Margin-top и проценты

/* [url]http://meyerweb.com/eric/tools/css/reset/[/url] 
   v2.0 | 20110126
   License: none (public domain)
*/
 
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, 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,
article, aside, canvas, details, embed, 
figure, figcaption, footer, header, hgroup, 
menu, nav, output, ruby, section, summary,
time, mark, audio, video {
    margin: 0;
    padding: 0;
    border: 0;
    font-size: 100%;
    font: inherit;
    vertical-align: baseline;
}
/* HTML5 display-role reset for older browsers */
article, aside, details, figcaption, figure, 
footer, header, hgroup, menu, nav, section {
    display: block;
}
body {
    line-height: 1;
}
ol, ul {
    list-style: none;
}
blockquote, q {
    quotes: none;
}
blockquote:before, blockquote:after,
q:before, q:after {
    content: '';
    content: none;
}
table {
    border-collapse: collapse;
    border-spacing: 0;
}
 
/*===============CSS===============*/
 
#page
{
    width: 100%;
    height: 100%;
    position: fixed;
}
 
#navigation
{
    float:left;
    width: 20%;
    height: 100%;
    background: rgba(255, 205, 0, 0.75);
    margin-left: 5%;
}
 
#content
{    
    background: rgba(255, 205, 0, 0.75);
    height: 100px;
    width: 65%;
    height: 70%;
    margin-top: 15%;
    margin-left: 30%;
}