HTML:
You can use:
background-position: center bottom;
Just to be clear, background-position percentages are calculated against BOTH the image and the background container. So, background-position: 25% 25%; would find the 25% point for both X and Y on the background container and align the image's 25%,25% point on top of that point.
If the bottom is more important: background-position: bottom;
background-position
also allows percentage values: 0% 0%;
by default.
The first value is the horizontal position and the second value is the vertical. The top left corner is 0% 0%. The right bottom corner is 100% 100%. If you only specify one value, the other value will be 50%.
You should try background-position: 0% -10%;