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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 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);
    display: flex;
    flex-direction: column;
    height: 90vh;
    max-height: 800px;
    overflow: hidden;
}

header {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 20px 30px;
    text-align: center;
}

header h1 {
    font-size: 24px;
    margin-bottom: 5px;
}

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

.chat-container {
    flex: 1;
    overflow-y: auto;
    padding: 20px;
    display: flex;
    flex-direction: column;
    gap: 15px;
    background: #f8f9fa;
}

.chat-container::-webkit-scrollbar {
    width: 6px;
}

.chat-container::-webkit-scrollbar-track {
    background: #f1f1f1;
}

.chat-container::-webkit-scrollbar-thumb {
    background: #888;
    border-radius: 3px;
}

.chat-container::-webkit-scrollbar-thumb:hover {
    background: #555;
}

.welcome-message {
    text-align: center;
    color: #666;
    padding: 20px;
    font-style: italic;
}

.message {
    display: flex;
    gap: 10px;
    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-content {
    max-width: 70%;
    padding: 12px 16px;
    border-radius: 18px;
    word-wrap: break-word;
    line-height: 1.5;
}

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

.message.assistant .message-content {
    background: #e9ecef;
    color: #333;
    border-bottom-left-radius: 4px;
}

.message.assistant .message-content.streaming {
    background: #e9ecef;
    position: relative;
}

.message.assistant .message-content.streaming::after {
    content: '▋';
    animation: blink 1s infinite;
    margin-left: 2px;
}

@keyframes blink {
    0%, 50% { opacity: 1; }
    51%, 100% { opacity: 0; }
}

.avatar {
    width: 32px;
    height: 32px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 18px;
    flex-shrink: 0;
}

.message.user .avatar {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    order: 2;
}

.message.assistant .avatar {
    background: #667eea;
    color: white;
}

.input-container {
    padding: 20px;
    background: white;
    border-top: 1px solid #e9ecef;
}

#chatForm {
    display: flex;
    gap: 10px;
    align-items: flex-end;
}

#messageInput {
    flex: 1;
    padding: 12px 16px;
    border: 2px solid #e9ecef;
    border-radius: 20px;
    font-size: 14px;
    font-family: inherit;
    resize: none;
    max-height: 120px;
    overflow-y: auto;
    transition: border-color 0.2s;
}

#messageInput:focus {
    outline: none;
    border-color: #667eea;
}

#messageInput:disabled {
    background: #f8f9fa;
    cursor: not-allowed;
}

#sendButton {
    width: 44px;
    height: 44px;
    border: none;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: transform 0.2s, opacity 0.2s;
    flex-shrink: 0;
}

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

#sendButton:active:not(:disabled) {
    transform: scale(0.95);
}

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

.error-message {
    background: #fee;
    color: #c33;
    padding: 12px 16px;
    border-radius: 18px;
    border: 1px solid #fcc;
    margin: 10px 0;
}

.loading {
    display: inline-block;
    width: 12px;
    height: 12px;
    border: 2px solid #667eea;
    border-radius: 50%;
    border-top-color: transparent;
    animation: spin 0.6s linear infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

@media (max-width: 600px) {
    .container {
        height: 100vh;
        max-height: 100vh;
        border-radius: 0;
    }
    
    .message-content {
        max-width: 85%;
    }
}