:root{--bg:#0f1a24;--panel:#1a2a3a;--text:#f0f6fc;--muted:#b6c7d8;--warn:#fbbf24;--good:#6ee7b7;--touch:72px}
*{box-sizing:border-box;margin:0;padding:0}
body{min-height:100dvh;font-family:"PingFang TC","Noto Sans TC",system-ui,sans-serif;background:radial-gradient(ellipse at 30% 0%,#1e3a5f,transparent 50%),var(--bg);color:var(--text);padding:max(.5rem,env(safe-area-inset-top)) .7rem;user-select:none}
button{font:inherit;border:none;cursor:pointer;color:inherit}
.app{max-width:500px;margin:0 auto;min-height:calc(100dvh - 1rem);display:flex;flex-direction:column}
.screen{display:flex;flex-direction:column;gap:.55rem;flex:1;min-height:0}
.hidden{display:none!important}
h1{text-align:center;font-size:clamp(1.1rem,3.8vw,1.35rem);color:#93c5fd;font-weight:900}
.gentle{text-align:center;color:var(--muted);font-weight:700}
.panel{background:var(--panel);border-radius:16px;padding:.95rem;border:2px solid rgba(147,197,253,.3)}
.label{color:var(--warn);font-weight:900;margin:.35rem 0;font-size:1.05rem}
.chips{display:flex;flex-wrap:wrap;gap:.5rem}
.chip,.chips button{min-height:var(--touch);padding:.55rem .85rem;border-radius:16px;background:rgba(0,0,0,.34);border:3px solid rgba(182,199,216,.4);font-weight:900;font-size:1.05rem}
.chip.active,.chips button.active{border-color:var(--warn);background:rgba(251,191,36,.28);color:#fde68a;box-shadow:0 0 0 3px rgba(251,191,36,.35)}
.cur{font-weight:900;font-size:1.05rem}.cur span{color:var(--warn)}
.btn-go{width:100%;min-height:72px;margin-top:.55rem;border-radius:16px;font-weight:900;font-size:1.2rem;background:linear-gradient(180deg,#93c5fd,#2563eb);color:#fff}
.btn{min-height:56px;border-radius:14px;font-weight:900;padding:0 .8rem;background:rgba(255,255,255,.12);flex:1;font-size:1.02rem}
.btn.ghost{background:rgba(0,0,0,.28)}
.bar{flex-shrink:0;display:flex;justify-content:space-between;font-weight:900;background:var(--panel);padding:.6rem .8rem;border-radius:14px;border:1px solid rgba(147,197,253,.25)}
.bar b{color:var(--warn)}
.board{display:grid;grid-template-columns:repeat(4,1fr);gap:5px;background:#020617;padding:8px;border-radius:16px;border:4px solid #64748b;box-shadow:inset 0 0 0 2px #0f172a}
.cell{aspect-ratio:1;border-radius:12px;background:#1e293b;font-size:clamp(1.65rem,9vw,2.35rem);font-weight:900;display:flex;align-items:center;justify-content:center;border:3px solid transparent;color:#f1f5f9}
.cell.fixed{background:#334155;color:#f8fafc;border-color:rgba(148,163,184,.35)}
.cell.sel{border-color:var(--warn);box-shadow:0 0 0 3px rgba(251,191,36,.5);background:#273549}
.cell.err{color:#fca5a5;border-color:#f87171}
.cell.ok{color:var(--good)}
.numpad{display:grid;grid-template-columns:repeat(5,1fr);gap:.45rem}
.numpad button{min-height:72px;border-radius:16px;font-size:1.55rem;font-weight:900;background:rgba(255,255,255,.14);border:3px solid rgba(255,255,255,.18)}
.numpad button:active{background:rgba(251,191,36,.25);border-color:var(--warn)}
.hint{text-align:center;color:var(--muted);font-weight:800}
.row{display:flex;gap:.45rem;flex-shrink:0}
.overlay{position:fixed;inset:0;background:rgba(5,12,20,.78);display:flex;align-items:center;justify-content:center;padding:1rem;z-index:20}
.card{background:var(--panel);border-radius:18px;padding:1.1rem;width:min(420px,100%);border:2px solid rgba(147,197,253,.35)}
.card h2{text-align:center;color:var(--warn);margin-bottom:.5rem}
#lb-table table{width:100%;border-collapse:collapse;font-size:.95rem}
#lb-table th,#lb-table td{padding:.45rem;border-bottom:1px solid rgba(255,255,255,.1);font-weight:800}
#lb-table tr.me td{color:var(--warn)}
html.elder-mode .cell{font-size:clamp(1.85rem,10vw,2.55rem)}
html.elder-mode .numpad button{min-height:80px;font-size:1.7rem}