JSFiddle - React, Tailwind, and code Playground

HTML

<div class="menu">
    <a>текст</a><a>текст</a><a>текст</a>
    <div class="menu-bottom"></div>
</div>

CSS

.menu{
    position:relative;
    border-bottom:1px solid #bbb;
    margin-bottom:5px;
}
.menu>a{
    display:inline-block;
    position:relative;
    padding:10px;
    border-right:1px solid #bbb;
    cursor:pointer;
}
.menu>a:after{
    content:'';
    position:absolute;
    left:1px;
    bottom:-5px;
    right:-3px;
    height:5px;
    border-left:1px solid #bbb;
    border-right:1px solid #bbb;
    -moz-transform:skewX(45deg);
    -ms-transform:skewX(45deg);
    -webkit-transform:skewX(45deg);
    -o-transform:skewX(45deg);
    transform:skewX(45deg);
}
.menu>a:first-child{
    margin-left:100px;
    border-left:1px solid #bbb;
}
.menu-bottom{
    position:absolute;
    bottom:-5px;
    width:100%;
    height:5px;
    border-bottom:1px solid #bbb;
}