To add a full-width separator, you need to go to Edit mode of your dashboard. Locate the right sidebar and select the Add Text Widget.
Then follow these steps:
Select Plain type of widget from the drop-down menu and click next;
2. Add a description of your widget, or skip this step and click next;
3. Type in the Widget title, select the size 4x1, and choose Auto Height Card as the Format. Click on Submit at the end, et voila!
You now have a full-width separator!