alert boxes need to be restyled to match color scheme

Bootstrap "alert" boxes (primary variant is the only one we currently use) should be restyled to be more consistent with the color scheme used across all Brigade sites.

Something like this maybe:

```
$colorm: #37b0e7;
$colorl: #EFF4F5;

.alert-primary {
border-color: $colorm !important;
background-color: $colorl !important;
}
```