.tab1 {
width:350px;
}

.case_a {
width:100px;
float:left;
}

.case_b {
width:156px;
float:left;
}

.case_c {
width:94px;
float:left;
}

.case_d {
width:20px;
float:left;
}

.case_e {
width:179px;
float:left;
}