body {
    padding-top: 50px;
}
.sent {
    border-top-left-radius: 2em;
    border-bottom-left-radius: 2em;
}
.received {
    border-top-right-radius: 2em;
    border-bottom-right-radius: 2em;
}
#initialisation{
    padding-left: 100px;
}