Irregular Div shape Distort one corner only - css

Question

How would i create a div shape like this? I have read a lot of techniques but i could not figure this one out. Inside the div is text that should not be distorted.
Every technique is welcome it does not have to be pure css.
My HTML structure:
<div class="intro">
<div class="intro-header">
<h1>Headline WOW</h1>
</div>
<div class="intro-text">
<p>Mieleni minun tekevi, aivoni ajattelevi lähteäni laulamahan, saa'ani sanelemasaa'ani sanelema sanelemasaa'ani sanelema </p>
</div>
</div>

Answer 1

you could use some skewed pseudo elements for this:
.first,
.last {
text-align: center;
line-height: 80px;
height: 80px;
background: green;
position: relative;
display: inline-block;
width: 400px;
margin-bottom: 20px;
}
.first:after {
content: "";
position: absolute;
bottom: 0;
left: 0;
height: 50%;
width: 100%;
transform: SkewY(2deg);
transform-origin: bottom left;
background: inherit;
}
.last:before {
content: "";
position: absolute;
top: 0;
left: 0;
height: 50%;
width: 100%;
transform: SkewY(2deg);
transform-origin: bottom right;
background: inherit;
}
<div class="first">FIRST LINE</div>
<div class="last">LAST LINE</div>
An alternative (possibly) would be to use a gradient (although this may lead to jagged edges). Solution credit to Harry
body {
background: -webkit-linear-gradient(0deg, crimson, indianred, purple);
}
div {
height: 400px;
width: 400px;
background: -webkit-linear-gradient(75deg, lightseagreen 45%, transparent 45%, transparent 55%, lightseagreen 55%);
}
<div></div>

Answer 2

You can do this with border cut-offs.
As an example:
.top {
height: 300px;
background: red;
position: relative;
width: 300px
}
.top:before {
content: '';
position: absolute;
bottom: 0;
right: 0;
border-bottom: 10px solid white;
border-right: 300px solid red;
width: 0;
}
.bottom {
height: 300px;
background: red;
position: relative;
width: 300px;
padding-top: 10px;
margin-top: 0px;
}
.bottom:before {
content: '';
position: absolute;
top: 0;
right: 0;
border-top: 10px solid white;
border-left: 300px solid red;
width: 0;
}
<div class="top">Text</div>
<div class="bottom">Text</div>

Answer 3

This should do it.
html,body{
margin:0;
height:100%;
}
.intro{
width:400px;
display:inline-block;
background:red;
padding:50px;
}
.intro-header,.intro-text{
width:100%;
display:inline-block;
background:#ccc;
text-align:center;
position:relative;
}
.intro-header{
margin-bottom:50px;
}
.intro-header:after{
position:absolute;
left:0;
content:"";
width: 0;
height: 0;
border-left: 400px solid transparent;
border-top: 20px solid #ccc;
}
.intro-text:after{
position:absolute;
top:-20px;
left:0;
content:"";
width: 0;
height: 0;
border-right: 400px solid transparent;
border-bottom: 20px solid #ccc;
}
Example: CodePen