:root {
  --primary: #dc2626;
  --secondary: #fef2f2;
  --accent: #2563eb;
  --text: #450a0a;
  --bg: #ffffff;
}

/* Glass-Frost Design System Customizations */
body {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: #fff;
  min-height: 100vh;
  font-family: 'Inter', sans-serif;
  overflow-x: hidden;
}

section {
  padding: 40px 16px;
}

@media (min-width: 768px) {
  section {
    padding: 64px 16px;
  }
}

.card {
  background: rgba(255, 255, 255, 0.12);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid rgba(255, 255, 255, 0.2);
  border-radius: 16px;
}

.btn {
  display: inline-block;
  min-height: 44px;
  border-radius: 12px;
  background: var(--primary);
  color: #ffffff;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.3);
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.btn:hover {
  background: #b91c1c;
  transform: translateY(-2px);
  box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.4);
}

/* Typography Scale via clamp() */
h1 {
  font-size: clamp(20px, 4.5vw, 32px);
}

h2 {
  font-size: clamp(18px, 3.5vw, 24px);
}

p, span, li, a {
  font-size: clamp(14px, 3vw, 16px);
}

/* Gallery Rules */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.gallery-main {
  position: relative;
  width: 100%;
  padding-bottom: 100%; /* Explicit height via padding ratio */
  overflow: hidden;
  border-radius: 12px;
}

.slide {
  position: absolute;
  inset: 0;
  opacity: 0;
  z-index: 1;
  transition: opacity 0.4s ease-in-out;
}

.slide img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  border-radius: 12px;
}

/* Radio-triggered Slide Display */
#img-1:checked ~ .gallery-main .slide-1,
#img-2:checked ~ .gallery-main .slide-2,
#img-3:checked ~ .gallery-main .slide-3,
#img-4:checked ~ .gallery-main .slide-4 {
  opacity: 1;
  z-index: 10;
}

/* Thumbnails */
.thumbnails {
  display: flex;
  gap: 12px;
  margin-top: 16px;
}

.thumbnails label {
  cursor: pointer;
  border: 2px solid transparent;
  border-radius: 8px;
  overflow: hidden;
  width: 25%;
  aspect-ratio: 1;
  transition: border-color 0.2s, transform 0.2s;
}

.thumbnails label:hover {
  transform: scale(1.05);
}

.thumbnails label img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

/* Active Thumbnail Highlight */
#img-1:checked ~ .thumbnails label[for="img-1"],
#img-2:checked ~ .thumbnails label[for="img-2"],
#img-3:checked ~ .thumbnails label[for="img-3"],
#img-4:checked ~ .thumbnails label[for="img-4"] {
  border-color: var(--primary);
  box-shadow: 0 0 8px rgba(220, 38, 38, 0.5);
}