so like the docs i made a css file in data/assets/modules/channel-web called chat.css

.bpw-from-bot .bpw-chat-bubble {
  background-color: #ececec;
}

.bpw-chat-bubble:last-of-type {
  border-bottom-right-radius: 20px;
  border-bottom-left-radius: 20px;
}

.bpw-chat-bubble:first-of-type {
  border-top-left-radius: 20px;
  border-top-right-radius: 20px;
}

.bpw-from-user .bpw-chat-bubble:last-of-type {
  border-bottom-right-radius: 0px;
}

.bpw-from-bot .bpw-chat-bubble:last-of-type {
  border-bottom-left-radius: 0px;
}

.bpw-from-user .bpw-chat-bubble {
  background-color: #4278f3;
  color: #ffffff;
}

.bpw-date-container .bpw-small-line {
  border-bottom: none;
}

.bpw-date-container {
  font-weight: 700;
  font-size: 14px;
}

.bpw-header-container {
  background-color: #f8f8f8;
  border-bottom: none;
}

.bpw-bot-avatar img,
.bpw-bot-avatar svg {
  border: none;
  border-radius: 50%;
}

.bpw-composer {
  padding: 10px;
  background: none;
  border: none;
}

.bpw-composer textarea {
  background: #ececec;
  border-radius: 20px;
  font-size: 1.25rem;
  overflow: hidden;
}

.send-btn {
  position: absolute;
  right: 30px;
  bottom: 28px;
  border: none;
  border-radius: 5px;
  background: #fff;
  padding: 5px;
  font-size: 14px;
  font-weight: 500;
  cursor: pointer;
}

.send-btn:hover {
  background: #d8d8d8;
}