This is details of app top, as it appears on device, bottom as it appears in designer. I've checked many times, all four reds are set to same red. I've tried setting the red to many different shades of red, none come even close to being red. Fonts are all set to default, the difference looks worse on device than the picture shows.
Since you are obviously very interested in layout/design, I don't understand why you are using the "Classic" theme. The Slider then looks really old-fashioned and ugly.
Well, I'm old fashioned and ugly. ----- Old anyway. I really don't like the little ball and thin line of the other views. If I could change that ball to some sort of image that would be cool. At some point I'll change the play, stop buttons to some image. Something of my own design.
Sometimes I try to make things easier to see for old tired eyes. I really dislike the dark themes the designers are using lately, hard for me to read.