* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 20px;
}

.container {
    background: white;
    border-radius: 12px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    max-width: 800px;
    width: 100%;
    height: 90vh;
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

header {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 24px;
    text-align: center;
}

header h1 {
    font-size: 28px;
    margin-bottom: 8px;
    font-weight: 600;
}

.subtitle {
    font-size: 14px;
    opacity: 0.95;
    line-height: 1.5;
}

.messages {
    flex: 1;
    overflow-y: auto;
    padding: 20px;
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.message {
    display: flex;
    animation: fadeIn 0.3s ease-in;
}

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

.message.user {
    justify-content: flex-end;
}

.message.assistant {
    justify-content: flex-start;
}

.message-bubble {
    max-width: 75%;
    padding: 12px 16px;
    border-radius: 18px;
    line-height: 1.5;
    white-space: pre-wrap;
    word-wrap: break-word;
}

.message.user .message-bubble {
    background: #667eea;
    color: white;
    border-bottom-right-radius: 4px;
}

.message.assistant .message-bubble {
    background: #f1f3f5;
    color: #212529;
    border-bottom-left-radius: 4px;
}

.input-area {
    padding: 20px;
    background: #f8f9fa;
    border-top: 1px solid #e9ecef;
    display: flex;
    gap: 12px;
}

#userInput {
    flex: 1;
    padding: 12px;
    border: 1px solid #dee2e6;
    border-radius: 8px;
    font-family: inherit;
    font-size: 14px;
    resize: none;
    outline: none;
    transition: border-color 0.2s;
}

#userInput:focus {
    border-color: #667eea;
}

#sendBtn {
    padding: 12px 24px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    transition: transform 0.2s, box-shadow 0.2s;
}

#sendBtn:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(102, 126, 234, 0.4);
}

#sendBtn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

.typing-indicator {
    display: flex;
    gap: 4px;
    padding: 12px 16px;
}

.typing-indicator span {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: #adb5bd;
    animation: typing 1.4s infinite;
}

.typing-indicator span:nth-child(2) {
    animation-delay: 0.2s;
}

.typing-indicator span:nth-child(3) {
    animation-delay: 0.4s;
}

@keyframes typing {
    0%, 60%, 100% {
        transform: translateY(0);
    }
    30% {
        transform: translateY(-10px);
    }
}

.messages::-webkit-scrollbar {
    width: 6px;
}

.messages::-webkit-scrollbar-track {
    background: transparent;
}

.messages::-webkit-scrollbar-thumb {
    background: #dee2e6;
    border-radius: 3px;
}

.messages::-webkit-scrollbar-thumb:hover {
    background: #adb5bd;
}