Add CSS Arrow to Top Left of Div - html

Question

I have tried to tweak the CSS from
http://jsfiddle.net/wn7JN/ to place an arrow in a <div> in the top left corner (see image below), but I can't seem to figure out how :before and :after in CSS work. Every time I update the bottom and left parameters I am left with a black arrow in the top left corner - I think the proper rotation is transform: rotate(220deg) but that is really a guess.
Edit: Is it possible to do this same CSS trick with an rgba color such as rgba(255, 123, 172, 0.25)? When I test it out the transparency becomes an issue with the border overlap.
Any help would be greatly appreciated.
.bubble {
position: relative;
width: 400px;
height: 250px;
padding: 0px;
background: #FFFFFF;
border: #000 solid 1px;
-webkit-border-radius: 10px;
-moz-border-radius: 10px;
border-radius: 10px;
}
.bubble:after {
content: "";
position: absolute;
bottom: -25px;
left: 175px;
border-style: solid;
border-width: 25px 25px 0;
border-color: #FFFFFF transparent;
display: block;
width: 0;
z-index: 1;
}
.bubble:before {
content: "";
position: absolute;
top: 250px;
left: 174px;
border-style: solid;
border-width: 26px 26px 0;
border-color: #000 transparent;
display: block;
width: 0;
z-index: 0;
}
<div class="bubble"> </div>

Answer 1

Try like this. Added a working copy.
.bubble {
position: relative;
background:#cbe8f0;
height: 100px;
width:170px;
margin-left:30px;
border-radius:2px;
}
.bubble:after{
content:'';
position:absolute;
border:10px solid transparent;
border-top:10px solid #cbe8f0;
top:0px;
left:-10px;
}
<div class="bubble"> </div>

Answer 2

You can ty this solution too based on the jsfiddle.
.bubble:after
{
content: "";
position: absolute;
top:0px;
left: -21px;
border-style: solid;
border-width: 24px 0px 0px 28px;
border-color: #FFFFFF transparent;
display: block;
width: 0;
z-index: 1;
}
.bubble:before
{
content: "";
position: absolute;
top:-1px;
left:-23px;
border-style: solid;
border-width:20px 0px 0px 23px;
border-color: #000 transparent;
display: block;
width: 0;
z-index: 0;
}
http://jsfiddle.net/wn7JN/1295/

Answer 3

So, here's your bubble code:
.bubble {
position: relative;
width: 400px;
height: 250px;
padding: 0px;
background: #FFFFFF;
border: #000 solid 1px;
-webkit-border-radius: 10px;
-moz-border-radius: 10px;
border-radius: 10px;
}
Add this line to the bottom of that: margin-left:25px; This allows there to be room to the side of your bubble for the arrow to even show up. Otherwise, it's there, but you can't see it.
for your bubble:after, change the bottom: -25px to top: 21px and change left: 175px to left: -37px, and add transform: rotate(90deg); to the bottom.
for your bubble:before, change the top: 250px to top: 20px and change left: 174px to left: -39px, and add transform: rotate(90deg); to the bottom.
You will wind up with something like this:
1
Final fiddle: http://jsfiddle.net/eq6mhbwy/