code: async function writeCustomPropertiesToCssFile(to, customProperties) {
  	const cssContent = Object.keys(customProperties).reduce((cssLines, name) => {
  		cssLines.push(`\t${name}: ${customProperties[name]};`);
  
  		return cssLines;
  	}, []).join('\n');
  	const css = `:root {\n${cssContent}\n}\n`;
  
  	await writeFile(to, css);
  }
docs: /* Write Custom Properties to CSS File
  /* ==========================================================================