Curved line, draw, and lockRight. An Arc

Hi,

I need to have a line, 10 to 20 pix width. Going full width of my web-page.

Now, how do I make it only 70% with one color and 30% with another color.

And all need to resize when I resize the window.

I want to use this as and indication of how much of a budget is spent. formula: y = sin(x/4) approx.

Example