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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    padding: 20px;
    color: #333;
}

.container {
    max-width: 900px;
    margin: 0 auto;
    background: white;
    border-radius: 20px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    overflow: hidden;
}

header {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 40px 30px;
    text-align: center;
}

header h1 {
    font-size: 2.5em;
    margin-bottom: 10px;
    font-weight: 700;
}

.subtitle {
    font-size: 1.1em;
    opacity: 0.9;
}

main {
    padding: 40px 30px;
}

.upload-section {
    margin-bottom: 40px;
}

.upload-area {
    border: 3px dashed #667eea;
    border-radius: 15px;
    padding: 60px 20px;
    text-align: center;
    background: #f8f9ff;
    cursor: pointer;
    transition: all 0.3s ease;
    margin-bottom: 20px;
}

.upload-area:hover {
    border-color: #764ba2;
    background: #f0f2ff;
    transform: translateY(-2px);
}

.upload-area.dragover {
    border-color: #764ba2;
    background: #e8ebff;
    transform: scale(1.02);
}

.upload-icon {
    font-size: 4em;
    margin-bottom: 20px;
}

.upload-text {
    font-size: 1.3em;
    color: #667eea;
    font-weight: 600;
    margin-bottom: 10px;
}

.upload-hint {
    font-size: 0.9em;
    color: #999;
}

.file-list {
    background: #f8f9ff;
    border-radius: 10px;
    padding: 20px;
    margin-bottom: 20px;
}

.file-list h3 {
    margin-bottom: 15px;
    color: #667eea;
}

.file-list ul {
    list-style: none;
}

.file-list li {
    padding: 12px;
    background: white;
    border-radius: 8px;
    margin-bottom: 10px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
}

.file-list li:last-child {
    margin-bottom: 0;
}

.file-name {
    flex: 1;
    color: #333;
    font-weight: 500;
}

.file-size {
    color: #999;
    font-size: 0.9em;
    margin-left: 15px;
}

.action-buttons {
    display: flex;
    gap: 15px;
    justify-content: center;
    margin-bottom: 20px;
}

.btn {
    padding: 15px 40px;
    border: none;
    border-radius: 8px;
    font-size: 1.1em;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
}

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

.btn-primary:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(102, 126, 234, 0.4);
}

.btn-primary:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.btn-secondary {
    background: #6c757d;
    color: white;
}

.btn-secondary:hover {
    background: #5a6268;
    transform: translateY(-2px);
}

.progress-section {
    margin-top: 20px;
}

.progress-bar {
    width: 100%;
    height: 30px;
    background: #e9ecef;
    border-radius: 15px;
    overflow: hidden;
    margin-bottom: 10px;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, #667eea 0%, #764ba2 100%);
    width: 0%;
    transition: width 0.3s ease;
    border-radius: 15px;
}

.progress-text {
    text-align: center;
    color: #667eea;
    font-weight: 500;
}

.message {
    padding: 15px;
    border-radius: 8px;
    margin-top: 20px;
    display: none;
}

.message.success {
    background: #d4edda;
    color: #155724;
    border: 1px solid #c3e6cb;
    display: block;
}

.message.error {
    background: #f8d7da;
    color: #721c24;
    border: 1px solid #f5c6cb;
    display: block;
}

.info-section {
    background: #f8f9ff;
    border-radius: 10px;
    padding: 25px;
    margin-top: 30px;
}

.info-section h3 {
    color: #667eea;
    margin-bottom: 15px;
}

.info-section ul {
    list-style: none;
    padding-left: 0;
}

.info-section li {
    padding: 10px 0;
    border-bottom: 1px solid #e0e0e0;
    color: #555;
}

.info-section li:last-child {
    border-bottom: none;
}

footer {
    background: #f8f9ff;
    padding: 20px;
    text-align: center;
    color: #999;
    font-size: 0.9em;
}

@media (max-width: 768px) {
    header h1 {
        font-size: 2em;
    }
    
    .upload-area {
        padding: 40px 15px;
    }
    
    .action-buttons {
        flex-direction: column;
    }
    
    .btn {
        width: 100%;
    }
}