<link href="//maxcdn.bootstrapcdn.com/bootstrap/3.3.0/css/bootstrap.min.css" rel="stylesheet" id="bootstrap-css">
<script src="//maxcdn.bootstrapcdn.com/bootstrap/3.3.0/js/bootstrap.min.js"></script>
<script src="//code.jquery.com/jquery-1.11.1.min.js"></script>
<!------ Include the above in your HEAD tag ---------->
<div class="container">
<div class="row">
<h2>Create your snippet's HTML, CSS and Javascript in the editor tabs</h2>
</div>
</div>
background: linear-gradient(-135deg, transparent 5em, #58a 0);
background:
linear-gradient(to left bottom,
transparent 50%, rgba(0,0,0,.4) 0)
no-repeat 100% 0 / 2em 2em;
// folded corner:
background: #58a; /* Fallback */
background:
linear-gradient(to left bottom,
transparent 50%, rgba(0,0,0,.4) 0)
no-repeat 100% 0 / 2em 2em,
linear-gradient(-135deg,
transparent 1.4em, #58a 0);
.note {
position: relative;
background: #58a; /* Fallback */
background:
linear-gradient(-150deg,
transparent 1.5em, #58a 0);
border-radius: .5em;
}
.note::before {
content: '';
position: absolute;
top: 0; right: 0;
background: linear-gradient(to left bottom,
transparent 50%, rgba(0,0,0,.2) 0, rgba(0,0,0,.4))
100% 0 no-repeat;
width: 1.73em;
height: 3em;
transform: translateY(-1.3em) rotate(-30deg);
transform-origin: bottom right;
border-bottom-left-radius: inherit;
box-shadow: -.2em .2em .3em -.1em rgba(0,0,0,.15);
}
@mixin folded-corner($background, $size,
$angle: 30deg) {
position: relative;
background: $background; /* Fallback */
background:
linear-gradient($angle - 180deg,
transparent $size, $background 0);
border-radius: .5em;
$x: $size / sin($angle);
$y: $size / cos($angle);
&::before {
content: '';
position: absolute;
top: 0; right: 0;
background: linear-gradient(to left bottom,
transparent 50%, rgba(0,0,0,.2) 0,
rgba(0,0,0,.4)) 100% 0 no-repeat;
width: $y; height: $x;
transform: translateY($y - $x)
rotate(2*$angle - 90deg);
transform-origin: bottom right;
border-bottom-left-radius: inherit;
box-shadow: -.2em .2em .3em -.1em rgba(0,0,0,.2);
}
}
/* used as... */
.note {
@include folded-corner(#58a, 2em, 40deg);
}