:root {
  --arthro-bg: #f4f8f7;
  --arthro-surface: #ffffff;
  --arthro-tone: #1e7a68;
  --arthro-tone-hover: #145548;
  --arthro-ink: #1a2a26;
  --arthro-accent: #e07a5f;
  --arthro-gradient: linear-gradient(135deg, #1e7a68 0%, #114b3f 100%);
  --font-display: 'Oswald', sans-serif;
  --font-body: 'Inter', sans-serif;
}

body {
  margin: 0;
  padding: 0;
  -webkit-font-smoothing: antialiased;
}

h1 {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* Custom Grid for Product Showcase */
.arthro-layout-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2rem;
}

@media (min-width: 768px) {
  .arthro-layout-grid {
    grid-template-columns: 1fr 1fr;
  }
}

/* CSS Radio Gallery Switcher */
.arthro-radio-toggle {
  display: none;
}

.arthro-slide {
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.3s ease, visibility 0.3s ease;
}

#arthro-img-1:checked ~ .arthro-main-viewer .arthro-slide-1,
#arthro-img-2:checked ~ .arthro-main-viewer .arthro-slide-2,
#arthro-img-3:checked ~ .arthro-main-viewer .arthro-slide-3,
#arthro-img-4:checked ~ .arthro-main-viewer .arthro-slide-4 {
  opacity: 1;
  visibility: visible;
}

.arthro-thumb-item {
  cursor: pointer;
  transition: transform 0.2s ease, opacity 0.2s ease;
}

.arthro-thumb-item img {
  border-color: #cbd5e1;
}

.arthro-thumb-item:hover {
  transform: translateY(-2px);
}

#arthro-img-1:checked ~ .arthro-thumbs-strip label[for="arthro-img-1"] img,
#arthro-img-2:checked ~ .arthro-thumbs-strip label[for="arthro-img-2"] img,
#arthro-img-3:checked ~ .arthro-thumbs-strip label[for="arthro-img-3"] img,
#arthro-img-4:checked ~ .arthro-thumbs-strip label[for="arthro-img-4"] img {
  border-color: var(--arthro-tone);
  box-shadow: 0 0 0 2px rgba(30, 122, 104, 0.3);
}

/* Preset B Button Effects */
.arthro-prime-button {
  transition: transform 0.2s ease, background-color 0.2s ease, box-shadow 0.2s ease;
}

.arthro-prime-button:hover {
  background-color: #c9654b !important;
  transform: translateY(-2px);
  box-shadow: 0 12px 24px rgba(224, 122, 95, 0.5) !important;
}