.tb_rltb_negro {
border-right: 1px solid #000000;  
border-left: 1px solid #000000;
border-top: 1px solid #000000;
border-bottom: 1px solid #000000;
}

.tb_r_negro { border-right: 1px solid #000000
}
.tb_l_negro { border-left: 1px solid #000000
}
.tb_t_negro { 
font-family: Verdana, Arial, Helvetica, sans-serif;
font-size: 10px;
border-top: 1px solid #000000

}
.tb_b_negro { border-bottom: 1px solid #000000
}

.tb_rl_negro { 
border-right: 1px solid #000000;
border-left: 1px solid #000000
}

.tb_rt_negro { 
border-right: 1px solid #000000;
border-top: 1px solid #000000
}

.tb_rb_negro { 
border-right: 1px solid #000000;
border-bottom: 1px solid #000000
}

.tb_lt_negro { 
border-left: 1px solid #000000;
border-top: 1px solid #000000
}

.tb_lb_negro { 
border-left: 1px solid #000000;
border-bottom: 1px solid #000000
}

.tb_tb_negro { 
border-top: 1px solid #000000;
border-bottom: 1px solid #000000
}

.tb_t_gris { 
border-top: 1px solid #CCCCCC

}