:root{--navy:#173b57;--teal:#087e8b;--coral:#e65245;--yellow:#ffd166;--cream:#fffaf0;--ink:#18303f;--muted:#58707e;--line:#c8d8df}
*{box-sizing:border-box}body{margin:0;color:var(--ink);background:linear-gradient(180deg,#e9f7f8 0 260px,var(--cream) 260px);font-family:"Yu Gothic","Hiragino Kaku Gothic ProN",Meiryo,sans-serif;line-height:1.75}.site-header{background:var(--navy);color:#fff}.header-inner{width:min(1180px,calc(100% - 32px));margin:auto;padding:18px 0;display:flex;align-items:center;justify-content:space-between;gap:20px}.brand{color:#fff;text-decoration:none;font-size:1.35rem;font-weight:900}.header-nav{display:flex;flex-wrap:wrap;gap:12px}.header-nav a{color:#fff;font-weight:700;text-decoration:none}.page{width:min(1180px,calc(100% - 32px));margin:34px auto 56px}.breadcrumb{margin-bottom:18px;color:var(--muted);font-size:.92rem}.breadcrumb a{color:var(--teal)}.hero{padding:clamp(28px,5vw,54px);border-radius:24px;background:#fff;box-shadow:0 14px 34px rgba(23,59,87,.13);text-align:center}.hero h1{margin:0 0 12px;color:var(--navy);font-size:clamp(1.8rem,4vw,3rem);line-height:1.35}.hero p{max-width:850px;margin:0 auto}.cta{display:inline-block;margin-top:22px;padding:14px 26px;border-radius:14px;background:var(--coral);color:#fff;text-decoration:none;font-weight:900}.intro{max-width:900px;margin:34px auto;text-align:center}.puzzle-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:20px}.puzzle-card{display:grid;grid-template-columns:190px 1fr;overflow:hidden;border:1px solid var(--line);border-radius:18px;background:#fff;color:var(--ink);text-decoration:none;box-shadow:0 8px 20px rgba(23,59,87,.08);transition:transform .18s ease,box-shadow .18s ease}.puzzle-card:hover,.puzzle-card:focus-visible{transform:translateY(-3px);box-shadow:0 12px 28px rgba(23,59,87,.15)}.puzzle-card img{width:100%;height:145px;object-fit:cover}.card-copy{padding:18px}.card-copy span{color:var(--teal);font-weight:800}.card-copy h2{margin:4px 0;font-size:1.2rem;color:var(--navy)}.card-copy p{margin:0;color:var(--muted);font-size:.92rem}.level-nav{display:grid;grid-template-columns:repeat(4,1fr);gap:12px;margin-top:34px}.level-nav a{padding:14px;border:2px solid var(--line);border-radius:14px;background:#fff;color:var(--navy);text-align:center;text-decoration:none;font-weight:800}.level-nav a[aria-current="page"]{border-color:var(--teal);background:#eaf8f7}.note{margin-top:32px;padding:22px;border-left:6px solid var(--teal);border-radius:14px;background:#fff}.site-footer{padding:24px;background:var(--navy);color:#fff;text-align:center}.site-footer a{color:#fff}@media(max-width:800px){.header-inner{align-items:flex-start;flex-direction:column}.puzzle-grid{grid-template-columns:1fr}.level-nav{grid-template-columns:repeat(2,1fr)}}@media(max-width:520px){.puzzle-card{grid-template-columns:1fr}.puzzle-card img{height:auto}.level-nav{grid-template-columns:1fr}}