文字对齐：对;无论我尝试什么，都要留有余地

I've got this simple code that displays the Day of the week, the time and the date. The text should be aligned on right, as specified in the css, but I don't know why it doesn't fix itself on the right side of the screen (excluding the margin) it always keep a big space between the side of the window and itself. I've got this simple code that displays the Day