How to set the width of a single character in html_html/css_WEB-ITnose

When displaying letters or numbers in HTML, when the font-size is the same, the width occupied by a single letter and number is inconsistent.
The current screen displays 000000. I use the keyboard to input ABCD and replace the previous 4 zeros in sequence. The entire character becomes ABCD00. At the same time, the width of the character also changes. How can I fix the width of the character? ?

Reply to discussion (solution)

Just use a monospace font

Use a monospace font It's ok

Thank you, I solved it with your method.