:root {
  font-family: -apple-system, BlinkMacSystemFont, "Hiragino Kaku Gothic ProN", "Yu Gothic", "Meiryo", sans-serif;
  color: #0a0a0a;
  background: #f3f3f1;
  font-synthesis: none;
  text-rendering: optimizeLegibility;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  min-width: 320px;
  background: #f3f3f1;
  line-height: 1.8;
}

a { color: inherit; }

.site-header,
.page-shell,
.site-footer {
  width: min(1040px, calc(100% - 40px));
  margin: 0 auto;
}

.site-header {
  min-height: 78px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  border-bottom: 1px solid #cfcfcb;
}

.brand {
  color: #000;
  text-decoration: none;
  font-size: 17px;
  font-weight: 900;
  letter-spacing: -0.04em;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 18px;
  color: #5f5f5b;
  font-size: 11px;
  font-weight: 700;
}

.site-nav a { text-decoration: none; }
.site-nav a:hover { color: #000; }

.breadcrumbs {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin: 34px 0 0;
  color: #777772;
  font-size: 10px;
}

.breadcrumbs a { text-decoration: none; }

.hero {
  padding: 82px 0 74px;
  border-bottom: 1px solid #cfcfcb;
}

.eyebrow {
  margin: 0 0 18px;
  color: #60605c;
  font-size: 10px;
  font-weight: 800;
  letter-spacing: 0.16em;
}

h1,
h2,
h3 {
  line-height: 1.3;
  letter-spacing: -0.04em;
}

h1 {
  max-width: 900px;
  margin: 0;
  font-size: clamp(40px, 7vw, 76px);
  line-height: 1.12;
  letter-spacing: -0.065em;
}

.lead {
  max-width: 760px;
  margin: 28px 0 0;
  color: #53534f;
  font-size: 16px;
}

.cta-row {
  display: flex;
  align-items: center;
  gap: 14px;
  flex-wrap: wrap;
  margin-top: 34px;
}

.primary-cta,
.secondary-cta {
  display: inline-flex;
  min-height: 52px;
  align-items: center;
  justify-content: center;
  padding: 0 24px;
  border: 1px solid #000;
  text-decoration: none;
  font-size: 12px;
  font-weight: 800;
}

.primary-cta { color: #fff; background: #000; }
.secondary-cta { color: #000; background: transparent; }

.content-section {
  padding: 70px 0;
  border-bottom: 1px solid #cfcfcb;
}

.content-section h2 {
  margin: 0 0 24px;
  font-size: clamp(28px, 4vw, 44px);
}

.content-section > p {
  max-width: 780px;
  margin: 0;
  color: #5b5b56;
  font-size: 14px;
}

.card-grid,
.step-grid,
.related-grid,
.prompt-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
  margin-top: 32px;
}

.step-grid { grid-template-columns: repeat(3, minmax(0, 1fr)); }

.card,
.step,
.related-card,
.prompt-card,
.faq-item {
  padding: 26px;
  background: #fff;
  border: 1px solid #d2d2ce;
}

.card h3,
.step h3,
.related-card h3,
.prompt-card h3,
.faq-item h3 {
  margin: 0 0 10px;
  font-size: 18px;
}

.card p,
.step p,
.related-card p,
.prompt-card p,
.faq-item p {
  margin: 0;
  color: #5c5c57;
  font-size: 13px;
}

.step-number {
  display: block;
  margin-bottom: 12px;
  color: #898984;
  font-size: 10px;
  font-weight: 800;
  letter-spacing: 0.12em;
}

.check-list,
.plain-list {
  margin: 24px 0 0;
  padding-left: 1.25em;
  color: #53534f;
  font-size: 14px;
}

.check-list li + li,
.plain-list li + li { margin-top: 8px; }

.note {
  margin-top: 28px;
  padding: 20px 22px;
  color: #444440;
  background: #e8e8e4;
  border-left: 4px solid #000;
  font-size: 13px;
}

.prompt-card code,
.prompt-block {
  display: block;
  margin-top: 14px;
  padding: 16px;
  overflow-x: auto;
  color: #171715;
  background: #efefec;
  border: 1px solid #d6d6d1;
  font-family: inherit;
  font-size: 12px;
  line-height: 1.8;
  white-space: pre-wrap;
}

.formula {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 10px;
  margin-top: 30px;
}

.formula span {
  padding: 18px 14px;
  text-align: center;
  background: #fff;
  border: 1px solid #d2d2ce;
  font-size: 12px;
  font-weight: 800;
}

.faq-list { display: grid; gap: 12px; margin-top: 28px; }

.related-card {
  display: block;
  text-decoration: none;
  transition: transform 160ms ease, border-color 160ms ease;
}

.related-card:hover { transform: translateY(-2px); border-color: #000; }

.site-footer {
  display: flex;
  justify-content: space-between;
  gap: 24px;
  padding: 32px 0 44px;
  color: #777772;
  font-size: 10px;
}

.site-footer nav { display: flex; gap: 16px; flex-wrap: wrap; }
.site-footer a { text-decoration: none; }

@media (max-width: 760px) {
  .site-header { align-items: flex-start; flex-direction: column; padding: 18px 0; }
  .site-nav { width: 100%; gap: 12px; flex-wrap: wrap; }
  .hero { padding: 54px 0 58px; }
  h1 { font-size: 42px; }
  .content-section { padding: 54px 0; }
  .card-grid, .step-grid, .related-grid, .prompt-grid, .formula { grid-template-columns: 1fr; }
  .site-footer { flex-direction: column; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { scroll-behavior: auto !important; transition-duration: 0.01ms !important; }
}