/* Smooth theme transitions */
html {
  transition: background-color 0.3s ease, color 0.3s ease;
}

body {
  transition: background-color 0.3s ease, color 0.3s ease;
}

/* Explicit light mode (default when no data-theme set) */
html:not([data-theme="dark"]),
html[data-theme="light"] {
  color-scheme: light;
}

html[data-theme="dark"] {
  color-scheme: dark;
}

/* Ensure theme toggle icons always work */
html:not([data-theme="dark"]) .theme-icon-moon,
html[data-theme="light"] .theme-icon-moon {
  display: none !important;
}

html[data-theme="dark"] .theme-icon-sun {
  display: none !important;
}

/* ========================================
   Image Compressor Hub - Main Stylesheet
   Production-Ready, Premium, Accessible
   ======================================== */

/* CSS Variables for Theming - with RGB variants for rgba() */
:root {
  --bg-primary: #ffffff;
  --bg-primary-rgb: 255, 255, 255;
  --bg-secondary: #f8f9fa;
  --bg-secondary-rgb: 248, 249, 250;
  --bg-tertiary: #e9ecef;
  --bg-tertiary-rgb: 233, 236, 239;
  --text-primary: #1a1a2e;
  --text-secondary: #4a5568;
  --text-muted: #718096;
  --accent: #2563eb;
  --accent-hover: #1d4ed8;
  --accent-light: #dbeafe;
  --border: #e2e8f0;
  --border-focus: #2563eb;
  --success: #059669;
  --success-rgb: 5, 150, 105;
  --success-bg: #d1fae5;
  --error: #dc2626;
  --error-rgb: 220, 38, 38;
  --error-bg: #fee2e2;
  --warning: #d97706;
  --warning-rgb: 217, 119, 6;
  --warning-bg: #fef3c7;
  --shadow-sm: 0 1px 2px 0 rgba(0,0,0,0.05);
  --shadow: 0 4px 6px -1px rgba(0,0,0,0.1), 0 2px 4px -1px rgba(0,0,0,0.06);
  --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.1), 0 4px 6px -2px rgba(0,0,0,0.05);
  --radius: 0.75rem;
  --radius-sm: 0.375rem;
  --radius-lg: 1rem;
  --transition: 150ms ease-in-out;
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --max-width: 1200px;
  --header-height: 4rem;
}

[data-theme="dark"] {
  --bg-primary: #0b0f1f;
  --bg-primary-rgb: 11, 15, 31;
  --bg-secondary: #111827;
  --bg-secondary-rgb: 17, 24, 39;
  --bg-tertiary: #1f2937;
  --bg-tertiary-rgb: 31, 41, 55;
  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  --accent: #38bdf8;
  --accent-hover: #0ea5e9;
  --accent-light: rgba(56, 189, 248, 0.12);
  --border: #1e293b;
  --border-focus: #38bdf8;
  --success: #34d399;
  --success-rgb: 52, 211, 153;
  --success-bg: rgba(52, 211, 153, 0.1);
  --error: #fb7185;
  --error-rgb: 251, 113, 133;
  --error-bg: rgba(251, 113, 133, 0.1);
  --warning: #fbbf24;
  --warning-rgb: 251, 191, 36;
  --warning-bg: rgba(251, 191, 36, 0.1);
  --shadow-sm: 0 1px 2px 0 rgba(0,0,0,0.4);
  --shadow: 0 4px 6px -1px rgba(0,0,0,0.4), 0 2px 4px -1px rgba(0,0,0,0.3);
  --shadow-lg: 0 10px 40px -10px rgba(0,0,0,0.6), 0 4px 12px -2px rgba(0,0,0,0.4);
}

/* Dark mode body background with subtle depth */
[data-theme="dark"] body {
  background: linear-gradient(180deg, #0b0f1f 0%, #0f172a 50%, #0b0f1f 100%);
  background-attachment: fixed;
}

/* Dark mode card glow effect */
[data-theme="dark"] .compressor-widget,
[data-theme="dark"] .preview-card,
[data-theme="dark"] .faq-accordion {
  border-color: rgba(56, 189, 248, 0.08);
  box-shadow: 0 0 0 1px rgba(56, 189, 248, 0.05), var(--shadow-lg);
}

/* Dark mode select dropdown enhanced */
[data-theme="dark"] .target-size-select {
  background-color: #111827;
  border-color: #1e293b;
}

[data-theme="dark"] .target-size-select:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(56, 189, 248, 0.15);
}

/* Dark mode stats bar */
[data-theme="dark"] .stats-bar {
  background: linear-gradient(90deg, rgba(56,189,248,0.05) 0%, rgba(52,211,153,0.05) 100%);
  border-color: rgba(56, 189, 248, 0.1);
}

/* Dark mode FAQ accordion */
[data-theme="dark"] .faq-toggle {
  background: transparent;
}

[data-theme="dark"] .faq-toggle:hover {
  background: rgba(56, 189, 248, 0.05);
}

[data-theme="dark"] .faq-panel {
  background: transparent;
}

/* Dark mode button enhancements */
[data-theme="dark"] .btn-primary {
  box-shadow: 0 0 20px rgba(56, 189, 248, 0.15);
}

[data-theme="dark"] .btn-success {
  box-shadow: 0 0 20px rgba(52, 211, 153, 0.15);
}

/* Dark mode header subtle glass effect */
[data-theme="dark"] .site-header {
  background: rgba(11, 15, 31, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom-color: rgba(56, 189, 248, 0.08);
}

/* Dark mode section alt */
[data-theme="dark"] .section-alt {
  background: linear-gradient(180deg, #0f172a 0%, #111827 100%);
}

/* Dark mode hero */
[data-theme="dark"] .hero {
  background: linear-gradient(180deg, rgba(56,189,248,0.03) 0%, transparent 100%);
}

/* Dark mode article cards / target grid */
[data-theme="dark"] .target-card {
  background: linear-gradient(135deg, #111827 0%, #0f172a 100%);
  border-color: rgba(56, 189, 248, 0.08);
}

[data-theme="dark"] .target-card:hover {
  border-color: rgba(56, 189, 248, 0.2);
  box-shadow: 0 0 30px rgba(56, 189, 248, 0.08);
}

/* Dark mode footer */
[data-theme="dark"] .site-footer {
  background: #080c18;
  border-top-color: rgba(56, 189, 248, 0.06);
}

/* Reset & Base */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-sans);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

img, picture, video, canvas, svg {
  display: block;
  max-width: 100%;
}

input, button, textarea, select {
  font: inherit;
  color: inherit;
}

a {
  color: var(--accent);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

/* Utility Classes */
.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;
}

.container {
  width: 100%;
  max-width: var(--max-width);
  margin-left: auto;
  margin-right: auto;
  padding-left: 1rem;
  padding-right: 1rem;
}

/* No-JS Fallback */
.noscript-notice {
  background: var(--warning-bg);
  color: var(--warning);
  padding: 1rem;
  text-align: center;
  font-weight: 600;
  border-bottom: 1px solid var(--warning);
}

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background-color: rgba(var(--bg-primary-rgb), 0.9);
  border-bottom: 1px solid var(--border);
  height: var(--header-height);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.logo {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: 0.5rem;
  flex-shrink: 0;
}

.logo:hover { text-decoration: none; }

.logo-icon {
  width: 2rem;
  height: 2rem;
  background: linear-gradient(135deg, var(--accent), var(--accent-hover));
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-weight: 800;
}

/* Navigation */
.site-nav {
  display: flex;
  align-items: center;
  gap: 1.5rem;
}

.nav-link {
  color: var(--text-secondary);
  font-weight: 500;
  font-size: 0.875rem;
  transition: color var(--transition);
}

.nav-link:hover {
  color: var(--text-primary);
  text-decoration: none;
}

/* Mobile Menu */
.mobile-menu-btn {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.5rem;
  color: var(--text-primary);
}

.mobile-nav {
  display: none;
  position: absolute;
  top: var(--header-height);
  left: 0;
  right: 0;
  background: var(--bg-primary);
  border-bottom: 1px solid var(--border);
  padding: 1rem;
  box-shadow: var(--shadow-lg);
  z-index: 40;
}

.mobile-nav.active { display: block; }

.mobile-nav .nav-link {
  display: block;
  padding: 0.75rem 0;
  font-size: 1rem;
  border-bottom: 1px solid var(--border);
}

.mobile-nav .nav-link:last-child { border-bottom: none; }

/* Theme Toggle */

.theme-toggle {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 0.5rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background var(--transition), border-color var(--transition);
}

.theme-toggle:hover {
  background: var(--bg-tertiary);
  border-color: var(--border-focus);
}

.theme-toggle:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.theme-icon {
  width: 1.25rem;
  height: 1.25rem;
  color: var(--text-primary);
}

/* Main Content */
main { flex: 1; }

/* Hero Section */
.hero {
  padding: 4rem 0 3rem;
  text-align: center;
  background: linear-gradient(180deg, var(--bg-secondary) 0%, var(--bg-primary) 100%);
}

.hero-title {
  font-size: clamp(2rem, 5vw, 3.5rem);
  font-weight: 800;
  line-height: 1.1;
  margin-bottom: 1rem;
  letter-spacing: -0.025em;
}

.hero-subtitle {
  font-size: clamp(1rem, 2vw, 1.25rem);
  color: var(--text-secondary);
  max-width: 600px;
  margin: 0 auto 2rem;
}

/* Compressor Widget */
.compressor-widget {
  background: var(--bg-primary);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 2rem;
  box-shadow: var(--shadow-lg);
  max-width: 900px;
  margin: 0 auto 3rem;
  position: relative;
}

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

.control-label {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--text-secondary);
}

.target-size-select {
  padding: 0.625rem 2.5rem 0.625rem 0.875rem;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  font-size: 1rem;
  appearance: none;
  -webkit-appearance: none;
  background-image: url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' fill='none' viewBox='0 0 20 20'%3e%3cpath stroke='%236b7280' stroke-linecap='round' stroke-linejoin='round' stroke-width='1.5' d='M6 8l4 4 4-4'/%3e%3c/svg%3e");
  background-position: right 0.75rem center;
  background-repeat: no-repeat;
  background-size: 1.25rem;
  cursor: pointer;
  transition: border-color var(--transition), box-shadow var(--transition);
}

.target-size-select:focus {
  outline: none;
  border-color: var(--border-focus);
  box-shadow: 0 0 0 3px var(--accent-light);
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.625rem 1.5rem;
  font-size: 0.9375rem;
  font-weight: 600;
  border-radius: var(--radius);
  border: 1px solid transparent;
  cursor: pointer;
  transition: background var(--transition), transform var(--transition), box-shadow var(--transition);
  white-space: nowrap;
  line-height: 1.5;
}

.btn:active { transform: translateY(1px); }

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

.btn-primary:hover {
  background: var(--accent-hover);
  border-color: var(--accent-hover);
  text-decoration: none;
}

.btn-primary:disabled {
  opacity: 0.6;
  cursor: not-allowed;
  transform: none;
}

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

.btn-secondary:hover {
  background: var(--bg-tertiary);
  text-decoration: none;
}

.btn-success {
  background: var(--success);
  color: white;
  border-color: var(--success);
}

.btn-success:hover {
  background: #047857;
  border-color: #047857;
  text-decoration: none;
}

.btn-sm {
  padding: 0.5rem 1rem;
  font-size: 0.875rem;
}

/* Preview Area */
.preview-area {
  margin-top: 2rem;
  display: none;
}

.preview-area.active { display: block; }

.preview-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.5rem;
  margin-bottom: 1.5rem;
}

.preview-card {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1rem;
}

.preview-card-title {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--text-secondary);
  margin-bottom: 0.75rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.preview-image-wrap {
  position: relative;
  width: 100%;
  aspect-ratio: 16/10;
  background: repeating-conic-gradient(var(--bg-tertiary) 0% 25%, transparent 0% 50%) 50% / 20px 20px;
  border-radius: var(--radius-sm);
  overflow: hidden;
}

.preview-image-wrap img,
.preview-image-wrap canvas {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: contain;
}

.preview-meta {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.75rem;
  margin-top: 1rem;
}

.meta-item {
  display: flex;
  flex-direction: column;
  gap: 0.125rem;
}

.meta-label {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-muted);
  font-weight: 600;
}

.meta-value {
  font-size: 0.9375rem;
  font-weight: 700;
  color: var(--text-primary);
}

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

/* Stats Bar */
.stats-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1rem 1.5rem;
  margin-bottom: 1.5rem;
  align-items: center;
  justify-content: space-between;
}

.stat-item {
  display: flex;
  flex-direction: column;
}

.stat-label {
  font-size: 0.75rem;
  color: var(--text-muted);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.stat-value {
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--text-primary);
}

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

.compression-badge {
  display: inline-flex;
  align-items: center;
  padding: 0.25rem 0.75rem;
  border-radius: 9999px;
  font-size: 0.875rem;
  font-weight: 700;
  background: var(--success-bg);
  color: var(--success);
}

/* Action Buttons */
.action-buttons {
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
}

/* Alerts */
.alert {
  padding: 1rem 1.25rem;
  border-radius: var(--radius);
  font-size: 0.9375rem;
  display: flex;
  align-items: flex-start;
  gap: 0.75rem;
  margin-top: 1rem;
}

.alert-error {
  background: var(--error-bg);
  color: var(--error);
  border: 1px solid var(--error);
}

.alert-warning {
  background: var(--warning-bg);
  color: var(--warning);
  border: 1px solid var(--warning);
}

.alert-success {
  background: var(--success-bg);
  color: var(--success);
  border: 1px solid var(--success);
}

.alert-icon {
  width: 1.25rem;
  height: 1.25rem;
  flex-shrink: 0;
  margin-top: 0.125rem;
}

/* Processing State */
.processing-overlay {
  display: none;
  position: absolute;
  inset: 0;
  background: rgba(var(--bg-primary-rgb), 0.88);
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 1rem;
  z-index: 10;
  border-radius: var(--radius-lg);
}

.processing-overlay.active { display: flex; }

.spinner {
  width: 2.5rem;
  height: 2.5rem;
  border: 3px solid var(--border);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

@keyframes spin {
  from { transform: rotate(0deg); }
  to { transform: rotate(360deg); }
}

.processing-text {
  font-weight: 600;
  color: var(--text-primary);
}

.progress-bar {
  width: 200px;
  height: 6px;
  background: var(--bg-tertiary);
  border-radius: 3px;
  overflow: hidden;
  margin-top: 0.5rem;
}

.progress-fill {
  height: 100%;
  background: var(--accent);
  border-radius: 3px;
  transition: width 0.3s ease;
  width: 0%;
}

.progress-label {
  font-size: 0.8125rem;
  color: var(--text-muted);
  margin-top: 0.25rem;
}

/* Target Size Grid (Hub) */
.target-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
  gap: 0.75rem;
  margin-top: 1.5rem;
}

.target-card {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 1rem;
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  font-weight: 600;
  color: var(--text-primary);
  transition: all var(--transition);
}

.target-card:hover {
  background: var(--accent-light);
  border-color: var(--accent);
  color: var(--accent);
  text-decoration: none;
  transform: translateY(-2px);
  box-shadow: var(--shadow);
}

.target-card[aria-current="page"] {
  background: var(--accent-light);
  border-color: var(--accent);
  color: var(--accent);
  box-shadow: var(--shadow);
}

/* Content Sections */
.section { padding: 3rem 0; }

.section-alt { background: var(--bg-secondary); }

.section-title {
  font-size: 1.875rem;
  font-weight: 700;
  margin-bottom: 1rem;
  letter-spacing: -0.025em;
}

.section-subtitle {
  color: var(--text-secondary);
  font-size: 1.125rem;
  margin-bottom: 2rem;
  max-width: 600px;
}

/* Cards */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 1.5rem;
}

.card {
  background: var(--bg-primary);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
  transition: box-shadow var(--transition), transform var(--transition);
}

.card:hover {
  box-shadow: var(--shadow-lg);
  transform: translateY(-2px);
}

.card-icon {
  width: 2.5rem;
  height: 2.5rem;
  background: var(--accent-light);
  color: var(--accent);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 1rem;
}

.card-title {
  font-size: 1.125rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
}

.card-text {
  color: var(--text-secondary);
  font-size: 0.9375rem;
  line-height: 1.6;
}

/* Comparison Table */
.compare-table-wrap {
  overflow-x: auto;
  margin: 1.5rem 0;
  border: 1px solid var(--border);
  border-radius: var(--radius);
}

.compare-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9375rem;
}

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

.compare-table th {
  background: var(--bg-secondary);
  font-weight: 700;
  color: var(--text-primary);
  font-size: 0.875rem;
  text-transform: uppercase;
  letter-spacing: 0.03em;
}

.compare-table td {
  color: var(--text-secondary);
}

.compare-table tr:last-child td { border-bottom: none; }

.compare-table tr:hover td { background: var(--bg-secondary); }

/* Breadcrumbs */
.breadcrumbs {
  padding: 1rem 0;
  font-size: 0.875rem;
  color: var(--text-muted);
}

.breadcrumbs a { color: var(--text-secondary); }

.breadcrumbs a:hover { color: var(--accent); }

.breadcrumbs .sep {
  margin: 0 0.5rem;
  opacity: 0.5;
}

/* Article Content */
.article {
  max-width: 768px;
  margin: 0 auto;
}

.article h2 {
  font-size: 1.5rem;
  font-weight: 700;
  margin: 2.5rem 0 1rem;
  letter-spacing: -0.025em;
}

.article h3 {
  font-size: 1.25rem;
  font-weight: 600;
  margin: 2rem 0 0.75rem;
}

.article p {
  color: var(--text-secondary);
  margin-bottom: 1rem;
  line-height: 1.75;
}

.article ul,
.article ol {
  color: var(--text-secondary);
  margin-bottom: 1.25rem;
  padding-left: 1.5rem;
}

.article li { margin-bottom: 0.5rem; }

.article strong {
  color: var(--text-primary);
  font-weight: 600;
}

/* Table of Contents */
.toc {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem 1.5rem;
  margin: 1.5rem 0;
}

.toc-title {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 0.75rem;
  color: var(--text-primary);
}

.toc ul {
  list-style: none;
  padding: 0;
  margin: 0;
}

.toc li { margin-bottom: 0.375rem; }

.toc a {
  color: var(--text-secondary);
  font-size: 0.9375rem;
  transition: color var(--transition);
}

.toc a:hover { color: var(--accent); }

/* Footer */
.site-footer {
  background: var(--bg-secondary);
  border-top: 1px solid var(--border);
  padding: 2.5rem 0 1.5rem;
  margin-top: auto;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr repeat(3, 1fr);
  gap: 2rem;
  margin-bottom: 2rem;
}

.footer-brand {
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 0.75rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.footer-desc {
  color: var(--text-secondary);
  font-size: 0.9375rem;
  line-height: 1.6;
}

.footer-title {
  font-size: 0.875rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-primary);
  margin-bottom: 1rem;
}

.footer-links {
  list-style: none;
  padding: 0;
}

.footer-links li { margin-bottom: 0.5rem; }

.footer-links a {
  color: var(--text-secondary);
  font-size: 0.9375rem;
  transition: color var(--transition);
}

.footer-links a:hover { color: var(--accent); }

.footer-bottom {
  border-top: 1px solid var(--border);
  padding-top: 1.5rem;
  text-align: center;
  color: var(--text-muted);
  font-size: 0.875rem;
}

/* Skip Link */
.skip-link {
  position: absolute;
  top: -40px;
  left: 0;
  background: var(--accent);
  color: white;
  padding: 0.5rem 1rem;
  z-index: 100;
  transition: top 0.2s;
}

.skip-link:focus { top: 0; }

/* Responsive */
@media (max-width: 768px) {
  .preview-grid { grid-template-columns: 1fr; }

  .preview-meta { grid-template-columns: 1fr 1fr; }

  .stats-bar {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.75rem;
  }

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

  .site-nav { display: none; }

  .mobile-menu-btn { display: block; }

  .hero { padding: 2.5rem 0 2rem; }

  .compressor-widget { padding: 1.25rem; }

  .section { padding: 2rem 0; }
}

@media (max-width: 480px) {
  .footer-grid { grid-template-columns: 1fr; }

  .action-buttons { width: 100%; }

  .action-buttons .btn { flex: 1; }
}

/* Reduced Motion */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
  html { scroll-behavior: auto; }
}

/* Focus Visible */
:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

/* High Contrast Mode */
@media (prefers-contrast: more) {
  .btn {
    border-width: 2px;
  }
}






/* ============================================================
   UPLOAD SECTION - Clean Modern Design
   ============================================================ */

[data-theme="dark"] #output-format-select option {
  background: var(--bg-primary);
  color: var(--text-primary);
  font-size: 0.9375rem;
}

/* ============================================================
   UPLOAD SECTION - Clean Div-Based Design
   ============================================================ */

.drop-zone {
  position: relative;
  border: 2px dashed var(--border);
  border-radius: var(--radius-lg);
  padding: 0;
  text-align: center;
  cursor: pointer;
  background: var(--bg-primary);
  transition: border-color 0.25s ease, background 0.25s ease, box-shadow 0.25s ease;
  overflow: hidden;
}

.drop-zone:hover,
.drop-zone.drag-over {
  border-color: var(--accent);
  background: var(--accent-light);
  box-shadow: 0 0 0 4px var(--accent-light);
}

.drop-zone:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

/* File input - completely hidden but clickable */
.drop-zone-input {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  opacity: 0;
  cursor: pointer;
  z-index: 20;
  padding: 0;
  margin: 0;
  border: none;
  font-size: 0;
}

/* Content wrapper */
.drop-zone-content {
  position: relative;
  z-index: 1;
  padding: 2.5rem 1.5rem;
  pointer-events: none;
}

/* Icon container */
.drop-zone-icon-wrap {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 4rem;
  height: 4rem;
  margin-bottom: 1rem;
  border-radius: var(--radius);
  background: linear-gradient(135deg, var(--accent-light) 0%, rgba(52,211,153,0.05) 100%);
  border: 1px solid var(--border);
  transition: transform 0.25s ease, border-color 0.25s ease;
}

.drop-zone:hover .drop-zone-icon-wrap,
.drop-zone.drag-over .drop-zone-icon-wrap {
  transform: scale(1.05);
  border-color: var(--accent);
}

.drop-zone-icon {
  width: 1.75rem;
  height: 1.75rem;
  color: var(--accent);
  flex-shrink: 0;
}

/* Main text */
.drop-zone-text {
  display: block;
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 0.25rem;
  line-height: 1.4;
}

/* Subtext */
.drop-zone-subtext {
  display: block;
  font-size: 0.9375rem;
  color: var(--text-secondary);
  margin-bottom: 0.625rem;
  line-height: 1.5;
}

/* Hint text */
.drop-zone-hint {
  display: block;
  font-size: 0.8125rem;
  color: var(--text-muted);
  max-width: 420px;
  margin: 0 auto;
  line-height: 1.6;
}

/* File type tags */
.drop-zone .file-types {
  display: flex;
  flex-wrap: wrap;
  gap: 0.375rem;
  justify-content: center;
  margin-top: 0.875rem;
}

.drop-zone .file-type-tag {
  display: inline-block;
  padding: 0.25rem 0.625rem;
  background: var(--bg-tertiary);
  border: 1px solid var(--border);
  border-radius: 999px;
  font-size: 0.6875rem;
  font-weight: 700;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.04em;
  line-height: 1;
}

/* File info display */
#file-info {
  display: block;
  margin-top: 0.875rem;
  padding: 0.5rem 0.875rem;
  background: var(--bg-tertiary);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  font-weight: 600;
  color: var(--accent);
  font-size: 0.875rem;
  max-width: 340px;
  margin-left: auto;
  margin-right: auto;
  line-height: 1.5;
  word-break: break-word;
}

/* Dark mode upload */
[data-theme="dark"] .drop-zone {
  background: var(--bg-secondary);
  border-color: rgba(56, 189, 248, 0.1);
}

[data-theme="dark"] .drop-zone:hover,
[data-theme="dark"] .drop-zone.drag-over {
  border-color: var(--accent);
  background: rgba(56, 189, 248, 0.04);
  box-shadow: 0 0 0 4px rgba(56, 189, 248, 0.06);
}

[data-theme="dark"] .drop-zone-icon-wrap {
  background: rgba(56, 189, 248, 0.06);
  border-color: rgba(56, 189, 248, 0.1);
}

[data-theme="dark"] .file-type-tag {
  background: rgba(56, 189, 248, 0.05);
  border-color: rgba(56, 189, 248, 0.08);
  color: #7dd3fc;
}

/* Output Format Select */
#output-format-select {
  min-width: 160px;
  cursor: pointer;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%2364748b' stroke-width='2.5' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='M6 9l6 6 6-6'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 0.75rem center;
  padding-right: 2.25rem;
  -webkit-appearance: none;
  -moz-appearance: none;
  appearance: none;
}

#output-format-select option {
  background: var(--bg-primary);
  color: var(--text-primary);
  font-size: 0.9375rem;
}

/* Compressor controls */
.compressor-controls {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-end;
  gap: 1rem;
  justify-content: center;
  margin-top: 1.5rem;
}

.compressor-controls .control-group {
  flex: 1 1 140px;
  min-width: 140px;
  max-width: 200px;
}

@media (max-width: 480px) {
  .compressor-controls {
    flex-direction: column;
    align-items: stretch;
  }
  .compressor-controls .control-group {
    max-width: 100%;
  }
  .compressor-controls .btn-primary {
    width: 100%;
  }
  .drop-zone-content {
    padding: 2rem 1rem;
  }
}

/* FAQ Accordion */
.faq-accordion {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
}

.faq-item {
  border-bottom: 1px solid var(--border);
}

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

.faq-toggle {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 1.125rem 1.25rem;
  background: var(--bg-primary);
  color: var(--text-primary);
  font-family: inherit;
  font-size: 1rem;
  font-weight: 600;
  text-align: left;
  border: none;
  cursor: pointer;
  transition: background 0.2s;
}

.faq-toggle:hover {
  background: var(--bg-secondary);
}

.faq-toggle:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: -2px;
}

.faq-toggle-icon {
  flex-shrink: 0;
  width: 1.25rem;
  height: 1.25rem;
  color: var(--text-secondary);
  transition: transform 0.25s;
}

.faq-item.active .faq-toggle-icon {
  transform: rotate(180deg);
}

.faq-panel {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease, padding 0.3s ease;
  background: var(--bg-primary);
}

.faq-item.active .faq-panel {
  max-height: 500px;
}

.faq-panel p {
  padding: 0 1.25rem 1.125rem;
  margin: 0;
  color: var(--text-secondary);
  font-size: 0.9375rem;
  line-height: 1.7;
}

/* Print */
@media print {
  .site-header, .site-footer, .theme-toggle, .btn, .preview-area { display: block !important; }
}


/* Additional Dark Mode Enhancements */
[data-theme="dark"] .compressor-widget {
  background: linear-gradient(145deg, #111827 0%, #0b0f1f 100%);
  border: 1px solid rgba(56, 189, 248, 0.08);
  box-shadow: 0 0 0 1px rgba(56, 189, 248, 0.04), 0 20px 50px -15px rgba(0,0,0,0.5);
}

[data-theme="dark"] .preview-card {
  background: linear-gradient(145deg, #111827 0%, #0f172a 100%);
  border: 1px solid rgba(56, 189, 248, 0.06);
}

[data-theme="dark"] .faq-accordion {
  background: linear-gradient(145deg, #111827 0%, #0b0f1f 100%);
  border: 1px solid rgba(56, 189, 248, 0.06);
}

[data-theme="dark"] .faq-item {
  border-color: rgba(56, 189, 248, 0.06);
}

[data-theme="dark"] .faq-toggle:hover {
  background: rgba(56, 189, 248, 0.04);
}

[data-theme="dark"] .stats-bar {
  background: linear-gradient(90deg, rgba(56,189,248,0.06) 0%, rgba(52,211,153,0.04) 100%);
  border: 1px solid rgba(56, 189, 248, 0.08);
}

[data-theme="dark"] .btn-primary {
  background: linear-gradient(135deg, var(--accent) 0%, #0ea5e9 100%);
  box-shadow: 0 4px 20px rgba(56, 189, 248, 0.25);
}

[data-theme="dark"] .btn-primary:hover {
  box-shadow: 0 6px 28px rgba(56, 189, 248, 0.35);
}

[data-theme="dark"] .btn-success {
  background: linear-gradient(135deg, var(--success) 0%, #10b981 100%);
  box-shadow: 0 4px 20px rgba(52, 211, 153, 0.2);
}

[data-theme="dark"] .more-dropdown {
  background: #111827;
  border-color: rgba(56, 189, 248, 0.12);
  box-shadow: 0 20px 50px -10px rgba(0,0,0,0.6), 0 0 0 1px rgba(56,189,248,0.05);
}

[data-theme="dark"] .target-size-select,
[data-theme="dark"] #output-format-select {
  background-color: #0f172a;
  border-color: rgba(56, 189, 248, 0.12);
  color: var(--text-primary);
}

[data-theme="dark"] .target-size-select:focus,
[data-theme="dark"] #output-format-select:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(56, 189, 248, 0.12);
}

[data-theme="dark"] .article h2 {
  color: #7dd3fc;
}

[data-theme="dark"] .article p {
  color: #94a3b8;
}

[data-theme="dark"] .hero-title {
  background: linear-gradient(135deg, #f8fafc 0%, #7dd3fc 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* ============================================================
   DARK MODE — PREMIUM ENHANCEMENTS
   (light mode is untouched; everything below is scoped to
   [data-theme="dark"] only)
   ============================================================ */

/* Ambient glow orbs behind the hero for depth */
[data-theme="dark"] .hero {
  position: relative;
  overflow: hidden;
  isolation: isolate;
}

[data-theme="dark"] .hero::before,
[data-theme="dark"] .hero::after {
  content: "";
  position: absolute;
  width: 32rem;
  height: 32rem;
  border-radius: 50%;
  filter: blur(90px);
  opacity: 0.16;
  z-index: -1;
  pointer-events: none;
  animation: auroraDrift 16s ease-in-out infinite alternate;
}

[data-theme="dark"] .hero::before {
  background: #38bdf8;
  top: -10rem;
  left: -8rem;
}

[data-theme="dark"] .hero::after {
  background: #34d399;
  bottom: -14rem;
  right: -8rem;
  animation-delay: -8s;
}

@keyframes auroraDrift {
  0%   { transform: translate(0, 0) scale(1); }
  100% { transform: translate(3rem, 2rem) scale(1.15); }
}

/* Selection color */
[data-theme="dark"] ::selection {
  background: rgba(56, 189, 248, 0.35);
  color: #f8fafc;
}

/* Custom scrollbar */
[data-theme="dark"] {
  scrollbar-color: #334155 #0b0f1f;
}

[data-theme="dark"] ::-webkit-scrollbar {
  width: 12px;
  height: 12px;
}

[data-theme="dark"] ::-webkit-scrollbar-track {
  background: #0b0f1f;
}

[data-theme="dark"] ::-webkit-scrollbar-thumb {
  background: #334155;
  border-radius: 999px;
  border: 3px solid #0b0f1f;
}

[data-theme="dark"] ::-webkit-scrollbar-thumb:hover {
  background: #475569;
}

/* Logo mark glow */
[data-theme="dark"] .logo-icon {
  background: linear-gradient(135deg, #38bdf8, #34d399);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  filter: drop-shadow(0 0 12px rgba(56, 189, 248, 0.35));
}

/* Nav link underline glow on hover/active */
[data-theme="dark"] .nav-link {
  position: relative;
}

[data-theme="dark"] .nav-link:hover {
  color: #7dd3fc;
  text-decoration: none;
}

[data-theme="dark"] .nav-link[aria-current="page"] {
  color: #7dd3fc;
}

/* Cards: soft glow border on hover instead of flat shadow */
[data-theme="dark"] .card {
  background: linear-gradient(160deg, #111827 0%, #0f172a 100%);
  border-color: rgba(56, 189, 248, 0.08);
}

[data-theme="dark"] .card:hover {
  border-color: rgba(56, 189, 248, 0.25);
  box-shadow: 0 0 0 1px rgba(56, 189, 248, 0.1), 0 20px 40px -20px rgba(56, 189, 248, 0.25);
}

[data-theme="dark"] .card-icon {
  background: rgba(56, 189, 248, 0.1);
  color: #7dd3fc;
}

/* Compression badge glow */
[data-theme="dark"] .compression-badge {
  box-shadow: 0 0 16px rgba(52, 211, 153, 0.25);
}

/* Table styling */
[data-theme="dark"] .compare-table th {
  background: rgba(56, 189, 248, 0.06);
}

[data-theme="dark"] .compare-table tr:hover td {
  background: rgba(56, 189, 248, 0.04);
}

/* TOC */
[data-theme="dark"] .toc {
  background: rgba(56, 189, 248, 0.04);
  border-color: rgba(56, 189, 248, 0.1);
}

/* File info pill */
[data-theme="dark"] #file-info {
  background: rgba(56, 189, 248, 0.08);
  border-color: rgba(56, 189, 248, 0.15);
  color: #7dd3fc;
}

/* Progress bar glow */
[data-theme="dark"] .progress-fill {
  background: linear-gradient(90deg, #38bdf8, #34d399);
  box-shadow: 0 0 10px rgba(56, 189, 248, 0.5);
}

/* Alerts with a touch of glass */
[data-theme="dark"] .alert-error   { background: rgba(251, 113, 133, 0.08); }
[data-theme="dark"] .alert-warning { background: rgba(251, 191, 36, 0.08); }
[data-theme="dark"] .alert-success { background: rgba(52, 211, 153, 0.08); }

/* Theme toggle button glow */
[data-theme="dark"] .theme-toggle:hover,
[data-theme="dark"] .mobile-menu-btn:hover,
[data-theme="dark"] .more-menu-btn:hover {
  background: rgba(56, 189, 248, 0.08);
  color: #7dd3fc;
}

/* Currently active target-size card (used on the size-specific tool pages) */
[data-theme="dark"] .target-card[aria-current="page"] {
  background: linear-gradient(135deg, rgba(56,189,248,0.16) 0%, rgba(52,211,153,0.08) 100%);
  border-color: #38bdf8;
  color: #7dd3fc;
  box-shadow: 0 0 20px rgba(56, 189, 248, 0.15);
}

/* Respect reduced-motion for the aurora effect too */
@media (prefers-reduced-motion: reduce) {
  [data-theme="dark"] .hero::before,
  [data-theme="dark"] .hero::after {
    animation: none;
  }
}