In truth using hidden divs is quite common and there's nothing wrong with it when done to improve the user experience or when used as an integral part of the page.
In general, there are a few things to be wary of.
- Do not hide text without good reason.
- Do not make the font colour the same as your background colour.
- Hidden or not, do not position a hidden div offscreen (outside browser dimensions) where it can't and won't ever be seen.
These things set off flags that usually result in a site being inspected and evaluated by a human reviewer.
Essentially, what matters to the reviewer is the intent behind using hidden text or divs. If the reviewer can plainly see that the hidden text or div is being used as a subversive method to game the search engine, they'll penalize the site.
Consider the following scenario:
HTML Code:
<style>
#myhiddendiv {
background-color:#fff;
color:#fff;
width:400px;
margin-left:-2000px;
display:none;
}
</style>
<div id="myhiddendiv">this is my hidden div with some invisible text.</div>
The intent here would be so blatantly obvious that a human review would get this site penalized or removed from the index entirely.