I discovered that there is a second portion of the answer to this.
The first portion helped me, but I still had a space to the right of my type=number
input. I had zeroed out the margin on the input, but apparently I had to zero out the margin on the spinner as well.
This fixed it:
input[type=number]::-webkit-inner-spin-button,
input[type=number]::-webkit-outer-spin-button {
-webkit-appearance: none;
margin: 0;
}