o;
  width: 50%;
}
</code></pre>

<h4 id="CSS_Quotation_Marks" class="numbered">CSS Quotation Marks</h4>

<p>Use single (<code>''</code>) rather than double (<code>""</code>) quotation marks for attribute
selectors and property values.</p>

<p>Do not use quotation marks in URI values (<code>url()</code>).</p>

<p>Exception: If you do need to use the <code>@charset</code> rule, use double quotation
marks—<a href="https://www.w3.org/TR/CSS21/syndata.html#charset">single quotation marks are not permitted</a>