JSFiddle - React, Tailwind, and code Playground

HTML

<ul class='tabs'>
<li >MENÜ 1</li>
<li class='active'>MENÜ 2</li>
<li>MENÜ 3</li>
<li>MENÜ 4</li></ul>

CSS

ul.tabs {
    width: 100%;
    float: left;
    border-bottom: 5px solid #000;
    background: url('logolar/passive.png') bottom repeat-x;
    text-align: center;
}

ul.tabs li {
    float: left;
    background: url('logolar/passive.png') white bottom repeat-x;
    width: 90px;
    height: 38px;
    line-height: 4;
    cursor: pointer;
    color: #000;
}

ul.tabs li.active {
    background: url('') #000;
    line-height: 3;
    border-top-left-radius: 15px;
    border-top-right-radius: 15px;
    margin-top: -1px;
    width: 138px;
    height: 39px;
    color: #fff;
    text-shadow: 1px 1px 2px rgba(0, 0, 0, .1);
}

ul.tabs .active {
    border: 1px solid #000;
    border-bottom: 0;
    width: 80px;
    height: 39px;
    position: relative;
    -moz-border-radius: 5px 5px 0 0;
    -webkit-border-radius: 5px 5px 0 -20px;
}

ul.tabs .active:after, ul.tabs  .active:before {
    content: '';
    width: 20px;
    height: 30px;
    border: 2px solid #000;
    position: absolute;
    bottom: -3px;
    border-top: 0;
    -webkit-box-shadow: -10px 0px 0px rgba(0, 0, 0, 1);
    -moz-box-shadow:    -10px 0px 0px rgba(0, 0, 0, 1);
    box-shadow:         -10px 0px 0px rgba(0, 0, 0, 1);
    border: none;
}

ul.tabs .active:after {
    border-left: 0;
    -moz-border-radius: 0 0 25px 0;
    -webkit-border-radius: 0 0 25px 0;
    left: -21px;
    -webkit-box-shadow: 10px 0px 0px rgba(0, 0, 0, 1);
    -moz-box-shadow:    10px 0px 0px rgba(0, 0, 0, 1);
    box-shadow:         10px 0px 0px rgba(0, 0, 0, 1);
}

ul.tabs .active:before {
    border-right: 0;
    -moz-border-radius: 0 0 0 25px;
    -webkit-border-radius: 0 0 0 25px;
    right: -21px;
}