尝试最多包含5个项目且只有3个项目的flexbox导航，但它并未在所有元素之间平均分配宽度。

* {

  font-size: 16px;

}



.tabs {

  max-width: 1010px;

  width: 100%;

  height: 5rem;

  border-bottom: solid 1px grey;

  margin: 0 0 0 6.5rem;

  display: table;

  table-layout: fixed;

}

.tabs ul {

  margin: 0;

  display: flex;

  flex-direction: row;

}

.tabs ul li {

  flex-grow: 1;

  list-style: none;

  text-align: center;

  font-size: 1.313rem;

  background: blue;

  color: white;

  height: inherit;

  left: auto;

  vertical-align: top;

  text-align: left;

  padding: 20px 20px 20px 70px;

  border-top-left-radius: 20px;

  border: solid 1px blue;

  cursor: pointer;

}

.tabs ul li.active {

  background: white;

  color: blue;

}

.tabs ul li:before {

  content: "";

}


<div class="tabs">

  <ul>

    <li class="active" data-tab="1">Pizza</li>

    <li data-tab="2">Chicken Noodle Soup</li>

    <li data-tab="3">Peanut Butter</li>

    <li data-tab="4">Fish</li>

  </ul>

</div>