:root {
  --bg: #f7f8fa;
  --surface: #ffffff;
  --surface-muted: #eef2f7;
  --text: #111827;
  --muted: #4b5563;
  --line: #e5e7eb;
  --primary: #2563eb;
  --primary-hover: #1d4ed8;
  --amazon: #f59e0b;
  --amazon-hover: #d97706;
  --radius: 8px;
  --shadow: 0 12px 30px rgba(17, 24, 39, 0.08);
  --container: 1180px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: Inter, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  font-size: 17px;
  line-height: 1.7;
}

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

a {
  color: inherit;
  text-decoration: none;
}

h1,
h2,
h3 {
  margin: 0;
  color: var(--text);
  font-family: "Space Grotesk", Inter, sans-serif;
  letter-spacing: 0;
  line-height: 1.12;
}

h1 {
  max-width: 820px;
  color: #ffffff;
  font-size: clamp(2.25rem, 5vw, 3.75rem);
  font-weight: 700;
}

h2 {
  font-size: clamp(1.8rem, 3vw, 2.45rem);
  font-weight: 700;
}

h3 {
  font-size: 1.25rem;
  font-weight: 700;
}

p {
  margin: 0;
  color: var(--muted);
}

.container {
  width: min(100% - 40px, var(--container));
  margin-inline: auto;
}

.site-header {
  position: absolute;
  z-index: 10;
  top: 0;
  left: 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  padding: 22px clamp(20px, 4vw, 48px);
  color: #ffffff;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
}

.brand-mark {
  display: inline-grid;
  width: 38px;
  height: 38px;
  place-items: center;
  border: 1px solid rgba(255, 255, 255, 0.32);
  border-radius: var(--radius);
  background: rgba(255, 255, 255, 0.12);
  color: #ffffff;
  font-size: 0.9rem;
}

.site-nav {
  display: flex;
  gap: 26px;
  color: rgba(255, 255, 255, 0.86);
  font-size: 0.95rem;
  font-weight: 600;
}

.site-nav a:hover {
  color: #ffffff;
}

.hero {
  position: relative;
  display: grid;
  min-height: 680px;
  overflow: hidden;
  place-items: center start;
  background:
    linear-gradient(90deg, rgba(17, 24, 39, 0.92) 0%, rgba(17, 24, 39, 0.62) 48%, rgba(17, 24, 39, 0.28) 100%),
    url("https://images.unsplash.com/photo-1551650975-87deedd944c3?auto=format&fit=crop&w=2200&q=85") center / cover;
}

.hero-overlay {
  position: absolute;
  inset: 0;
  background: rgba(17, 24, 39, 0.12);
}

.hero-inner {
  position: relative;
  z-index: 1;
  width: min(100% - 40px, var(--container));
  margin-inline: auto;
  padding-block: 120px 92px;
}

.eyebrow {
  margin-bottom: 14px;
  color: #bfdbfe;
  font-size: 0.78rem;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.eyebrow.dark {
  color: var(--primary);
}

.hero-copy {
  max-width: 660px;
  margin-top: 22px;
  color: #e5e7eb;
  font-size: 1.12rem;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  margin-top: 34px;
}

.button {
  display: inline-flex;
  min-height: 48px;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius);
  font-weight: 700;
  line-height: 1.2;
  transition: transform 0.18s ease, background 0.18s ease, box-shadow 0.18s ease;
}

.button:hover {
  transform: translateY(-1px);
}

.button-primary {
  background: var(--primary);
  box-shadow: 0 8px 20px rgba(37, 99, 235, 0.25);
  color: #ffffff;
  padding: 14px 24px;
}

.button-primary:hover {
  background: var(--primary-hover);
}

.button-secondary {
  border: 1px solid rgba(255, 255, 255, 0.35);
  background: rgba(255, 255, 255, 0.12);
  color: #ffffff;
  padding: 14px 24px;
}

.button-amazon {
  align-self: flex-start;
  background: var(--amazon);
  color: #111827;
  padding: 13px 18px;
}

.button-amazon:hover {
  background: var(--amazon-hover);
}

.section {
  padding-block: 88px;
}

.section-muted {
  background: var(--surface-muted);
}

.intro-grid {
  display: grid;
  grid-template-columns: 0.8fr 1.2fr;
  gap: 52px;
}

.intro-copy {
  display: grid;
  gap: 22px;
}

.intro-copy strong {
  color: var(--text);
}

.section-heading {
  max-width: 760px;
  margin-bottom: 42px;
}

.section-heading.center {
  margin-inline: auto;
  text-align: center;
}

.section-heading p:not(.eyebrow) {
  margin-top: 16px;
}

.category-grid,
.guide-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 24px;
}

.card,
.product-card {
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
  box-shadow: 0 10px 26px rgba(17, 24, 39, 0.06);
}

.category-card img,
.guide-card img {
  aspect-ratio: 16 / 9;
  object-fit: cover;
}

.card-body {
  display: grid;
  gap: 16px;
  padding: 24px;
}

.text-button {
  display: inline-flex;
  width: fit-content;
  align-items: center;
  border: 1px solid var(--primary);
  border-radius: var(--radius);
  color: var(--primary);
  font-weight: 700;
  padding: 11px 16px;
}

.text-button:hover {
  background: var(--primary);
  color: #ffffff;
}

.product-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 22px;
}

.product-card {
  display: grid;
  grid-template-columns: 0.38fr 0.62fr;
  gap: 20px;
  padding: 20px;
}

.product-card-wide {
  grid-column: 1 / -1;
}

.product-image {
  display: grid;
  min-height: 100%;
  overflow: hidden;
  place-items: center;
  border-radius: var(--radius);
  background: var(--bg);
}

.product-image img {
  height: 100%;
  aspect-ratio: 1 / 1;
  object-fit: cover;
}

.product-content {
  display: grid;
  align-content: start;
  gap: 12px;
}

.badge {
  width: fit-content;
  border-radius: 999px;
  background: #dbeafe;
  color: var(--primary-hover);
  font-size: 0.78rem;
  font-weight: 800;
  padding: 4px 10px;
}

.site-footer {
  background: #111827;
  color: #ffffff;
  padding-block: 56px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 0.9fr 1.1fr;
  gap: 56px;
}

.footer-brand {
  margin-bottom: 18px;
}

.site-footer p {
  color: #d1d5db;
  font-size: 0.95rem;
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 18px;
  margin-top: 22px;
  color: #e5e7eb;
  font-size: 0.95rem;
  font-weight: 600;
}

.footer-links a:hover {
  color: #ffffff;
}

.affiliate-note {
  display: grid;
  gap: 12px;
}

.affiliate-note h2 {
  color: #ffffff;
  font-size: 1.1rem;
}

.page-header {
  background: #111827;
  color: #ffffff;
  padding: 120px 0 70px;
}

.page-header h1 {
  color: #ffffff;
}

.page-header p {
  max-width: 760px;
  margin-top: 18px;
  color: #d1d5db;
  font-size: 1.08rem;
}

.article-layout {
  display: grid;
  grid-template-columns: minmax(0, 760px) minmax(240px, 1fr);
  gap: 48px;
  align-items: start;
}

.article-content,
.simple-page {
  display: grid;
  gap: 24px;
}

.article-content h2,
.simple-page h2 {
  margin-top: 18px;
}

.article-content ul,
.simple-page ul {
  margin: 0;
  padding-left: 22px;
  color: var(--muted);
}

.article-content li,
.simple-page li {
  margin-bottom: 10px;
}

.toc-card {
  position: sticky;
  top: 24px;
  display: grid;
  gap: 12px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
  box-shadow: 0 10px 26px rgba(17, 24, 39, 0.06);
  padding: 22px;
}

.toc-card h2 {
  font-size: 1rem;
}

.toc-card a {
  color: var(--primary);
  font-weight: 700;
}

.notice {
  border-left: 4px solid var(--primary);
  border-radius: var(--radius);
  background: var(--surface-muted);
  padding: 18px;
}

@media (max-width: 900px) {
  .site-nav {
    display: none;
  }

  .hero {
    min-height: 560px;
    background:
      linear-gradient(90deg, rgba(17, 24, 39, 0.9) 0%, rgba(17, 24, 39, 0.72) 100%),
      url("https://images.unsplash.com/photo-1551650975-87deedd944c3?auto=format&fit=crop&w=1400&q=85") center / cover;
  }

  .intro-grid,
  .category-grid,
  .guide-grid,
  .product-grid,
  .footer-grid,
  .article-layout {
    grid-template-columns: 1fr;
  }

  .product-card,
  .product-card-wide {
    grid-template-columns: 1fr;
    grid-column: auto;
  }

  .product-image img {
    height: auto;
  }

  .toc-card {
    position: static;
  }
}

@media (max-width: 640px) {
  body {
    font-size: 16px;
  }

  .container,
  .hero-inner {
    width: min(100% - 32px, var(--container));
  }

  .site-header {
    padding: 18px 20px;
  }

  .hero {
    min-height: 540px;
  }

  .hero-inner {
    padding-block: 92px 64px;
  }

  .hero-actions,
  .button,
  .text-button {
    width: 100%;
  }

  .section {
    padding-block: 60px;
  }

  .section-heading {
    margin-bottom: 30px;
  }

  .card-body,
  .product-card {
    padding: 20px;
  }

  .footer-grid {
    gap: 34px;
  }
}