The interpolation of the rem-calc function made the code harder to read.
Besides, for new code we've already agreed upon using rem units instead
of `rem-calc`.
For instance, we had the following code:
```
width: calc(100% - #{2 * rem-calc(10)});
```
Now, `2 * rem-calc(10)` is the same as `rem-calc(20)`, but we were using
`2 *` to make it clear that this value was related to the value of the
`margin-left` property, which was `rem-calc(10)`.
IMHO using `0.625rem` for the margin and `2 * 0.625rem` for the width
the code is easier to read because there are no interpolation and no
complex operations involved.
Before commit 28caabecd, it was clear which budgets were in draft mode
because their phase was "drafting".
Now the phase isn't "drafting" anymore, so we have to make it clear
somehow that the budget is a draft.
I'm using styles similar to the ones we added in commit 2f636eaf7 for
completed budgets but at the same time making them slightly different so
it's easy to differenciate completed and drafting budgets.
