Bug report: HR display style is inline

In the HTML specification and in Microsoft’s documentation, a horizontal rule
element is a block element and its display style should be "block" but it is
"inline" by default. This element is rendered as an inline element of width
100%. You can manually set all instances of HR to block display via CSS
which allows you to remove its vertical margins (which is good). This fix
should not harm other browsers because HR should have block display style
anyway.