Add HSLA colors with Sass map fallbacks

sass/themes/basic.sass

@@ -0,0 +1,7 @@
+\:root
+  --black: #{$black}
+  --black-70: rgba(0, 0, 0, 0.7)
+  --white: #{$white}
+  // +registerCSSVarColor('primary', ($primary, $primary-invert, $primary-light, $primary-dark))
+  @each $name, $components in $colors
+    +registerCSSVarColor($name, $components)