body {
  margin: 0;
  font-family: 'Segoe UI', sans-serif;
  background: linear-gradient(to right, #83a4d4, #b6fbff);
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
}
.container {
  width: 100%;
  max-width: 700px;
}
.card {
  background: white;
  border-radius: 12px;
  box-shadow: 0 4px 20px rgba(0,0,0,0.2);
  padding: 20px;
  animation: fadeIn 0.5s ease-in-out;
}
.chat-header {
  display: flex;
  align-items: center;
  gap: 15px;
  border-bottom: 1px solid #ccc;
  padding-bottom: 10px;
}
.avatar {
  width: 50px; height: 50px;
  background: #0078d7;
  border-radius: 50%;
}
.chat-body {
  display: flex;
  gap: 10px;
}
.chat-users {
  width: 120px;
  border-right: 1px solid #ddd;
}
.chat-users div {
  background: #f0f0f0;
  padding: 6px;
  margin: 4px 0;
  border-radius: 8px;
}
.chat-messages {
  flex: 1;
  height: 300px;
  overflow-y: auto;
  background: #fdfdfd;
  padding: 10px;
}
.chat-input {
  margin-top: 10px;
  display: flex;
  gap: 5px;
}
.chat-input input[type="text"] {
  flex: 1;
  padding: 8px;
}
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}