Modèle

<link href="https://fonts.googleapis.com/css?family=Lato:400,700" rel="stylesheet">

<style type='text/css'>.vtel{background-image: url(http://i.imgur.com/xA5has3.png); width: 350px; height: 600px; margin: auto; text-align: center;}.vpseudo{font-family: Lato, sans-serif; font-size: 13px; color: black; font-weight: bold; padding-top: 80px; padding-bottom: 5px;}.vbg{width: 240px; height: 357px; margin-left: 52px; padding-top: 8px; overflow: auto;}.vm1{width: 180px; background-color: #007dfd; float: right; color: white; font-family: Lato, sans-serif; font-size: 10px; text-align: justify; margin-right: 5px; padding: 5px 8px; margin-bottom: 8px; border-radius: 15px; position: relative;}.vf1{width: 0; height: 0; border-right: 4px solid #007dfd; border-bottom: 4px solid #007dfd; border-top: 4px solid transparent; border-left: 4px solid transparent; position: absolute; bottom: 6px; right: 0px;}.vm2{width: 180px; background-color: #E6E5EB; float: left; color: black; font-family: Lato, sans-serif; font-size: 10px; text-align: justify; margin-left: 5px; padding: 5px 8px; margin-bottom: 8px; border-radius: 15px; position: relative;}.vf2{width: 0; height: 0; border-left: 4px solid #E6E5EB; border-bottom: 4px solid #E6E5EB; border-top: 4px solid transparent; border-right: 4px solid transparent; position: absolute; bottom: 6px; left: 0px;}/*fait par vercors sur bazzart, merci de ne pas vous l'approrier*/</style>

<div class="vtel"><div class="vpseudo">Pseudo</div><div class="vbg"><div class="vm1"><div class="vf1"></div>message envoyé ici. message envoyé ici. message envoyé ici.</div>
<div class="vm2"><div class="vf2"></div>message reçu là. message reçu là. message reçu là.</div>
</div></div>

<div class="vm2"><div class="vf2"></div>message reçu.</div>

<div class="vm1"><div class="vf1"></div>message envoyé.</div>