.tb1 {  border-color: black #737373; border-style: solid; border-top-width: 0px; border-right-width: 1px; border-bottom-width: 1px; border-left-width: 1px}
.tb2 {  border-color: #737373; border-style: solid; border-top-width: 1px; border-right-width: 0px; border-bottom-width: 1px; border-left-width: 0px}
.tb3 {  border-color: #737373; border-style: solid; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 1px; border-left-width: 0px}