you have 1 div that uses position:absolute;
and another that uses position:relative;
when css calculates the stacking order, it first looks at position.
absolute is stacked on top of relative, within the absolute stack, it looks at the z-index and within the relative stack it looks at z-index.
you could set the z-index in the relative stack to 1000, but it will still be below a div in the absolute stack with a z-index of 1.
add the link to a absolute z-index div or set the z-index for the absolute div to -1