Make bolder work with Barlow

Author: andreslucena

src/css/vars.css

@@ -25,7 +25,7 @@
   --body-line-height: 1.15;
   --body-font-color: var(--color-jet-70);
   --body-font-family: "Barlow", sans-serif;
-  --body-font-weight-bold: 500;
+  --body-font-weight-bold: 600;
   --monospace-font-family: "Roboto Mono", monospace;
   --monospace-font-weight-bold: 500;
   /* base */