JSFiddle - React, Tailwind, and code Playground

HTML

<button>
    <span>
        Sign in --
    </span>
</button>

CSS

button {
    border:0;
    padding:3px;
    background:#735544;
    background-image: -webkit-gradient(
        linear,
        left bottom,
        left top,
        color-stop(0.18, #271D1B),
        color-stop(0.59, #735544)
        );
    background-image: -moz-linear-gradient(
        center bottom,
        #271D1B 18%,
        #735544 59%
        );
    border-radius:8px;
    -moz-border-radius:8px;
    -webkit-border-radius:8px;   
}


button span {
    display:block;
    color:#fff;
    font:900 18px arial;
    text-transform:uppercase;
    padding:.35em 1.3em;
    background:#382B25;
    background-image: -webkit-gradient(
        linear,
        left bottom,
        left top,
        color-stop(0.18, #382B25),
        color-stop(0.59, #C2A489)
        );
    background-image: -moz-linear-gradient(
        center bottom,
        #382B25 18%,
        #C2A489 59%
        );   
    border-radius:400px;
    -moz-border-radius:4px;
    -webkit-border-radius:4px;   
}


body{
    background:#530804;   
}