How to redefine a block in css cascade so that it is 100% if there is a centering class in main?

Question

Layout

Main contains the .centerer class. There is a block that is inside main, but the background of which should be full width. How to redefine the block in the cascade so that the block width becomes 100% of the screen width.
centerer-

.container {
  width: 940px;
  margin: 0 auto;
  padding: 0 10px;
}
<img src="https://habrastorage.org/webt/5e/ac/5e/5eac5ee1d63b0829723197.png" alt="image"/>

Answer 1

Set the position: absolute to the block, while DO NOT set the main position, so the block will be absolutely positioned relative to the body