*,*:before,*:after{box-sizing:border-box}html,body{margin:0;min-height:100%;font-family:system-ui,-apple-system,sans-serif;background:#fff;color:#1a1a1a;--grid-line: #d1d5db;--edge-unknown: #9ca3af;--wall-color: #ef4444;--accent: #3b82f6;--cell-bg: #f9fafb;user-select:none;-webkit-user-select:none;-webkit-touch-callout:none;touch-action:pan-x pan-y}#app{min-height:100dvh;padding:env(safe-area-inset-top) env(safe-area-inset-right) env(safe-area-inset-bottom) env(safe-area-inset-left)}.shell{max-width:28rem;margin:0 auto;display:flex;flex-direction:column;min-height:calc(100dvh - env(safe-area-inset-top) - env(safe-area-inset-bottom));padding:1rem}.toolbar-area{position:relative;margin-top:auto}.toolbar{display:grid;grid-template-columns:1fr 1fr 1fr;gap:.75rem;padding:1rem 0}.options-menu{position:fixed;bottom:calc(env(safe-area-inset-bottom) + 5.5rem);right:1rem;min-width:13rem;max-height:calc(100dvh - env(safe-area-inset-top) - env(safe-area-inset-bottom) - 6rem);overflow-y:auto;-webkit-overflow-scrolling:touch;list-style:none;margin:0;padding:.3rem 0;background:#fff;border:1px solid #e5e7eb;border-radius:14px;box-shadow:0 8px 32px #00000024;z-index:100}.menu-item{display:flex;align-items:center;gap:.6rem;padding:.7rem 1.1rem;font:inherit;font-size:1rem;color:#111827;cursor:pointer;user-select:none;-webkit-user-select:none}.menu-item:active{background:#f3f4f6}.menu-check{width:1.1rem;flex-shrink:0;font-size:.9rem;color:#3b82f6}.menu-item--checked .menu-check:before{content:"✓"}.menu-item--disabled{color:#9ca3af;cursor:default}.menu-divider{height:1px;background:#f3f4f6;margin:.25rem 0}.menu-build{padding:.4rem 1.1rem .5rem;font-size:.72rem;color:#9ca3af;user-select:none;-webkit-user-select:none}.toolbar button{font:inherit;font-weight:500;padding:.75rem .5rem;border-radius:12px;border:1px solid #e5e7eb;background:#f3f4f6;color:#1f2937;cursor:pointer;touch-action:manipulation;transition:all .1s ease}.toolbar button:active{background:#e5e7eb;transform:scale(.96)}.toolbar button:disabled{opacity:.3;cursor:not-allowed}.status{min-height:3.5rem;margin:.5rem 0;font-size:.95rem;line-height:1.4;text-align:center;color:#4b5563;display:flex;align-items:center;justify-content:center}.status--solved{color:#10b981;font-size:1.5rem;font-weight:800;letter-spacing:.1em}.board{display:grid;grid-template-columns:repeat(var(--cols),minmax(0,1fr));gap:0;margin:0 auto;width:100%;max-width:22rem;touch-action:none;user-select:none;-webkit-user-select:none;border:3px solid #111827;background:#111827;border-radius:4px;overflow:hidden}.cell{aspect-ratio:1;display:flex;align-items:center;justify-content:center;font-size:clamp(1.1rem,6vw,1.6rem);font-weight:700;background:var(--cell-bg);color:#111827;cursor:pointer;padding:0;margin:-1.5px;line-height:1;-webkit-tap-highlight-color:transparent;transition:background .12s ease;position:relative;border:3px solid var(--grid-line)}.cell--drag-start{background:#eff6ff;z-index:3}.cell--drag-start:after{content:"";position:absolute;top:0;right:0;bottom:0;left:0;border:4px solid var(--accent);pointer-events:none}.cell--drag-target{background:#ecfdf5;z-index:3}.cell--drag-target:after{content:"";position:absolute;top:0;right:0;bottom:0;left:0;border:4px dashed #10b981;pointer-events:none}.cell--error{background:#fee2e2!important;color:#991b1b}.cell--warning{background:#fef3c7!important;color:#92400e}.board--locked{opacity:.8}.board--locked .cell{background:#f3f4f6;color:#6b7280}