.bus{
     width:250px;text-align:center; margin: 0 auto;
}
.bus button{
     width:22%; float:left;  display:block; font-size:1.3em; border:dotted 1px black; margin:1%; height: 30px;
}
.busy{
     width:22%; float:left; font-size:1.3em; color:white; border:dotted 1px black; background-color:red; margin:1%; height: 30px;
}
.reserve{
    width:22%; float:left; font-size:1.3em; color:white; border:dotted 1px black; background-color:green; margin:1%;  height: 30px;
}