/* ============================================
   PNG to AVIF Converter - Stylesheet
   Uses SURITD TOOLS design system variables
   Dark mode via [data-theme="dark"]
   ============================================ */

/* Tool-specific overrides (inherits from custom_styles.css) */
.tool-container {
    max-width: 1000px;
    margin: 0 auto;
    padding: 2rem;
}

/* Header */
.tool-header {
    text-align: center;
    margin-bottom: 2rem;
}

.tool-title-row {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 1rem;
    margin-bottom: 1rem;
}

.tool-icon-wrapper {
    width: 56px;
    height: 56px;
    background: var(--accent-color);
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    color: #fff;
    flex-shrink: 0;
}

.tool-icon-wrapper svg,
.tool-icon-wrapper i {
    width: 26px;
    height: 26px;
}

.tool-title {
    font-size: clamp(1.75rem, 4vw, 2.25rem);
    font-weight: 700;
    margin: 0;
    color: var(--text-primary);
    letter-spacing: -0.02em;
}

.tool-description {
    font-size: 1.05rem;
    color: var(--text-secondary);
    max-width: 800px;
    margin: 0 auto;
    line-height: 1.7;
}

.tool-description a {
    color: var(--link-color);
    text-decoration: none;
}

.tool-description a:hover {
    color: var(--link-hover);
    text-decoration: underline;
}

/* Main Tool Area */
.tool-main {
    background: var(--card-bg);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-md);
    overflow: hidden;
    border: 1px solid var(--border-color);
    transition: background-color var(--transition-speed), border-color var(--transition-speed);
}

/* Upload Section */
.upload-section {
    padding: 3rem;
}

.upload-area {
    border: 2px dashed var(--border-color);
    border-radius: var(--radius-lg);
    padding: 4rem 2rem;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s ease;
    background: var(--card-secondary);
    position: relative;
    overflow: hidden;
}

.upload-area:hover,
.upload-area.dragover,
.upload-area.active {
    border-color: var(--accent-color);
    background: var(--primary-light);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.upload-content {
    position: relative;
    z-index: 1;
}

.upload-icon {
    color: var(--accent-color);
    margin-bottom: 1.5rem;
    transition: transform 0.3s ease;
}

.upload-area:hover .upload-icon {
    transform: translateY(-5px);
}

.upload-title {
    font-size: 1.4rem;
    font-weight: 600;
    color: var(--text-primary);
    margin: 0 0 0.5rem;
}

.upload-subtitle {
    color: var(--text-secondary);
    margin: 0 0 1rem;
    font-size: 1rem;
}

.upload-hint {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    background: var(--primary-light);
    color: var(--accent-color);
    padding: 0.5rem 1rem;
    border-radius: var(--radius-full);
    font-size: 0.875rem;
    font-weight: 500;
}

.upload-hint i,
.upload-hint svg {
    width: 14px;
    height: 14px;
    flex-shrink: 0;
}

/* Editor Section */
.editor-section {
    padding: 0;
}

/* Files Header */
.files-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 2rem;
    background: var(--card-secondary);
    border-bottom: 1px solid var(--border-color);
    transition: background-color var(--transition-speed);
}

.files-header-left {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-weight: 600;
    color: var(--text-primary);
}

.files-header-left svg,
.files-header-left i {
    color: var(--accent-color);
}

.btn-text {
    display: flex;
    align-items: center;
    gap: 0.25rem;
    background: none;
    border: none;
    color: var(--accent-color);
    font-weight: 600;
    font-size: 0.9rem;
    cursor: pointer;
    padding: 0.5rem 0.75rem;
    border-radius: var(--radius-md);
    transition: all 0.2s ease;
}

.btn-text:hover {
    background: var(--primary-light);
}

/* Files List */
.files-list {
    max-height: 300px;
    overflow-y: auto;
    border-bottom: 1px solid var(--border-color);
}

.file-item {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 1rem 2rem;
    border-bottom: 1px solid var(--border-light);
    transition: background 0.2s ease;
}

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

.file-item:hover {
    background: var(--card-secondary);
}

.file-preview {
    width: 48px;
    height: 48px;
    border-radius: var(--radius-md);
    background:
        linear-gradient(45deg, var(--checker-color) 25%, transparent 25%),
        linear-gradient(-45deg, var(--checker-color) 25%, transparent 25%),
        linear-gradient(45deg, transparent 75%, var(--checker-color) 75%),
        linear-gradient(-45deg, transparent 75%, var(--checker-color) 75%);
    background-size: 10px 10px;
    background-position: 0 0, 0 5px, 5px -5px, -5px 0px;
    overflow: hidden;
    flex-shrink: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    border: 1px solid var(--border-color);
}

.file-preview img {
    max-width: 100%;
    max-height: 100%;
    object-fit: contain;
}

.file-info {
    flex: 1;
    min-width: 0;
}

.file-name {
    font-weight: 600;
    color: var(--text-primary);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    font-size: 0.95rem;
}

.file-meta {
    display: flex;
    gap: 1rem;
    font-size: 0.85rem;
    color: var(--text-muted);
    margin-top: 0.25rem;
}

.file-remove {
    width: 32px;
    height: 32px;
    border: none;
    border-radius: var(--radius-full);
    background: var(--error-bg);
    color: var(--error-color);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.2s ease;
    flex-shrink: 0;
}

.file-remove:hover {
    background: var(--error-color);
    color: #fff;
}

/* Settings Panel */
.settings-panel {
    padding: 2rem;
}

.panel-header {
    margin-bottom: 1.5rem;
}

.panel-header h3 {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-primary);
    margin: 0;
}

.panel-header h3 svg,
.panel-header h3 i {
    color: var(--accent-color);
}

/* Quality Section */
.quality-section {
    margin-bottom: 1.5rem;
}

.section-label {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.75rem;
}

.section-label svg,
.section-label i {
    color: var(--accent-color);
}

.quality-slider-row {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-bottom: 0.5rem;
}

.slider-input {
    flex: 1;
    width: 100%;
    height: 10px;
    border-radius: var(--radius-full);
    background: linear-gradient(to right, #e64e4e, #f59e0b, #339966);
    outline: none;
    -webkit-appearance: none;
    appearance: none;
    cursor: pointer;
}

.slider-input::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 22px;
    height: 22px;
    border-radius: 50%;
    background: #fff;
    border: 3px solid var(--accent-color);
    cursor: pointer;
    box-shadow: var(--shadow-sm);
    transition: all 0.2s ease;
}

.slider-input::-webkit-slider-thumb:hover {
    transform: scale(1.1);
}

.slider-input::-moz-range-thumb {
    width: 22px;
    height: 22px;
    border-radius: 50%;
    background: #fff;
    border: 3px solid var(--accent-color);
    cursor: pointer;
    box-shadow: var(--shadow-sm);
}

.quality-value-display {
    min-width: 64px;
    padding: 0.5rem 0.75rem;
    background: var(--accent-color);
    color: #fff;
    border-radius: var(--radius-md);
    font-weight: 600;
    font-size: 0.9rem;
    text-align: center;
}

.slider-labels {
    display: flex;
    justify-content: space-between;
    font-size: 0.8rem;
    color: var(--text-muted);
    margin-top: 0.5rem;
}

/* Quality Presets */
.quality-presets {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-top: 1rem;
    flex-wrap: wrap;
}

.preset-label {
    font-size: 0.85rem;
    color: var(--text-secondary);
    font-weight: 500;
}

.preset-btn {
    padding: 0.4rem 0.9rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-full);
    background: var(--card-bg);
    color: var(--text-secondary);
    font-size: 0.85rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s ease;
}

.preset-btn:hover {
    border-color: var(--accent-color);
    color: var(--accent-color);
}

.preset-btn.active {
    background: var(--accent-color);
    border-color: var(--accent-color);
    color: #fff;
}

/* Options Grid */
.options-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1rem;
    margin-top: 1.5rem;
}

.option-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.option-group label {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-primary);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.option-group label svg,
.option-group label i {
    color: var(--accent-color);
    width: 16px;
    height: 16px;
}

/* Styled Dropdown */
.styled-dropdown {
    width: 100%;
    padding: 0.75rem 1rem;
    border-radius: var(--radius-md);
    border: 1px solid var(--border-color);
    background: var(--input-bg);
    color: var(--text-primary);
    font-size: 0.95rem;
    appearance: none;
    -webkit-appearance: none;
    -moz-appearance: none;
    background-image: url("data:image/svg+xml;charset=UTF-8,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%233498db' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3e%3cpolyline points='6 9 12 15 18 9'%3e%3c/polyline%3e%3c/svg%3e");
    background-repeat: no-repeat;
    background-position: right 12px center;
    background-size: 16px;
    cursor: pointer;
    transition: all 0.2s ease;
}

.styled-dropdown:hover {
    border-color: var(--accent-color);
}

.styled-dropdown:focus {
    outline: none;
    border-color: var(--accent-color);
    box-shadow: 0 0 0 3px rgba(52, 152, 219, 0.15);
}

[data-theme="dark"] .styled-dropdown {
    background-image: url("data:image/svg+xml;charset=UTF-8,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%2360a5fa' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3e%3cpolyline points='6 9 12 15 18 9'%3e%3c/polyline%3e%3c/svg%3e");
}

/* Checkbox Option */
.checkbox-wrapper {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.75rem 1rem;
    background: var(--input-bg);
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all 0.2s ease;
    border: 1px solid var(--border-color);
}

.checkbox-wrapper:hover {
    background: var(--primary-light);
    border-color: var(--accent-color);
}

.checkbox-wrapper input[type="checkbox"] {
    width: 18px;
    height: 18px;
    accent-color: var(--accent-color);
    cursor: pointer;
}

.checkbox-label {
    font-size: 0.9rem;
    color: var(--text-primary);
    cursor: pointer;
}

/* Quality Info Tip */
.quality-info {
    display: flex;
    gap: 0.75rem;
    align-items: flex-start;
    margin-top: 1.5rem;
    padding: 1rem;
    background: var(--info-bg);
    border-radius: var(--radius-md);
    transition: background-color var(--transition-speed);
}

.info-icon {
    flex-shrink: 0;
    color: var(--info-color);
}

.info-text {
    font-size: 0.9rem;
    color: var(--text-secondary);
    line-height: 1.5;
}

.info-text strong {
    color: var(--text-primary);
}

/* Action Bar */
.action-bar {
    display: flex;
    gap: 1rem;
    padding: 1.5rem 2rem 2rem;
    justify-content: center;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.875rem 1.75rem;
    border-radius: var(--radius-full);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
    border: none;
    text-decoration: none;
}

.btn svg,
.btn i {
    flex-shrink: 0;
}

.btn-primary {
    background: var(--accent-color);
    color: #fff;
    box-shadow: var(--shadow-primary);
}

.btn-primary:hover:not(:disabled) {
    background: var(--accent-hover);
    transform: translateY(-2px);
    box-shadow: var(--shadow-primary-hover);
}

.btn-primary:disabled {
    background: var(--text-muted);
    cursor: not-allowed;
    box-shadow: none;
}

.btn-secondary {
    background: var(--card-bg);
    color: var(--text-primary);
    border: 2px solid var(--border-color);
}

.btn-secondary:hover {
    border-color: var(--accent-color);
    color: var(--accent-color);
    background: var(--primary-light);
}

.btn-success {
    background: var(--success-color);
    color: #fff;
    box-shadow: 0 4px 14px rgba(46, 204, 113, 0.3);
}

.btn-success:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(46, 204, 113, 0.4);
}

/* Processing Overlay */
.processing-overlay {
    position: fixed;
    inset: 0;
    background: var(--overlay-bg);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
}

.processing-content {
    background: var(--card-bg);
    padding: 3rem;
    border-radius: var(--radius-xl);
    text-align: center;
    max-width: 400px;
    width: 90%;
    border: 1px solid var(--border-color);
}

.processing-spinner {
    width: 56px;
    height: 56px;
    border: 4px solid var(--primary-light);
    border-top-color: var(--accent-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin: 0 auto 1.5rem;
}

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

.processing-title {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--text-primary);
    margin: 0 0 0.5rem;
}

.processing-subtitle {
    color: var(--text-secondary);
    margin: 0;
}

/* Progress Bar */
.progress-bar {
    height: 8px;
    background: var(--primary-light);
    border-radius: var(--radius-full);
    overflow: hidden;
    margin-top: 1.5rem;
}

.progress-fill {
    height: 100%;
    background: var(--accent-color);
    border-radius: var(--radius-full);
    transition: width 0.3s ease;
}

.progress-text {
    font-size: 0.85rem;
    color: var(--text-secondary);
    margin-top: 0.5rem;
}

/* Results Section */
.results-section {
    padding: 3rem;
    text-align: center;
}

.results-header {
    margin-bottom: 2rem;
}

.results-icon {
    width: 72px;
    height: 72px;
    background: var(--success-color);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 1.5rem;
    color: #fff;
}

.results-title {
    font-size: 1.4rem;
    font-weight: 700;
    color: var(--text-primary);
    margin: 0 0 0.5rem;
}

.results-subtitle {
    color: var(--text-secondary);
    margin: 0;
}

/* Results Actions */
.results-actions {
    display: flex;
    justify-content: center;
    gap: 1rem;
    flex-wrap: wrap;
}

/* Converted Files List */
.converted-files-list {
    margin: 1.5rem 0;
    text-align: left;
}

.converted-file-item {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 1rem;
    background: var(--card-secondary);
    border-radius: var(--radius-md);
    margin-bottom: 0.75rem;
    transition: all 0.2s ease;
}

.converted-file-item:hover {
    background: var(--primary-light);
}

.converted-file-preview {
    width: 40px;
    height: 40px;
    border-radius: var(--radius-sm);
    background:
        linear-gradient(45deg, var(--checker-color) 25%, transparent 25%),
        linear-gradient(-45deg, var(--checker-color) 25%, transparent 25%),
        linear-gradient(45deg, transparent 75%, var(--checker-color) 75%),
        linear-gradient(-45deg, transparent 75%, var(--checker-color) 75%);
    background-size: 8px 8px;
    background-position: 0 0, 0 4px, 4px -4px, -4px 0px;
    overflow: hidden;
    flex-shrink: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    border: 1px solid var(--border-color);
}

.converted-file-preview img {
    max-width: 100%;
    max-height: 100%;
    object-fit: contain;
}

.converted-file-info {
    flex: 1;
    min-width: 0;
}

.converted-file-name {
    font-weight: 600;
    color: var(--text-primary);
    font-size: 0.9rem;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.converted-file-meta {
    display: flex;
    gap: 1rem;
    font-size: 0.8rem;
    color: var(--text-muted);
    margin-top: 0.25rem;
}

.converted-file-savings {
    color: var(--success-color);
    font-weight: 600;
}

.converted-file-download {
    padding: 0.5rem 1rem;
    background: var(--accent-color);
    color: #fff;
    border: none;
    border-radius: var(--radius-full);
    font-size: 0.85rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
    display: inline-flex;
    align-items: center;
    gap: 0.35rem;
    text-decoration: none;
}

.converted-file-download:hover {
    background: var(--accent-hover);
    color: #fff;
    transform: translateY(-1px);
}

/* Error Message */
.error-message {
    margin: 1rem 2rem;
    padding: 1rem 1.5rem;
    background: var(--error-bg);
    border: 1px solid var(--error-color);
    border-radius: var(--radius-md);
    color: var(--error-color);
    font-weight: 500;
    line-height: 1.6;
}

.error-message a {
    color: var(--error-color);
    font-weight: 600;
    text-decoration: underline;
}

/* Browser Support Notice */
.browser-support {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    margin: 1.5rem 0;
    padding: 1rem 1.5rem;
    background: var(--info-bg);
    border-radius: var(--radius-lg);
    font-size: 0.9rem;
    color: var(--text-secondary);
    transition: background-color var(--transition-speed);
}

.browser-support svg,
.browser-support i {
    flex-shrink: 0;
    color: var(--accent-color);
}

/* Related Tools */
.related-tools {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin: 2rem 0;
    padding: 1.25rem 1.5rem;
    background: var(--card-bg);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    flex-wrap: wrap;
    border: 1px solid var(--border-color);
    transition: background-color var(--transition-speed), border-color var(--transition-speed);
}

.related-label {
    font-weight: 600;
    color: var(--text-primary);
    font-size: 0.9rem;
}

.related-links {
    display: flex;
    gap: 0.75rem;
    flex-wrap: wrap;
}

.related-link {
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
    padding: 0.5rem 1rem;
    background: var(--card-secondary);
    color: var(--text-secondary);
    text-decoration: none;
    border-radius: var(--radius-full);
    font-size: 0.875rem;
    font-weight: 500;
    transition: all 0.2s ease;
    border: 1px solid var(--border-color);
}

.related-link:hover {
    background: var(--accent-color);
    color: #fff;
    border-color: var(--accent-color);
    transform: translateY(-2px);
}

.related-link svg,
.related-link i {
    flex-shrink: 0;
}

/* Info Sections - clean, no background/shadow/border */
.info-sections {
    display: grid;
    gap: 2rem;
    margin-top: 3rem;
}

.info-card {
    padding: 0 0 1.5rem;
}

.info-card h2 {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    font-size: 1.3rem;
    color: var(--text-primary);
    margin: 0 0 1.25rem;
}

.info-card h2 svg,
.info-card h2 i {
    color: var(--accent-color);
    flex-shrink: 0;
}

/* Steps List */
.steps-list {
    list-style: none;
    padding: 0;
    margin: 0;
    counter-reset: step;
}

.steps-list li {
    position: relative;
    padding-left: 3.5rem;
    padding-bottom: 1.25rem;
    counter-increment: step;
    color: var(--text-secondary);
    line-height: 1.6;
}

.steps-list li:not(:last-child)::after {
    content: '';
    position: absolute;
    left: calc(1rem - 1px);
    top: 2rem;
    bottom: 0;
    width: 2px;
    background: var(--primary-light);
}

.steps-list li::before {
    content: counter(step);
    position: absolute;
    left: 0;
    top: 0;
    width: 2rem;
    height: 2rem;
    background: var(--accent-color);
    color: #fff;
    border-radius: var(--radius-full);
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 0.875rem;
    z-index: 1;
}

/* Format Explanations */
.format-explanations,
.mode-explanations {
    display: grid;
    gap: 1rem;
}

.format-explain,
.mode-explain {
    display: flex;
    gap: 1rem;
    align-items: flex-start;
}

.format-tag,
.mode-tag {
    flex-shrink: 0;
    padding: 0.35rem 0.85rem;
    border-radius: var(--radius-full);
    font-size: 0.8rem;
    font-weight: 600;
    color: #fff;
}

.format-tag.png { background: #e64e4e; }
.format-tag.avif { background: #3399cc; }
.mode-tag.high { background: #339966; }
.mode-tag.medium { background: #3399cc; }
.mode-tag.low { background: #f59e0b; }

.format-explain p,
.mode-explain p {
    margin: 0;
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.6;
}

.format-explain p a,
.mode-explain p a {
    color: var(--link-color);
    text-decoration: none;
}

.format-explain p a:hover,
.mode-explain p a:hover {
    color: var(--link-hover);
    text-decoration: underline;
}

/* FAQ */
.faq-list {
    display: grid;
    gap: 0.75rem;
}

.faq-item {
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    overflow: hidden;
    transition: border-color var(--transition-speed);
}

.faq-question {
    width: 100%;
    padding: 1rem 1.25rem;
    background: var(--card-secondary);
    border: none;
    text-align: left;
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-primary);
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: all 0.2s ease;
    font-family: inherit;
}

.faq-question:hover {
    background: var(--card-bg);
}

.faq-question svg,
.faq-question i {
    color: var(--accent-color);
    transition: transform 0.3s ease;
    flex-shrink: 0;
}

.faq-item.open .faq-question svg,
.faq-item.open .faq-question i {
    transform: rotate(180deg);
}

.faq-answer {
    display: none;
    padding: 0 1.25rem 1rem;
    background: var(--card-bg);
}

.faq-item.open .faq-answer {
    display: block;
}

.faq-answer p {
    margin: 0;
    color: var(--text-secondary);
    line-height: 1.7;
}

.faq-answer p a {
    color: var(--link-color);
    text-decoration: none;
}

.faq-answer p a:hover {
    color: var(--link-hover);
    text-decoration: underline;
}

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

    .tool-title-row {
        gap: 0.75rem;
    }

    .tool-icon-wrapper {
        width: 44px;
        height: 44px;
    }

    .tool-icon-wrapper svg,
    .tool-icon-wrapper i {
        width: 22px;
        height: 22px;
    }

    .upload-section,
    .results-section {
        padding: 2rem 1.5rem;
    }

    .upload-area {
        padding: 2.5rem 1.5rem;
    }

    .settings-panel {
        padding: 1.5rem;
    }

    .options-grid {
        grid-template-columns: 1fr;
    }

    .action-bar {
        flex-direction: column;
        padding: 1.5rem;
    }

    .btn {
        width: 100%;
    }

    .files-header {
        padding: 1rem 1.5rem;
    }

    .file-item {
        padding: 1rem 1.5rem;
    }

    .related-tools {
        flex-direction: column;
        text-align: center;
    }

    .related-links {
        justify-content: center;
    }

    .format-explain,
    .mode-explain {
        flex-direction: column;
    }

    .browser-support {
        flex-direction: column;
        text-align: center;
    }
}

@media (max-width: 480px) {
    .tool-title {
        font-size: 1.5rem;
    }

    .files-header {
        flex-direction: column;
        gap: 0.75rem;
        align-items: flex-start;
    }

    .file-item {
        flex-wrap: wrap;
    }

    .file-preview {
        width: 40px;
        height: 40px;
    }

    .steps-list li {
        padding-left: 3rem;
    }

    .quality-presets {
        justify-content: flex-start;
    }
}

/* Animations */
@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

.editor-section,
.results-section {
    animation: fadeIn 0.4s ease;
}

/* Reduced Motion */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        transition-duration: 0.01ms !important;
    }
}