FIG. 1 is a perspective view of a curtain runner showing my new design; FIG. 2 is a front view of the article shown in FIG. 1; FIG. 3 is a rear view of the article shown in FIG. 1; FIG. 4 is a left side view of the article shown in FIG. 1; FIG. 5 is a right side view of the article shown in FIG. 1; FIG. 6 is a top view of the article shown in FIG. 1; and, FIG. 7 is a bottom view of the article shown in FIG. 1.