Create CSS Semi-Circles

Question

I have a filled circle that contains a number like so:

How would I go about splitting this into two semi-circles, so that I can store two different numbers within it, like so:

My CSS is as follows:

.oval {
    display: inline-block;
    width: 75px;
    height: 75px;
    border-radius: 50%;
    background: #000000;
    color: white;
    line-height: 75px;
    font-size: medium;
}

Answer 1

You can use border-radius

.left-half,
.right-half {
  float: left;
  width: 40px;
  height: 80px;
  line-height: 80px;
  color: white;
  text-align: center;
  margin: 0 1px;
  background: black;
}
.left-half:nth-child(1) {
  border-radius: 80px 0 0 80px;
}
.right-half:nth-child(2) {
  border-radius: 0 80px 80px 0;
}

<div class="circle">
  <div class="left-half">21</div>
  <div class="right-half">12</div>
</div>

Or you can use SVG

.text {
  font-size: 16px;
  fill: white;
}

<svg width="105.5px" height="97.874px" viewBox="0 0 105.5 97.874">
  <path d="M50.423,0.609v96.76c-26.72,0-48.38-21.66-48.38-48.38C2.043,22.269,23.703,0.609,50.423,0.609z" />
  <path d="M103.526,49.494c0,26.72-21.66,48.38-48.38,48.38V1.114C81.866,1.114,103.526,22.774,103.526,49.494z" />
  <text transform="matrix(1 0 0 1 20.0771 52.5107)" class="text">21</text>
  <text transform="matrix(1 0 0 1 73.1807 53.0166)" class="text">12</text>
</svg>

---

Update: You could also just create circle with two spans inside and add one line in middle with pseudo-class

.circle {
  width: 70px;
  height: 70px;
  background: black;
  border-radius: 50%;
  display: flex;
  align-items: center;
  color: white;
  position: relative;
}
span {
  flex: 1;
  text-align: center;
}
.circle:before {
  content: "";
  width: 2px;
  position: absolute;
  height: 100%;
  background: white;
  top: 0;
  left: 50%;
  transform: translateX(-50%);
}

<div class="circle">
  <span>12</span><span>24</span>
</div>

Answer 2

You only need to add a line in the middle (either using a pseudo-element or using a gradient like in the below snippet) and then place the content inside it using two span elements.

.oval {
  display: inline-block;
  width: 75px;
  height: 75px;
  border-radius: 50%;
  background: #000000;
  color: white;
  line-height: 75px;
  font-size: medium;
  background-image: linear-gradient(to right, transparent calc(50% - 1px), white calc(50% - 1px), white calc(50% + 1px), transparent calc(50% + 1px));
}
span {
  float: left;
  width: 50%;
  line-height: 75px;
  text-align: center;
}

<div class='oval'>
  <span>21</span>
  <span>12</span>
</div>

---

Or you can do it like in the below snippet where the semi-circles are created using a pseudo-element.

.oval {
  position: relative;
  float: left;
  width: 37.5px;
  height: 75px;
  color: white;
  line-height: 75px;
  font-size: medium;
  text-align: center;
  margin: 1px;
  overflow: hidden;
}
.oval:before {
  position: absolute;
  content: '';
  height: 100%;
  width: 200%;
  top: 0px;
  border-radius: 50%;
  background: black;
  z-index: -1;
}
.oval:nth-of-type(1):before {
  left: 0px;
}
.oval:nth-of-type(2):before {
  right: 0px;
}

<div class='oval'>
  21
</div>
<div class='oval'>
  12
</div>

---

Or you can even use radial-gradient background. This is just another method (for fun) and I don't really recommend this option.

.oval {
  float: left;
  width: 37.5px;
  height: 75px;
  color: white;
  line-height: 75px;
  font-size: medium;
  text-align: center;
  margin: 1px;
}
div:nth-of-type(1) {
  background: radial-gradient(circle closest-corner at center right, black 97.5%, transparent 100%);
}
div:nth-of-type(2) {
  background: radial-gradient(circle closest-corner at center left, black 97.5%, transparent 100%);
}

<div class='oval'>21</div>
<div class='oval'>12</div>