<a class="bn48" href="/">Button</a>
.bn48 {
background: linear-gradient(90deg, #1e39a5, #c50e07);
background-size: auto;
background-clip: border-box;
-webkit-background-clip: text;
background-clip: text;
background-size: 300% 300%;
-webkit-text-fill-color: transparent;
}