different style for continuous css class

Question

I'm trying to have different css styles for a div that has same css class in a row and different for a single div for the same class.

Here's what I'm trying to achieve if the explanation is confusing.

.row {
  display: flex;
  margin: 20px;
}

.number {
  width: 32px;
  height: 32px;
  display: flex;
  justify-content: center;
  align-items: center;
}

.number.bg {
  background-color: #e24381;
  color: #ffffff;
  border-radius: 24px 0 0 24px;
}

.number.bg ~ .number.bg {
  border-radius: 0 24px 24px 0;
}

<div class="row">
  <div class="number">1</div>
  <div class="number bg">2</div>
  <div class="number bg">3</div>
  <div class="number bg">4</div>
  <div class="number">5</div>
  <div class="number">6</div>
  <div class="number bg">7</div>
</div>

This should be the output:

Can it be done by CSS only or does it require JavaScript too?

Answer 1

For a vanilla CSS solution, you can use a pseudo element to do this for you:

• set border-radius: 25px to the bg element,

• fill the border gaps in successive bg elements using a pseudo element that is positioned absolutely and stacked behind the bg elements, and shifted using a negative margin.

See demo below:

.row {
  display: flex;
  margin: 20px;
}

.number {
  width: 32px;
  height: 32px;
  display: flex;
  justify-content: center;
  align-items: center;
}

.number.bg {
  background-color: #e24381;
  color: #ffffff;
  border-radius: 25px;
  position: relative;
}

.number.bg+.bg:before {
  content: '';
  display: block;
  background-color: #e24381;
  margin-left: -50%;
  left: 0;
  top: 0;
  width: 100%;
  height: 100%;
  z-index: -1;
  position: absolute;
}

<div class="row">
  <div class="number">1</div>
  <div class="number bg">2</div>
  <div class="number bg">3</div>
  <div class="number bg">4</div>
  <div class="number">5</div>
  <div class="number">6</div>
  <div class="number bg">7</div>
</div>