Broken style for Space Tools button and links in the page tree

Issue Summary

This is reproducible on Data Center: yes

• The Space Tools button isn't visible when clicked; the text becomes white without a background, making it difficult to read; this was not the case in older versions.
• When applying custom color for "Links" from Space Tools >> Look and Feel >> Color Scheme , this does not apply to the links of the pages in the page tree 

Steps to Reproduce

1. Go to a space >> Click on "Space Tools" in the lower left corner, the button has a transparent background, resulting in invisible text
2. Go to Space Tools >> Look and Feel >> Color Scheme >> Select Custom >> Change the color for "Links" to red >> Save. Go back to the page tree, and notice that the links are not using the color expected

Expected Results

The space tools button should be visible when clicked and custom color for links should be applied for page titles in the page tree

Actual Results

The space tools button is not visible when clicked and the custom color for links is not applied for links in the page tree

Workaround

Go to General Configuration >> Stylesheet, and add the following custom CSS

.ia-fixed-sidebar div.plugin_pagetree ul.plugin_pagetree_children_list .plugin_pagetree_children_span a {color: var(--confluence-color-scheme-linkColor, var(--ds-link)) !important;}

.aui-button.active:not(.aui-button-link) {--aui-btn-text: var(--confluence-color-scheme-linkColor, var(--ds-link))!important;}