I love the look of a sheer top over a button-down; it's one of my favorite ways to layer in the summer months without adding too much bulk. And as I've mentioned before, sheer garments add sexiness to an outfit even when they're only revealing areas that don't need to be covered anyway.
In this outfit, the sheer top is completely superfluous from a coverage point of view, and yet it brings a softness to the structured button-down and gives it a playful, lingerie sort of look. This is a great way to add a feminine touch to a even a conservative, corporate-worthy outfit. For more examples of sheer tops layered over button-downs, check out this post and this one.
Sheer top, belt: Red Dress Shoppe