body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    background-color: #f4f4f9;
}

#app {
    width: 100%;
    max-width: 400px;
    margin: auto;
    text-align: center;
    background: #fff;
    border-radius: 8px;
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.2);
    overflow: hidden;
}

#login-screen, #chat-screen {
    padding: 20px;
}

input[type="text"] {
    width: calc(100% - 20px);
    padding: 10px;
    margin-bottom: 10px;
    border: 1px solid #ddd;
    border-radius: 4px;
}

button {
    width: 100%;
    padding: 10px;
    background-color: #007bff;
    color: #fff;
    border: none;
    border-radius: 4px;
    cursor: pointer;
}

button:hover {
    background-color: #0056b3;
}

#chat-container {
    height: 300px;
    overflow-y: auto;
    border: 1px solid #ddd;
    padding: 10px;
    margin-bottom: 10px;
    background: #fafafa;
}

#messages {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.message {
    text-align: left;
    padding: 10px;
    background: #e9ecef;
    border-radius: 4px;
}