:root {
  --primary: #475569;
  --secondary: #f8fafc;
  --accent: #3b82f6;
  --text: #0f172a;
  --bg: #ffffff;
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  background-color: var(--secondary);
  color: #1e293b;
  margin: 0;
  padding: 0;
  overflow-x: hidden;
  font-size: clamp(14px, 4vw, 16px);
}

header {
  border-bottom: 3px solid var(--primary, #2563eb);
}

.header-title {
  font-size: clamp(20px, 4vw, 28px);
}

.card {
  background: var(--bg);
  border: 1px solid #e2e8f0;
  border-radius: 8px;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
}

.btn {
  border-radius: 6px;
  font-weight: 600;
  min-height: 44px;
}

.btn-cta {
  background-color: var(--accent);
  color: #ffffff !important;
  text-decoration: none;
}

.btn-cta:hover {
  background-color: #2563eb;
}

/* Accessibility SR-Only */
.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;
}

/* Image Gallery Logic (No JS) */
.gallery-main {
  position: relative;
  width: 100%;
  padding-bottom: 100%;
  overflow: hidden;
}

.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;
  display: block;
}

/* Switch active slide */
#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;
}

/* Highlight active thumbnail */
#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(--accent);
  box-shadow: 0 0 0 1px var(--accent);
}