alex-shpak#59, Allow customize SASS vars, add example of dark theme

assets/_variables.scss

@@ -1,43 +1,43 @@
 // Used in layout
-$padding-1: 1px;
-$padding-4: 0.25rem;
-$padding-8: 0.5rem;
-$padding-16: 1rem;
+$padding-1: 1px !default;
+$padding-4: 0.25rem !default;
+$padding-8: 0.5rem !default;
+$padding-16: 1rem !default;
 
-$font-size-base: 16px;
-$font-size-12: 0.75rem;
-$font-size-14: 0.875rem;
-$font-size-16: 1rem;
+$font-size-base: 16px !default;
+$font-size-12: 0.75rem !default;
+$font-size-14: 0.875rem !default;
+$font-size-16: 1rem !default;
 
-$border-radius: 0.15rem;
+$border-radius: 0.15rem !default;
 
 // Grayscale
-$white: #ffffff;
-$gray-100: #f8f9fa;
-$gray-200: #e9ecef;
-$gray-300: #dee2e6;
-$gray-400: #ced4da;
-$gray-500: #adb5bd;
-$gray-600: #868e96;
-$gray-700: #495057;
-$gray-800: #343a40;
-$gray-900: #212529;
-$black: #000;
-
-$color-link: #004ed0;
-$color-visited-link: #8440f1;
-$color-dark-link: $gray-800;
-
-$body-background: white;
-$body-font-color: $gray-800;
-$body-font-weight: normal;
-
-$body-min-width: 20rem;
-$container-max-width: 80rem;
-
-$header-height: 3.5rem;
-$menu-width: 16rem;
-$toc-width: 16rem;
-
-$md-breakpoint: $menu-width + $body-min-width * 1.25 + $toc-width;
-$sm-breakpoint: $menu-width + $body-min-width;
+$white: #ffffff !default;
+$gray-100: #f8f9fa !default;
+$gray-200: #e9ecef !default;
+$gray-300: #dee2e6 !default;
+$gray-400: #ced4da !default;
+$gray-500: #adb5bd !default;
+$gray-600: #868e96 !default;
+$gray-700: #495057 !default;
+$gray-800: #343a40 !default;
+$gray-900: #212529 !default;
+$black: #000 !default;
+
+$color-link: #004ed0 !default;
+$color-visited-link: #8440f1 !default;
+$color-dark-link: $gray-800 !default;
+
+$body-background: white !default;
+$body-font-color: $gray-800 !default;
+$body-font-weight: normal !default;
+
+$body-min-width: 20rem !default;
+$container-max-width: 80rem !default;
+
+$header-height: 3.5rem !default;
+$menu-width: 16rem !default;
+$toc-width: 16rem !default;
+
+$md-breakpoint: $menu-width + $body-min-width * 1.25 + $toc-width !default;
+$sm-breakpoint: $menu-width + $body-min-width !default;

exampleSite/assets/_custom.scss

@@ -1 +1,2 @@
 @import "variables";
+// You can add custom styles here.

exampleSite/assets/_variables.scss

@@ -0,0 +1,13 @@
+// You can override SASS variables here. Below example of simple dark theme.
+
+/*
+$gray-100: rgba(255, 255, 255, 0.1);
+$gray-200: rgba(255, 255, 255, 0.2);
+
+$body-background: #343a40;
+$body-font-color: #e9ecef;
+
+$color-link: #84b2ff;
+$color-visited-link: #b88dff;
+$color-dark-link: $body-font-color;
+*/