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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    color: #333;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
}

header {
    text-align: center;
    margin-bottom: 30px;
    color: white;
}

header h1 {
    font-size: 2.5rem;
    margin-bottom: 10px;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.3);
}

header p {
    font-size: 1.1rem;
    opacity: 0.9;
}

.main-content {
    display: grid;
    grid-template-columns: 1fr 2fr;
    gap: 30px;
    margin-bottom: 30px;
}

.upload-section, .chat-section {
    background: white;
    border-radius: 15px;
    padding: 25px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.2);
}

.upload-section h2, .chat-section h2 {
    margin-bottom: 20px;
    color: #4a5568;
    font-size: 1.5rem;
}

.file-upload-area {
    border: 3px dashed #cbd5e0;
    border-radius: 10px;
    padding: 40px 20px;
    text-align: center;
    transition: all 0.3s ease;
    cursor: pointer;
}

.file-upload-area:hover {
    border-color: #667eea;
    background-color: #f7fafc;
}

.file-upload-area.dragover {
    border-color: #667eea;
    background-color: #edf2f7;
}

.upload-icon {
    font-size: 3rem;
    margin-bottom: 15px;
}

.upload-btn {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border: none;
    padding: 12px 24px;
    border-radius: 8px;
    cursor: pointer;
    font-size: 1rem;
    transition: transform 0.2s ease;
}

.upload-btn:hover {
    transform: translateY(-2px);
}

.file-info {
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: #f7fafc;
    padding: 15px;
    border-radius: 8px;
    margin-top: 15px;
}

.remove-btn {
    background: #e53e3e;
    color: white;
    border: none;
    padding: 8px 16px;
    border-radius: 6px;
    cursor: pointer;
    font-size: 0.9rem;
}

.remove-btn:hover {
    background: #c53030;
}

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

.chat-messages {
    flex: 1;
    overflow-y: auto;
    padding: 15px;
    background: #f8f9fa;
    border-radius: 10px;
    margin-bottom: 15px;
    border: 1px solid #e2e8f0;
}

.message {
    margin-bottom: 15px;
    display: flex;
    flex-direction: column;
}

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

.ai-message {
    align-items: flex-start;
}

.message-content {
    max-width: 80%;
    padding: 12px 16px;
    border-radius: 18px;
    word-wrap: break-word;
}

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

.ai-message .message-content {
    background: white;
    border: 1px solid #e2e8f0;
    color: #2d3748;
}

.chat-input-container {
    display: flex;
    gap: 10px;
    align-items: flex-end;
}

#chatInput {
    flex: 1;
    padding: 12px 16px;
    border: 2px solid #e2e8f0;
    border-radius: 10px;
    resize: vertical;
    font-family: inherit;
    font-size: 1rem;
    transition: border-color 0.3s ease;
}

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

#sendBtn {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border: none;
    padding: 12px 24px;
    border-radius: 10px;
    cursor: pointer;
    font-size: 1rem;
    transition: transform 0.2s ease;
    white-space: nowrap;
}

#sendBtn:hover {
    transform: translateY(-2px);
}

#sendBtn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
    transform: none;
}

.loading {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0,0,0,0.7);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    z-index: 1000;
}

.spinner {
    width: 50px;
    height: 50px;
    border: 5px solid #f3f3f3;
    border-top: 5px solid #667eea;
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin-bottom: 20px;
}

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

.loading p {
    color: white;
    font-size: 1.2rem;
}

/* Responsive Design */
@media (max-width: 768px) {
    .main-content {
        grid-template-columns: 1fr;
        gap: 20px;
    }
    
    .container {
        padding: 15px;
    }
    
    header h1 {
        font-size: 2rem;
    }
    
    .chat-container {
        height: 400px;
    }
    
    .message-content {
        max-width: 90%;
    }
}

/* Scrollbar Styling */
.chat-messages::-webkit-scrollbar {
    width: 6px;
}

.chat-messages::-webkit-scrollbar-track {
    background: #f1f1f1;
    border-radius: 3px;
}

.chat-messages::-webkit-scrollbar-thumb {
    background: #c1c1c1;
    border-radius: 3px;
}

.chat-messages::-webkit-scrollbar-thumb:hover {
    background: #a8a8a8;
}