#tabla_teachers td:nth-child(2),#tabla_teachers td:nth-child(4),#tabla_teachers td:nth-child(6),#tabla_teachers td:nth-child(8),#tabla_teachers td:nth-child(10),#tabla_teachers td:nth-child(12),#tabla_teachers td:nth-child(14),#tabla_teachers td:nth-child(16),#tabla_teachers td:nth-child(18),#tabla_teachers td:nth-child(20),#tabla_teachers td:nth-child(22),#tabla_teachers td:nth-child(24),#tabla_teachers td:nth-child(26),#tabla_teachers td:nth-child(28),#tabla_teachers td:nth-child(30),#tabla_teachers td:nth-child(32),#tabla_teachers td:nth-child(34),#tabla_teachers td:nth-child(36){background-color:#e8e8e8!important}