title: Need to change section to Roman, but keep Arabic for for subsection and subsubsection
body: <p>I need to change my section numbering from Arabic, to Roman, beet keep the Arabic numbering in subsections and subsubsections. For example:</p>
  
  <p>I. Section</p>
  
  <p>1.1. Subsection</p>
  
  <p>1.1.1. Subsubsection</p>
  
  <p>II. Section</p>
  
  <p>2.1 Subsection</p>
  
  <p>...</p>
  
  <p>So I know that with sections i can do "\renewcommand \thesection{\roman{section}}", but this command changes also subsections and subsubsections, like that:</p>
  
  <p>I. Section</p>
  
  <p>I.1. Subsection</p>
  
  <p>I.1.1. Subsubsection</p>
  
  <p>II Section</p>
  
  <p>II.1. Subsection</p>
  
  <p>...</p>
  
  <p>So I need to keep subsections ans subsubsections from Roman numbering.</p>