I need assistance with emergency landing

The parent div's background-color is not working ,and I cannot find out the issue why. But it shows up when I put the rest of the children div in comment. Here is the css code.

*{margin:0%;}  

/spacing and neatiness/ body{background-color:blue;}

#head{background-color:orange;
   height:20%;
   width:100%;
   position:relative;}

#menu{position:absolute;
    top:0%;
    left:70%;}

 #menu1{position:absolute;
     top:0%;
     left:0%;}

 li{list-style-type:none;
 border:5px outset gray;
 float:left;
 margin:5px;
 border-radius:10px;
 width:100px;
 background-color:#00ff00;
 text-align:center;}

 a{text-decoration:none;
display:block;}

  a:hover{border:5px inset gray;
      background-color:gray;}

  a:visited{border:none;
        background-color:blue;
        color:white;}

Thanks