Untitled

<section>

  <div>div1</div>

  <div>div2</div>

  <div>div3</div>

</section>

section {

  display: flex;

}

section div {

  flex: 1;

}

section {

  background-color: aqua;

  padding: 2px 5px;

  width: 960px;

}

section div {

  background-color: white;

  margin-right: 10px;

  min-width: 100px;

}