Redefined all -invcolor variables

Used Chroma-js with adjusted inverted luminance:

    function inv(str)
    {
      var c = Chroma(str);
      // sqrt bends the luminance curve to improve light-on-dark contrast
      c2 = c.set('lch.l', 100 * Math.sqrt((100 - c.get('lch.l')) / 100));
      return c2
    }

app/assets/stylesheets/parameters.scss

@@ -80,61 +80,62 @@ $small-body-small-nav-primary-ul-li-border-color: #eee;
 
 
 
-$offwhite-invcolor: #08080f;
-$blue-invcolor: #0953b7;
-$lightblue-invcolor: #1f3052;
-$green-invcolor: #0e510a;
-$vibrant-green-invcolor: #004f00;
-$grey-invcolor: #2c2c2c;
-$lightgrey-invcolor: #131313;
-$darkgrey-invcolor: #666;
-$list-highlight-invcolor: #0e0a00;
+$offwhite-invcolor: #25252a;
+$blue-invcolor: #6b8efa;
+$lightblue-invcolor: #5c6990;
+$green-invcolor: #539046;
+$vibrant-green-invcolor: #3d8e1b;
+$grey-invcolor: #646464;
+$lightgrey-invcolor: #3a3a3a;
+$darkgrey-invcolor: #a0a0a0;
+
+$list-highlight-invcolor: #212100;
 
 $common-fillL-background-invcolor: black;
-$common-body-invcolor: #d9d9d9;
+$common-body-invcolor: #ebebeb;
 $common-body-background-invcolor: #000;
-$common-a-invcolor: #8582ff;
+$common-a-invcolor: #b9aeff;
 $common-header-h1-a-invcolor: #ffffff;
-$common-count-number-invcolor: #c3c3c3;
-$common-leaflet-control-control-button-background-invcolor: #c3c3c3;
+$common-count-number-invcolor: #dfdfdf;
+$common-leaflet-control-control-button-background-invcolor: #dfdfdf;
 $common-leaflet-control-control-button-background-shade-invcolor: rgba(255, 255, 255, .6);
 $common-leaflet-control-control-button-hover-background-invcolor: white;
-$common-leaflet-control-control-button-disabled-background-invcolor: #c3c3c3;
+$common-leaflet-control-control-button-disabled-background-invcolor: #dfdfdf;
 $common-leaflet-control-control-button-disabled-background-shade-invcolor: rgba(255, 255, 255, .5);
 $common-map-layout-sidebar-background-invcolor: #000;
 $common-map-layout-welcome-button-learn-more-border-invcolor: #000;
 $common-map-layout-map-ui-background-invcolor: black;
-$common-map-layout-map-ui-a-close-button-invcolor: #d9d9d9;
+$common-map-layout-map-ui-a-close-button-invcolor: #ebebeb;
 $common-layers-ui-base-layers-li-border-invcolor: #000;
 $common-layers-ui-base-layers-li-label-text-invstroke: #000;
 $common-layers-ui-base-layers-li-label-background-invcolor: rgba(0,0,0,.9);
 $common-share-ui-share-tabs-a-invcolor: #000;
 $common-share-ui-share-tabs-a-border-invcolor: #000;
-$common-search-results-error-invcolor: #e90000;
+$common-search-results-error-invcolor: #ff502e;
 $common-sidebar-content-browse-field-p-background-invcolor: #000;
 $common-sidebar-content-browse-tag-list-browse-tag-v-background-invcolor: #000;
 $common-sidebar-content-browse-tag-list-colour-preview-box-border-invcolor: rgba(255, 255, 255, .1);
-$common-diary-post-deleted-background-invcolor: #1a0c0c;
-$common-diary-entries-diary-comment-deleted-background-invcolor: #1a0c0c;
-$common-messages-inbox-row-unread-background-invcolor: #092200;
-$common-flash-error-background-invcolor: #a2172a;
-$common-flash-warning-background-invcolor: #281500;
-$common-flash-notice-background-invcolor: #092200;
+$common-diary-post-deleted-background-invcolor: #3d3031;
+$common-diary-entries-diary-comment-deleted-background-invcolor: #3d3031;
+$common-messages-inbox-row-unread-background-invcolor: #325215;
+$common-flash-error-background-invcolor: #ed6062;
+$common-flash-warning-background-invcolor: #584131;
+$common-flash-notice-background-invcolor: #325215;
 $common-form-error-invcolor: #000;
-$common-form-error-background-invcolor: #a2172a;
-$common-error-explanation-border-invcolor: #a2172a;
-$common-error-explanation-background-invcolor: #111;
-$common-error-explanation-h2-background-invcolor: #fd4528;
+$common-form-error-background-invcolor: #ed6062;
+$common-error-explanation-border-invcolor: #ed6062;
+$common-error-explanation-background-invcolor: #363636;
+$common-error-explanation-h2-background-invcolor: #ff7c55;
 $common-error-explanation-h2-invcolor: #000;
-$common-error-explanation-p-invcolor: #c3c3c3;
+$common-error-explanation-p-invcolor: #dfdfdf;
 $common-standard-form-a-button-invcolor: black;
-$common-standard-form-textarea-invcolor: #d9d9d9;
+$common-standard-form-textarea-invcolor: #ebebeb;
 $common-standard-form-textarea-background-invcolor: #000;
-$common-standard-form-textarea-field-with-errors-border-invcolor: #a2172a;
+$common-standard-form-textarea-field-with-errors-border-invcolor: #ed6062;
 $common-standard-form-search-directions-form-input-error-background-invcolor: rgba(233, 0, 0, 0.5);
-$common-site-welcome-fixthemap-icon-note-background-invcolor: #c3c3c3;
-$common-site-about-content-inner-invcolor: #c3c3c3;
-$common-site-about-content-attr-background-invcolor: #c3c3c3;
+$common-site-welcome-fixthemap-icon-note-background-invcolor: #dfdfdf;
+$common-site-about-content-inner-invcolor: #dfdfdf;
+$common-site-about-content-attr-background-invcolor: #dfdfdf;
 $common-site-about-content-attr-background-shade-invcolor: rgba(255, 255, 255, .8);
 $common-site-about-attr-byosm-invcolor: #000;
 $common-site-about-content-text-background-invcolor: black;
@@ -147,5 +148,8 @@ $common-nav-primary-secondary-hover-active-invcolor: black;
 $common-buttons-button-to-border-invcolor: black;
 
 $small-body-small-nav-header-background-invcolor: #000;
-$small-body-small-nav-primary-ul-border-invcolor: #131313;
-$small-body-small-nav-primary-ul-li-border-invcolor: #131313;
+$small-body-small-nav-primary-ul-border-invcolor: #3a3a3a;
+$small-body-small-nav-primary-ul-li-border-invcolor: #3a3a3a;
+
+$common-body-invcolor: #515151;
+$common-body-background-invcolor: #ffffff;