/* ===== Palette: navy & electric cyan ===== */
:root {
  --navy-950: #0a1430;
  --navy-800: #13265c;
  --blue-600: #2563eb;
  --cyan-500: #06b6d4;
  --cyan-100: #cffafe;
  --ice-50:   #f2f7ff;
  --text:     #1b2540;
  --muted:    #64708a;
  --line:     #e2e8f2;
  --star:     #f5a623;
}

*, *::before, *::after { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--ice-50);
  color: var(--text);
  font-family: 'Hind', system-ui, -apple-system, 'Segoe UI', Arial, sans-serif;
  font-size: 17px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

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

.product-title,
.section-subtitle,
.reviews-heading,
.site-name,
.cta-button {
  font-family: 'Poppins', 'Hind', system-ui, sans-serif;
}

/* ===== Header ===== */
.site-header {
  background: var(--navy-950);
  border-bottom: 3px solid var(--cyan-500);
}
.site-name {
  display: block;
  color: #fff;
  font-weight: 600;
  font-size: 0.92rem;
  line-height: 1.6;
}
@media (min-width: 768px) {
  .site-name { font-size: 1rem; }
}

/* ===== Product card ===== */
.product-card {
  background: #fff;
  border-radius: 20px;
  padding: 18px;
  border: 1px solid var(--line);
  box-shadow: 0 18px 40px rgba(10, 20, 48, 0.08);
}
@media (min-width: 768px) {
  .product-card { padding: 38px; }
}

/* ===== Gallery (radio + CSS) ===== */
.gallery-radio {
  position: absolute;
  opacity: 0;
  pointer-events: none;
}
.gallery-main {
  position: relative;
  aspect-ratio: 1 / 1;
  border-radius: 16px;
  overflow: hidden;
  background: linear-gradient(160deg, #ffffff 0%, var(--ice-50) 55%, var(--cyan-100) 100%);
}
.slide {
  display: none;
  position: absolute;
  inset: 0;
}
.slide img {
  width: 100%;
  height: 100%;
  object-fit: contain;
}
#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 { display: block; }

.nav {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: var(--navy-950);
  color: var(--cyan-500);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  font-size: 1rem;
  transition: background .2s, color .2s;
  user-select: none;
}
.nav:hover { background: var(--cyan-500); color: var(--navy-950); }
.nav.prev { left: 10px; }
.nav.next { right: 10px; }

.thumb {
  display: block;
  aspect-ratio: 1 / 1;
  border-radius: 12px;
  overflow: hidden;
  cursor: pointer;
  background: var(--ice-50);
  border: 2px solid var(--line);
  transition: border-color .2s, box-shadow .2s;
}
.thumb img { width: 100%; height: 100%; object-fit: cover; }
.thumb:hover { border-color: var(--cyan-500); }

#img-1:checked ~ .gallery-thumbs .thumb-1,
#img-2:checked ~ .gallery-thumbs .thumb-2,
#img-3:checked ~ .gallery-thumbs .thumb-3,
#img-4:checked ~ .gallery-thumbs .thumb-4 {
  border-color: var(--blue-600);
  box-shadow: 0 0 0 3px rgba(6, 182, 212, 0.25);
}

/* ===== Product info ===== */
.product-title {
  font-size: 1.25rem;
  font-weight: 700;
  line-height: 1.55;
  color: var(--navy-950);
}
@media (min-width: 768px) {
  .product-title { font-size: 1.5rem; }
}
.section-subtitle {
  font-size: 0.85rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 1.5px;
  color: var(--blue-600);
}
.features { list-style: none; padding: 0; margin: 0; }
.features li {
  position: relative;
  padding: 0 0 14px 18px;
  margin-bottom: 14px;
  border-bottom: 1px solid var(--line);
  font-size: 0.97rem;
}
.features li:last-child { border-bottom: 0; margin-bottom: 0; }
.features li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.4em;
  width: 4px;
  height: 1.1em;
  border-radius: 2px;
  background: linear-gradient(180deg, var(--cyan-500), var(--blue-600));
}
.features strong { color: var(--navy-800); }

.info-note {
  background: var(--navy-950);
  color: #dbe7ff;
  border-radius: 12px;
  padding: 14px 16px;
  font-size: 0.92rem;
}

/* ===== CTA ===== */
.cta-button {
  display: inline-block;
  width: 100%;
  max-width: 480px;
  padding: 20px 32px;
  background: linear-gradient(90deg, var(--blue-600), var(--cyan-500));
  color: #fff;
  font-size: 1.3rem;
  font-weight: 700;
  text-decoration: none;
  border-radius: 14px;
  box-shadow: 0 12px 28px rgba(37, 99, 235, 0.35);
  transition: transform .2s, box-shadow .2s;
}
.cta-button:hover,
.cta-button:focus {
  transform: translateY(-3px);
  box-shadow: 0 16px 34px rgba(6, 182, 212, 0.45);
}
@media (min-width: 768px) {
  .cta-button { font-size: 1.45rem; padding: 22px 44px; }
}

/* ===== Reviews (Amazon-like) ===== */
.reviews {
  max-width: 820px;
  margin: 0 auto;
}
.reviews-heading {
  font-size: 1.4rem;
  font-weight: 700;
  color: var(--navy-950);
  padding-bottom: 12px;
  margin-bottom: 8px;
  border-bottom: 1px solid var(--line);
}
.review { padding: 22px 0; }
.review + .review {
  border-top: 1px solid var(--line);
  margin-top: 6px;
}
.avatar {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  object-fit: cover;
  flex-shrink: 0;
  margin-right: 14px;
  background: var(--cyan-100);
}
.review-name {
  font-size: 0.95rem;
  font-weight: 600;
  line-height: 1.4;
}
.stars {
  color: var(--star);
  font-size: 1.05rem;
  letter-spacing: 1px;
  line-height: 1.3;
}
.review-title {
  font-size: 1rem;
  font-weight: 600;
  line-height: 1.45;
  margin-top: 2px;
  color: var(--navy-950);
}
.review-meta {
  margin-top: 10px;
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--blue-600);
}
.review-text {
  margin-top: 8px;
  font-size: 0.97rem;
}
.review-photos { margin-top: 12px; }
.review-photos img {
  width: 96px;
  height: 96px;
  object-fit: cover;
  border-radius: 10px;
  border: 1px solid var(--line);
}
@media (min-width: 768px) {
  .review-photos img { width: 120px; height: 120px; }
}

/* ===== Footer ===== */
.site-footer {
  margin-top: 48px;
  background: var(--navy-950);
  color: #c9d6f2;
}
.footer-name {
  font-weight: 500;
  font-size: 0.9rem;
  line-height: 1.6;
}
.footer-links a {
  color: var(--cyan-500);
  text-decoration: none;
  font-size: 0.92rem;
}
.footer-links a:hover { color: #fff; text-decoration: underline; }
.footer-copy { font-size: 0.8rem; opacity: 0.6; }