It seems to me that my way isn't good("padding-top: 25px;")
Correct, this is bad as it's not self adjusting if anything in the measurements or sizes changes.
auntnini's trick will work. Optionally you can use flex layout which enables for easy and clear vertical centering.
align-items: center; /* for vertical centering */
justify-content: center; /* for horizontal centering */
Additionally I recommend to do without fixed height. As a result the size will be self adjusting when the content changes. You can the adjust the layout by padding or margin.