## Background-Size

By carefully adjusting the ratio of the stripe width to the size of the background tile using trigonometric identities, you can create repeating, diagonal stripes with the `linear-gradient` function.

## With trig!

The length of the red line (repeat width of the stripes), and the angles are known. The width and height of the black rectangle has to be calculated.

Using the small triangle, we get `width = (stripeRepeatWidth) * sin(angle)` , using the large triangle we get `height = (stripeRepeatWidth) * cos(angle)` .