kbd { 
    width: 30px;
    display: inline-block;
    text-align: center;
}
box { 
    width: 48px;
    display: inline-block;
}
mbox { 
    width: 52px;
    display: inline-block;
}
left-space{ 
    width: 168px;
    display: inline-block;
}
mid{ 
    width: 4px;
    display: inline-block;
}