Adjust colours to meet WCAG 2 AA (#68)

See https://dequeuniversity.com/rules/axe/2.2/color-contrast

Author: tony-ho

_sass/basically-basic/_variables.scss

@@ -50,8 +50,8 @@ $monospace-font-family: Menlo, Consolas, Monaco, "Courier New", Courier,
 
 /* Colors */
 $base-color: #393e46 !default;
-$text-color: #222831 !default;
-$accent-color: #00848a !default;
+$text-color: #181c22 !default;
+$accent-color: #00838a !default;
 $background-color: #fff !default;
 $code-background-color: tint($base-color, 95%) !default;
 $border-color: tint($base-color, 80%) !default;