Adding a customized color to your dashboard gives it personality and brings it to life! You can choose either a light or dark theme and one of 14 color palettes.
Themes and color palettes helps you organize the data on your dashboard. For example, you can highlight a set of summary metrics by choosing a dark theme and setting it against a light-themed dashboard.
Step 1: Select Dashboard and either create a New Dashboard or Edit a Dashboard. For this tutorial, we will be editing a dashboard. Click here to learn how to create a new dashboard.
Step 2: Click edit beside the Dashboard of your choice.
Step 3: Click the Edit Dashboard Properties icon to edit the Dashboard Theme and Dashboard Palette. The entire dashboard color will be updated and you are also able to choose from one of the 14 color palettes. Your dashboard now has a customized color palette and theme!
If the Dashboard Theme is not available within properties, you will have to enable the Change Dashboard Colors permission set for the System Administrator profile. Follow the steps below:
Step 1: Select Setup, then Users, then Permission Sets.
Step 2: Click New. Name the Label Change Dashboard Colors. Name the API Name Change_Dashboard_Colors.
Step 3: Select the Salesforce license. Click Save.
Step 4: Click Manage Assignments then Add Assignments.
Step 5: Select the System Administrator profile so that you are able to grant permission to change your dashboard colors. Click Assign and then Done.
Step 6: Select Back to: Permission Set. Select System Permissions. Select Edit. Make sure that the Change Dashboard Colors checkbox is checked. Click Save.
Helpful Link:
Color Dashboard Data with Themes and Palettes