How to make a doughnut segment using only CSS

Question

How to make this shape use only css

What I have tried:

.button-up {
  border-top: 100px solid red;
  border-left: 50px solid transparent;
  border-right: 50px solid transparent;
  border-top-left-radius: 50%;
  border-top-right-radius: 50%;
  border-bottom: 35px solid transparent;
  width: 200px;
}

<div class="button-up"></div>

Answer 1

I would go with some linear/radial-gradient like this:

.box {
  width:200px;
  height:200px;
  border-radius:50%;
  background:
   linear-gradient(-30deg, white 50%,transparent 50.5%),
   linear-gradient(30deg,  white 50%,transparent 50.5%),
   radial-gradient(farthest-side at center,transparent 40%,blue 41%);
}

<div class="box">

</div>

And with border:

.box {
  width:200px;
  height:200px;
  border-radius:50%;
  background:
   linear-gradient(to top,white 58.5%,transparent 60%),
   linear-gradient(-30deg, white calc(50% - 4px),green calc(50% - 4px) 50%,transparent 0),
   linear-gradient(30deg,  white calc(50% - 4px),green calc(50% - 4px) 50%,transparent 0),
   radial-gradient(farthest-side at center,
    transparent calc(42% - 5px),
    green calc(42% - 4px) 42%,
    blue 42% calc(100% - 4px),green calc(100% - 3px));
}

<div class="box">

</div>

You can also consider SVG which can be easier:

<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 64 64' width='300' height='300' fill='blue'>
  <path stroke="green" stroke-width=1 d='M24 32 C28 28 37 28 40 32 L52 22 C38 8 26 8 12 22 Z' />
</svg>

Here is another Idea with clip-path:

.box {
  width:200px;
  height:200px;
  border-radius:50%;
  background:
  radial-gradient(farthest-side at center,transparent 40%,blue 41%);
  clip-path: polygon(0 0,0 10%, 50% 50%, 100% 10%,100% 0);
}

<div class="box">

</div>

Related question: CSS Only Pie Chart - How to add spacing/padding between slices?

Answer 2

In case you prefer your border method more than SVG or gradients, here is an approach using just border-radius, the pseudo element ::after and some positioning:

.shape,
.shape::after {
  position: absolute;
  border-radius: 100%;
}

.shape {
  height: 200px;
  width: 200px;
  border: 100px solid transparent;
  border-top: 100px solid #375c89;
}

.shape::after {
  content: '';
  height: 190px;
  width: 198px;
  top: -95px;
  left: -89px;
  border: 90px solid transparent;
  border-top: 90px solid #4f81bc;
}

<div class="shape"></div>

How it works

You can create this shape in two steps.

Step 1: Create a doughnut segment using border-radius: 100% to give it a circle like shape. Then apply a color only to the top border and make the other borders transparent. This way you get a circle segment. Now give your element a width and a height greater than 0 to transform the circle into a doughnut.

Step 2: Apply the same styles to the pseudo element ::after but giving it a slightly less width,height and border width. Adjust the values for your needs. Now position both elements with position: absolute to adjust the position of the overlapping pseudo element to center it properly over the main element.

The good

• Better browser compatibility especially for older browsers than gradients, clip-path or SVG.
• The angle of the circular shape can simply be adjusted with height and width

The bad

• As the other parts of the border are still there (transparent) you need to adjust the size of the parent element according to the shape and set overflow: hidden;
• for changing the border width of the shape, you need to reposition the ::after element

---

You can as well use both pseudo elements ::before and ::after to create the shape and easily adjust the position with sizing and margin (thanks to Temani for pointing this out in the comments):

.shape {
  position: relative;
  width: 400px;
  height: 400px;
}

.shape::before,
.shape::after {
  content: '';
  position: absolute;
  border-radius: 100%;
  right: 0;
  left: 0;
  bottom: 0;
  top: 0;
}

.shape:before {
  border: 100px solid transparent;
  border-top-color: #375c89;
}

.shape::after {
  margin: 5px 12px;
  border: 90px solid transparent;
  border-top-color: #4f81bc;
  height: 45%;
}

<div class="shape"></div>