BI-48490 refactor: 加颜色

src/less/lib/colors.less

@@ -58,6 +58,10 @@
 @color-bi-background-light-gray: @background-color-light-gray;
 //深色主题灰色背景
 @color-bi-background-light-gray-theme-dark: @background-color-light-gray-theme-dark;
+//灰色背景(中)
+@color-bi-background-medium-gray: @background-color-medium-gray;
+//深色主题灰色背景(中)
+@color-bi-background-medium-gray-theme-dark: @background-color-medium-gray-theme-dark;
 //灰化背景
 @color-bi-background-disabled: @background-color-disabled;
 //深色主题灰化背景

src/less/lib/constant.less

@@ -62,6 +62,8 @@
 @background-color-dark: #d4dadd;
 @background-color-light-gray: #f2f4f7;
 @background-color-light-gray-theme-dark: #292f45;
+@background-color-medium-gray: #e8eaed;
+@background-color-medium-gray-theme-dark: #363e55;
 @background-color-dark-gray: #d0d4da;
 @background-color-dark-gray-theme-dark: #606479;
 @background-color-disabled: #f2f4f7;