From Documentation
Firebug is a plugin for Firefox. You can use it to inspect how a ZK component is rendered into html, and what CSS is applying. For example, the following zul
<textbox/>
When you open firebug, and inspect the textbox
You can see the box is rendered to html as:
<input id="z_3r_1" class="z-textbox" type="text" z.mcls="z-textbox" z.type="zul.vd.Txbox"/>
And its relevant CSS part is:
.z-textbox, .z-decimalbox, .z-intbox, .z-longbox, .z-doublebox {normmoz.css.dsp (line 1)
background:#FFFFFF url(/zksTest/zkau/web/zul/img/grid/text-bg.gif) repeat-x scroll 0 0;
border:1px solid #7F9DB9;
font-family:Verdana,Tahoma,Arial,Helvetica,sans-serif;
font-size:12px;
font-weight:normal;
}
You can modify it to see the effect.