When a CSS propriety is specified twice, the browser will commonly use the last one. Let’s see an example:

#main {
width:600px;
width:800px;
}
In this example the browser will assign width 800 pixels to the #main element.
The declaration !important can be used in cascading style sheets to give priority to some parameters.

#main {
width:600px !important;
width:800px;
}
In the example above the browser [...]