Indented line blocks do not render indented

[mwchase]

What's happening?

(From #285)

There is no specific styling for line blocks, so, among other things, indented lines are not indented.

I looked at the sphinx-rtd theme, and the following lines appear to be responsible for styling line blocks:

.rst-content .line-block {
 margin-left:0;
 margin-bottom:24px;
 line-height:24px
}
.rst-content .line-block .line-block {
 margin-left:24px;
 margin-bottom:0
}

The .line-block .line-block handles indenting text as needed.

Reproducer

1. Add line blocks with indent to sphinx documentation:

| Here is a line
|   Here is an indented line
| Here is a non-indented line

2. Build HTML with alabaster theme.
3. "Here is an indented line" displays indented.
   
4. Change them to furo
5. The lines no longer display indented
   
6. Add styles to .line-block .line-block
7. The lines display indented
   

Expectation

Furo should behave like other themes with regard to indented line blocks.

Code of Conduct

• I agree to follow the Code of Conduct.