--- a/mail/components/extensions/parent/ext-theme.js
+++ b/mail/components/extensions/parent/ext-theme.js
@@ -356,16 +356,21 @@ class Theme {
 
           let tiling = [];
           for (let i = 0, l = styles.additionalBackgrounds.length; i < l; ++i) {
             tiling.push(val[i] || "no-repeat");
           }
           styles.backgroundsTiling = tiling.join(",");
           break;
         }
+        case "color_scheme":
+        case "content_color_scheme": {
+          styles[property] = val;
+          break;
+        }
         default: {
           if (
             this.experiment &&
             this.experiment.properties &&
             property in this.experiment.properties
           ) {
             styles.experimental.properties[property] = val;
           } else {

--- a/mail/components/extensions/schemas/theme.json
+++ b/mail/components/extensions/schemas/theme.json
@@ -370,16 +370,36 @@
                     "no-repeat",
                     "repeat",
                     "repeat-x",
                     "repeat-y"
                   ]
                 },
                 "maxItems": 15,
                 "optional": true
+              },
+              "color_scheme": {
+                "description": "If set, overrides the general 'toolbar theme'.",
+                "optional": true,
+                "type": "string",
+                "enum": [
+                  "light",
+                  "dark",
+                  "auto"
+                ]
+              },
+              "content_color_scheme": {
+                "description": "If set, overrides the color scheme for the content area.",
+                "optional": true,
+                "type": "string",
+                "enum": [
+                  "light",
+                  "dark",
+                  "auto"
+                ]
               }
             },
             "additionalProperties": {
               "type": "string"
             }
           }
         },
         "additionalProperties": {

--- a/mail/themes/addons/dark/manifest.json
+++ b/mail/themes/addons/dark/manifest.json
@@ -41,16 +41,17 @@
       "button_hover": "rgb(82, 82, 94)",
       "button_active": "rgb(91, 91, 102)",
       "error_text_color": "rgb(255, 154, 162)",
       "input_background": "#42414d",
       "input_color": "#bfbfc9",
       "input_border": "#8f8f9d"
     },
     "properties": {
+      "color_scheme": "dark",
       "panel_hover": "color-mix(in srgb, currentColor 9%, transparent)",
       "panel_active": "color-mix(in srgb, currentColor 14%, transparent)",
       "panel_active_darker": "color-mix(in srgb, currentColor 25%, transparent)"
     }
   },
 
   "theme_experiment": {
     "stylesheet": "experiment.css",

--- a/mail/themes/addons/light/manifest.json
+++ b/mail/themes/addons/light/manifest.json
@@ -40,16 +40,17 @@
       "sidebar_highlight": "#2292d0",
       "sidebar_highlight_text": "#fff",
       "sidebar_highlight_border": "#0060df",
       "button": "rgba(207, 207, 216, 0.33)",
       "button_hover": "rgba(207, 207, 216, 0.66)",
       "button_active": "rgb(207, 207, 216)"
     },
     "properties": {
+      "color_scheme": "light",
       "panel_hover": "color-mix(in srgb, currentColor 12%, transparent)",
       "panel_active": "color-mix(in srgb, currentColor 20%, transparent)",
       "panel_active_darker": "color-mix(in srgb, currentColor 27%, transparent)"
     }
   },
 
   "theme_experiment": {
     "stylesheet": "experiment.css",