JSFiddle - React, Tailwind, and code Playground

by Michael Danilov

HTML

<div class="btn__wrap">
    <div class="btn btn_corner">Кнопка</div>
</div>

CSS

.btn__wrap {
    height: 32px;
    margin-left: 100px;
    margin-top: 100px;
    position: relative;
    overflow: hidden;
    width: 120px;
}
.btn_corner {
    border-color: #000 transparent;
    border-width: 1px;
    border-style: solid;
    display: block;
    height: 30px;
    line-height: 29px;
    text-align: center;
    width: 80px;
    margin-left: 15px;
}
.btn_corner:before {
    border-color: rgba(0, 0, 0, 0) rgba(0, 0, 0, 0) #000000 #000000;
    border-style: solid;
    border-width: 1px;
    content: " ";
    display: block;
    font-size: 0;
    height: 21px;
    left: 0;
    margin-left: 16px;
    position: absolute;
    top: 0;
    -webkit-transform: rotate(45deg);
    -moz-transform: rotate(45deg);
    -ms-transform: rotate(45deg);
    -o-transform: rotate(45deg);
    transform: rotate(45deg);
    -webkit-transform-origin: 0 0 0;
    -moz-transform-origin: 0 0 0;
    -ms-transform-origin: 0 0;
    -o-transform-origin: 0 0;
    transform-origin: 0 0 0;
    width: 21px;
}
.btn_corner:after {
    border-color: #000000 #000000 rgba(0, 0, 0, 0) rgba(0, 0, 0, 0);
    border-style: solid;
    border-width: 1px;
    content: " ";
    display: block;
    font-size: 0;
    height: 21px;
    margin: 0;
    position: absolute;
    right: 0;
    top: 0;
    -webkit-transform: rotate(45deg);
    -moz-transform: rotate(45deg);
    -ms-transform: rotate(45deg);
    -o-transform: rotate(45deg);
    transform: rotate(45deg);
    -webkit-transform-origin: 0 0 0;
    -moz-transform-origin: 0 0 0;
    -ms-transform-origin: 0 0;
    -o-transform-origin: 0 0;
    transform-origin: 0 0 0;
    width: 21px;
}

.btn__wrap:hover .btn_corner:before {
    border-color: rgba(0, 0, 0, 0) rgba(0, 0, 0, 0) #f00 #f00;
}
.btn__wrap:hover .btn_corner:after {
    border-color: #f00 #f00 rgba(0, 0, 0, 0) rgba(0, 0, 0, 0);
}
.btn__wrap:hover .btn_corner {
    border-color: #f00 transparent;
    color: #f00;
}