Dividing line(The function of dividing, organizing, and refining content makes your design look more orderly, and the content presented on the page makes it easier for customers to understand.)
If you want to adjust the size, you can select "divider" and set "width" and "height" in "Size" on the right.
If you want to change the color, you can change it in "Decoration" - "Background" - "Background Color"