On many WordPress themes, the default search bar when viewed on an iPhone or iPad doesn’t look too great. The rounded corners can completely ruin an otherwise amazing design. Fortunately, there’s a really easy way to remove those rounded corners from your search bar. Just copy and paste the following code into your custom CSS file or plugin.
/* Search Box - Remove Rounded Corners */
border-radius: 0px !important;
-webkit-appearance: none !important;