Cerulean inconsistent setting of color.

[ekrichbaum]

.bg-primary h1, .bg-primary .h1,
.bg-primary h2,
.bg-primary .h2,
.bg-primary h3,
.bg-primary .h3,
.bg-primary h4,
.bg-primary .h4,
.bg-primary h5,
.bg-primary .h5,
.bg-primary h6,
.bg-primary .h6,
.bg-success h1,
.bg-success .h1,
.bg-success h2,
.bg-success .h2,
.bg-success h3,
.bg-success .h3,
.bg-success h4,
.bg-success .h4,
.bg-success h5,
.bg-success .h5,
.bg-success h6,
.bg-success .h6,
.bg-info h1,
.bg-info .h1,
.bg-info h2,
.bg-info .h2,
.bg-info h3,
.bg-info .h3,
.bg-info h4,
.bg-info .h4,
.bg-info h5,
.bg-info .h5,
.bg-info h6,
.bg-info .h6,
.bg-warning h1,
.bg-warning .h1,
.bg-warning h2,
.bg-warning .h2,
.bg-warning h3,
.bg-warning .h3,
.bg-warning h4,
.bg-warning .h4,
.bg-warning h5,
.bg-warning .h5,
.bg-warning h6,
.bg-warning .h6,
.bg-danger h1,
.bg-danger .h1,
.bg-danger h2,
.bg-danger .h2,
.bg-danger h3,
.bg-danger .h3,
.bg-danger h4,
.bg-danger .h4,
.bg-danger h5,
.bg-danger .h5,
.bg-danger h6,
.bg-danger .h6,
.bg-dark h1,
.bg-dark .h1,
.bg-dark h2,
.bg-dark .h2,
.bg-dark h3,
.bg-dark .h3,
.bg-dark h4,
.bg-dark .h4,
.bg-dark h5,
.bg-dark .h5,
.bg-dark h6,
.bg-dark .h6 {
  color: #fff;
}

but never sets for bg-secondary, i.e.

.bg-secondary h2,
.bg-secondary .h2 {
    color: #343a40;
}

I thought we had fixed this previously, but that may have been on other themes... found it, we were talking about lux and zephyr then.
#1186

Looking again at that one, it isn't very clear what the best fix is (card h2, bg-secondary h2, etc.).