The advantage of HTML here is that the browser dynamically adjusts the
column widths to prevent things like in your screenshot from happening.
LaTeX does no such thing. If you tell it that the column width 20%, the
column will not be enlarged to fit if the contained text is longer.

Standard LaTeX tables don't even bother with relative widths: if you
don't explicitly set a width for a column, the column will be stretched
so that all text fits in one line, no matter how wide the table gets.

The L tabulary entry is the best compromise I could find for automatic
handling: it calculates widths based on cell contents. But as said
above, no handling of overlapping text is done, and I couldn't find a
package that helps with that problem.