During CSS parsing It gets converted to “ and ” Browser engine has no idea about an element with this selector value - input[type=“submit” ] and ends up finding no element from the HTML document so you see no style applied to input>submit element .
A simple Proof of Concept: [Pls ignore, Not relevant to the current exercise. Just make sure to not use special quotes]
<!-- This works -->
<input type="“submit”" value="submit"