:root {
  /* Typography */
  --font-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
  --font-heading: 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  --line-height-base: 1.6;

  /* Palette */
  --color-primary: #667eea;
  --color-primary-dark: #5568d3;
  --color-secondary: #764ba2;
  --color-accent: #ffc107;
  --color-info: #0c5460;
  --color-success: #38a169;
  --color-warning: #d69e2e;
  --color-danger: #e53e3e;

  --color-text: #333333;
  --color-text-muted: #666666;
  --color-surface: #ffffff;
  --color-surface-alt: #f8f9fa;
  --color-border: rgba(102, 126, 234, 0.25);
  --color-overlay: rgba(0, 0, 0, 0.1);

  --app-background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  --color-on-hero: #ffffff;

  /* Layout */
  --container-max: 1200px;
  --container-narrow: 900px;
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.08);
  --shadow-md: 0 6px 20px rgba(0, 0, 0, 0.12);
  --shadow-lg: 0 10px 40px rgba(0, 0, 0, 0.2);

  --space-xs: 0.5rem;
  --space-sm: 0.75rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2.5rem;
  --space-xxl: 3.5rem;

  /* Animation */
  --transition-base: 0.3s ease;
  --transition-fast: 0.2s ease;
}

[data-theme="dark"],
body.theme-dark {
  --color-text: #f5f5ff;
  --color-text-muted: rgba(245, 245, 255, 0.75);
  --color-surface: #1f2340;
  --color-surface-alt: #2a2f4d;
  --color-border: rgba(255, 255, 255, 0.08);
  --app-background: radial-gradient(circle at top left, #2a2f4d 0%, #181b33 45%, #0f1124 100%);
  --color-on-hero: #f5f5ff;
  color-scheme: dark;
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  min-height: 100vh;
  font-family: var(--font-sans);
  line-height: var(--line-height-base);
  color: var(--color-text);
  background: var(--app-background);
  transition: background 0.6s ease, color var(--transition-base);
}

img {
  max-width: 100%;
  display: block;
}

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color var(--transition-fast), opacity var(--transition-fast);
}

a:hover {
  color: var(--color-primary-dark);
}

.container {
  width: min(100% - 2rem, var(--container-max));
  margin: 0 auto;
  padding: var(--space-lg) 0;
}

.container--narrow {
  width: min(100% - 2rem, var(--container-narrow));
}

.site-header {
  text-align: center;
  color: var(--color-on-hero);
  padding: clamp(2.5rem, 8vw, 5rem) 1.5rem 2rem;
}

.site-header--compact {
  padding: clamp(2rem, 6vw, 3.5rem) 1.5rem;
}

.hero-title {
  font-family: var(--font-heading);
  font-size: clamp(2.25rem, 5vw, 3.5rem);
  margin-bottom: var(--space-md);
  text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.3);
}

.tagline {
  font-size: clamp(1.1rem, 2.8vw, 1.6rem);
  opacity: 0.95;
}

.surface {
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  padding: clamp(1.5rem, 4vw, 2.75rem);
  margin: var(--space-xl) auto;
  box-shadow: var(--shadow-lg);
}

.surface--narrow {
  margin: var(--space-lg) auto;
}

.section {
  padding: var(--space-lg);
  border-radius: var(--radius-md);
  background: var(--color-surface-alt);
}

.info-section {
  margin: var(--space-lg) 0;
  padding: clamp(1.5rem, 4vw, 2.5rem);
  border-radius: var(--radius-md);
  background: var(--color-surface-alt);
}

.section-title {
  color: var(--color-primary);
  margin: var(--space-xl) 0 var(--space-lg);
  font-size: clamp(1.75rem, 3.5vw, 2.25rem);
  font-family: var(--font-heading);
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: var(--space-lg);
  margin: var(--space-xl) 0;
}

.card,
.feature-card {
  padding: clamp(1.5rem, 3vw, 2rem);
  border-radius: var(--radius-md);
  background: var(--color-surface-alt);
  border-left: 4px solid var(--color-primary);
  transition: transform var(--transition-base), box-shadow var(--transition-base);
}

.feature-card:hover,
.card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-md);
}

.feature-card h3,
.card h3 {
  color: var(--color-primary);
  margin-bottom: var(--space-sm);
  font-size: 1.4rem;
}

.feature-card p,
.card p {
  color: var(--color-text-muted);
  line-height: 1.8;
}

.flex {
  display: flex;
}

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

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

.gap-sm {
  gap: var(--space-sm);
}

.gap-md {
  gap: var(--space-md);
}

.gap-lg {
  gap: var(--space-lg);
}

.cta-buttons {
  display: flex;
  gap: var(--space-md);
  justify-content: center;
  flex-wrap: wrap;
  margin: var(--space-xl) 0;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.9rem 2.5rem;
  border-radius: 999px;
  font-weight: 600;
  font-size: 1.05rem;
  text-decoration: none;
  transition: transform var(--transition-fast), box-shadow var(--transition-fast), background var(--transition-fast), color var(--transition-fast);
  border: 2px solid transparent;
}

.btn-primary {
  background: var(--color-primary);
  color: #ffffff;
  box-shadow: 0 4px 15px rgba(102, 126, 234, 0.4);
}

.btn-primary:hover {
  background: var(--color-primary-dark);
  transform: translateY(-3px);
  box-shadow: 0 6px 20px rgba(102, 126, 234, 0.55);
}

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

.btn-secondary:hover {
  background: var(--color-primary);
  color: #ffffff;
  transform: translateY(-3px);
}

.badge {
  display: inline-block;
  padding: 0.4rem 0.85rem;
  border-radius: var(--radius-sm);
  font-size: 0.85rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.02em;
}

.badge-warning {
  background: rgba(255, 193, 7, 0.2);
  color: var(--color-warning);
}

.update-date {
  color: var(--color-text-muted);
  font-style: italic;
  margin-bottom: var(--space-lg);
  text-align: center;
}

.back-link {
  color: var(--color-on-hero);
  font-size: 1.05rem;
  display: inline-flex;
  align-items: center;
  gap: var(--space-xs);
  margin-bottom: var(--space-md);
  opacity: 0.92;
}

.back-link:hover {
  opacity: 1;
  text-decoration: underline;
}

.important {
  background: #fff3cd;
  border-left: 4px solid var(--color-accent);
  padding: var(--space-md);
  border-radius: var(--radius-sm);
  margin: var(--space-lg) 0;
}

.important--info {
  background: #d1ecf1;
  border-color: var(--color-info);
  color: var(--color-info);
}

.highlight {
  background: var(--color-surface-alt);
  padding: var(--space-lg);
  border-radius: var(--radius-md);
  margin: var(--space-lg) 0;
}

.table-responsive {
  overflow-x: auto;
}

table {
  width: 100%;
  border-collapse: collapse;
  margin: var(--space-lg) 0;
}

th,
td {
  border: 1px solid var(--color-border);
  padding: 0.75rem;
  text-align: left;
}

th {
  background: var(--color-primary);
  color: #ffffff;
}

tr:nth-child(even) {
  background: var(--color-surface-alt);
}

footer {
  text-align: center;
  padding: var(--space-xl) 1.5rem;
  color: var(--color-on-hero);
  margin-top: var(--space-xxl);
}

footer a {
  color: inherit;
  text-decoration: underline;
  margin: 0 var(--space-sm);
}

.footer-links {
  margin-bottom: var(--space-md);
}

.footer-note {
  margin-top: var(--space-md);
  opacity: 0.9;
}

.links-section {
  margin: var(--space-md) 0;
}

/* Typography helpers */
.text-center {
  text-align: center;
}

.text-right {
  text-align: right;
}

.text-left {
  text-align: left;
}

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

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

.text-muted {
  color: var(--color-text-muted);
}

.font-bold {
  font-weight: 700;
}

/* Spacing utilities */
.mt-0 {
  margin-top: 0;
}

.mt-sm {
  margin-top: var(--space-sm);
}

.mt-md {
  margin-top: var(--space-md);
}

.mt-lg {
  margin-top: var(--space-lg);
}

.mt-xl {
  margin-top: var(--space-xl);
}

.mb-0 {
  margin-bottom: 0;
}

.mb-sm {
  margin-bottom: var(--space-sm);
}

.mb-md {
  margin-bottom: var(--space-md);
}

.mb-lg {
  margin-bottom: var(--space-lg);
}

.mb-xl {
  margin-bottom: var(--space-xl);
}

/* Responsive utilities */
.stack-sm {
  display: flex;
  gap: var(--space-md);
}

@media (max-width: 768px) {
  .stack-sm {
    flex-direction: column;
  }

  .container,
  .container--narrow {
    width: min(100% - 1.5rem, var(--container-max));
  }

  .surface {
    padding: var(--space-lg);
  }

  .hero-title {
    font-size: clamp(2rem, 6vw, 2.5rem);
  }

  .section-title {
    font-size: clamp(1.5rem, 5vw, 1.8rem);
  }

  table {
    font-size: 0.95rem;
  }
}

/* Animations */
@keyframes fade-in-up {
  from {
    opacity: 0;
    transform: translateY(15px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes float {
  0% {
    transform: translateY(0px);
  }
  50% {
    transform: translateY(-6px);
  }
  100% {
    transform: translateY(0px);
  }
}

.animate-fade-in {
  animation: fade-in-up 0.6s ease forwards;
}

.animate-delay-1 {
  animation-delay: 0.1s;
}

.animate-delay-2 {
  animation-delay: 0.2s;
}

.animate-delay-3 {
  animation-delay: 0.3s;
}

.animate-float {
  animation: float 6s ease-in-out infinite;
}

/* Link helpers */
.link-accent {
  color: var(--color-primary);
  font-weight: 600;
}

.link-accent:hover {
  color: var(--color-primary-dark);
  text-decoration: underline;
}

/* Lists */
ul,
ol {
  margin-left: 1.75rem;
  margin-bottom: var(--space-md);
}

li {
  margin-bottom: 0.6rem;
}

p {
  margin-bottom: var(--space-md);
}

/* Theme mixins */
[data-theme="dark"] .important {
  background: rgba(214, 158, 46, 0.18);
  border-color: rgba(214, 158, 46, 0.6);
}

[data-theme="dark"] .important--info {
  background: rgba(12, 84, 96, 0.25);
  border-color: rgba(12, 84, 96, 0.5);
  color: rgba(193, 230, 236, 0.9);
}

[data-theme="dark"] .highlight {
  background: rgba(255, 255, 255, 0.08);
}

[data-theme="dark"] .feature-card,
[data-theme="dark"] .card {
  background: rgba(255, 255, 255, 0.04);
}

[data-theme="dark"] table tr:nth-child(even) {
  background: rgba(255, 255, 255, 0.04);
}

/* Screenshot Gallery Styles */
.screenshot-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--space-xl);
  margin: var(--space-xl) 0;
}

.screenshot-item {
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-md);
  transition: transform var(--transition-base), box-shadow var(--transition-base);
}

.screenshot-item:hover {
  transform: translateY(-8px);
  box-shadow: var(--shadow-lg);
}

.screenshot-item img {
  width: 100%;
  height: auto;
  display: block;
  border-bottom: 1px solid var(--color-border);
}

.screenshot-item figcaption {
  padding: var(--space-lg);
}

.screenshot-item figcaption strong {
  display: block;
  color: var(--color-primary);
  font-size: 1.15rem;
  margin-bottom: var(--space-sm);
}

.screenshot-item figcaption p {
  color: var(--color-text-muted);
  margin: 0;
  line-height: 1.6;
}

/* Testimonials Styles */
.testimonial-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--space-lg);
  margin: var(--space-xl) 0;
}

.testimonial {
  background: var(--color-surface-alt);
  padding: clamp(1.5rem, 3vw, 2rem);
  border-radius: var(--radius-lg);
  border-left: 4px solid var(--color-accent);
  position: relative;
  transition: transform var(--transition-base), box-shadow var(--transition-base);
}

.testimonial:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
}

.testimonial-quote {
  font-size: 4rem;
  color: var(--color-primary);
  opacity: 0.2;
  position: absolute;
  top: 0.5rem;
  left: 1rem;
  line-height: 1;
  font-family: Georgia, serif;
}

.testimonial p {
  font-style: italic;
  color: var(--color-text);
  margin-bottom: var(--space-md);
  padding-top: var(--space-lg);
  position: relative;
  z-index: 1;
}

.testimonial footer {
  margin-top: var(--space-md);
  padding-top: var(--space-md);
  border-top: 1px solid var(--color-border);
  text-align: left;
}

.testimonial footer strong {
  display: block;
  color: var(--color-primary);
  font-weight: 600;
  margin-bottom: 0.25rem;
}

.testimonial footer span {
  display: block;
  color: var(--color-text-muted);
  font-size: 0.9rem;
}

/* Documentation Links Grid */
.links-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: var(--space-lg);
  margin: var(--space-xl) 0;
}

.link-card {
  background: var(--color-surface-alt);
  padding: clamp(1.5rem, 3vw, 2rem);
  border-radius: var(--radius-lg);
  text-decoration: none;
  border: 2px solid transparent;
  transition: all var(--transition-base);
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
}

.link-card:hover {
  transform: translateY(-6px);
  border-color: var(--color-primary);
  box-shadow: var(--shadow-md);
  background: var(--color-surface);
}

.link-card-icon {
  font-size: 3rem;
  margin-bottom: var(--space-md);
  transition: transform var(--transition-fast);
}

.link-card:hover .link-card-icon {
  transform: scale(1.15);
}

.link-card h3 {
  color: var(--color-primary);
  margin-bottom: var(--space-sm);
  font-size: 1.25rem;
}

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

/* Badge Styles */
.badge-primary {
  background: var(--color-primary);
  color: #ffffff;
  display: inline-block;
  padding: 0.35rem 0.75rem;
  border-radius: var(--radius-sm);
  font-size: 0.8rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

/* Dark theme adjustments */
[data-theme="dark"] .screenshot-item {
  background: rgba(255, 255, 255, 0.06);
}

[data-theme="dark"] .testimonial {
  background: rgba(255, 255, 255, 0.04);
  border-left-color: var(--color-accent);
}

[data-theme="dark"] .link-card {
  background: rgba(255, 255, 255, 0.04);
}

[data-theme="dark"] .link-card:hover {
  background: rgba(255, 255, 255, 0.08);
}

/* Media queries for larger screens */
@media (min-width: 1200px) {
  .feature-grid {
    gap: var(--space-xl);
  }
  
  .screenshot-grid {
    grid-template-columns: repeat(3, 1fr);
  }
  
  .testimonial-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

@media (max-width: 768px) {
  .screenshot-grid {
    grid-template-columns: 1fr;
  }
  
  .testimonial-grid {
    grid-template-columns: 1fr;
  }
  
  .links-grid {
    grid-template-columns: 1fr;
  }
}