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.
This way we remove duplication and it'll be easier to add better support
for RTL languages.
In a few years this might not be necessary since support for the `gap`
property in a flexbox layout will improve. At the time of writing,
however, only 86.5% of the browsers support it [1].
[1] https://caniuse.com/flexbox-gap
We can give the padding to the whole page instead of giving it to
individual elements.
On the minus side, now padding in the SDG pages is not the same as the
padding in the homepage, so we need to add an extra padding to the
participation feeds in only one of these cases.
The elements were given a minimum width of `rem-calc(240)` (that is,
15rem). Considering one element is double the width of the other one,
that means that in screens between 40rem and 45rem there would be a
horizontal scrollbar.
Adding a `flex-wrap: wrap` property fixes the problem. We're also using
`flex-basis` to guarantee a minimum width and make one element be double
the size of the other one when they're on the same line. No need to add
breakpoint rules due.
Finally, we're adding an artifitial gap between flex elements so we can
remove the `@include grid-col` rules.
There are two bugs in Internet Explorer which caused our footer to be
rendered incorrectly.
First, the `flex: 1` property doesn't work so well when `flex-direction`
is set to `column`. We're replacing it with `flex-grow: 1`. No need to
set other `flex-basis` nor `flex-shrink` in this case since in this case
the default values will work just fine.
Second, it didn't handle the body height being set to `100%` so well,
and the footer was rendered after that 100% point, even if the content
still continued.
So we're using `min-height` instead, which is actually a bit more
accurate (since the body is usually taller than the document root
element). This causes a different issue since on IE the `flex-grow: 1`
property becomes useless. This will only affect IE users with very large
screens, though, and it's way better than rendering the footer
overlapping the main content, so we can live with that. The page won't
look as great as in other browser, but it will still be usable.
