:root{--bg: #0a0d14;--panel: #121826;--panel-2: #1b2436;--edge: #2c3a55;--ink: #eaf1ff;--muted: #93a4c4;--white: #f1ead4;--black: #4b4570;--accent: #5ad1c8;--gold: #e7b955;--danger: #ff6b6b;font-family:Segoe UI,system-ui,sans-serif}*{box-sizing:border-box}html,body{margin:0;height:100%}body{background:radial-gradient(900px 620px at 50% -10%,#16243a 0%,var(--bg) 60%);color:var(--ink);display:flex;justify-content:center;-webkit-font-smoothing:antialiased}#app{width:min(580px,100%);padding:14px 16px 30px}.topbar{display:flex;align-items:center;gap:10px;margin-bottom:8px;flex-wrap:wrap}.title{font-weight:800;letter-spacing:.5px;font-size:20px}.title .a{color:var(--accent)}.spacer{flex:1}button{font:inherit;cursor:pointer;color:var(--ink);background:var(--panel-2);border:1px solid var(--edge);border-radius:10px;padding:7px 12px;transition:transform .06s,background .15s,opacity .15s}button:hover:not(:disabled){background:#25324b}button:active:not(:disabled){transform:translateY(1px)}button:disabled{opacity:.45;cursor:default}.icon-btn{padding:7px 10px}.seg{display:inline-flex;border:1px solid var(--edge);border-radius:10px;overflow:hidden}.seg button{border:0;border-radius:0;padding:7px 11px;font-size:13px;background:transparent}.seg button.on{background:var(--panel-2);color:#fff;font-weight:700}.seg button+button{border-left:1px solid var(--edge)}button.primary{background:linear-gradient(180deg,#6ee3da,#2fa79c);border-color:#8af0e8;color:#042622;font-weight:700}button.ghost{background:transparent}.statusbar{display:flex;align-items:center;gap:10px;background:var(--panel);border:1px solid var(--edge);border-radius:12px;padding:9px 14px;margin-bottom:10px}.turn{display:inline-flex;align-items:center;gap:8px;font-weight:700}.dot{width:16px;height:16px;border-radius:50%;border:1px solid rgba(0,0,0,.4)}.dot.white{background:radial-gradient(circle at 35% 30%,#fff,var(--white))}.dot.black{background:radial-gradient(circle at 35% 30%,#7c75aa,var(--black))}.statusbar .hint{margin-left:auto;color:var(--muted);font-size:13px}.statusbar .hint.warn{color:var(--gold)}.board-wrap{background:var(--panel);border:1px solid var(--edge);border-radius:16px;padding:8px;box-shadow:0 10px 30px #00000080;position:relative}canvas{display:block;width:100%;height:auto;touch-action:manipulation;border-radius:8px}.controls{display:flex;gap:8px;justify-content:center;margin-top:10px;flex-wrap:wrap}.controls .big{font-weight:700;padding:9px 18px}.legend{display:flex;gap:16px;justify-content:center;color:var(--muted);font-size:12px;margin-top:8px;flex-wrap:wrap}.legend span{display:inline-flex;align-items:center;gap:6px}.legend .sw{width:12px;height:12px;border-radius:3px}.overlay{position:fixed;inset:0;background:#060910db;backdrop-filter:blur(3px);display:flex;align-items:center;justify-content:center;z-index:20}.modal{background:var(--panel);border:1px solid var(--edge);border-radius:16px;padding:22px;width:min(440px,92%);text-align:center;box-shadow:0 10px 30px #00000080}.modal h2{margin:0 0 6px}.modal p{color:var(--muted);margin:0 0 12px;font-size:14px}.modal .row{display:flex;gap:8px;justify-content:center;margin-top:16px;flex-wrap:wrap}.help-content{text-align:left;max-height:64vh;overflow-y:auto}.help-content h3{margin:12px 0 4px;color:var(--accent);font-size:14px}.help-content p,.help-content li{color:var(--muted);font-size:13px;line-height:1.5}.help-content ul{margin:4px 0;padding-left:18px}.help-content b{color:var(--ink)}.handoff{text-align:center}.handoff h2{margin:0 0 8px}.handoff .who{color:var(--accent);font-weight:800}