*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
:root{--bg:#f7f7f5;--surface:#fff;--text:#1a1a1a;--muted:#6b6b6b;--border:#e4e4e0;
--accent:#9944ff;--accent-soft:#efe6ff;--given:#ececea;--shade:#f3edff}
@media (prefers-color-scheme:dark){:root{--bg:#0f0f0f;--surface:#1a1a1a;--text:#f0f0ee;
--muted:#8a8a84;--border:#2e2e2e;--accent:#b78aff;--accent-soft:#2a1d40;--given:#2a2a2a;--shade:#1f1830}}
html{-webkit-text-size-adjust:100%}
body{font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Helvetica,Arial,sans-serif;
background:var(--bg);color:var(--text);line-height:1.65;font-size:16px}
.wrap{max-width:720px;margin:0 auto;padding:0 20px}
a{color:var(--accent)}
.top{border-bottom:1px solid var(--border);background:var(--surface);margin-bottom:36px}
.top .wrap:first-child{display:flex;align-items:center;justify-content:space-between;padding-top:16px}
.brand{display:inline-flex;align-items:center;gap:10px;font-weight:700;color:var(--text);text-decoration:none}
.logo{width:30px;height:30px;border-radius:7px;background:var(--accent);color:#fff;display:grid;
place-items:center;font:700 15px ui-monospace,monospace}
.play{font-weight:600;text-decoration:none;font-size:15px}
nav{display:flex;gap:4px 16px;flex-wrap:wrap;padding-top:10px;padding-bottom:12px;font-size:14px}
nav a{color:var(--muted);text-decoration:none}
nav a:hover,nav a[aria-current]{color:var(--text)}
nav a[aria-current]{font-weight:600}
h1{font-size:32px;line-height:1.2;letter-spacing:-.5px;margin-bottom:14px}
h2{font-size:21px;line-height:1.3;margin:36px 0 10px}
p,ol,ul.list{margin-bottom:14px}
ol,ul.list{padding-left:22px}
li{margin-bottom:8px}
.lede{font-size:18px;color:var(--muted)}
.cards{list-style:none;display:grid;gap:12px;margin:24px 0}
.cards a{display:block;padding:16px 18px;border:1px solid var(--border);border-radius:12px;
background:var(--surface);text-decoration:none;color:var(--text)}
.cards a:hover{border-color:var(--accent)}
.cards strong{display:block;margin-bottom:2px}
.cards span{color:var(--muted);font-size:15px}
figure{margin:20px 0;text-align:center}
figcaption{font-size:14px;color:var(--muted);margin-top:8px;max-width:420px;margin-inline:auto}
.pair{display:flex;flex-wrap:wrap;justify-content:center;gap:0 32px}
.pair figure{flex:0 1 auto;max-width:300px}
svg.grid{max-width:100%;height:auto}
.grid .c{fill:var(--surface)}
.grid .given{fill:var(--given)}
.grid .mark{fill:var(--accent-soft)}
.grid .shade{fill:var(--shade)}
.grid .thin{stroke:var(--border);stroke-width:1}
.grid .wall{stroke:var(--text);stroke-width:2.5;stroke-linecap:square}
.grid .frame{fill:none;stroke:var(--text);stroke-width:3}
.grid text{text-anchor:middle;font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif}
.grid text.given{fill:var(--text);font-weight:700}
.grid text.mark{fill:var(--accent);font-weight:700}
.grid text.fill{fill:var(--muted)}
.grid text.note{fill:var(--accent);font-weight:600}
.puzzle{border-top:1px solid var(--border);margin-top:28px}
.tag{font-size:13px;font-weight:500;color:var(--muted);margin-left:8px}
details{margin:4px 0 12px;text-align:center}
summary{cursor:pointer;color:var(--accent);font-weight:600}
.pager{display:flex;justify-content:space-between;margin:48px 0 24px;padding-top:20px;
border-top:1px solid var(--border);font-weight:600}
.pager a{text-decoration:none}
footer{padding-bottom:48px;font-size:14px}
.muted{color:var(--muted)}
@media print{.top nav,.play,.pager,footer,summary{display:none}
body{background:#fff;color:#000}.puzzle{break-inside:avoid}}