Adjust settings that apply to your entire web map in the Map properties pane. You can enable a background color, preserve the map scale, and configure the time slider for maps with time-enabled data.
Enable a background color
You can use background color on its own or in combination with layer blending. In some cases, especially when using custom basemaps, you may need to set a background color for areas the basemap doesn't cover. The basemap color can be part of the overall thematic focus of the map, or it can be a color that corresponds with organizational themes.
To enable background color, do the following:
- Confirm that you are signed in and, if you want to save your changes, that you have privileges to create content.
- In Map Viewer, on the Contents (dark) toolbar, click Map properties
.
- In the Background section of the Map properties pane, turn on the Enable background color toggle button.
The color picker appears.
- Select a color from the color picker, or type an RGB or hexadecimal value into the text box. Click Add
to save a custom color and click Remove 
to remove a saved color. Colors are saved only for the browser session. Click Done when you are finished selecting a color.The background color changes in real time as you make your color selection. View the background color by zooming out to the map's full extent.
- Save the map.
Preserve the map scale
You may want a map to open at a specific scale regardless of the device or screen size. For example, if the map has multiple layers with predefined visible ranges, you can set the scale at which the map opens to highlight certain layers and features.
To preserve map scale, do the following:
- If necessary, zoom in or out on the map to display the scale you want.
- On the Contents (dark) toolbar, click Map properties .
- In the Map view section of the Map properties pane, turn on the Preserve map scale toggle button.
- Save the map.