Amends bhollis#98 with a more reliable declaration ensuring visible ellipsis with
any font's normal line height, incl. custom line-height.

'lh' is more recently implemented CSS unit:

-   https://developer.mozilla.org/en-US/docs/Web/CSS/length#lh
-   https://developer.mozilla.org/en-US/docs/Learn/CSS/Building_blocks/Values_and_units#line_height_units

so keep the original `line-height: 1.2` as a fallback.

-   https://developer.mozilla.org/en-US/docs/Web/CSS/word-break

Alternative could be:

    overflow-wrap: break-word;

but the former ensures the value starts at the same line as the property
name, for example.

Standard metadata names
<https://developer.mozilla.org/en-US/docs/Web/HTML/Element/meta/name>:

>   color-scheme: specifies one or more color schemes with which
>   the document is compatible.  The browser will use this information
>   in tandem with the user's browser or device settings to determine
>   what colors to use for everything from background and foregrounds
>   to form controls and scrollbars.

This also adjusts the selection/highlight colors, all CSS system colors:

-   https://drafts.csswg.org/css-color/#css-system-colors

It could prevent "white flashes" in some contexts.

The difference with the CSS `color-scheme` property [1] is, for example,
with Firefox View > Page Style > No Style it still honors the browser's
color theme.

[1] https://developer.mozilla.org/en-US/docs/Web/CSS/color-scheme

This avoids somewhat annoying translucent-background selection overlays.

-   https://developer.mozilla.org/en-US/docs/Web/CSS/::selection