:root {
  --color-ink: #20302a;
  --color-muted: #627069;
  --color-primary: #194f3c;
  --color-primary-dark: #103a2d;
  --color-primary-soft: #e7f0eb;
  --color-paper: #fffef9;
  --color-beige: #f5f0e5;
  --color-border: #d9ded8;
  --color-brown: #856b46;
  --color-white: #ffffff;
  --shadow-soft: 0 12px 32px rgba(24, 51, 41, 0.08);
  --radius: 14px;
  --max-width: 1120px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  color: var(--color-ink);
  background: var(--color-paper);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans JP", "Hiragino Kaku Gothic ProN", Meiryo, sans-serif;
  font-size: 16px;
  line-height: 1.85;
  overflow-wrap: anywhere;
}
a { color: var(--color-primary); text-underline-offset: 0.2em; }
a:hover { color: var(--color-brown); }
img { max-width: 100%; height: auto; }
.skip-link { position: absolute; left: -9999px; top: 0; }
.skip-link:focus { left: 1rem; top: 1rem; z-index: 20; padding: .6rem 1rem; background: var(--color-white); }
.container { width: min(calc(100% - 40px), var(--max-width)); margin-inline: auto; }
.site-header { position: sticky; top: 0; z-index: 10; border-bottom: 1px solid rgba(217, 222, 216, .9); background: rgba(255, 254, 249, .96); backdrop-filter: blur(10px); }
.header-inner { min-height: 72px; display: flex; align-items: center; justify-content: space-between; gap: 24px; }
.brand { color: var(--color-primary-dark); font-family: Georgia, "Yu Mincho", serif; font-size: 1.14rem; font-weight: 700; text-decoration: none; letter-spacing: .03em; }
.site-nav { display: flex; gap: 20px; flex-wrap: wrap; }
.site-nav a { color: var(--color-ink); font-size: .91rem; font-weight: 650; text-decoration: none; }
.site-nav a:hover { color: var(--color-primary); }
.hero { position: relative; overflow: hidden; padding: 88px 0 76px; background: linear-gradient(135deg, var(--color-primary-dark), var(--color-primary)); color: var(--color-white); }
.hero::after { content: ""; position: absolute; width: 420px; height: 420px; right: -120px; bottom: -270px; border: 1px solid rgba(255,255,255,.22); border-radius: 50%; box-shadow: 0 0 0 52px rgba(255,255,255,.035), 0 0 0 104px rgba(255,255,255,.025); }
.hero-inner { position: relative; z-index: 1; max-width: 800px; }
.eyebrow { margin: 0 0 10px; color: var(--color-brown); font-size: .82rem; font-weight: 800; letter-spacing: .14em; text-transform: uppercase; }
.hero .eyebrow { color: #d9c9a8; }
.hero h1 { margin: 0; font-family: Georgia, "Yu Mincho", serif; font-size: clamp(2.05rem, 5vw, 4rem); line-height: 1.3; letter-spacing: .02em; }
.hero-lead { max-width: 690px; margin: 22px 0 0; color: #edf4f0; font-size: clamp(1rem, 2vw, 1.15rem); }
.hero-actions { display: flex; gap: 12px; margin-top: 30px; flex-wrap: wrap; }
.button { display: inline-flex; align-items: center; justify-content: center; min-height: 48px; padding: 0 20px; border: 1px solid var(--color-primary); border-radius: 999px; background: var(--color-primary); color: var(--color-white); font-weight: 750; text-decoration: none; }
.button:hover { background: var(--color-primary-dark); color: var(--color-white); }
.button-light { border-color: var(--color-white); background: var(--color-white); color: var(--color-primary-dark); }
.button-ghost { border-color: rgba(255,255,255,.55); background: transparent; color: var(--color-white); }
.section { padding: 70px 0; }
.section-tint { background: var(--color-beige); }
.section-head { display: flex; align-items: end; justify-content: space-between; gap: 24px; margin-bottom: 28px; }
.section-head h2, .section-title { margin: 0; color: var(--color-primary-dark); font-family: Georgia, "Yu Mincho", serif; font-size: clamp(1.55rem, 3vw, 2.25rem); line-height: 1.4; }
.section-head p { max-width: 600px; margin: 0; color: var(--color-muted); }
.grid { display: grid; gap: 20px; }
.grid-2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid-3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.category-grid { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.card { display: flex; flex-direction: column; min-height: 100%; padding: 24px; border: 1px solid var(--color-border); border-radius: var(--radius); background: var(--color-white); box-shadow: 0 1px 0 rgba(25, 79, 60, .02); }
.card:hover { border-color: #b9c8c0; box-shadow: var(--shadow-soft); transform: translateY(-2px); transition: .18s ease; }
.card h2, .card h3 { margin: 7px 0 10px; font-size: 1.12rem; line-height: 1.55; }
.card h2 a, .card h3 a { color: var(--color-ink); text-decoration: none; }
.card p { margin: 0; color: var(--color-muted); font-size: .94rem; }
.card-meta { margin-top: auto; padding-top: 18px; color: var(--color-muted); font-size: .82rem; }
.category-mark { display: inline-flex; align-items: center; justify-content: center; width: 34px; height: 34px; border-radius: 10px; background: var(--color-primary-soft); color: var(--color-primary); font-family: Georgia, serif; font-weight: 800; }
.text-link { font-weight: 750; text-decoration: none; }
.learning-path { padding: 30px; border-left: 5px solid var(--color-brown); border-radius: var(--radius); background: var(--color-white); box-shadow: var(--shadow-soft); }
.learning-path ol { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; margin: 22px 0 0; padding: 0; counter-reset: path; list-style: none; }
.learning-path li { padding: 20px; border-radius: 12px; background: var(--color-primary-soft); }
.learning-path li::before { counter-increment: path; content: "0" counter(path); display: block; margin-bottom: 8px; color: var(--color-brown); font-family: Georgia, serif; font-size: .9rem; font-weight: 800; }
.breadcrumb { padding: 18px 0; color: var(--color-muted); font-size: .84rem; }
.breadcrumb ol { display: flex; flex-wrap: wrap; gap: 8px; margin: 0; padding: 0; list-style: none; }
.breadcrumb li:not(:last-child)::after { content: "/"; margin-left: 8px; color: #a3aaa6; }
.page-hero { padding: 54px 0 44px; border-bottom: 1px solid var(--color-border); background: linear-gradient(180deg, var(--color-beige), var(--color-paper)); }
.page-hero h1 { max-width: 850px; margin: 6px 0 12px; color: var(--color-primary-dark); font-family: Georgia, "Yu Mincho", serif; font-size: clamp(2rem, 4vw, 3.1rem); line-height: 1.45; }
.page-hero p { max-width: 760px; margin: 0; color: var(--color-muted); }
.article-shell { display: grid; grid-template-columns: minmax(0, 760px) minmax(220px, 1fr); gap: 44px; align-items: start; }
.article-meta { display: flex; gap: 14px; flex-wrap: wrap; color: var(--color-muted); font-size: .86rem; }
.article-body { font-size: 1.03rem; }
.article-body h2 { margin: 2.8em 0 .8em; padding-bottom: .35em; border-bottom: 2px solid var(--color-primary-soft); color: var(--color-primary-dark); font-family: Georgia, "Yu Mincho", serif; font-size: 1.62rem; line-height: 1.5; }
.article-body h3 { margin: 2.1em 0 .6em; color: var(--color-primary-dark); font-size: 1.2rem; }
.article-body p { margin: 1.1em 0; }
.article-body ul, .article-body ol { padding-left: 1.5em; }
.article-body li + li { margin-top: .45em; }
.article-body blockquote { margin: 1.8em 0; padding: 16px 20px; border-left: 4px solid var(--color-brown); background: var(--color-beige); }
.article-body table { width: 100%; margin: 1.5em 0; border-collapse: collapse; font-size: .92rem; }
.article-body th, .article-body td { padding: 12px; border: 1px solid var(--color-border); text-align: left; }
.article-body th { background: var(--color-primary-soft); }
.toc { position: sticky; top: 96px; padding: 20px; border: 1px solid var(--color-border); border-radius: var(--radius); background: var(--color-white); }
.toc strong { color: var(--color-primary-dark); }
.toc ol { margin: 12px 0 0; padding-left: 1.2em; font-size: .87rem; line-height: 1.55; }
.toc li + li { margin-top: 8px; }
.notice { margin: 42px 0 0; padding: 22px; border: 1px solid #d2c29f; border-radius: var(--radius); background: #fbf7ec; color: #514b3e; font-size: .9rem; }
.notice strong { display: block; margin-bottom: 5px; color: var(--color-brown); }
.related-block { margin-top: 54px; }
.tag { display: inline-flex; padding: 4px 10px; border-radius: 999px; background: var(--color-primary-soft); color: var(--color-primary-dark); font-size: .78rem; font-weight: 750; text-decoration: none; }
.empty-state { padding: 28px; border: 1px dashed var(--color-border); border-radius: var(--radius); color: var(--color-muted); text-align: center; }
.prose { max-width: 800px; }
.prose h2 { margin-top: 2.2em; color: var(--color-primary-dark); font-family: Georgia, "Yu Mincho", serif; }
.prose h3 { margin-top: 1.8em; color: var(--color-primary-dark); }
.prose li + li { margin-top: .4em; }
.site-footer { margin-top: 64px; padding: 48px 0 28px; background: var(--color-primary-dark); color: #dbe7e1; }
.footer-grid { display: grid; grid-template-columns: 1.5fr 1fr 1fr; gap: 30px; }
.footer-title { margin: 0 0 10px; color: var(--color-white); font-family: Georgia, "Yu Mincho", serif; font-weight: 700; }
.footer-links { margin: 0; padding: 0; list-style: none; }
.footer-links a { color: #dbe7e1; text-decoration: none; }
.footer-note { margin-top: 30px; padding-top: 18px; border-top: 1px solid rgba(255,255,255,.14); color: #aebfb7; font-size: .8rem; }

@media (max-width: 860px) {
  .category-grid, .grid-3 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .article-shell { grid-template-columns: 1fr; }
  .toc { position: static; grid-row: 1; }
  .learning-path ol { grid-template-columns: 1fr; }
}

@media (max-width: 640px) {
  body { font-size: 15px; }
  .container { width: min(calc(100% - 28px), var(--max-width)); }
  .header-inner { align-items: flex-start; flex-direction: column; padding: 14px 0; gap: 8px; }
  .site-header { position: static; }
  .site-nav { gap: 10px 16px; }
  .site-nav a { font-size: .82rem; }
  .hero { padding: 62px 0 56px; }
  .section { padding: 50px 0; }
  .section-head { align-items: flex-start; flex-direction: column; }
  .category-grid, .grid-2, .grid-3 { grid-template-columns: 1fr; }
  .page-hero { padding: 38px 0 32px; }
  .article-body { font-size: 1rem; }
  .footer-grid { grid-template-columns: 1fr; }
}