Yahoo YUI developer explains how to absorb gap between various browsers. They recommend to include this css in beginning of your css first.

Click here to get Yahoo YUI website.

body,div,dl,dt,dd,ul,ol,li,h1,h2,h3,h4,h5,h6,pre,form,fieldset,input,textarea,p,blockquote,th,td { 
 margin:0;
 padding:0;
}
table {
 border-collapse:collapse;
 border-spacing:0;
}
fieldset,img { 
 border:0;
}
address,caption,cite,code,dfn,em,strong,th,var {
 font-style:normal;
 font-weight:normal;
}
ol,ul {
 list-style:none;
}
caption,th {
 text-align:left;
}
h1,h2,h3,h4,h5,h6 {
 font-size:100%;
 font-weight:normal;
}
q:before,q:after {
 content:'';
}
abbr,acronym { border:0;
}