Half circle with CSS (border, outline only)

Question

I\'m trying to create a circle with CSS, which looks exactly like on the following picture:

Answer 1

Below is a minimal code to achieve the effect.

This also works responsively since the border-radius is in percentage.

.semi-circle{
width: 200px;
height: 100px;
border-radius: 50% 50% 0 0 / 100% 100% 0 0;
border: 10px solid #000;
border-bottom: 0;
}