body {
  font-family: sans-serif;
  background: #f5f5f5;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  height: 100vh;
}
header {
  background: #0078d7;
  color: white;
  padding: 10px;
  text-align: center;
}
main {
  flex: 1;
  display: flex;
  flex-direction: column;
  padding: 10px;
}
#chat-box {
  flex: 1;
  overflow-y: auto;
  background: white;
  padding: 10px;
  margin-bottom: 10px;
  border-radius: 8px;
}
#chat-box p {
  margin: 5px 0;
}
form {
  display: flex;
}
input[type="text"] {
  flex: 1;
  padding: 10px;
  border-radius: 8px 0 0 8px;
  border: 1px solid #ccc;
}
button {
  padding: 10px 15px;
  border: none;
  background: #0078d7;
  color: white;
  border-radius: 0 8px 8px 0;
  cursor: pointer;
}