Load majrivers.shp into QGIS. We will use this data to create a line style that consists of two colors: a fill color and an outline color. To do this, open the Layer Styling panel and select a single symbol. Beneath this symbology, click on the green plus icon to add a new Simple line. You should now have two lines showing, which look similar to the following screenshot:
Layer styling on lines
The lower line will be our outline color, and the upper one will be the fill color. Select the upper simple line and change the color to blue and the width to 0.5 millimeters. Next, select the lower simple ...
