Warnings:
Content-Security-Policy HTTP header: Bad content security policy: Source list contains duplicate source expression "*.sdn.szn.cz". All but the first instance will be ignored.
The “banner” role is unnecessary for element “header”.
The “navigation” role is unnecessary for element “nav”.
The “main” role is unnecessary for element “main”.
Article lacks heading. Consider using “h2”-“h6” elements to add identifying headings to all articles.
Section lacks heading. Consider using “h2”-“h6” elements to add identifying headings to all sections.
The “complementary” role is unnecessary for element “aside”.
A table row was 10 columns wide, which is less than the column count established by the first row (100).
A table row was 9 columns wide, which is less than the column count established by the first row (100).
Empty heading.
The “contentinfo” role is unnecessary for element “footer”.
Errors:
Bad value “previewimage” for attribute “rel” on element “link”: The string “previewimage” is not a registered keyword.
“=” in an unquoted attribute value. Probable causes: Attributes running together or a URL query string in an unquoted attribute value.
Element “style” not allowed as child of element “div” in this context. (Suppressing further errors from this subtree.)
CSS: “scrollbar-width”: Property “scrollbar-width” doesn't exist.
Attribute “amp-fx” not allowed on element “header” at this point.
Bad value “navigation” for attribute “role” on element “button”.
An “img” element must have an “alt” attribute, except under certain conditions. For details, consult guidance on providing text alternatives for images.
Attribute “datetime” not allowed on element “div” at this point.
Bad value “” for attribute “sizes” on element “img”: Must not be empty.
Bad value “” for attribute “srcset” on element “img”: Must contain one or more image candidate strings.
Duplicate attribute “src”.
The “acronym” element is obsolete. Use the “abbr” element instead.
Table columns in range 11…100 established by element “th” have no cells beginning in them.
Attribute “left” not allowed on element “svg” at this point.
The “aria-labelledby” attribute must point to an element in the same document.
Czech Republic CZ