[Tutorial Feedback]

In the Tips and Tricks section of the Web Accessibility Tutorials (Guidance
on how to create websites that meet WCAG)
<https://www.w3.org/WAI/tutorials/>on
https://www.w3.org/WAI/tutorials/tables/tips/

it says

   -

   *Alignment:* Align text to the left and numeric data to the right (in
   left-to-right languages), so that people using larger text sizes or smaller
   screens will be able to find it. This is especially useful if a cell spans
   more than one column. It’s helpful to give column headers the same
   alignment as the data in the cells below.

but it doesn't say how to do this. I tried using style="text-align: left;"
in the following:

<thead>
<tr class="headertype1_pad7">
<th id="c1" scope="col" style=text-align: left;">Membership Category</th>
<th id="c2" scope="col" style=text-align: left;">2020 Rate</th>
</tr>
</thead>

<tbody>
<tr class="white_pad7" style="vertical-align: top;">
<td scope="row" colspan="1" style="font-size: 100%; background-color:
#fff;">
Professional &amp; Academic</td>
<td scope="row" colspan="1" style="font-size: 100%; background-color:
#fff;">
$225</td>
</tr>

my syntax checker said:

"Document type doesn't permit attribute “left;"” within element “<th>”.

"Document type doesn't permit attribute “scope” within element “<td>”.

Why can't it go into the style element?