em>number</em> and <em>letter</em>. You can set the style separately for columns and
rows with <strong>Column style</strong> and <strong>Row style</strong>, respectively. The letter style
works as follows: <code class="docutils literal notranslate"><span class="pre">A</span></code> corresponds to <code class="docutils literal notranslate"><span class="pre">0</span></code>, <code class="docutils literal notranslate"><span class="pre">B</span></code> to <code class="docutils literal notranslate"><span class="