Face not work on outline buffer unless load the org feature

Hi, the outline face will not work until org feature been loaded. Here is reproduce steps: 1. Start emacs -q , and load the spacemacs-theme, apply the `spacemacs-dark` theme; 2. Open a file /tmp/a and `M-x outline-mode`, type follow two lines, the outline face does not work: ``` * a0 ** a1 ``` For comparison, the outline-face will work: a) Without applying the `spacemacs-dark`, the emacs builtin theme will work directly with the outline mode. Or, b) `(require 'org)` will let the `spacemacs-dark` theme works on outline-mode buffers. Please consider fix the issue, thanks