JSFiddle - React, Tailwind, and code Playground

HTML

<div class="top_menu">
  <ul class="menu">
    <li>Понятие</li>
    <li>Описание</li>
    <li>Ссылки</li>
  </ul>
</div>

CSS

body {
  margin:0;
  padding:0;
}

.top_menu {
  background:#3eabf6;
  min-height:20px;
  text-align:center;
}

.menu {
  margin:0;
  padding:0;
  list-style:none;
  font-size:0px;
  display:inline;
}

.menu li {
  display:inline-block;
  font-size:14px;
  font-family:sans-serif;
  background-color:#fff;
  background-image:linear-gradient(-45deg, #3eabf6 20%,#fff 20%,  #fff 80%, #3eabf6 80%);
  padding:5px 50px;
  color:#3eabf6;
}