<button id="new-tab" title="New Tab">
<img src="assets/images/ui/plus.svg" title="New Tab">
</button>
button {
width: 30px;
height: 30px;
text-align: center;
align-items: center;
justify-content: center;
}
button {
width: 30px;
height: 30px;
display: flex;
align-items: center;
justify-content: center;
}