How to make a Yandex map from square to round?

Question

css

I prescribe css, but everything is useless, as the map was square, it remains so.

Answer 1

wrap in div and set (for div)
div{border-radius: 50%;overflow: hidden;}

Answer 2

Dear tell me, did you solve your question?
So far I've only been able to make it round in chrome.
Like this:

.ymaps-2-1-29-map{
        -webkit-border-radius: 250px;
           -moz-border-radius: 250px;
                border-radius: 250px;
        -webkit-mask-image: url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAAGXRFWHRTb2Z0d2FyZQBBZG9iZSBJbWFnZVJlYWR5ccllPAAAAA5JREFUeNpiYGBgAAgwAAAEAAGbA+oJAAAAAElFTkSuQmCC);
    }

where ".ymaps-2-1-29-map" is the class that is generated in my container div by yandex itself. the mask property does not work in other browsers.
To be honest, it’s brazenly stolen, so I didn’t go into the essence of the work.