Change Search Icon

Halo, my website now are using wplms CHILDONE theme, the search icon on the header, you can see the height are not same (see picture, www.mediafire.com/view/qe12mbwgnzcf358/Untitled-1.jpg#, i have draw a green color line to show the height are not same), how do i  can have same icon of the http://themes.vibethemes.com/wplms/skins/demo2/, you can see the icon in demo2 are same height. I have try to edit all the css have related with "icon-search-2" in the wordpress wpllms install folder, but no result... If possible, please give a solution way by adding custom coding, i can't change the the theme, theme skin layout or other customize option because i had some custom coding inside the website and i maybe lost them if changing by customize option . Thanks.