style.css

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

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

.container {
    width: 100%;
    max-width: 800px;
    background: white;
    border-radius: 20px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    overflow: hidden;
    position: relative;
}

header {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 25px;
    text-align: center;
}

header h1 {
    font-size: 28px;
    margin-bottom: 5px;
}

header p {
    opacity: 0.9;
    font-size: 14px;
}

.chat-container {
    display: flex;
    flex-direction: column;
    height: 500px;
}

.chat-messages {
    flex: 1;
    overflow-y: auto;
    padding: 20px;
    background: #f8f9fa;
}

.message {
    display: flex;
    margin-bottom: 15px;
    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-content {
    max-width: 70%;
    padding: 12px 16px;
    border-radius: 18px;
    word-wrap: break-word;
    line-height: 1.4;
}

.message.user .message-content {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border-bottom-right-radius: 4px;
}

.message.assistant .message-content {
    background: white;
    color: #333;
    border-bottom-left-radius: 4px;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
}

.input-container {
    display: flex;
    padding: 20px;
    background: white;
    border-top: 1px solid #e0e0e0;
    gap: 10px;
}

#userInput {
    flex: 1;
    padding: 12px 16px;
    border: 2px solid #e0e0e0;
    border-radius: 25px;
    font-size: 16px;
    outline: none;
    transition: border-color 0.3s;
}

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

#userInput:disabled {
    background: #f5f5f5;
    cursor: not-allowed;
}

#sendButton {
    width: 50px;
    height: 50px;
    border-radius: 50%;
    border: none;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: transform 0.2s, opacity 0.2s;
}

#sendButton:hover:not(:disabled) {
    transform: scale(1.05);
}

#sendButton:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.loading-indicator {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    text-align: center;
    background: white;
    padding: 30px;
    border-radius: 15px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
    z-index: 10;
}

.spinner {
    width: 50px;
    height: 50px;
    border: 4px solid #f3f3f3;
    border-top: 4px solid #667eea;
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin: 0 auto 15px;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

.typing-indicator {
    display: inline-flex;
    gap: 4px;
}

.typing-indicator span {
    width: 8px;
    height: 8px;
    background: #667eea;
    border-radius: 50%;
    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);
        opacity: 0.5;
    }
    30% {
        transform: translateY(-10px);
        opacity: 1;
    }
}

.error-message {
    color: #d32f2f;
    font-size: 16px;
}

@media (max-width: 600px) {
    .container {
        border-radius: 0;
        height: 100vh;
        max-width: 100%;
    }
    
    .chat-container {
        height: calc(100vh - 120px);
    }
    
    .message-content {
        max-width: 85%;
    }
    
    header h1 {
        font-size: 24px;
    }
}