Should condo owner be responsible for repair of stoop and stairs?

Our condo association states that exclusive common areas are the responsibility of the condo owner. I am trying to find out if repairs to external stairs and stoop should be my responsibility. I question it because my insurance only covers from drywall in.

Here is the problem. I live in a 6 unit condo association building and each unit has its own entrance. My building sits on a slab, and my entrance has 2 pillars and a set of stairs with an iron railing on each side. It was built 15 years ago (I am an original owner), and within a 1 year period I had to repair the stairs because they were crumbling. The construction supervisor at the time explained to me that they had trouble with the concrete and had to switch to a different company. The sidewalk that sits in front of my unit was also cracking and crumbling, and 2 sections were replaced.

Over the years, my front stoop has been sinking. The first step is now only about 3 inches from where it sits with the sidewalk, and a few years ago a crack developed from the second step up and across the entire stoop. I had put concrete filler in, but the crack has since separated after this past winter. Due to the progressive sinking, the iron rails have broken away on both sides. My driveway, which sits a couple of feet from the stoop, has also sunk down. Finally, there is a downspout on the side of my stoop that I feel is contributing to ground instability, causing the stoop to sink.

The condo association states that this repair is my responsibility. My feeling is that the stoop is part of the foundation, and that I should not be responsible for the repair. Does anyone have any information that can help to guide me on this issue?