var pageSettings = {
  red: 200,
  green: 200,
  blue: 200,
background: [
'https://pictures.s3.yandex.net/background.jpg', 'https://pictures.s3.yandex.net/cover-color.jpg', 'https://pictures.s3.yandex.net/cover-grid.jpg', 'https://pictures.s3.yandex.net/cover-typo.jpg', 'https://pictures.s3.yandex.net/cover-wall.jpg'
]
};
var bgColor = 'rgb(' + pageSettings.red + ', ' + pageSettings.green + ', ' + pageSettings.blue + ')';
document.body.style.backgroundColor = bgColor;
var header = document.getElementById('main-header');
console.log(header);
header.style.backgroundImage = 'url(' + pageSettings.background + ')';
header.style.backgroundImage = 'url(' + pageSettings.background[2] + ')';
pageSettings.background[pageSettings.background.length - 1];