Lediglich ein Experiment ...

html, body {padding: 0; margin: 0; overflow:auto; 
color:#fff;/*SEITE_SCHRIFT_FARBE*/background-color:#223;
min-width: 100%; width: 100%;min-height:100%; height:100%; 
}
.center_top {position:absolute;top:0;left:50%;margin-right:-50%;transform: translate(-50%,0);}

.menu_padding_left{display:inline-block;margin-left:0em;}
.menu_padding_right{display:inline-block;margin-right:10em;}
a.a {text-decoration:none;font:normal 1.5em/1.6em Verdana,Tahoma,Geneva, sans-serif;
     margin:0 0.2em;padding:0.1em 0.2em;border-bottom:none; color:#ffd98e; }
a.a:hover {border-bottom:0.3em ridge #fff; }