How to refer to a block within a block in css?

Question

css

Hello!
What is the correct way to refer to blocks within blocks?
Here is the code in SASS
.block1 {
.block2 {
.block3 {
}
}
}
How to refer to block 3 in CSS? Or will it be enough just to write .block3 {} ​​right away?

Answer 1

Well, if you write
.block3 {}
​​then all elements on the page with class block3 get the styles described in this block. If like this
.block1 .block2 .block 3 {}
then only the block3 elements that are inside the block2 block that is inside the block1 block will apply styles to themselves.

Answer 2

and to take and see the compiled css of your scss yourself is not destiny?
skrinshoter.ru/v/140519/ixSskVbO?a
https://codepen.io/anon/pen/arpvjQ