// Obsoletes HTML tags (https://developer.mozilla.org/fr/docs/Web/HTML/Element)
acronym,
applet,
basefont,
bgsound,
big,
blink,
center,
command,
content,
dir,
element,
font,
frame,
frameset,
image,
isindex,
keygen,
listing,
marquee,
menuitem,
multicol,
nextid,
nobr,
noembed,
noframes,
plaintext,
shadow,
spacer,
strike,
tt,
xmp {
  @include error("Obsolete tags");
}

// old tags that need modernization
i {
  @include warning("Use <em> instead");
}
b {
  @include warning("Use <strong> instead");
}
u {
  @include warning("Use css text-decoration: underline; instead");
}