Half circle with CSS (border, outline only)

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

...with only one div:

<div class="myCircle"></div>

and by using only CSS definitions. No SVG, WebGL, DirectX, [...] allowed.

I've tried to draw a full circle and fading half of it with another div, and it does work, but I'm looking for a more elegant alternative.

You could use border-top-left-radius and border-top-right-radius properties to round the corners on the box according to the box's height (and added borders).

Then add a border to top/right/left sides of the box to achieve the effect.

Here you go:

.half-circle {
    width: 200px;
    height: 100px; /* as the half of the width */
    background-color: gold;
    border-top-left-radius: 110px;  /* 100px of height + 10px of border */
    border-top-right-radius: 110px; /* 100px of height + 10px of border */
    border: 10px solid gray;
    border-bottom: 0;
}

WORKING DEMO.

Alternatively, you could add box-sizing: border-box to the box in order to calculate the width/height of the box including borders and padding.

.half-circle {
    width: 200px;
    height: 100px; /* as the half of the width */
    border-top-left-radius: 100px;
    border-top-right-radius: 100px;
    border: 10px solid gray;
    border-bottom: 0;
    
    -webkit-box-sizing: border-box;
    -moz-box-sizing: border-box;
    box-sizing: border-box;
}

UPDATED DEMO. (Demo without background color)

I had a similar issue not long time ago and this was how I solved it

.rotated-half-circle {
  /* Create the circle */
  width: 40px;
  height: 40px;
  border: 10px solid black;
  border-radius: 50%;
  /* Halve the circle */
  border-bottom-color: transparent;
  border-left-color: transparent;
  /* Rotate the circle */
  transform: rotate(-45deg);
}

<div class="rotated-half-circle"></div>

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; }

I use a percentage method to achieve

        border: 3px solid rgb(1, 1, 1);
        border-top-left-radius: 100% 200%;
        border-top-right-radius: 100% 200%;

try this:

.top {
  height: 30px;
  width: 30px * 2;
  border-top-left-radius: 30px * 2;
  border-top-right-radius: 30px * 2;
}

 <div class="top"></div>