The default Google Analytics installation measures bounce rate as "the percentage of single-page visits or visits in which the person left your site from the entrance (landing) page."
Your 85% bounce rate isn't worrying to me because in my experience GA's default bounce rate measurement doesn't lead to actionable metrics. Many users find what they are looking for on the first page and leave satisfied. By default Google Analytics counts those users as bouncing.
Bounce rate should really tell you how many users leave quickly and unsatisfied. If people are spending 3-4 minutes on a page they really shouldn't count as a bounce.
Luckily you can send extra data to Google Analytics in the form of events to help determine what people are doing on the page. Google won't count users as bouncing if there are additional interaction events in their session, even if the users only visit the one page.
Unless you spend time implementing events, I wouldn't pay any attention to the GA bounce rate metric. Most sites have pages where a user can consume just one page and be satisfied. You can implement events for:
- Scroll depth (especially important for article pages)
- Time spent on page
- Video playback
- Loading AJAX content
- Typing something on the page
- Clicking on things in the page
Once you start implementing events, bounce rate becomes a much more interesting metric. At that point you can use it to judge other changes to your site. For example you will know if your new color scheme is good or bad by seeing how it changes your bounce rate.
You don't want to try to game bounce rate by making changes that hurt user experience. For example, it isn't helpful to divide an article between several pages so that users have to click to multiple pages to have to read the article. That technique was popular a few years ago, but it has fallen out of favor because it tends to make some users not come back even though the bounce rate stats may look better.
It is also worth noting that Google doesn't use Google Analytics data (including bounce rate) for determining how sites rank in their search results. Google may use "bounce back rate" where it observes users shortly coming back to the search results after trying your page. See Does a site's bounce rate influence Google rankings? and my answer that talks a lot more about the difference between "bounce rate" and "bounce back rate."