What color and with what angles should the triangle be in this example?

Question

Design

Good afternoon. Perhaps there is an experienced designer who can help us in this situation.

We make the site on our own, we can’t solve an easy task at first sight. What color is better to make triangles? We made it the color to which the gradient goes, but something is not right.
And in what ratio should the legs of the triangle be?
We apologize for the rather stupid question, we understand that there can be no exact answer, but we still hope for your understanding. Thank you.

Answer 1

Make it darker. They are visually further away, which means they cannot be lighter than the red top of the stripe. And since your top is rectangular, then try right angles below. In general, it looks fine.