We recommend only using the block CSS to style blocks. Please don't attempt to write CSS selectors in style.scss for blocks. If you want to style a default block, make a new block based on it and change its style instead.
When you open a block you get access to its own HTML/CSS/JS in the bottom right corner.
Snowfire will automatically add a namespace for your block. This makes it safe to use simple class names such as .post, .author and so on. Consider the following CSS code in a block:
.content {
background: #00ff00;
}
This will then be translated by Snowfire to the this code:
.sf-block-40[data-block-id="77"] .content {
background: #00ff00;
}
This means that your .content class won't conflict with any other block,