I love Twitter Bootstrap. The button classes are hugely convenient and the CSS3 animation is a great touch. Bootstrap comes with a few different default button colors you can implement by using the built in CSS classes.

[html]
//Default gray button
<button class="btn">Primary</button>
//Blue button
<button class="btn btn-primary">Primary</button>
//Orange button
<button class="btn btn-warning">Warning</button>
//Red button
<button class="btn btn-danger">Danger</button>
//Green button
<button class="btn btn-success">Success</button>
//Aqua button
<button class="btn btn-info">Info</button>
//Black button
<button class="btn btn-inverse">Inverse</button>
[/html]

All of the above have associated :hover, :active and .disabled styles as well. So let’s you want to add your own button in the color of your choice? Let’s take a look at the CSS (LESS) that makes these buttons. For the sake of brevity, lets look at the CSS needed for “.btn-primary”:

[css]
.btn {
display: inline-block;
*display: inline;
/* IE7 inline-block hack */

*zoom: 1;
padding: 4px 12px;
margin-bottom: 0;
font-size: 14px;
line-height: 20px;
text-align: center;
vertical-align: middle;
cursor: pointer;
color: #333333;
text-shadow: 0 1px 1px rgba(255, 255, 255, 0.75);
background-color: #f5f5f5;
background-image: -moz-linear-gradient(top, #ffffff, #e6e6e6);
background-image: -webkit-gradient(linear, 0 0, 0 100%, from(#ffffff), to(#e6e6e6));
background-image: -webkit-linear-gradient(top, #ffffff, #e6e6e6);
background-image: -o-linear-gradient(top, #ffffff, #e6e6e6);
background-image: linear-gradient(to bottom, #ffffff, #e6e6e6);
background-repeat: repeat-x;
filter: progid:DXImageTransform.Microsoft.gradient(startColorstr=’#ffffffff’, endColorstr=’#ffe6e6e6′, GradientType=0);
border-color: #e6e6e6 #e6e6e6 #bfbfbf;
border-color: rgba(0, 0, 0, 0.1) rgba(0, 0, 0, 0.1) rgba(0, 0, 0, 0.25);
*background-color: #e6e6e6;
/* Darken IE7 buttons by default so they stand out more given they won’t have borders */

filter: progid:DXImageTransform.Microsoft.gradient(enabled = false);
border: 1px solid #cccccc;
*border: 0;
border-bottom-color: #b3b3b3;
-webkit-border-radius: 4px;
-moz-border-radius: 4px;
border-radius: 4px;
*margin-left: .3em;
-webkit-box-shadow: inset 0 1px 0 rgba(255,255,255,.2), 0 1px 2px rgba(0,0,0,.05);
-moz-box-shadow: inset 0 1px 0 rgba(255,255,255,.2), 0 1px 2px rgba(0,0,0,.05);
box-shadow: inset 0 1px 0 rgba(255,255,255,.2), 0 1px 2px rgba(0,0,0,.05);
}
.btn:hover,
.btn:active,
.btn.active,
.btn.disabled,
.btn[disabled] {
color: #333333;
background-color: #e6e6e6;
*background-color: #d9d9d9;
}
.btn:active,
.btn.active {
background-color: #cccccc \9;
}
.btn:first-child {
*margin-left: 0;
}
.btn:hover {
color: #333333;
text-decoration: none;
background-position: 0 -15px;
-webkit-transition: background-position 0.1s linear;
-moz-transition: background-position 0.1s linear;
-o-transition: background-position 0.1s linear;
transition: background-position 0.1s linear;
}
.btn:focus {
outline: thin dotted #333;
outline: 5px auto -webkit-focus-ring-color;
outline-offset: -2px;
}
.btn.active,
.btn:active {
background-image: none;
outline: 0;
-webkit-box-shadow: inset 0 2px 4px rgba(0,0,0,.15), 0 1px 2px rgba(0,0,0,.05);
-moz-box-shadow: inset 0 2px 4px rgba(0,0,0,.15), 0 1px 2px rgba(0,0,0,.05);
box-shadow: inset 0 2px 4px rgba(0,0,0,.15), 0 1px 2px rgba(0,0,0,.05);
}
.btn.disabled,
.btn[disabled] {
cursor: default;
background-image: none;
opacity: 0.65;
filter: alpha(opacity=65);
-webkit-box-shadow: none;
-moz-box-shadow: none;
box-shadow: none;
}
.btn-primary.active,
.btn-warning.active,
.btn-danger.active,
.btn-success.active,
.btn-info.active,
.btn-inverse.active {
color: rgba(255, 255, 255, 0.75);
}
.btn-primary {
color: #ffffff;
text-shadow: 0 -1px 0 rgba(0, 0, 0, 0.25);
background-color: #006dcc;
background-image: -moz-linear-gradient(top, #0088cc, #0044cc);
background-image: -webkit-gradient(linear, 0 0, 0 100%, from(#0088cc), to(#0044cc));
background-image: -webkit-linear-gradient(top, #0088cc, #0044cc);
background-image: -o-linear-gradient(top, #0088cc, #0044cc);
background-image: linear-gradient(to bottom, #0088cc, #0044cc);
background-repeat: repeat-x;
filter: progid:DXImageTransform.Microsoft.gradient(startColorstr=’#ff0088cc’, endColorstr=’#ff0044cc’, GradientType=0);
border-color: #0044cc #0044cc #002a80;
border-color: rgba(0, 0, 0, 0.1) rgba(0, 0, 0, 0.1) rgba(0, 0, 0, 0.25);
*background-color: #0044cc;
/* Darken IE7 buttons by default so they stand out more given they won’t have borders */

filter: progid:DXImageTransform.Microsoft.gradient(enabled = false);
}
.btn-primary:hover,
.btn-primary:active,
.btn-primary.active,
.btn-primary.disabled,
.btn-primary[disabled] {
color: #ffffff;
background-color: #0044cc;
*background-color: #003bb3;
}
.btn-primary:active,
.btn-primary.active {
background-color: #003399 \9;
}
[/css]

Well, Hmmff. That’s a lot. No, not everything needs to be overwritten but it’s certainly a bit cumbersome working your way though all the declarations figuring out which ones to overwrite. here’s where LESS is hugely helpful.

[css]
.my-new-button {
.buttonBackground(@lighterColor, @darkerColor);
}
[/css]

Or as I like to do it:

[css]
.my-new-button {
.buttonBackground(lighten(@myColor, 10%), darken(@myColor, 10%));
}
[/css]