:root{
  --bg:#faf8f5; --surface:#ffffff; --ink:#1f2328; --muted:#6a6f76; --line:#e6e1da;
  --accent:#1f4d4a; --accent-soft:#e8f0ee; --accent-ink:#ffffff; --warm:#f1ece4;
  --radius:14px;
}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{margin:0;background:var(--bg);color:var(--ink);line-height:1.85;
  font-family:-apple-system,BlinkMacSystemFont,"Hiragino Sans","Hiragino Kaku Gothic ProN","Noto Sans JP","Yu Gothic",Meiryo,sans-serif;
  font-size:16px}
a{color:var(--accent);text-underline-offset:3px}
a:hover{text-decoration-thickness:2px}
img,svg{max-width:100%}
.wrap{max-width:1040px;margin:0 auto;padding:0 20px}
.narrow{max-width:760px}

/* header */
.site-header{background:rgba(250,248,245,.92);backdrop-filter:blur(8px);position:sticky;top:0;z-index:20;border-bottom:1px solid var(--line)}
.site-header .wrap{display:flex;align-items:center;justify-content:space-between;gap:16px;min-height:64px}
.brand{font-weight:700;letter-spacing:.04em;font-size:1.08rem;color:var(--ink);text-decoration:none;display:flex;align-items:center;gap:10px}
.brand .mark{width:26px;height:26px;border-radius:7px;background:var(--accent);display:inline-block;position:relative}
.brand .mark:after{content:"";position:absolute;inset:7px;border:2px solid #fff;border-radius:3px;border-top-color:transparent}
.nav{display:flex;gap:4px;flex-wrap:wrap}
.nav a{color:var(--ink);text-decoration:none;padding:8px 12px;border-radius:999px;font-size:.92rem}
.nav a:hover,.nav a[aria-current=page]{background:var(--accent-soft);color:var(--accent)}

/* hero */
.hero{padding:72px 0 56px;background:linear-gradient(180deg,var(--warm),var(--bg))}
.hero .wrap{display:grid;grid-template-columns:1.25fr .75fr;gap:40px;align-items:center}
.eyebrow{font-size:.8rem;letter-spacing:.18em;color:var(--accent);font-weight:700;text-transform:uppercase;margin:0 0 14px}
.hero h1{font-family:"Hiragino Mincho ProN","Yu Mincho","Noto Serif JP",serif;font-weight:600;font-size:clamp(1.9rem,4.6vw,2.9rem);line-height:1.4;margin:0 0 18px;letter-spacing:.02em}
.hero p.lead{color:#3b4148;font-size:1.05rem;margin:0 0 26px;max-width:34em}
.btns{display:flex;flex-wrap:wrap;gap:12px}
.btn{display:inline-block;padding:12px 22px;border-radius:999px;background:var(--accent);color:var(--accent-ink);text-decoration:none;font-weight:600;font-size:.95rem;border:1px solid var(--accent)}
.btn:hover{filter:brightness(1.12)}
.btn.ghost{background:transparent;color:var(--accent)}
.hero-art{background:var(--surface);border:1px solid var(--line);border-radius:22px;padding:26px;min-height:260px}
.hero-art h2{font-size:.95rem;margin:0 0 14px;color:var(--muted);font-weight:600}
.checklist{list-style:none;margin:0;padding:0}
.checklist li{display:flex;gap:12px;padding:12px 0;border-top:1px solid var(--line);font-size:.95rem}
.checklist li:first-child{border-top:0;padding-top:0}
.checklist .n{flex:none;width:26px;height:26px;border-radius:50%;background:var(--accent-soft);color:var(--accent);font-weight:700;font-size:.82rem;display:flex;align-items:center;justify-content:center}

/* sections */
section.block{padding:56px 0}
section.block.alt{background:var(--warm)}
.sec-head{display:flex;align-items:baseline;justify-content:space-between;gap:12px;margin-bottom:24px}
.sec-head h2{font-size:1.45rem;margin:0;font-family:"Hiragino Mincho ProN","Yu Mincho","Noto Serif JP",serif;font-weight:600}
.sec-head a{font-size:.9rem}
.grid{display:grid;gap:18px}
.grid.cols3{grid-template-columns:repeat(3,1fr)}
.grid.cols2{grid-template-columns:repeat(2,1fr)}
.card{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);padding:22px;display:block;color:inherit;text-decoration:none;transition:border-color .15s,transform .15s}
a.card:hover{border-color:var(--accent);transform:translateY(-2px)}
.card h3{margin:0 0 8px;font-size:1.05rem;line-height:1.5}
.card p{margin:0;color:var(--muted);font-size:.92rem;line-height:1.75}
.card .tag{display:inline-block;font-size:.74rem;color:var(--accent);background:var(--accent-soft);padding:2px 10px;border-radius:999px;margin-bottom:10px;font-weight:600}
.card .meta{margin-top:12px;font-size:.8rem;color:var(--muted)}
.ico{width:44px;height:44px;border-radius:12px;background:var(--accent-soft);display:flex;align-items:center;justify-content:center;margin-bottom:14px}
.ico svg{width:24px;height:24px;stroke:var(--accent);fill:none;stroke-width:1.7;stroke-linecap:round;stroke-linejoin:round}
.principles{display:grid;grid-template-columns:repeat(3,1fr);gap:28px}
.principles h3{font-size:1rem;margin:0 0 6px}
.principles p{margin:0;color:var(--muted);font-size:.92rem}
.principles .num{font-family:Georgia,serif;font-size:2rem;color:var(--accent);line-height:1;margin-bottom:8px}
.notice{background:var(--surface);border:1px solid var(--line);border-left:4px solid var(--accent);border-radius:10px;padding:16px 18px;font-size:.92rem;color:#3b4148}

/* article */
.page-head{padding:48px 0 12px}
.page-head h1{font-family:"Hiragino Mincho ProN","Yu Mincho","Noto Serif JP",serif;font-weight:600;font-size:clamp(1.6rem,3.6vw,2.2rem);line-height:1.45;margin:6px 0 10px}
.page-head .sub{color:var(--muted);margin:0}
.crumbs{font-size:.82rem;color:var(--muted)}
.crumbs a{color:var(--muted)}
article.prose{padding:8px 0 56px}
.prose h2{font-size:1.3rem;margin:2.4em 0 .6em;padding-top:.4em;border-top:1px solid var(--line);font-family:"Hiragino Mincho ProN","Yu Mincho","Noto Serif JP",serif;font-weight:600}
.prose h3{font-size:1.05rem;margin:1.8em 0 .4em}
.prose p{margin:.9em 0}
.prose ul,.prose ol{padding-left:1.4em}
.prose li{margin:.4em 0}
.prose table{width:100%;border-collapse:collapse;margin:1.2em 0;font-size:.93rem;background:var(--surface);border:1px solid var(--line);border-radius:10px;overflow:hidden}
.prose th,.prose td{padding:10px 14px;border-bottom:1px solid var(--line);text-align:left;vertical-align:top}
.prose th{background:var(--warm);font-weight:600;width:34%}
.toc{background:var(--surface);border:1px solid var(--line);border-radius:12px;padding:16px 20px;margin:20px 0}
.toc b{font-size:.9rem}
.toc ol{margin:8px 0 0}
.callout{background:var(--accent-soft);border-radius:12px;padding:16px 18px;margin:1.4em 0}
.callout b{color:var(--accent)}
.byline{font-size:.84rem;color:var(--muted);margin-top:8px}
.related{margin-top:40px}

/* footer */
.site-footer{background:#1d2a29;color:#cfd8d6;padding:44px 0 28px;margin-top:0}
.site-footer a{color:#e8f0ee}
.foot-grid{display:grid;grid-template-columns:1.4fr 1fr 1fr;gap:28px}
.site-footer h4{margin:0 0 10px;font-size:.85rem;letter-spacing:.1em;color:#9fb3b0}
.site-footer ul{list-style:none;margin:0;padding:0}
.site-footer li{margin:6px 0;font-size:.92rem}
.site-footer .copy{border-top:1px solid #34504d;margin-top:28px;padding-top:16px;font-size:.8rem;color:#9fb3b0}

@media(max-width:820px){
  .hero{padding:44px 0 36px}
  .hero .wrap{grid-template-columns:1fr}
  .grid.cols3,.principles,.foot-grid{grid-template-columns:1fr}
  .grid.cols2{grid-template-columns:1fr}
  .site-header .wrap{flex-direction:column;align-items:flex-start;padding-top:10px;padding-bottom:8px;gap:2px}
  .nav a{padding:6px 10px;font-size:.88rem}
  .prose th{width:40%}
}

.pr{font-size:.85rem;color:#6b7280;border-left:3px solid #cbd5e1;padding:2px 10px;margin:0 0 14px}