background-position:url(image) horizontal (X) vertical (Y)
If the horizontal (X) is a positive number and the vertical (Y) is a negative number, it means taking the upper right corner of the picture as the coordinate and moving each displacement, such as 8 -8 (taking the upper right corner, move 8px to the right and move 8px up);
If the horizontal (X) is a negative number and the vertical (Y) is a negative number, it means taking the upper left corner of the picture as the coordinate and moving each displacement, such as -8 -8 (taking the upper left corner, move 8px left and 8px up);
If the horizontal (X) is a positive number and the vertical (Y) is a positive number, it means taking the lower right corner of the picture as the coordinate and moving each displacement, such as 8 8 (taking the lower right corner, move 8px to the right and move 8px up);
If the horizontal (X) is a negative number and the vertical (Y) is a positive number, it means taking the lower left corner of the picture as the coordinate and moving each displacement, such as 8 8 (taking the lower left corner, move 8px to the left and move 8px up);