%= Constants::SiteConfig::DETAILS[:default_font][:description] %></div>
             </div>
+            <div class="form-group">
+              <%= f.label :primary_brand_color_hex %>
+              <%= f.text_field :primary_brand_color_hex,
+                               class: "form-control",
+                               value: SiteConfig.primary_brand_color_hex,
+                               pattern: "^#+([a-fA-F0-9]{6})$",
+                               placeholder: Constants::SiteConfig::DETAILS[:primary_brand_color_hex][:placeholder] %>
+              <div class="alert alert-info"><%= Constants::SiteConfig::DETAILS[:primary_brand_color_hex][:description] %></div>
+            </div>
             <div class="form-group">
               <%= admin_config_label :public %>
               <%= f.check_box :public, checked: SiteConfig.public %>
diff --git a/app/views/shell/_top.html.erb b/app/views/shell/_top.html.erb
index b00a45225..502ba964c 100644
--- a/app/views/shell/_top.html.erb
+++ b/app/views/shell/_top.html.erb
@@ -55,7 +55,16 @@
         class="<%= SiteConfig.default_font.tr("_", "-") %>-article-body"
         data-pusher-key="<%= ApplicationConfig["PUSHER_KEY"] %>"
         data-app-name="<%= ApplicationConfig["APP_NAME"] %>">
-        <div id="body-styles"></div>
+        <div id="body-styles">
+          <style>
+            :root {
+              --accent-brand: <%= SiteConfig.primary_brand_color_hex %>;
+              --accent-brand-darker: <%= HexComparer.new([SiteConfig.primary_brand_color_hex]).brightness(0.85) %>;
+              --accent-brand-lighter: <%= HexComparer.new([SiteConfig.primary_brand_color_hex]).brightness(1.1) %>;
+              --accent-brand-a10: #{rgba(<%= SiteConfig.primary_brand_color_hex %>, 0.1)};
+            }
+          </style>
+        </div>
         <% if user_signed_in? %>
           <%= render "layouts/user_config" %>
         <% end %>
diff --git a/spec/requests/admin/configs_spec.rb b/spec/requests/admin/configs_spec.rb
index 46590355d..56a16b706 100644
--- a/spec/requests/admin/configs_spec.rb
+++ b/spec/requests/admin/configs_spec.rb
@@ -589,6 +589,28 @@ RSpec.describe "/admin/config", type: :request do
           expect(SiteConfig.feed_style).to eq(feed_style)
         end
 
+        it "updates the brand color if proper hex" do
+          hex = "#0a0a0a" # dark enough
+          post "/admin/config", params: { site_config: { primary_brand_color_hex: hex },
+                                          confirmation: confirmation_message }
+          expect(SiteConfig.primary_brand_color_hex).to eq(hex)
+        end
+
+        it "does not update brand color if hex not contrasting enough" do
+          hex = "#bd746f" # not dark enough
+          post "/admin/config", params: { site_config: { primary_brand_color_hex: hex },
+                                          confirmation: confirmation_message }
+          expect(SiteConfig.primary_brand_color_hex).not_to eq(hex)
+        end
+
+        it "does not update brand color if hex not a hex with proper format" do
+          hex = "0a0a0a" # dark enough, but not proper format
+          post "/admin/config", params: { site_config: { primary_brand_color_hex: hex },
+                                          confirmation: confirmation_message }
+          expect(SiteConfig.primary_brand_color_hex).not_to eq(hex)
+        end
+
+
         it "updates public to true" do
           is_public = true
           post "/admin/config", params: { site_config: { public: is_public },
diff --git a/spec/services/color/accessibility_spec.rb b/spec/services/color/accessibility_spec.rb
new file mode 100644
index 000000000..cb26f95b1
--- /dev/null
+++ b/spec/services/color/accessibility_spec.rb
@@ -0,0 +1,27 @@
+require "rails_helper"
+
+RSpec.describe Color::Accessibility, type: :service do
+  it "determines low contrast with default compared color" do
+    expect(described_class.new("#8a9bb8").low_contrast?).to be true
+  end
+
+  it "determines low contrast with compared color input" do
+    expect(described_class.new("#041d4a").low_contrast?("#1a3669")).to be true
+  end
+
+  it "determines low contrast with compared color and rate" do
+    expect(described_class.new("#225CC9").low_contrast?("#ffffff", 10.0)).to be true
+  end
+
+  it "determines sufficient contrast with default compared color" do
+    expect(described_class.new("#041d4a").low_contrast?).to be false
+  end
+
+  it "determines sufficient contrast with compared color input" do
+    expect(described_class.new("#041d4a").low_contrast?("#e6eaf0")).to be false
+  end
+
+  it "determines sufficient contrast with compared color and rate" do
+    expect(described_class.new("#225CC9").low_contrast?("#ffffff", 1.0)).to be false
+  end
+end
diff --git a/vendor/cache/wcag_color_contrast-0.1.0.gem b/vendor/cache/wcag_color_contrast-0.1.0.gem
new file mode 100644
index 000000000..f0417e2e3
Binary files /dev/null and b/vendor/cache/wcag_color_contrast-0.1.0.gem differ