* {
    padding: 0;
    margin: 0 auto;
}

header {
    text-align: center;     
    font-family: monospace;    
    font-weight: bold;        
    line-height: 300%;            
    font-size: 14px;
    padding: 20px;
    margin: 20px auto;
    background-color: #ccc;   
    border: 1px solid #000;       
    width: 800px;    
    box-shadow: 0 0 15px #888;    
        -moz-box-shadow: 0 0 15px #888;                             
        -webkit-box-shadow: 0 0 15px#888;
}

button {         
    width: 100px;            
    border: 1px solid #000;
}

a {
    text-decoration: none;
    color: #0000EE;
}

a:hover {
    color: #990000;
}

.resaltar {             
    color: white;
}

.visible {
    display: inline;
}

.invisible {
    display: none;
}

#valorResultado {
    background-color: #EEE;            
    border: 1px dashed #000;
    font-size: 18px;
    padding: 6px;
    display: inline;
}