HTL conditional in styling

<div style="${properties.position == 'bottom'? 'bottom: ${properties.HeightValue}' : ': unset' @ context='styleString'}">

hello guys, I'm trying to add a condition inside of my AEM's inline style code, both values are existing. I can only see the first condition, ${properties.position == 'bottom' worked, but ${properties.HeightValue} is showing as string.

ON DOM, it's showing like this below: <div style="bottom: ${properties.HeightValue}">

I tried some other method like but still did not work, wonder if you guys do know how to work this around. thank you!