:root{--ink:#1d1a16;--paper:#fbf7ef;--card:#fff;--line:#e4dccd;--accent:#8a1d1d;--accent2:#b5502a;--muted:#6b645a;--amz:#f0a532}
*{box-sizing:border-box}html{scroll-behavior:smooth}
body{margin:0;font-family:"Hiragino Sans","Hiragino Kaku Gothic ProN","Yu Gothic","Noto Sans JP",Meiryo,sans-serif;color:var(--ink);background:var(--paper);line-height:1.8}
a{color:var(--accent)}img{max-width:100%;height:auto;display:block}
.wrap{max-width:1040px;margin:0 auto;padding:0 20px}
header.top{background:#fff;border-bottom:1px solid var(--line);position:sticky;top:0;z-index:10}
header.top .wrap{display:flex;align-items:center;justify-content:space-between;height:60px}
.brand{font-weight:700;text-decoration:none;color:var(--ink);font-size:18px;letter-spacing:.04em;white-space:nowrap}
.brand b{color:var(--accent)}
nav a{color:var(--ink);text-decoration:none;margin-left:16px;font-size:14px}
nav a:hover{color:var(--accent)}
@media(max-width:720px){nav a{margin-left:9px;font-size:12px}nav a.hide-m{display:none}}
.hero{padding:48px 0 36px;background:linear-gradient(180deg,#fff 0%,var(--paper) 100%)}
.hero h1{font-size:clamp(24px,4vw,38px);line-height:1.35;margin:0 0 14px;letter-spacing:.02em}
.hero p.lead{font-size:17px;color:var(--muted);max-width:680px;margin:0 0 22px}
.btn{display:inline-block;padding:11px 20px;border-radius:8px;text-decoration:none;font-weight:700;font-size:15px;border:2px solid var(--accent);color:var(--accent);background:#fff;transition:.15s;cursor:pointer;font-family:inherit}
.btn:hover{background:var(--accent);color:#fff}
.btn.amz{background:var(--amz);border-color:var(--amz);color:#1d1a16}.btn.amz:hover{filter:brightness(.93)}
.btn.sm{padding:7px 13px;font-size:13px}.btn.ghost{border-color:var(--line);color:var(--ink)}.btn.ghost:hover{background:#f3e9dc;color:var(--ink)}
section{padding:40px 0}section h2{font-size:23px;margin:0 0 6px;padding-left:12px;border-left:6px solid var(--accent)}
section p.sub{margin:0 0 20px;color:var(--muted)}
.card{background:var(--card);border:1px solid var(--line);border-radius:12px;padding:22px}
.daily{display:grid;grid-template-columns:minmax(260px,440px) 1fr;gap:26px;align-items:start}
@media(max-width:720px){.daily{grid-template-columns:1fr}}
.board{border:1px solid var(--line);border-radius:8px;background:#fff;width:100%;max-width:520px}
canvas.board{aspect-ratio:1/1.06}
.tag{display:inline-block;font-size:12px;padding:2px 10px;border-radius:999px;background:#f3e9dc;color:var(--accent2);font-weight:700;margin:0 6px 4px 0;text-decoration:none}
a.tag:hover{background:var(--accent2);color:#fff}
.answer{display:none;margin-top:14px;padding:14px;background:#fbf2e6;border-radius:8px;font-size:18px;font-weight:700;letter-spacing:.05em}
.answer.open{display:block}
.moves span{white-space:nowrap;margin-right:.6em}
.books{display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:18px}
.book{display:flex;flex-direction:column}
.book img{border-radius:6px;box-shadow:0 6px 18px rgba(0,0,0,.14);margin-bottom:12px;max-width:200px}
.book h3{margin:0 0 4px;font-size:18px}.book .who{font-size:13px;color:var(--muted);flex:1}
.price{font-size:14px;margin:8px 0 10px}.price b{font-size:18px;color:var(--accent)}
.grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(230px,1fr));gap:16px}
.prob{background:#fff;border:1px solid var(--line);border-radius:10px;padding:12px;display:block;text-decoration:none;color:var(--ink)}
.prob:hover{border-color:var(--accent2)}
.prob h3{margin:0 0 8px;font-size:14px}.prob .note{display:block;margin-top:6px}
.cta{background:var(--ink);color:#fff;text-align:center;padding:44px 20px;border-radius:14px}
.cta h2{border:0;padding:0;color:#fff;font-size:25px}.cta p{color:#d9d2c5}.cta a{color:#fff}
.steps{display:grid;grid-template-columns:repeat(auto-fit,minmax(200px,1fr));gap:16px;counter-reset:s}
.steps div{background:#fff;border:1px solid var(--line);border-radius:10px;padding:16px;counter-increment:s}
.steps.num div::before{content:counter(s);display:inline-block;width:28px;height:28px;border-radius:50%;background:var(--accent);color:#fff;text-align:center;line-height:28px;font-weight:700;margin-bottom:8px}
footer{border-top:1px solid var(--line);padding:30px 0;font-size:13px;color:var(--muted)}
footer a{color:var(--muted)}footer .cols{display:grid;grid-template-columns:repeat(auto-fit,minmax(180px,1fr));gap:14px;margin-bottom:18px}
footer .cols b{display:block;color:var(--ink);margin-bottom:4px}footer .cols a{display:block;text-decoration:none;line-height:1.9}
.note{font-size:12px;color:var(--muted)}
.crumb{font-size:13px;color:var(--muted);padding:12px 0 0}.crumb a{color:var(--muted);text-decoration:none}
.ctl{display:flex;gap:6px;flex-wrap:wrap;margin-top:10px;align-items:center}.ctl .lbl{font-size:14px;color:var(--muted);margin-left:6px}
.article{max-width:760px}.article h2{font-size:21px;margin:34px 0 10px}.article table{border-collapse:collapse;width:100%;font-size:14px;background:#fff}
.article th,.article td{border:1px solid var(--line);padding:8px 10px;text-align:left}.article th{background:#f3e9dc}
.article ol,.article ul{padding-left:1.4em}.article code{background:#f3e9dc;padding:1px 6px;border-radius:4px;font-size:.92em}
.pager{display:flex;gap:6px;flex-wrap:wrap;margin:22px 0}.pager a,.pager span{padding:6px 11px;border:1px solid var(--line);border-radius:6px;text-decoration:none;font-size:14px;background:#fff}
.pager span.cur{background:var(--accent);color:#fff;border-color:var(--accent)}
.pn{display:flex;justify-content:space-between;gap:10px;margin-top:22px;font-size:14px}
.kv{font-size:13px;color:var(--muted)}.kv code{background:#fff;border:1px solid var(--line);padding:2px 6px;border-radius:4px;word-break:break-all;font-size:12px}
.ex{display:grid;grid-template-columns:repeat(auto-fill,minmax(200px,1fr));gap:12px;margin:14px 0 22px}
textarea.sfen{width:100%;font-family:monospace;font-size:14px;padding:10px;border:1px solid var(--line);border-radius:8px;min-height:64px}
.two{display:grid;grid-template-columns:1fr 1fr;gap:22px;align-items:start}@media(max-width:720px){.two{grid-template-columns:1fr}}
.lock{background:#fff8ec;border:1px dashed var(--amz);border-radius:8px;padding:14px;margin-top:14px}