:root {
  color-scheme: light;
  --background: #faf8f5;
  --surface: #ffffff;
  --surface-soft: #f6efe7;
  --text: #3f312e;
  --muted: #7a6a65;
  --line: #eadfd2;
  --accent: #e62937;
  --accent-soft: #fff1f2;
  --brand: #8c6b63;
  --brand-dark: #3f312e;
  --brand-soft: #eadfd2;
  --blue: #8c6b63;
  --shadow: 0 18px 44px rgba(63, 49, 46, 0.12);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--background);
  color: var(--text);
  font-family: Inter, "Meiryo", "Yu Gothic", system-ui, sans-serif;
  line-height: 1.75;
}

a {
  color: var(--blue);
}

.layout {
  display: grid;
  grid-template-columns: 280px minmax(0, 1fr);
  min-height: 100vh;
}

.sidebar {
  position: sticky;
  top: 0;
  align-self: start;
  height: 100vh;
  overflow: auto;
  padding: 30px 24px;
  border-right: 1px solid var(--line);
  background: rgba(250, 248, 245, 0.96);
  color: var(--text);
}

.sidebar h1 {
  margin: 0 0 8px;
  font-size: 21px;
  line-height: 1.35;
  font-family: Georgia, "Times New Roman", serif;
  font-weight: 700;
}

.sidebar p {
  margin: 0 0 22px;
  color: var(--muted);
  font-size: 13px;
}

.toc {
  display: grid;
  gap: 6px;
}

.toc a {
  display: block;
  padding: 8px 12px;
  border: 1px solid transparent;
  border-radius: 999px;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.35;
  text-decoration: none;
}

.toc a:hover {
  border-color: var(--line);
  background: #fff;
  color: var(--brand-dark);
}

.content {
  width: min(1120px, 100%);
  margin: 0 auto;
  padding: 42px 34px 72px;
}

.hero {
  padding: 42px 34px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: linear-gradient(180deg, #fffdf9 0%, #f8f1ea 100%);
  box-shadow: var(--shadow);
  text-align: center;
}

.hero h2 {
  margin: 0 0 12px;
  font-size: clamp(36px, 6vw, 64px);
  line-height: 1.25;
  font-family: Georgia, "Times New Roman", serif;
  letter-spacing: 0;
}

.hero p {
  max-width: 760px;
  margin: 0 auto;
  color: var(--muted);
  font-size: 18px;
}

.info-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
  margin: 24px 0;
}

.info-box {
  padding: 20px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
}

.info-box h3 {
  margin: 0 0 10px;
  font-size: 18px;
}

.info-box ul {
  margin: 0;
  padding-left: 22px;
}

.step {
  margin-top: 34px;
  padding: 30px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
}

.step h2 {
  margin: 0 0 12px;
  font-size: 26px;
  line-height: 1.35;
  color: var(--brand-dark);
}

.operation {
  margin: 18px 0;
  padding: 14px 18px;
  border: 1px solid var(--brand-soft);
  border-left: 5px solid var(--brand);
  border-radius: 8px;
  background: #fbf6ef;
  font-weight: 700;
}

.figure-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(280px, 34%);
  gap: 18px;
  align-items: start;
  margin-top: 18px;
}

figure {
  margin: 0;
}

.manual-image,
.zoom-image {
  display: block;
  width: 100%;
  height: auto;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fff;
  cursor: zoom-in;
}

.zoom-card {
  padding: 14px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface-soft);
}

.zoom-card h3 {
  margin: 0 0 10px;
  font-size: 16px;
}

figcaption {
  margin-top: 8px;
  color: var(--muted);
  font-size: 13px;
}

.checklist {
  margin-top: 34px;
  padding: 26px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
}

.checklist h2 {
  margin-top: 0;
}

.checklist ul {
  margin-bottom: 0;
}

.modal {
  position: fixed;
  inset: 0;
  z-index: 50;
  display: none;
  place-items: center;
  padding: 24px;
  background: rgba(8, 13, 23, 0.78);
}

.modal.is-open {
  display: grid;
}

.modal button {
  position: absolute;
  top: 18px;
  right: 18px;
  width: 42px;
  height: 42px;
  border: 0;
  border-radius: 50%;
  background: #ffffff;
  color: var(--brand-dark);
  font-size: 26px;
  cursor: pointer;
}

.modal img {
  max-width: min(94vw, 1440px);
  max-height: 88vh;
  border-radius: 8px;
  background: #fff;
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.4);
}

@media (max-width: 980px) {
  .layout {
    display: block;
  }

  .sidebar {
    position: static;
    height: auto;
  }

  .toc {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .figure-grid,
  .info-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 620px) {
  .content {
    padding: 24px 14px 48px;
  }

  .hero,
  .step,
  .checklist {
    padding: 20px;
  }

  .toc {
    grid-template-columns: 1fr;
  }
}