STARS MADE FORM CSS TRIANGLES, which have been rotated into place using the rotation.css stylesheet.

Each star consists of the requisite number of css triangles, absolutely positioned inside a relatively-positioned container div. (The triangles may have position left and top to center them in their containers).

As with the css polygons, it can take a bit of trial and error to find the right border-width values needed to create regular stars.

The key difference between these stars and the polygons is that the rotated triangles require their transform-origin to be set:
transform-origin:50% 100%.

Setting the property with these values shifts the triangles so that they rotate around the middle of the bottom edge of their defined border-bottoms.
(Other values can create some interesting effects, however.)

Note that some of these stars could be made more simply: Star 6 could be made from two equilateral triangles, Star 9 from three equilateral triangles,
and Star 8 could be made from two squares, but I leave this exercise to the reader.

Note: This demo uses the rotation.css stylesheet.