JSFiddle - React, Tailwind, and code Playground

HTML

<ul>
    <li class="menu__item"><a href="#">Главная</a></li>
    <li class="menu__item"><a href="#">Тех. Поддержка</a></li>
    <li class="menu__item"><a href="#">Контакты</a></li>
</ul>

CSS

ul {
  list-style:none;
}

.menu__item {
  float:left;
  
}

.menu__item:hover {}

.menu__item:last-child {
  margin:0;
}

ul li a {
  color:#000;
  font-family:ChevinPro-Medium;
  font-size:140%;
  line-height:48px;
  text-decoration:none;
  text-transform:uppercase;
  position: relative;
  margin-right:30px;
  border-bottom:16px solid #75b815;
  display: block;
}

ul li a:hover {
  font-weight:700;
  margin-right: 27px;
}