Dear @giacas 

Your problem is caused by a bug, that skin-text variable is not used in Sidenav's accordion text.

For a workaround, please use the below code. I have replaced order of skin definitions with imports, added $skin-text variable, and used it in three places: "skin-text", two classes.

/* You can add global styles to this file, and also import other style files */

$skin-text: red;

// Custom skin for JJ
$skins: () !default;
$skins: map-merge((
  "jjlovesu": (
    "skin-primary-color": #d9a0b5,
    "skin-navbar": #fff,
    "skin-footer-color": #fff,
    "skin-accent": #e9bdcd,
    "skin-flat": #404f9f,
    "skin-sidenav-item": rgba(250, 80, 121, .8),
    "skin-sidenav-item-hover": #e9bdcd,
    "skin-gradient-start": #272d6e,
    "skin-gradient-end": #90a8ff,
    "skin-mask-slight": rgba(35, 65, 134, .5),
    "skin-mask-light": rgba(35, 65, 134, .65),
    "skin-mask-strong": rgba(35, 65, 134, .8),
    "skin-sn-child": #ff89ac,
    "skin-btn-primary": #fd668c,
    "skin-btn-secondary": #3c61ae,
    "skin-btn-default": #9095aa,
    "skin-text": $skin-text
  )
), $skins);
@import "~ng-uikit-pro-standard/assets/scss/core/colors";
@import "~ng-uikit-pro-standard/assets/scss/core/variables";
@import "~ng-uikit-pro-standard/assets/scss/pro/variables";
@import "~ng-uikit-pro-standard/assets/scss/core/mixins";
@import "~ng-uikit-pro-standard/assets/scss/pro/skins";



.side-nav .collapsible .card .card-header a h5 {
  color: $skin-text;
}

.side-nav .collapsible .card-body li a {
  color: $skin-text;
}

Best Regards,

Damian