* {
    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;
    padding: 20px;
}

.container {
    max-width: 800px;
    margin: 0 auto;
    background: rgba(255, 255, 255, 0.95);
    border-radius: 20px;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.1);
    overflow: hidden;
    backdrop-filter: blur(10px);
}

.header {
    background: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
    color: white;
    padding: 30px;
    text-align: center;
}

.header h1 {
    font-size: 2.5rem;
    margin-bottom: 10px;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
}

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

.main-content {
    padding: 40px;
}

.upload-section {
    border: 3px dashed #4facfe;
    border-radius: 15px;
    padding: 40px;
    text-align: center;
    margin-bottom: 30px;
    background: rgba(79, 172, 254, 0.05);
    transition: all 0.3s ease;
    cursor: pointer;
}

.upload-section:hover {
    border-color: #00f2fe;
    background: rgba(79, 172, 254, 0.1);
    transform: translateY(-2px);
}

.upload-section.dragover {
    border-color: #00f2fe;
    background: rgba(79, 172, 254, 0.15);
    transform: scale(1.02);
}

.upload-icon {
    font-size: 4rem;
    color: #4facfe;
    margin-bottom: 20px;
}

.upload-text {
    font-size: 1.2rem;
    color: #333;
    margin-bottom: 15px;
}

.upload-subtext {
    color: #666;
    font-size: 0.9rem;
}

#fileInput {
    display: none;
}

.file-list {
    margin: 30px 0;
}

.file-item {
    display: flex;
    align-items: center;
    padding: 15px;
    background: #f8f9fa;
    border-radius: 10px;
    margin-bottom: 10px;
    border-left: 4px solid #4facfe;
    transition: all 0.3s ease;
}

.file-item:hover {
    background: #e9ecef;
    transform: translateX(5px);
}

.file-info {
    flex: 1;
    margin-left: 15px;
}

.file-name {
    font-weight: bold;
    color: #333;
    margin-bottom: 5px;
}

.file-size {
    color: #666;
    font-size: 0.9rem;
}

.file-status {
    padding: 5px 15px;
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: bold;
}

.status-ready {
    background: #e3f2fd;
    color: #1976d2;
}

.status-converting {
    background: #fff3e0;
    color: #f57c00;
}

.status-complete {
    background: #e8f5e8;
    color: #388e3c;
}

.remove-btn {
    background: #ff4757;
    color: white;
    border: none;
    padding: 8px 12px;
    border-radius: 5px;
    cursor: pointer;
    margin-left: 10px;
    transition: background 0.3s;
}

.remove-btn:hover {
    background: #ff3838;
}

.convert-section {
    text-align: center;
    margin: 30px 0;
}

.convert-btn {
    background: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
    color: white;
    border: none;
    padding: 15px 40px;
    font-size: 1.1rem;
    border-radius: 50px;
    cursor: pointer;
    transition: all 0.3s ease;
    font-weight: bold;
    text-transform: uppercase;
    letter-spacing: 1px;
    box-shadow: 0 10px 30px rgba(79, 172, 254, 0.3);
}

.convert-btn:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 15px 40px rgba(79, 172, 254, 0.4);
}

.convert-btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
    transform: none;
}

.progress-bar {
    width: 100%;
    height: 8px;
    background: #e9ecef;
    border-radius: 4px;
    overflow: hidden;
    margin: 20px 0;
    display: none;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, #4facfe, #00f2fe);
    width: 0%;
    transition: width 0.3s ease;
}

.download-section {
    margin-top: 30px;
    padding: 20px;
    background: rgba(79, 172, 254, 0.05);
    border-radius: 15px;
    display: none;
}

.download-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 10px 0;
    border-bottom: 1px solid rgba(79, 172, 254, 0.2);
}

.download-item:last-child {
    border-bottom: none;
}

.download-btn {
    background: #28a745;
    color: white;
    border: none;
    padding: 8px 20px;
    border-radius: 5px;
    cursor: pointer;
    transition: background 0.3s;
}

.download-btn:hover {
    background: #218838;
}

.download-all-btn {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border: none;
    padding: 12px 24px;
    border-radius: 25px;
    cursor: pointer;
    font-weight: bold;
    font-size: 0.9rem;
    transition: all 0.3s ease;
    box-shadow: 0 5px 15px rgba(102, 126, 234, 0.3);
}

.download-all-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(102, 126, 234, 0.4);
}

.download-all-btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
    transform: none;
}

.file-icon {
    font-size: 2rem;
    color: #4facfe;
}

@media (max-width: 768px) {
    .container {
        margin: 10px;
    }
    
    .main-content {
        padding: 20px;
    }
    
    .header h1 {
        font-size: 2rem;
    }
    
    .upload-section {
        padding: 20px;
    }
}