Button Set 1 (ala github)

by gk

HTML

<button class="login" data-disable-invalid="" data-disable-with="" tabindex="2" type="submit">Login</button>
<button class="add-post" data-disable-invalid="" data-disable-with="" tabindex="2" type="submit">Submit</button>
<button class="update" data-disable-invalid="" data-disable-with="" tabindex="2" type="submit">Update</button>
<button class="xtra" data-disable-invalid="" data-disable-with="" tabindex="2" type="submit">xtra</button>

CSS

/*  buttons
----------------------------------------------------------------------*/

/*  login  */
 .login {
    position: relative;
    display: inline-block;
    font-size: 13px;
    font-weight: bold;
    line-height: 20px;
    color: rgb(51, 51, 51);
    cursor: pointer;
    background-color: rgb(238, 238, 238);
    background-image: linear-gradient(rgb(252, 252, 252), rgb(238, 238, 238));
    white-space: nowrap;
    vertical-align: middle;
    -moz-user-select: none;
    padding: 6px 12px;
    border-radius: 3px 3px 3px 3px;
    border: 1px solid rgb(213, 213, 213);
}
.login:hover {
    text-decoration:none;
    background-color:#ddd;
    background-image:-webkit-linear-gradient(#eee, #ddd);
    background-image:linear-gradient(#eee, #ddd);
    border-color:#ccc
}
/*  add post  */
 .add-post {
    color: rgb(255, 255, 255);
    text-shadow: 0px -1px 0px rgba(0, 0, 0, 0.15);
    background-color: rgb(96, 176, 68);
    background-image: -webkit-gradient(linear, 0 0, 0 100%, from(rgb(138, 221, 109)), to(rgb(96, 176, 68)));
    background-image: -webkit-linear-gradient(rgb(138, 221, 109), rgb(96, 176, 68));
    background-image: -moz-linear-gradient(rgb(138, 221, 109), rgb(96, 176, 68));
    background-image: -o-linear-gradient(rgb(138, 221, 109), rgb(96, 176, 68));
    background-image: linear-gradient(rgb(138, 221, 109), rgb(96, 176, 68));
    border: 1px solid rgb(213, 213, 213);
    border-radius: 3px 3px 3px 3px;
    position: relative;
    display: inline-block;
    padding: 6px 12px;
    font-size: 13px;
    font-weight: bold;
    line-height: 20px;
    white-space: nowrap;
    vertical-align: middle;
    cursor: pointer;
}
.add-post:hover {
    color:#fff;
    background-color:#569e3d;
    background-image:-webkit-linear-gradient(#79d858, #569e3d);
    background-image:linear-gradient(#79d858, #569e3d);
    border-color:#4a993e
}
/*  update post  */
 .update {
    background-color: rgb(41, 127, 199);
    color: rgb(255, 255, 255);
    border-radius:...