The lines separate the two columns and are not very bold.
The solid lines are used to separate different parts of the website.
2. The shape
The shape, or the form, is the second most used element of a web design. They are actually lines combined in different shapes. The forms are still popular and this is because if there is something that needs to stand out, forms are one of the ways to do it. There can be circles, squares, rectangles, triangles or any other abstract shape; most of the designs include at least one of these. Minimalistic designs use it a lot, because they are often based on illustrations and drawings.
The old style of designing websites included shapes too, so they remained popular throughout the time and will probably continue being like that. Like lines, shapes are also associated by the human mind with different movements. For example, circles are associated with movement and nature, while squares are often seen as structured, basic designs. Just like with the lines, the color, style, background or texture of a shape can totally change the viewer’s perception.