Enter Your 9-Digit Code

"Design a **single div container** holding **9 input boxes**, each representing one numeric digit. The inputs should be styled to appear as separate boxes with an underline beneath each input field. The underline should be gray by default. As the user enters digits one by one, focus should automatically move to the next input. The active input (the one currently being filled) should have a **red underline** to indicate where the user is typing. Once all 9 inputs are filled, the underline for all boxes should turn **green**, and the 'Submit Code' button, initially disabled, should become enabled. The design should ensure smooth user interaction and clear visual feedback."