Suddenly background is not visible in my chrome.Iam able to set only background color but not background image.why is this happening suddenly? : body{
  background-image:linear-gradient(rgba(0, 0, 0, 0.5),rgba(0, 0, 0, 0.5)),url("images/smile.jpg");


height:100vh;
`
`width:100%;
`
`background-size: cover;
 `
` background-position: center;
  `
`margin:0 auto;

}

