* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: Arial, sans-serif;
}

body {
    background-color: #f5f5f5;
    height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
}

.chat-container {
    width: 90%;
    max-width: 800px;
    height: 80vh;
    background-color: #fff;
    border-radius: 10px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

.chat-header {
    background-color: #4a6fa5;
    color: white;
    padding: 15px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.username-container {
    display: flex;
    align-items: center;
    gap: 10px;
}

.username-container input {
    padding: 5px 10px;
    border: none;
    border-radius: 3px;
    font-size: 14px;
}

.chat-messages {
    flex: 1;
    padding: 15px;
    overflow-y: auto;
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.message {
    padding: 10px 15px;
    border-radius: 18px;
    max-width: 75%;
    word-wrap: break-word;
    position: relative;
    animation: fadeIn 0.3s ease;
}

.message .username {
    font-weight: bold;
    font-size: 14px;
    margin-bottom: 3px;
}

.message .timestamp {
    font-size: 11px;
    color: #777;
    margin-top: 5px;
    text-align: right;
}

.message-container {
    display: flex;
    flex-direction: column;
    width: 100%;
}

.message-container.user-message {
    align-items: flex-end;
}

.user-message .message {
    background-color: #4a6fa5;
    color: white;
    border-bottom-right-radius: 3px;
}

.other-message .message {
    background-color: #e9e9e9;
    color: #333;
    border-bottom-left-radius: 3px;
}

.chat-input {
    padding: 15px;
    background-color: #f9f9f9;
    border-top: 1px solid #ddd;
}

.chat-input form {
    display: flex;
    gap: 10px;
}

.chat-input input {
    flex: 1;
    padding: 10px 15px;
    border: 1px solid #ddd;
    border-radius: 25px;
    font-size: 16px;
    outline: none;
}

.chat-input button {
    background-color: #4a6fa5;
    color: white;
    border: none;
    padding: 10px 20px;
    border-radius: 25px;
    cursor: pointer;
    font-size: 16px;
    transition: background-color 0.2s;
}

.chat-input button:hover {
    background-color: #3a5d8f;
}

.loading-message {
    text-align: center;
    color: #777;
    margin: auto;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

/* Responsive design */
@media (max-width: 768px) {
    .chat-container {
        width: 95%;
        height: 90vh;
    }
    
    .chat-header {
        flex-direction: column;
        gap: 10px;
        align-items: flex-start;
    }
    
    .message {
        max-width: 85%;
    }
}