I know this is a very basic question but I have tried many StackOverflow solutions but nothing worked for me.
This is the HTML content which I am using.
<html><style>
div:after {
content: "\A";
position: absolute;
width: 100%;
height: 100%;
top: 0;
left: 0;
background: rgba(0, 0, 0, 0.5);
background: -moz-linear-gradient(top, rgba(0, 0, 0, 0.5) 0%, rgba(216, 38, 38, 0.7) 100%);
/* FF3.6+ */
background: -webkit-gradient(linear, left top, left bottom, color-stop(0%, rgba(0, 0, 0, 0.5)), color-stop(100%, rgba(216, 38, 38, 0.7)));
/* Chrome,Safari4+ */
background: -webkit-linear-gradient(top, rgba(0, 0, 0, 0.5) 0%, rgba(216, 38, 38, 0.7) 100%);
/* Chrome10+,Safari5.1+ */
background: -o-linear-gradient(top, rgba(0, 0, 0, 0.5) 0%, rgba(216, 38, 38, 0.7) 100%);
/* Opera 11.10+ */
background: -ms-linear-gradient(top, rgba(0, 0, 0, 0.5) 0%, rgba(216, 38, 38, 0.7) 100%);
/* IE10+ */
background: linear-gradient(to bottom, rgba(0, 0, 0, 0.5) 0%, rgba(216, 38, 38, 0.7) 100%);
/* W3C */
}</style><div style="background:rgba(0,0,0,0.5);background:-moz-linear-gradient(top,rgba(0,0,0,0.5) 0%,rgba(0,0,0,0.7) 100%);background:-o-linear-gradient(top,rgba(0,0,0,0.5) 0%,rgba(0,0,0,0.7) 100%);background:-ms-linear-gradient(top,rgba(0,0,0,0.5) 0%,rgba(0,0,0,0.7) 100%);background: rgba(0,0,0,0.5);background: -moz-linear-gradient(top, rgba(0,0,0,0.5) 0%,rgba(0,0,0,0.7) 100%); /* FF3.6+ */background: -webkit-gradient(linear, left top, left bottom, color-stop(0%,rgba(0,0,0,0.5)), color-stop(100%,rgba(0,0,0,0.7))); /* Chrome,Safari4+ *//* background: -webkit-linear-gradient(top, rgba(0,0,0,0.5) 0%,rgba(0,0,0,0.7) 100%); */ /* Chrome10+,Safari5.1+ */background: -o-linear-gradient(top, rgba(0,0,0,0.5) 0%,rgba(0,0,0,0.7) 100%); /* Opera 11.10+ */background: -ms-linear-gradient(top, rgba(0,0,0,0.5) 0%,rgba(0,0,0,0.7) 100%); /* IE10+ */background: linear-gradient(to bottom, rgba(0,0,0,0.5) 0%,rgba(216, 30, 30, 0.7) 100%); /* W3C */"><p>This is heading</p></div></html>It is working on Gmail but not in Outlook.
Screenshot of the Gmail
Screenshot of the Outlook
Please correct me what I am doing wrong.