/* CSS Variables & Design System */
:root {
  --primary: #166534;
  --secondary: #f0fdf4;
  --accent: #fbbf24;
  --text: #f5f5f5;
  --bg: #0f0f0f;
  --card-bg: #1a1a1a;
  --border: #333333;
}

/* Base Styles */
body {
  background: var(--bg);
  color: var(--text);
  font-family: 'Inter', sans-serif;
  font-size: clamp(14px, 4vw, 16px);
  line-height: 1.6;
}

section {
  padding: 64px 16px;
}

.card {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: 12px;
}

.btn {
  border-radius: 8px;
  background: var(--primary);
  color: #ffffff;
  font-weight: 700;
  min-height: 44px;
}

h1 {
  font-size: clamp(20px, 4vw, 28px);
  font-weight: 800;
}

h2 {
  font-size: clamp(18px, 4vw, 24px);
  font-weight: 700;
}

/* Accessible Screen Reader Only Utility */
.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;
}

/* CSS-Only Gallery Styling */
.gallery-main {
  position: relative;
  width: 100%;
  padding-bottom: 100%; /* Perfect square ratio */
  overflow: hidden;
  border-radius: 8px;
  border: 1px solid var(--border);
  background-color: var(--card-bg);
}

.slide {
  position: absolute;
  inset: 0;
  opacity: 0;
  z-index: 1;
  transition: opacity 0.3s ease-in-out;
}

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

/* Thumbnails */
.thumbnails {
  display: flex;
  gap: 8px;
  margin-top: 12px;
}

.thumbnails label {
  cursor: pointer;
  border: 2px solid transparent;
  border-radius: 6px;
  overflow: hidden;
  width: 25%;
  aspect-ratio: 1;
  transition: border-color 0.2s ease-in-out;
}

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

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

#img-1:checked ~ .thumbnails label[for="img-1"] { border-color: var(--accent); }
#img-2:checked ~ .thumbnails label[for="img-2"] { border-color: var(--accent); }
#img-3:checked ~ .thumbnails label[for="img-3"] { border-color: var(--accent); }
#img-4:checked ~ .thumbnails label[for="img-4"] { border-color: var(--accent); }