* {
    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, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    padding: 20px;
    color: #1f2937;
}

.container {
    max-width: 800px;
    margin: 0 auto;
    background: white;
    border-radius: 16px;
    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;
    text-align: center;
}

header h1 {
    font-size: 2.5rem;
    margin-bottom: 10px;
}

header p {
    font-size: 1.1rem;
    opacity: 0.95;
}

main {
    padding: 40px;
}

.upload-section {
    margin-bottom: 30px;
}

input[type="file"] {
    display: none;
}

.file-label {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 12px;
    padding: 30px;
    border: 3px dashed #d1d5db;
    border-radius: 12px;
    cursor: pointer;
    transition: all 0.3s ease;
    background: #f9fafb;
}

.file-label:hover {
    border-color: #667eea;
    background: #f3f4f6;
}

.file-icon {
    font-size: 2rem;
}

.file-text {
    font-size: 1.1rem;
    color: #4b5563;
    font-weight: 500;
}

.file-name {
    margin-top: 15px;
    padding: 12px;
    background: #f0fdf4;
    border-radius: 8px;
    color: #166534;
    font-weight: 500;
    min-height: 20px;
    text-align: center;
}

.settings-section {
    margin-bottom: 30px;
    padding: 20px;
    background: #f9fafb;
    border-radius: 12px;
}

.setting-group {
    margin-bottom: 20px;
}

.setting-group:last-child {
    margin-bottom: 0;
}

.settings-section label {
    display: block;
    margin-bottom: 10px;
    font-weight: 600;
    color: #374151;
}

input[type="number"],
.format-select {
    width: 100%;
    padding: 12px;
    border: 2px solid #e5e7eb;
    border-radius: 8px;
    font-size: 1rem;
    transition: border-color 0.3s ease;
    background: white;
}

input[type="number"]:focus,
.format-select:focus {
    outline: none;
    border-color: #667eea;
}

.format-select {
    cursor: pointer;
}

.process-btn {
    width: 100%;
    padding: 16px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border: none;
    border-radius: 12px;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.process-btn:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 8px 20px rgba(102, 126, 234, 0.4);
}

.process-btn:disabled {
    background: #9ca3af;
    cursor: not-allowed;
}

.progress-section {
    margin-top: 30px;
    padding: 20px;
    background: #f9fafb;
    border-radius: 12px;
}

.progress-bar {
    width: 100%;
    height: 12px;
    background: #e5e7eb;
    border-radius: 6px;
    overflow: hidden;
    margin-bottom: 15px;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, #10b981 0%, #059669 100%);
    width: 0%;
    transition: width 0.3s ease;
    border-radius: 6px;
}

.progress-text {
    text-align: center;
    font-weight: 500;
    color: #374151;
}

.results-section {
    margin-top: 30px;
    padding: 20px;
    background: #f0fdf4;
    border-radius: 12px;
}

.results-section h2 {
    margin-bottom: 20px;
    color: #166534;
}

.download-links {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.download-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px;
    background: white;
    border-radius: 8px;
    border: 1px solid #d1fae5;
}

.download-info {
    color: #374151;
    font-weight: 500;
}

.download-link {
    padding: 8px 16px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    text-decoration: none;
    border-radius: 6px;
    font-weight: 600;
    transition: transform 0.2s ease;
}

.download-link:hover {
    transform: translateY(-2px);
}

.info-section {
    margin-top: 40px;
    padding: 25px;
    background: #eff6ff;
    border-radius: 12px;
    border-left: 4px solid #3b82f6;
}

.info-section h3 {
    margin-bottom: 15px;
    color: #1e40af;
}

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

.info-section li {
    padding: 8px 0;
    color: #1e40af;
    position: relative;
    padding-left: 25px;
}

.info-section li::before {
    content: "✓";
    position: absolute;
    left: 0;
    font-weight: bold;
    color: #3b82f6;
}

.seo-content {
    margin-top: 40px;
    padding: 30px;
    background: #fefefe;
    border-radius: 12px;
    border: 1px solid #e5e7eb;
    line-height: 1.8;
}

.seo-content h2 {
    color: #1f2937;
    margin-bottom: 15px;
    font-size: 1.5rem;
}

.seo-content h3 {
    color: #374151;
    margin-top: 20px;
    margin-bottom: 10px;
    font-size: 1.2rem;
}

.seo-content p {
    color: #4b5563;
    margin-bottom: 15px;
}

.seo-content ul {
    list-style: none;
    padding-left: 0;
}

.seo-content li {
    padding: 8px 0;
    color: #4b5563;
    position: relative;
    padding-left: 25px;
}

.seo-content li::before {
    content: "•";
    position: absolute;
    left: 0;
    font-weight: bold;
    color: #667eea;
    font-size: 1.5rem;
    line-height: 1.2;
}

.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border-width: 0;
}

footer {
    padding: 20px;
    text-align: center;
    background: #f9fafb;
    color: #6b7280;
    font-size: 0.9rem;
}

footer p {
    margin: 5px 0;
}

@media (max-width: 640px) {
    header h1 {
        font-size: 1.8rem;
    }

    header p {
        font-size: 0.95rem;
    }

    main {
        padding: 20px;
    }

    .download-item {
        flex-direction: column;
        gap: 10px;
        align-items: flex-start;
    }

    .download-link {
        width: 100%;
        text-align: center;
    }
}