/* This is the global reset to allow fresh styling for each build.
-----------------------------------------------------------------------------*/
html, body, div, span, applet, object, iframe,
h1, h2, h3, h4, h5, h6, p, blockquote, pre,
a, abbr, acronym, address, big, cite, code,
del, dfn, em, font, img, ins, kbd, q, s, samp,
small, strike, strong, sub, sup, tt, var,
b, u, i, center,
dl, dt, dd, ol, ul, li,
fieldset, form, label, legend,
table, caption, tbody, tfoot, thead, tr, th, td,
.contentpaneopen, .contentheading {
    margin: 0;
    padding: 0;
    border: 0;
    outline: 0;
    font-size: 100%;
    outline:none;
    line-height:normal;
    vertical-align:top;
}

Custom css reset with elements added for Joomla! development - just includes the .contentpaneopen and .contentheading on top of standard CSS.  You may need to add border:none; depending on project - YMMV.

Global CSS Reset for Joomla

CSS