This stylelint-scss rule is useful because we were inconsistent when
using calc(); sometimes we added interpolation to Sass variables, and
sometimes we didn't. The reason why we originally added interpolation
was that it was necessary until we migrated to Dart Sass in commit
d54971e53. Since then, we can omit the interpolation, which is also what
the Sass documentation recommends [1].
[1] https://sass-lang.com/documentation/values/calculations/
We hadn't added this rule before because there was no such rule in
scss-lint. Instead, we were following it without a linter, and so we
unintentionally broke it sometimes.
But now we're using Stylelint, so we can add the rule and let the linter
check we're still following it.
The division operator `/` from Sass is deprecated because `/` is used in
CSS for uses other than dividing numbers. That's why we were getting
many warnings like:
```
Deprecation Warning: Using / for division outside of calc() is
deprecated and will be removed in Dart Sass 2.0.0.
Recommendation: math.div($line-height, 2) or calc($line-height / 2)
More info and automated migrator: https://sass-lang.com/d/slash-div
margin-top: $line-height / 2;
```
Since using math.div makes the code harder to read and `calc` is
universally supported by all browsers (although the implementation in
Internet Explorer doesn't work in certain cases), we're using `calc`
when assigning the value to a CSS property.
However, we're also using divisions when assigning Sass variables, and
in those cases using `calc` is trickier because sometimes these
variables are used in other operations. We'll handle these cases in the
next commit.
Using the `document` or `documents` classes meant styles defined for the
public list of documents conflict with these ones.
So now we're using HTML classes that match the name of the Ruby
component classes, as we usually do.
The Web Content Accessibility Guidelines version 2.1 added a success
criterion called Non-text Contrast [1], which mentions that the focus
indicator must contrast with the background, and version 2.2 introduced
a specific one regarding focus appearance [2]. According to that
criterion, the focus indicator:
* is at least as large as the area of a 2 CSS pixel thick perimeter of
the unfocused component or sub-component
* has a contrast ratio of at least 3:1 between the same pixels in the
focused and unfocused states.
Our current solution for highlighting elements on focus has a couple of
issues:
* It doesn't offer enough contrast against the default white background
(1.6:1)
* It offers even less contrast against other backgrounds, like the
homepage banner or the featured proposals/debates
Making the color of the outline darker would increase the contrast
against these backgrounds, but it would reduce the contrast against
other backgrounds like our default brand color.
For this reason, most modern browsers use a special double outline with
two different colors [3], and we're choosing to combine an outline and a
box shadow to emulate it, using the brand color as the second color.
However, this double-colored outline doesn't work so well when focusing
on dark buttons surrounded by a light background, so instead we're using
a triple outline, which works well on any color combination [4]. Since I
feel that making the third outline 2px wide makes the overall outline
too wide, I'm making the inner outline just 1px wide since that's enough
to prevent edge cases.
Note that Foundation adds a transition for the `box-shadow` property on
`select` controls, which gets in the way of the focus we use on the
language selector. So we're removing the transition.
Also note that the box-shadow style didn't work properly with the
box-shadow we added on the `:hover` status on cards, so we're changing
the code in order to cover this case.
Finally, note that the box-shadow isn't displayed properly on multiline
links (in Chrome, not even with `box-decoration-break: clone`), like the
ones in debates/proposals/polls/investments/processes titles, so we're
changing the style of these links to `inline-block`.
[1] https://www.w3.org/TR/WCAG21/#non-text-contrast
[2] https://www.w3.org/TR/WCAG22/#focus-appearance
[3] https://www.sarasoueidan.com/blog/focus-indicators/#examining-(current)-browser-focus-indicators-against-wcag-requirements
[4] https://www.erikkroes.nl/blog/the-universal-focus-state/
In commit cc6f9391f we made the images and documents file inputs
invisible (instead of using `display: none`) in order to make it
possible to attach images and documents using the keyboard.
However, since the error messages associated to these inputs has the
same HTML class as the inputs, we were also hiding them (the `display:
none` didn't affect the error messages because they've also got the
`is-visible` class).
Using the `[type=file]` selector we make it more explicit that we only
want to style these inputs.
I'm not adding a test for this scenario because technically the text is
there and I'm not sure how to test for the presence of invisible
elements.
We were hiding the file input and styling the label as a button instead.
Since clicking on a label has the same effect as clicking on the input,
the input worked properly for mouse and touch screen users.
However, hiding the input makes it inaccessible for keyboard users,
since labels don't get keyboard focus, but inputs do.
So we must not hide the input but make it invisible instead. But we
still need to hide the input (alongside the label) after a file has been
attached.
We could add some extra JavaScript to hide the input when we hide the
label. Since the JavaScript is already quite complex and my first few
attempts at changing it failed, I've opted to assume that the input (and
its label) must be hidden whenever there's already a file name, and
implement that rule with CSS.
Note we're using the `:focus-within` pseudoclass to style a label when
focus is on the input. This rule (at the time of writing) is only
supported by 93.5% of the browsers. Keyboard users without a screen
reader and using the other 6.5% of the browsers will still be able to
focus on the field but might not notice the field has received focus.
Since the percentage of affected users will decrease over time and until
now 100% of keyboard users were completely unable to focus on these
fields, for now we think this is a good-enough solution.
This way screen reader users will hear the name of the file before
hearing about the link to destroy it. We were already displaying it this
way visually by having the file name on the left and the destroy link on
the right.
Thanks to this change we can also simplify the code which dynamically
changed the layout.
One file was OK when we only had a couple of mixins, but recently we've
been adding quite a few.
We can now avoid a SCSS Lint warning by excluding just the file with the
affected mixin.
