line 1 column 1 - Warning: missing <!DOCTYPE> declaration
line 6 column 1 - Warning: missing </font> before <h1>
line 6 column 23 - Warning: inserting implicit <font>
line 6 column 39 - Warning: discarding unexpected </font>
line 10 column 1 - Warning: missing </span> before <h1>
line 10 column 23 - Warning: inserting implicit <span>
line 10 column 39 - Warning: discarding unexpected </span>
line 10 column 1 - Warning: <span> proprietary attribute "color"
line 10 column 23 - Warning: <span> proprietary attribute "color"
line 6 column 1 - Warning: trimming empty <font>
line 10 column 1 - Warning: trimming empty <span>
Info: Document content looks like XHTML5
11 warnings, 0 errors were found!

You are recommended to use CSS to specify the font and
properties such as its size and color. This will reduce
the size of HTML files and make them easier to maintain
compared with using <FONT> elements.

About HTML Tidy: https://github.com/htacg/tidy-html5
Bug reports and comments: https://github.com/htacg/tidy-html5/issues
Or send questions and comments to: https://lists.w3.org/Archives/Public/public-htacg/
Latest HTML specification: http://dev.w3.org/html5/spec-author-view/
Validate your HTML documents: http://validator.w3.org/nu/
Lobby your company to join the W3C: http://www.w3.org/Consortium