I am trying to place a sentence in the middle of the page. This is the code I came up with:
font-family: 'Roboto Mono', sans-serif;
This in your code:
left: 50%; right: 50%
causes that element to have zero width: The left border is 50% from the left side, the right border is 50% from the right side. Remaining space: 0
Just erase these two,
text-align: center; is sufficient...
P.S.: Since position is absolute, you'll need to define a width, go for 100%. (or use