Copy link to clipboard
Copied
You cannot see the fill because it is a straight line. If line was curved you would see the fill between the start and end point of the curve.
If you want a red line with a thin black line around it, you could add an additional black stroke below the red one in the Appearance panel and make both a different size.
Copy link to clipboard
Copied
Try using the rectangle tool and adjust from result.
Copy link to clipboard
Copied
You cannot see the fill because it is a straight line. If line was curved you would see the fill between the start and end point of the curve.
If you want a red line with a thin black line around it, you could add an additional black stroke below the red one in the Appearance panel and make both a different size.