:root{--navy:#28569a;--navy-deep:#1d3f73;--ink:#333;--muted:#6b6b6b;--paper:#fff;--ground:#f3f5f8;--line:#d9e1ec;--info-bg:#eaf4fc;--info-line:#a9cdea;--info-mark:#4a90d0;--alert-bg:#fdf0f0;--alert-line:#f0b9b9;--alert-mark:#e87a7a;--q-bg:#fff8e6;--q-line:#f1d48a;--q-mark:#e0a800;--marker:#fff38a;--red:#d33}*{box-sizing:border-box}html{-webkit-text-size-adjust:100%;scroll-behavior:smooth}body{background:var(--ground);color:var(--ink);margin:0;font-family:system-ui,-apple-system,Hiragino Kaku Gothic ProN,Hiragino Sans,Meiryo,sans-serif;font-size:16px;line-height:1.85}a{color:var(--navy)}img{max-width:100%;height:auto}.masthead{background:var(--paper);text-align:center;padding:.4rem 1rem 1.6rem}.tagline{color:var(--muted);margin:0 0 .9rem;font-size:.85rem}.brand{color:var(--ink);letter-spacing:.06em;font-size:2rem;text-decoration:none}.menu{background:var(--navy);box-shadow:0 2px 4px #0000001f}.menu ul{flex-wrap:wrap;justify-content:center;max-width:1200px;margin:0 auto;padding:0;list-style:none;display:flex}.menu li{text-align:center;flex:auto}.menu a{color:#fff;letter-spacing:.04em;padding:.95rem .8rem;text-decoration:none;display:block}.menu a:hover,.menu a[aria-current=page]{background:var(--navy-deep)}.layout{grid-template-columns:minmax(0,1fr) 300px;align-items:start;gap:1.6rem;max-width:1200px;margin:1.6rem auto;padding:0 1rem;display:grid}.article,.side{background:var(--paper);border:1px solid var(--line);border-radius:4px}.article{padding:2rem 2.2rem 2.4rem}.side{text-align:center;padding:1.4rem 1rem}.side-title{margin:0 0 .8rem;font-size:1.05rem;font-weight:400}.ad-slot{justify-content:center;display:flex}.ad-slot+.ad-slot{margin-top:1.2rem}.ad-top{margin:0 0 1.6rem}.ad-bottom{margin:2rem 0 0}.ad-inline{margin:1.6rem 0}.layout.no-side{grid-template-columns:minmax(0,1fr);max-width:940px}.embed{margin:0 0 1.2rem}.article h1{margin:0 0 1.5rem;font-size:1.75rem;line-height:1.4}.article h2{border-top:2px solid var(--navy);border-bottom:2px solid var(--navy);background:#f2f6fb;margin:2.4rem 0 1.1rem;padding:.6rem .9rem;font-size:1.3rem;line-height:1.5}.article h3{border-left:5px solid var(--navy);margin:1.9rem 0 .7rem;padding-left:.6rem;font-size:1.15rem}.article h4{border-bottom:1px dashed var(--navy);margin:1.7rem 0 .6rem;padding-bottom:.2rem;font-size:1.05rem}.article p{margin:0 0 1.1rem}.article ul,.article ol{margin:0 0 1.2rem;padding-left:1.4em}.article figure{margin:1.2rem 0}.article figure.center{text-align:center}.article iframe{border:0;max-width:100%}.center{text-align:center}.right{text-align:right}.fz-14{font-size:.875rem}.fz-16{font-size:1rem}.fz-28{font-size:1.75rem;font-weight:700;line-height:1.4}mark{background:var(--marker);color:inherit;padding:0 .1em}.under{background:linear-gradient(transparent 60%, var(--marker) 60%)}.under.red{background:linear-gradient(#0000 60%,#ffc8c8 60%)}.red{color:var(--red)}.box{border:1px solid;border-radius:6px;margin:0 0 1.4rem;padding:1rem 1.2rem 1rem 3.6rem;position:relative}.box:before{color:#fff;text-align:center;border-radius:50%;width:1.7rem;height:1.7rem;font-weight:700;line-height:1.7rem;position:absolute;top:1rem;left:1rem}.box>:last-child{margin-bottom:0}.box-info{background:var(--info-bg);border-color:var(--info-line)}.box-info:before{content:"i";background:var(--info-mark);font-family:Georgia,serif}.box-alert{background:var(--alert-bg);border-color:var(--alert-line)}.box-alert:before{content:"!";background:var(--alert-mark)}.box-question{background:var(--q-bg);border-color:var(--q-line)}.box-question:before{content:"?";background:var(--q-mark)}details{border:1px solid var(--line);background:#fafbfd;border-radius:6px;margin:0 0 1.2rem}summary{cursor:pointer;color:var(--navy);padding:.7rem 1rem;font-weight:700}details>div{padding:0 1rem 1rem}.toc{border:1px solid var(--line);background:#fbfcfe;max-width:30rem;margin:1.4rem auto 2rem;padding:1rem 1.6rem}.toc-title{text-align:center;margin:0 0 .5rem;font-weight:700}.toc ol{margin:0;padding-left:1.4em}.foot{text-align:center;color:var(--muted);padding:2rem 1rem 3rem}.foot a{color:inherit;text-decoration:none}@media (width<=860px){.layout{grid-template-columns:1fr}.article{padding:1.4rem 1.1rem 1.8rem}.brand{font-size:1.5rem}.menu li{flex:33%}.menu a{padding:.75rem .4rem;font-size:.92rem}}