/* ============================================
   Compression Analyzer - Modern Stylesheet
   Dark Mode Support with Light Mode Default
   Theme: Blue (#3399cc)
   ============================================ */

/* CSS Variables - Light Mode (Default) */
:root {
    --transition-speed: 0.25s;
    
    /* Primary Colors - Blue Theme */
    --primary: #3399cc;
    --primary-light: #e8f4fc;
    --primary-dark: #2980b9;
    --accent: #60a5fa;
    
    /* Format Colors */
    --png-color: #e64e4e;
    --jpg-color: #f59e0b;
    --webp-color: #339966;
    --avif-color: #8b5cf6;
    
    /* Status Colors */
    --success: #339966;
    --success-light: #E8F5E9;
    --warning: #f59e0b;
    --warning-light: #FEF3C7;
    --danger: #e64e4e;
    --danger-light: #FEE2E2;
    
    /* Background Colors */
    --bg: #f0f7fc;
    --bg-elevated: #ffffff;
    --bg-secondary: #f1f5f9;
    --bg-tertiary: #e2e8f0;
    
    /* Text Colors */
    --text: #1e293b;
    --text-secondary: #475569;
    --text-muted: #64748b;
    
    /* Border Colors */
    --border: #cce5f0;
    --border-light: #e2e8f0;
    
    /* Shadows */
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.08);
    --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.1);
    --shadow-xl: 0 20px 25px -5px rgba(0,0,0,0.1);
    --shadow-primary: 0 4px 14px rgba(51, 153, 204, 0.25);
    --shadow-primary-hover: 0 6px 20px rgba(51, 153, 204, 0.35);
    
    /* Radius */
    --radius-sm: 6px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 24px;
    --radius-full: 9999px;
    
    /* Checkerboard */
    --checker-light: #f0f0f0;
    --checker-dark: #e0e0e0;
    
    /* Input */
    --input-bg: #ffffff;
    --input-border: #cce5f0;
    
    /* Scrollbar */
    --scrollbar-track: var(--bg);
    --scrollbar-thumb: var(--text-muted);
    --scrollbar-thumb-hover: var(--text-secondary);
}

/* Dark Mode Colors */
[data-theme="dark"] {
    --primary: #60a5fa;
    --primary-light: rgba(96, 165, 250, 0.15);
    --primary-dark: #3b82f6;
    --accent: #93c5fd;
    
    /* Format Colors - slightly brighter for dark mode */
    --png-color: #f87171;
    --jpg-color: #fbbf24;
    --webp-color: #4ade80;
    --avif-color: #a78bfa;
    
    /* Status Colors */
    --success: #4ade80;
    --success-light: rgba(74, 222, 128, 0.15);
    --warning: #fbbf24;
    --warning-light: rgba(251, 191, 36, 0.15);
    --danger: #f87171;
    --danger-light: rgba(248, 113, 113, 0.15);
    
    /* Background Colors */
    --bg: #0f172a;
    --bg-elevated: #1e293b;
    --bg-secondary: #334155;
    --bg-tertiary: #475569;
    
    /* Text Colors */
    --text: #f1f5f9;
    --text-secondary: #cbd5e1;
    --text-muted: #94a3b8;
    
    /* Border Colors */
    --border: #334155;
    --border-light: #475569;
    
    /* Shadows */
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.3);
    --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.4);
    --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.4);
    --shadow-xl: 0 20px 25px -5px rgba(0,0,0,0.5);
    --shadow-primary: 0 4px 14px rgba(96, 165, 250, 0.2);
    --shadow-primary-hover: 0 6px 20px rgba(96, 165, 250, 0.3);
    
    /* Checkerboard */
    --checker-light: #334155;
    --checker-dark: #475569;
    
    /* Input */
    --input-bg: #334155;
    --input-border: #475569;
    
    /* Scrollbar */
    --scrollbar-track: var(--bg-elevated);
    --scrollbar-thumb: var(--text-muted);
    --scrollbar-thumb-hover: var(--text-secondary);
}

/* Base Styles */
* {
    box-sizing: border-box;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.6;
    margin: 0;
    padding: 0;
    transition: background-color var(--transition-speed), color var(--transition-speed);
}

/* Container */
.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: 64px;
    height: 64px;
    background: var(--primary);
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    box-shadow: var(--shadow-primary);
    flex-shrink: 0;
    transition: background-color var(--transition-speed), box-shadow var(--transition-speed);
}

.tool-icon-wrapper svg,
.tool-icon-wrapper i {
    width: 28px;
    height: 28px;
}

.tool-title {
    font-size: clamp(1.75rem, 4vw, 2.5rem);
    font-weight: 700;
    margin: 0;
    color: var(--primary);
    letter-spacing: -0.02em;
}

.tool-description {
    font-size: 1.1rem;
    color: var(--text-secondary);
    max-width: 800px;
    margin: 0 auto;
    line-height: 1.7;
}

.tool-description a {
    color: var(--primary);
    text-decoration: none;
    font-weight: 500;
}

.tool-description a:hover {
    text-decoration: underline;
}

/* Main Tool Area */
.tool-main {
    background: var(--bg-elevated);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-xl);
    overflow: hidden;
    border: 1px solid var(--border);
    margin-bottom: 2rem;
    transition: background-color var(--transition-speed), border-color var(--transition-speed);
}

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

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

.upload-area::before {
    content: '';
    position: absolute;
    inset: 0;
    background: var(--primary-light);
    opacity: 0;
    transition: opacity 0.3s ease;
}

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

.upload-area:hover::before,
.upload-area.dragover::before {
    opacity: 0.5;
}

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

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

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

.upload-title {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text);
    margin: 0 0 0.5rem;
}

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

.file-types {
    display: flex;
    gap: 0.5rem;
    justify-content: center;
    flex-wrap: wrap;
    margin-bottom: 1rem;
}

.file-type-badge {
    background: var(--primary-light);
    color: var(--primary);
    padding: 0.35rem 0.85rem;
    border-radius: var(--radius-full);
    font-size: 0.8rem;
    font-weight: 600;
    transition: background-color var(--transition-speed), color var(--transition-speed);
}

.upload-hint {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--text-muted);
    font-size: 0.875rem;
}

/* ============================================
   ANALYSIS SECTION
   ============================================ */
.analysis-section {
    padding: 0;
}

/* Original Image Info */
.original-info {
    display: grid;
    grid-template-columns: 300px 1fr;
    gap: 2rem;
    padding: 2rem;
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border);
    transition: background-color var(--transition-speed), border-color var(--transition-speed);
}

.original-preview {
    display: flex;
    align-items: center;
    justify-content: center;
}

.preview-wrapper {
    width: 100%;
    max-width: 280px;
    aspect-ratio: 1;
    border-radius: var(--radius-md);
    background-image: 
        linear-gradient(45deg, var(--checker-light) 25%, transparent 25%),
        linear-gradient(-45deg, var(--checker-light) 25%, transparent 25%),
        linear-gradient(45deg, transparent 75%, var(--checker-light) 75%),
        linear-gradient(-45deg, transparent 75%, var(--checker-light) 75%);
    background-size: 16px 16px;
    background-position: 0 0, 0 8px, 8px -8px, -8px 0px;
    overflow: hidden;
    display: flex;
    align-items: center;
    justify-content: center;
    border: 1px solid var(--border);
    transition: border-color var(--transition-speed);
}

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

.original-details h3 {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text);
    margin: 0 0 1.25rem;
}

.original-details h3 svg,
.original-details h3 i {
    color: var(--primary);
}

.detail-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1rem;
    margin-bottom: 1.25rem;
}

.detail-item {
    background: var(--bg-elevated);
    padding: 0.875rem 1rem;
    border-radius: var(--radius-md);
    border: 1px solid var(--border);
    transition: background-color var(--transition-speed), border-color var(--transition-speed);
}

.detail-label {
    display: block;
    font-size: 0.75rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-bottom: 0.25rem;
}

.detail-value {
    display: block;
    font-size: 1rem;
    font-weight: 600;
    color: var(--text);
}

.detail-value.highlight {
    color: var(--primary);
    font-size: 1.1rem;
}

.image-type-detection {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.875rem 1rem;
    background: var(--primary-light);
    border-radius: var(--radius-md);
    transition: background-color var(--transition-speed);
}

.detection-label {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.detection-label svg,
.detection-label i {
    color: var(--primary);
}

.detection-value {
    font-weight: 600;
    color: var(--primary);
}

/* ============================================
   QUALITY CONTROL PANEL
   ============================================ */
.quality-control-panel {
    padding: 1.5rem 2rem;
    background: var(--bg-elevated);
    border-bottom: 1px solid var(--border);
    transition: background-color var(--transition-speed), border-color var(--transition-speed);
}

.quality-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
}

.quality-header h3 {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 1rem;
    font-weight: 600;
    color: var(--text);
    margin: 0;
}

.quality-header h3 svg,
.quality-header h3 i {
    color: var(--primary);
}

.quality-value-display {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--primary);
    background: var(--primary-light);
    padding: 0.35rem 1rem;
    border-radius: var(--radius-full);
    min-width: 70px;
    text-align: center;
}

.quality-slider-container {
    margin-bottom: 1rem;
}

.quality-slider {
    width: 100%;
    height: 10px;
    border-radius: var(--radius-full);
    background: linear-gradient(to right, var(--danger), var(--warning), var(--success));
    -webkit-appearance: none;
    appearance: none;
    cursor: pointer;
}

.quality-slider::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 24px;
    height: 24px;
    border-radius: 50%;
    background: var(--bg-elevated);
    border: 3px solid var(--primary);
    cursor: pointer;
    box-shadow: var(--shadow-md);
    transition: transform 0.15s ease;
}

.quality-slider::-webkit-slider-thumb:hover {
    transform: scale(1.15);
}

.quality-slider::-moz-range-thumb {
    width: 24px;
    height: 24px;
    border-radius: 50%;
    background: var(--bg-elevated);
    border: 3px solid var(--primary);
    cursor: pointer;
    box-shadow: var(--shadow-md);
}

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

.quality-presets {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    flex-wrap: wrap;
}

.preset-label {
    font-size: 0.875rem;
    color: var(--text-muted);
    font-weight: 500;
}

.preset-btn {
    padding: 0.4rem 0.875rem;
    border: 1px solid var(--border);
    border-radius: var(--radius-full);
    background: var(--bg-elevated);
    color: var(--text);
    font-size: 0.85rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s ease;
}

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

.preset-btn.active {
    background: var(--primary);
    border-color: var(--primary);
    color: white;
}

/* ============================================
   FORMAT COMPARISON
   ============================================ */
.comparison-section {
    padding: 2rem;
}

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

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

.comparison-header h3 svg,
.comparison-header h3 i {
    color: var(--primary);
}

.comparison-header p {
    color: var(--text-muted);
    font-size: 0.95rem;
    margin: 0;
}

.format-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 1rem;
}

.format-card {
    background: var(--bg-secondary);
    border-radius: var(--radius-lg);
    overflow: hidden;
    border: 1px solid var(--border);
    transition: all 0.3s ease;
}

.format-card:hover {
    border-color: var(--primary);
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
}

.format-card.best {
    border-color: var(--success);
    box-shadow: 0 0 0 2px var(--success-light);
}

.format-card.best::before {
    content: 'Best';
    position: absolute;
    top: 8px;
    right: 8px;
    background: var(--success);
    color: white;
    font-size: 0.7rem;
    font-weight: 700;
    padding: 0.2rem 0.5rem;
    border-radius: var(--radius-full);
    text-transform: uppercase;
    z-index: 1;
}

.format-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.75rem 1rem;
    color: white;
}

.format-header.png { background: var(--png-color); }
.format-header.jpg { background: var(--jpg-color); }
.format-header.webp { background: var(--webp-color); }
.format-header.avif { background: var(--avif-color); }

.format-name {
    font-weight: 700;
    font-size: 1rem;
}

.format-type {
    font-size: 0.7rem;
    opacity: 0.9;
    text-transform: uppercase;
}

.format-preview {
    position: relative;
    height: 120px;
    background-image: 
        linear-gradient(45deg, var(--checker-light) 25%, transparent 25%),
        linear-gradient(-45deg, var(--checker-light) 25%, transparent 25%),
        linear-gradient(45deg, transparent 75%, var(--checker-light) 75%),
        linear-gradient(-45deg, transparent 75%, var(--checker-light) 75%);
    background-size: 12px 12px;
    background-position: 0 0, 0 6px, 6px -6px, -6px 0px;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
}

.preview-loading {
    position: absolute;
    inset: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--bg-secondary);
    z-index: 2;
    transition: opacity 0.3s ease;
}

.preview-loading.hidden {
    opacity: 0;
    pointer-events: none;
}

.spin {
    animation: spin 1s linear infinite;
    color: var(--primary);
}

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

.format-canvas {
    max-width: 100%;
    max-height: 100%;
    object-fit: contain;
}

.format-stats {
    padding: 0.875rem 1rem;
    background: var(--bg-elevated);
    transition: background-color var(--transition-speed);
}

.stat-row {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 0.35rem;
}

.stat-row:last-child {
    margin-bottom: 0;
}

.stat-label {
    font-size: 0.8rem;
    color: var(--text-muted);
}

.stat-value {
    font-weight: 600;
    font-size: 0.9rem;
    color: var(--text);
}

.stat-value.savings {
    color: var(--success);
}

.stat-value.increase {
    color: var(--danger);
}

.format-actions {
    display: flex;
    gap: 0.5rem;
    padding: 0.75rem 1rem;
    background: var(--bg-secondary);
    transition: background-color var(--transition-speed);
}

.download-btn {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.35rem;
    padding: 0.5rem;
    background: var(--primary);
    color: white;
    border-radius: var(--radius-md);
    text-decoration: none;
    font-size: 0.8rem;
    font-weight: 600;
    transition: all 0.2s ease;
}

.download-btn:hover {
    background: var(--primary-dark);
}

.convert-link {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.25rem;
    padding: 0.5rem 0.75rem;
    background: var(--bg-elevated);
    color: var(--text-secondary);
    border-radius: var(--radius-md);
    text-decoration: none;
    font-size: 0.75rem;
    font-weight: 500;
    border: 1px solid var(--border);
    transition: all 0.2s ease;
}

.convert-link:hover {
    border-color: var(--primary);
    color: var(--primary);
}

/* ============================================
   RECOMMENDATION SECTION
   ============================================ */
.recommendation-section {
    margin: 1.5rem 2rem;
    padding: 1.5rem;
    background: var(--success-light);
    border-radius: var(--radius-lg);
    border: 1px solid var(--success);
    transition: background-color var(--transition-speed), border-color var(--transition-speed);
}

.recommendation-header {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    margin-bottom: 1rem;
}

.recommendation-header i,
.recommendation-header svg {
    color: var(--success);
}

.recommendation-header h3 {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--success);
    margin: 0;
}

.recommendation-content {
    margin-bottom: 1rem;
}

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

.recommendation-content strong {
    color: var(--text);
}

.recommendation-actions {
    display: flex;
    gap: 0.75rem;
    flex-wrap: wrap;
}

.recommendation-actions .btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.625rem 1.25rem;
    border-radius: var(--radius-full);
    font-size: 0.9rem;
    font-weight: 600;
    text-decoration: none;
    transition: all 0.2s ease;
}

.recommendation-actions .btn-primary {
    background: var(--success);
    color: white;
}

.recommendation-actions .btn-primary:hover {
    background: #2d8659;
}

.recommendation-actions .btn-secondary {
    background: var(--bg-elevated);
    color: var(--text);
    border: 1px solid var(--border);
}

.recommendation-actions .btn-secondary:hover {
    border-color: var(--primary);
    color: var(--primary);
}

/* ============================================
   DETAILED ANALYSIS
   ============================================ */
.detailed-analysis {
    padding: 2rem;
    border-top: 1px solid var(--border);
    transition: border-color var(--transition-speed);
}

.analysis-header h3 {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text);
    margin: 0 0 1.25rem;
}

.analysis-header h3 svg,
.analysis-header h3 i {
    color: var(--primary);
}

.analysis-tabs {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 1.5rem;
    border-bottom: 1px solid var(--border);
    padding-bottom: 1rem;
}

.tab-btn {
    padding: 0.625rem 1.25rem;
    border: 1px solid var(--border);
    border-radius: var(--radius-full);
    background: var(--bg-elevated);
    color: var(--text-secondary);
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s ease;
}

.tab-btn:hover {
    border-color: var(--primary);
    color: var(--primary);
}

.tab-btn.active {
    background: var(--primary);
    border-color: var(--primary);
    color: white;
}

.tab-content {
    display: none;
}

.tab-content.active {
    display: block;
}

/* Size Chart */
.size-chart {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.size-bar-item {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.size-bar-label {
    width: 60px;
    font-weight: 600;
    font-size: 0.9rem;
    color: var(--text);
}

.size-bar-container {
    flex: 1;
    height: 32px;
    background: var(--bg-secondary);
    border-radius: var(--radius-md);
    overflow: hidden;
    position: relative;
}

.size-bar {
    height: 100%;
    border-radius: var(--radius-md);
    transition: width 0.5s ease;
    display: flex;
    align-items: center;
    justify-content: flex-end;
    padding-right: 0.75rem;
}

.size-bar.png { background: var(--png-color); }
.size-bar.jpg { background: var(--jpg-color); }
.size-bar.webp { background: var(--webp-color); }
.size-bar.avif { background: var(--avif-color); }
.size-bar.original { background: var(--text-muted); }

.size-bar-value {
    font-size: 0.8rem;
    font-weight: 600;
    color: white;
    white-space: nowrap;
}

.size-bar-percent {
    width: 80px;
    text-align: right;
    font-size: 0.875rem;
    font-weight: 600;
}

.size-bar-percent.positive { color: var(--success); }
.size-bar-percent.negative { color: var(--danger); }
.size-bar-percent.neutral { color: var(--text-muted); }

/* Features Table */
.features-table {
    overflow-x: auto;
}

.features-table table {
    width: 100%;
    border-collapse: collapse;
}

.features-table th,
.features-table td {
    padding: 0.875rem 1rem;
    text-align: center;
    border-bottom: 1px solid var(--border);
}

.features-table th {
    background: var(--bg-secondary);
    font-weight: 600;
    font-size: 0.9rem;
    color: var(--text);
}

.features-table th:first-child {
    text-align: left;
}

.features-table td:first-child {
    text-align: left;
    font-weight: 500;
    color: var(--text);
}

.features-table td.yes { color: var(--success); }
.features-table td.no { color: var(--danger); }
.features-table td.partial { color: var(--warning); font-size: 0.85rem; }
.features-table td.excellent { color: var(--success); font-weight: 600; }
.features-table td.good { color: var(--primary); }
.features-table td.moderate { color: var(--warning); }
.features-table td.best { color: var(--success); font-weight: 700; }

/* Use Cases Grid */
.use-cases-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 1rem;
}

.use-case-card {
    padding: 1.5rem;
    background: var(--bg-secondary);
    border-radius: var(--radius-lg);
    text-align: center;
    transition: all 0.3s ease;
}

.use-case-card:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-md);
}

.use-case-icon {
    width: 56px;
    height: 56px;
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 1rem;
    color: white;
}

.use-case-icon.png { background: var(--png-color); }
.use-case-icon.jpg { background: var(--jpg-color); }
.use-case-icon.webp { background: var(--webp-color); }
.use-case-icon.avif { background: var(--avif-color); }

.use-case-card h4 {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text);
    margin: 0 0 0.5rem;
}

.use-case-card p {
    font-size: 0.875rem;
    color: var(--text-secondary);
    line-height: 1.6;
    margin: 0;
}

.use-case-card p a {
    color: var(--primary);
    text-decoration: none;
}

.use-case-card p a:hover {
    text-decoration: underline;
}

/* ============================================
   ACTION BAR
   ============================================ */
.action-bar {
    display: flex;
    justify-content: center;
    padding: 1.5rem 2rem;
    border-top: 1px solid var(--border);
    background: var(--bg-secondary);
    transition: background-color var(--transition-speed), border-color var(--transition-speed);
}

.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;
    text-decoration: none;
    border: none;
}

.btn-primary {
    background: var(--primary);
    color: white;
    box-shadow: var(--shadow-primary);
}

.btn-primary:hover {
    background: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: var(--shadow-primary-hover);
}

.btn-secondary {
    background: var(--bg-elevated);
    color: var(--text);
    border: 1px solid var(--border);
}

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

/* Error Message */
.error-message {
    background: var(--danger-light);
    border: 1px solid var(--danger);
    color: var(--danger);
    padding: 1rem 1.25rem;
    border-radius: var(--radius-md);
    margin: 1.25rem;
    font-weight: 500;
}

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

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

.related-label svg,
.related-label i {
    color: var(--primary);
}

.related-links {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

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

.related-link:hover {
    background: var(--primary);
    color: white;
    border-color: var(--primary);
    transform: translateY(-2px);
}

/* ============================================
   INFO SECTIONS
   ============================================ */
.info-sections {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.info-card {
    background: var(--bg-elevated);
    border-radius: var(--radius-xl);
    padding: 2rem;
    box-shadow: var(--shadow-md);
    border: 1px solid var(--border);
    transition: background-color var(--transition-speed), border-color var(--transition-speed);
}

.info-card h2 {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    font-size: 1.3rem;
    color: var(--text);
    margin: 0 0 1.5rem;
}

.info-card h2 svg,
.info-card h2 i {
    color: var(--primary);
}

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

.steps-list li {
    position: relative;
    padding-left: 3.25rem;
    margin-bottom: 1rem;
    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(--primary);
    color: white;
    border-radius: var(--radius-full);
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    font-size: 0.875rem;
    z-index: 1;
}

.steps-list li:last-child {
    margin-bottom: 0;
}

.steps-list li a {
    color: var(--primary);
    text-decoration: none;
}

.steps-list li a:hover {
    text-decoration: underline;
}

/* Steps Tip */
.steps-tip {
    display: flex;
    align-items: flex-start;
    gap: 0.75rem;
    margin-top: 1.5rem;
    padding: 1rem 1.25rem;
    background: var(--warning-light);
    border-radius: var(--radius-md);
    font-size: 0.9rem;
    color: var(--text-secondary);
    line-height: 1.6;
}

.steps-tip i,
.steps-tip svg {
    color: var(--warning);
    flex-shrink: 0;
    margin-top: 2px;
}

.steps-tip a {
    color: var(--warning);
    font-weight: 600;
    text-decoration: none;
}

.steps-tip a:hover {
    text-decoration: underline;
}

/* Compression Explanations */
.compression-explanations {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.compression-explain {
    display: flex;
    align-items: flex-start;
    gap: 1rem;
}

.compression-tag {
    flex-shrink: 0;
    padding: 0.4rem 1rem;
    border-radius: var(--radius-full);
    font-size: 0.85rem;
    font-weight: 600;
    color: white;
}

.compression-tag.lossless { background: var(--primary); }
.compression-tag.lossy { background: var(--warning); }

.compression-explain p {
    margin: 0;
    color: var(--text-secondary);
    line-height: 1.6;
}

.compression-explain p a {
    color: var(--primary);
    text-decoration: none;
}

.compression-explain p a:hover {
    text-decoration: underline;
}

/* ============================================
   FAQ
   ============================================ */
.faq-list {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

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

.faq-question {
    width: 100%;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 1.25rem;
    background: var(--bg-secondary);
    border: none;
    cursor: pointer;
    font-size: 1rem;
    font-weight: 500;
    color: var(--text);
    text-align: left;
    transition: all 0.2s ease;
}

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

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

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

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease;
}

.faq-item.open .faq-answer {
    max-height: 300px;
}

.faq-answer p {
    padding: 1rem 1.25rem;
    margin: 0;
    color: var(--text-secondary);
    line-height: 1.7;
    border-top: 1px solid var(--border);
    background: var(--bg-elevated);
}

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

.faq-answer a:hover {
    text-decoration: underline;
}

/* ============================================
   RESPONSIVE
   ============================================ */
@media (max-width: 1000px) {
    .format-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .use-cases-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 768px) {
    .tool-container {
        padding: 1rem;
    }
    
    .tool-title-row {
        gap: 0.75rem;
    }
    
    .tool-icon-wrapper {
        width: 50px;
        height: 50px;
    }
    
    .upload-section {
        padding: 2rem 1.5rem;
    }
    
    .upload-area {
        padding: 2.5rem 1.5rem;
    }
    
    .original-info {
        grid-template-columns: 1fr;
        gap: 1.5rem;
        padding: 1.5rem;
    }
    
    .preview-wrapper {
        max-width: 200px;
        margin: 0 auto;
    }
    
    .detail-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .quality-control-panel {
        padding: 1.25rem 1.5rem;
    }
    
    .comparison-section {
        padding: 1.5rem;
    }
    
    .recommendation-section {
        margin: 1.25rem 1.5rem;
        padding: 1.25rem;
    }
    
    .detailed-analysis {
        padding: 1.5rem;
    }
    
    .analysis-tabs {
        flex-wrap: wrap;
    }
    
    .features-table {
        font-size: 0.85rem;
    }
    
    .features-table th,
    .features-table td {
        padding: 0.625rem 0.5rem;
    }
    
    .action-bar {
        padding: 1.25rem 1.5rem;
    }
    
    .related-tools {
        flex-direction: column;
        align-items: flex-start;
    }
    
    .info-card {
        padding: 1.5rem;
    }
    
    .compression-explain {
        flex-direction: column;
        gap: 0.5rem;
    }
}

@media (max-width: 600px) {
    .format-grid {
        grid-template-columns: 1fr 1fr;
    }
    
    .use-cases-grid {
        grid-template-columns: 1fr;
    }
    
    .detail-grid {
        grid-template-columns: 1fr;
    }
    
    .quality-presets {
        flex-direction: column;
        align-items: flex-start;
    }
    
    .quality-presets .preset-label {
        margin-bottom: 0.25rem;
    }
    
    .size-bar-item {
        flex-wrap: wrap;
    }
    
    .size-bar-label {
        width: 100%;
        margin-bottom: 0.25rem;
    }
    
    .size-bar-container {
        flex: 1 1 100%;
    }
    
    .size-bar-percent {
        width: 100%;
        text-align: left;
        margin-top: 0.25rem;
    }
}

@media (max-width: 480px) {
    .tool-title-row {
        flex-direction: column;
    }
    
    .format-grid {
        grid-template-columns: 1fr;
    }
    
    .format-card {
        max-width: 280px;
        margin: 0 auto;
    }
}

/* ============================================
   SCROLLBAR
   ============================================ */
::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}

::-webkit-scrollbar-track {
    background: var(--scrollbar-track);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb {
    background: var(--scrollbar-thumb);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--scrollbar-thumb-hover);
}

/* Selection */
::selection {
    background: rgba(51, 153, 204, 0.2);
    color: var(--text);
}

[data-theme="dark"] ::selection {
    background: rgba(96, 165, 250, 0.3);
}

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

.analysis-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;
    }
}