fix(render): using only one 'styles.scss' file

Author: leomp12

scss/_functions.scss

@@ -0,0 +1,11 @@
+// Color contrast
+// Ref.: https://github.com/twbs/bootstrap/blob/master/scss/_functions.scss
+@function color-yiq($color, $dark: $dark, $light: $light) {
+  $r: red($color);
+  $g: green($color);
+  $b: blue($color);
+
+  $yiq: (($r * 299) + ($g * 587) + ($b * 114)) / 1000;
+
+  @return if($yiq >= 150, $dark, $light);
+}

scss/_variables.scss

@@ -0,0 +1,4 @@
+$dark: #212529;
+$light: #f8f9fa;
+$gray: #ebebeb;
+$primary: #007bff;