app.css

.app{
  display:flex;
  flex-direction: row;
  flex-wrap: nowrap;
  height: 100vh;
  font-size: 16px;
}
.nav{
  flex-basis: 20%;
}

.messages-container{
  flex-basis: 80%;
  margin-bottom: 0;
  height: 100vh;
}
.support, .users{
  height: 50vh;
  margin-bottom: 0;
}
.channels, .users, .messages{
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}
.channels, .users{
  height: 88%;
}
.messages{
  height: 94%;
}
.channels > ul, .messages > ul, .users > ul{
  flex: 1;
  overflow-y: auto;
}
.message{
  /*display: flex;*/
}
.message > .author{
  flex-basis: 100%;
}
.message > .body{
  flex-basis: 100%;
}
.active {
  background-color: #E8E8E8;
}
.timestamp{
  color: #808080;
  font-style: italic;
  padding-left: 10px;
  font-size: 13px;
}
.form-group{
  margin-bottom: 0;
}
ul{
  list-style-type:none;
  padding: 0;
}
li{
  padding: 0 4px 0 4px;
}
a{
  cursor: pointer;
}