.myTable table>thead .slds-cell-fixed.slds-has-button-menu, .myTable table>thead .slds-cell-fixed.slds-has-button-menu:hover{
    background: #EEEE00;
}
.conTable td,th{
    border: 1px dashed #D4D4D4;
}
.conTable tr{
    border: 1px dashed #D4D4D4;
}