<button class="button">
<div class="button__line button__line--first"></div>
<div class="button__line button__line--second"></div>
</button>
.button {
background-color: transparent;
border-color: transparent;
cursor: pointer;
height: 32px;
width: 32px;
position: relative;
}
.button__line {
background-color: rgba(0, 0, 0, 0.3);
position: absolute;
height: 1px;
width: 100%;
}
.button__line--first {
left: 0px;
top: 50%;
transform: translate(0%, -50%) rotate(45deg);
height: 1px;
width: 100%;
}
.button__line--second {
left: 50%;
top: 0px;
transform: translate(-50%, 0%) rotate(45deg);
height: 100%;
width: 1px;
}