Read CSS padding clockwise:

padding:25px 50px 75px 100px;
shorthand property for:

    top padding is 25px
    right padding is 50px
    bottom padding is 75px
    left padding is 100px

padding:25px 50px 75px;

    top padding is 25px
    right and left paddings are 50px
    bottom padding is 75px

padding:25px 50px;

    top and bottom paddings are 25px
    right and left paddings are 50px

padding:25px;
all four paddings are 25px