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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background: #f5f7fa;
    min-height: 100vh;
    padding: 0;
    color: #333;
    margin: 0;
}

.container {
    max-width: 900px;
    margin: 0 auto;
    background: white;
    min-height: 100vh;
    box-shadow: 0 0 20px rgba(0, 0, 0, 0.05);
}

header {
    background: #007bff;
    color: white;
    padding: 25px 40px;
    text-align: left;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

header h1 {
    font-size: 1.8rem;
    margin: 0;
    font-weight: 500;
}

.subtitle {
    font-size: 0.95rem;
    opacity: 0.9;
    margin-top: 5px;
}

main {
    padding: 50px 60px;
    max-width: 700px;
    margin: 0 auto;
}

.conversion-type-section {
    margin-bottom: 35px;
}

.conversion-label {
    display: block;
    font-size: 1rem;
    font-weight: 500;
    color: #495057;
    margin-bottom: 10px;
}

.conversion-select {
    width: 100%;
    padding: 12px 16px;
    font-size: 0.95rem;
    color: #495057;
    background: white;
    border: 1px solid #ced4da;
    border-radius: 4px;
    cursor: pointer;
    transition: all 0.2s ease;
    outline: none;
}

.conversion-select:hover {
    border-color: #80bdff;
}

.conversion-select:focus {
    border-color: #80bdff;
    box-shadow: 0 0 0 0.2rem rgba(0, 123, 255, 0.25);
}

.drop-zone {
    border: 2px dashed #dee2e6;
    border-radius: 4px;
    padding: 50px 30px;
    text-align: center;
    cursor: pointer;
    transition: all 0.2s ease;
    background: #f8f9fa;
}

.drop-zone:hover {
    border-color: #007bff;
    background: #e7f1ff;
}

.drop-zone.drag-over {
    border-color: #007bff;
    background: #cfe2ff;
    border-style: solid;
}

.upload-icon {
    width: 80px;
    height: 80px;
    color: #007bff;
    margin-bottom: 20px;
}

.drop-zone h3 {
    font-size: 1.5rem;
    color: #2d3748;
    margin-bottom: 10px;
}

.drop-zone p {
    color: #718096;
    font-size: 1rem;
    margin-bottom: 5px;
}

.file-format {
    font-size: 0.875rem;
    color: #a0aec0;
    margin-top: 15px;
}

.file-info {
    display: flex;
    align-items: center;
    justify-content: space-between;
    background: #f7fafc;
    padding: 20px;
    border-radius: 12px;
    border: 2px solid #e2e8f0;
}

.file-details {
    display: flex;
    align-items: center;
    gap: 15px;
}

.file-icon {
    width: 40px;
    height: 40px;
    color: #007bff;
}

.file-name {
    font-weight: 600;
    color: #2d3748;
    margin-bottom: 5px;
}

.file-size {
    font-size: 0.875rem;
    color: #718096;
}

.btn-remove {
    width: 32px;
    height: 32px;
    border-radius: 50%;
    border: none;
    background: #fc8181;
    color: white;
    font-size: 1.2rem;
    cursor: pointer;
    transition: all 0.2s;
}

.btn-remove:hover {
    background: #f56565;
    transform: scale(1.1);
}

.actions {
    margin-top: 30px;
    text-align: center;
}

.btn-primary {
    background: #007bff;
    color: white;
    border: none;
    padding: 12px 40px;
    font-size: 1rem;
    font-weight: 500;
    border-radius: 4px;
    cursor: pointer;
    transition: all 0.2s ease;
    display: inline-flex;
    align-items: center;
    gap: 8px;
}

.btn-primary:hover:not(:disabled) {
    background: #0056b3;
}

.btn-primary:disabled {
    opacity: 0.65;
    cursor: not-allowed;
}

.btn-primary:active:not(:disabled) {
    background: #004085;
}

.spinner {
    width: 20px;
    height: 20px;
    border: 3px solid rgba(255, 255, 255, 0.3);
    border-top-color: white;
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

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

.result-section, .error-section {
    margin-top: 30px;
    animation: slideIn 0.4s ease;
}

@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.result-card {
    background: linear-gradient(135deg, #d4fc79 0%, #96e6a1 100%);
    padding: 30px;
    border-radius: 12px;
    text-align: center;
}

.result-header {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 15px;
    margin-bottom: 20px;
}

.success-icon {
    width: 40px;
    height: 40px;
    color: #22543d;
}

.result-header h3 {
    font-size: 1.8rem;
    color: #22543d;
}

.result-stats {
    background: rgba(255, 255, 255, 0.5);
    padding: 20px;
    border-radius: 8px;
    margin-bottom: 20px;
    text-align: left;
}

.result-stats p {
    color: #22543d;
    font-size: 0.95rem;
    margin-bottom: 8px;
    font-weight: 500;
}

.result-stats strong {
    font-weight: 700;
}

.btn-download {
    background: #22543d;
    color: white;
    border: none;
    padding: 14px 40px;
    font-size: 1rem;
    font-weight: 600;
    border-radius: 10px;
    cursor: pointer;
    transition: all 0.3s ease;
    display: inline-flex;
    align-items: center;
    gap: 10px;
}

.btn-download:hover {
    background: #1a3e2e;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(34, 84, 61, 0.3);
}

.btn-download svg {
    width: 20px;
    height: 20px;
}

.error-card {
    background: linear-gradient(135deg, #fc8181 0%, #f56565 100%);
    padding: 30px;
    border-radius: 12px;
    text-align: center;
    color: white;
}

.error-icon {
    width: 50px;
    height: 50px;
    margin: 0 auto 15px;
}

.error-card h3 {
    font-size: 1.5rem;
    margin-bottom: 15px;
}

.error-card p {
    font-size: 1rem;
    opacity: 0.95;
}

footer {
    background: #f8f9fa;
    padding: 20px 40px;
    text-align: center;
    color: #6c757d;
    border-top: 1px solid #dee2e6;
    margin-top: 50px;
}

footer p {
    margin-bottom: 5px;
    font-size: 0.9rem;
}

.version {
    font-size: 0.8rem;
    color: #a0aec0;
}

.hidden {
    display: none !important;
}

/* Responsive */
@media (max-width: 768px) {
    header h1 {
        font-size: 2rem;
    }
    
    .subtitle {
        font-size: 1rem;
    }
    
    main {
        padding: 30px 20px;
    }
    
    .drop-zone {
        padding: 40px 20px;
    }
    
    .btn-primary {
        width: 100%;
    }
}