* {
    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, #f5f7fa 0%, #c3cfe2 100%);
    min-height: 100vh;
    line-height: 1.6;
}

.main-container {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    position: relative;
}

.header {
    text-align: center;
    padding: 1.5rem 1rem 0.5rem;
    background: transparent;
}

.logo {
    height: 220px;
    width: auto;
    margin-bottom: 0.5rem;
    filter: drop-shadow(0 4px 8px rgba(0,0,0,0.1));
}

.title {
    font-size: clamp(1.4rem, 3vw, 2.2rem);
    font-weight: 700;
    color: #4a5568;
    text-shadow: none;
    margin: 0;
}

.content {
    flex: 1;
    display: flex;
    align-items: flex-start;
    justify-content: center;
    padding: 1rem 1rem 2rem;
}

.upload-card {
    background: transparent;
    max-width: 500px;
    width: 100%;
    text-align: center;
}

.upload-area {
    border: none;
    padding: 2rem;
    cursor: pointer;
    background: transparent;
}

.upload-text {
    font-size: 1.2rem;
    font-weight: 600;
    color: #2d3748;
    margin-bottom: 1rem;
}

.btn {
    background: rgba(255, 255, 255, 0.8);
    color: #4a5568;
    border: 1px solid rgba(74, 85, 104, 0.2);
    padding: 0.75rem 2rem;
    border-radius: 50px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    backdrop-filter: blur(10px);
}

.btn:hover {
    background: rgba(255, 255, 255, 0.9);
    border-color: rgba(74, 85, 104, 0.3);
}

#fileInput {
    display: none;
}

.progress-container {
    display: none;
    margin-top: 2rem;
}

.progress-bar {
    width: 100%;
    height: 8px;
    background: #e2e8f0;
    border-radius: 4px;
    overflow: hidden;
    margin-bottom: 1rem;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, #667eea, #764ba2);
    width: 0%;
    transition: width 0.3s ease;
    border-radius: 4px;
}

.progress-text {
    color: #4a5568;
    font-weight: 500;
}

.result-container {
    display: none;
    text-align: center;
    margin-top: 2rem;
    background: transparent;
}

.result-title {
    font-size: 1rem;
    font-weight: 600;
    color: #2d3748;
    margin-bottom: 0.5rem;
}

.result-text {
    color: #718096;
    margin-bottom: 1.5rem;
}

.download-section {
    margin-top: 1rem;
}

.download-btn {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border: none;
    padding: 0.875rem 2rem;
    border-radius: 50px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px rgba(102, 126, 234, 0.3);
    margin-bottom: 1rem;
    display: block;
    width: 100%;
    max-width: 280px;
    margin: 0 auto 1rem;
}

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

.download-btn:disabled {
    opacity: 0.7;
    cursor: not-allowed;
    transform: none;
}

.file-info {
    color: #718096;
    font-size: 0.9rem;
    margin-top: 0.5rem;
}

.error-container {
    display: none;
    background: transparent;
    color: #c53030;
    padding: 1rem;
    margin-top: 1rem;
}

.footer {
    text-align: center;
    padding: 1rem;
    color: rgba(74, 85, 104, 0.7);
    font-size: 0.9rem;
}

/* Responsive Design */
@media (max-width: 768px) {
    .header {
        padding: 1.5rem 1rem;
    }

    .logo {
        height: 120px;
    }

    .upload-card {
        padding: 2rem 1.5rem;
        margin: 0 1rem;
    }

    .upload-area {
        padding: 1.5rem;
    }

    .upload-text {
        font-size: 1rem;
    }
}

@media (max-width: 480px) {
    .header {
        padding: 1rem;
    }

    .logo {
        height: 100px;
    }

    .upload-card {
        padding: 1.5rem 1rem;
        border-radius: 15px;
    }

    .upload-area {
        padding: 1rem;
    }

    .btn {
        padding: 0.6rem 1.5rem;
        font-size: 0.9rem;
    }
    
    .download-btn {
        padding: 0.75rem 1.5rem;
        font-size: 0.9rem;
        max-width: 100%;
    }
}