Ordered List Combined by numbers, lower case, and roman numerals

I had a similar situation where I needed to have full control over my ordered list.

This page needed to combine numbers, upper and lower case, and roman numerals.

I also had to control the initial number, letter, or roman numeral on independent sections.

Here is a summary of the CSS and HTML I currently use as a guideline.

ol.upper-letter {
  list-style-type: upper-alpha;
}
    ol.lower-letter {
  list-style-type: lower-alpha;
}
ol.upper-roman-numerals {
  list-style-type: upper-roman;
}
ol.lower-roman-numerals {
  list-style-type: lower-roman;
}

<h4> Ordered List Combined by Numbers, Lower Case, and Roman Numerals</h4>
<ol start=”1”>
  <li>first level</li>
      <ol type='a' class='lower-letter' start='1'>
          <li>second level</li>
          <li>second level</li>
       </ol>
  <li>first level</li>
       <ol type='a' class='lower-letter' start='3'>
          <li>second level</li>
             <ol type='i' class='lower-roman-numerals' start='1'>
                  <li>third level</li>
                  <li>third level</li>
              </ol>
          <li>second level</li>
       </ol>
 <li>first level</li>
</ol>