display one entry centered vertically

[pixellated]

hi! here's what i'm trying to achieve: i want my journal's main page to display one entry (the most recent one), and i want that entry to be vertically centered, so that the distance from the top of the entry to the navstrip is the same as the distance from the bottom of the entry to the bottom of the page. here is a quick mockup of what i have in mind:


click here for fullsize
i've tried using margin: auto for this, but it didn't work; googling around leads me to believe that that's because the entry container is an inline element and thus doesn't have a specified height, which you need for that to work. i thought about using a flexbox inside the entry with three elements arranged in a column, with the middle element holding the actual contents of the entry and the top and bottom elements growing/shrinking to provide padding, to achieve something visually similar, but i don't think that would work either for the same reason (no specified height).

is there any way to do this? the theme i'm currently using is blanket, but i'm not married to it, so if there is a different theme that allows me to do this, i will happily switch.

thank you!