Is it possible that the header (circled in blue) also feels like it is "behind" the black transparent screen? I.e the only thing in the foreground should be the buttons.
To make it really visually clear, we would like to make sure the visual hierarchy places the buttons as the foremost objects. To that end:
a) can we increase the size of the white button so the width aligns with the left of the "previous" button and the right of the "next" button;
b) can the text be bigger so that it is larger than the header text and previous/next texts;
c) can we try to make them feel more clickable by adding a very small drop shadow?