* {
  box-sizing: border-box;
}

html, body {
  width: 100%;
  height: 100%;
  margin: 0;
  background: #fff;
  font-family: Arial, sans-serif;
}

#ai-chatbot {
  height: 100%;
  display: flex;
  flex-direction: column;
}

/* header */
#chat-header {
  background: #c40000;
  color: #fff;
  padding: 12px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

/* body */
#chat-body {
  flex: 1;
  padding: 10px;
  overflow-y: auto;
  background: #fafafa;
}

/* footer */
#chat-footer {
  display: flex;
  border-top: 1px solid #ddd;
}

#chat-input {
  flex: 1;
  padding: 10px;
  border: none;
}

#chat-send {
  padding: 0 16px;
  border: none;
  background: #c40000;
  color: #fff;
  cursor: pointer;
}

#chat-close {
  background: none;
  border: none;
  color: #fff;
  font-size: 18px;
  cursor: pointer;
}