As we all know by now, consistently styling form elements with CSS is virtually impossible. However, with a few tweaks and after reading Firefox’s user-agent CSS file forms.css, I discovered the following: button::-moz-focus-inner,  input[type="reset"]::-moz-focus-inner,  input[type="button"]::-moz-focus-inner,  input[type="submit"]::-moz-focus-inner, input[type="file"] > input[type="button"]::-moz-focus-inner {     border: 1px dotted transparent;     padding: 0 2px; } … Firefox uses [...]