:root{--bg:#fff;--bg-secondary:#f5f5f3;--text:#1a1a1a;--text-secondary:#6b6b6b;--text-tertiary:#999;--border:#0000001f;--border-strong:#1a1a1a;--accent:#378add;--accent-soft:#378add2e;--accent-strong:#378add59;--error:#e24b4a;--radius-sm:6px;--radius-md:8px;--radius-lg:12px;--font-sans:-apple-system, BlinkMacSystemFont, "Segoe UI", system-ui, sans-serif;--font-mono:ui-monospace, SFMono-Regular, Menlo, monospace}@media (prefers-color-scheme:dark){:root{--bg:#1a1a1a;--bg-secondary:#262626;--text:#f5f5f3;--text-secondary:#a3a3a3;--text-tertiary:#6b6b6b;--border:#ffffff26;--border-strong:#f5f5f3}}*{box-sizing:border-box}html,body,#root{min-height:100vh;margin:0;padding:0}body{font-family:var(--font-sans);color:var(--text);background:var(--bg);line-height:1.5}button{font-family:inherit;font-size:inherit;color:inherit}.app{max-width:560px;margin:0 auto;padding:2rem 1rem}.game-header{justify-content:space-between;align-items:center;gap:12px;margin-bottom:1rem;display:flex}.game-difficulty{color:var(--text-secondary);text-transform:capitalize;font-size:13px}.back-btn{cursor:pointer;color:var(--text-secondary);background:0 0;border:none;padding:4px 0;font-family:inherit;font-size:14px}.back-btn:hover{color:var(--text)}.app-header{justify-content:space-between;align-items:center;margin-bottom:1.5rem;display:flex}.app-header h1{margin:0}.error-banner{background:var(--accent-soft);border:.5px solid var(--accent);border-radius:var(--radius-md);color:var(--text);margin-bottom:1rem;padding:10px 14px;font-size:13px}.cell{aspect-ratio:1;background:var(--bg);border:none;border-right:.5px solid var(--border);border-bottom:.5px solid var(--border);cursor:pointer;color:var(--text);-webkit-user-select:none;user-select:none;justify-content:center;align-items:center;padding:0;font-size:20px;font-weight:500;transition:background 80ms;display:flex}.cell:focus-visible{outline:2px solid var(--accent);outline-offset:-2px;z-index:1}.cell.given{color:var(--text)}.cell.user{color:var(--accent)}.cell.error{color:var(--error)}.cell.related{background:var(--bg-secondary)}.cell.same-value{background:var(--accent-soft)}.cell.selected{background:var(--accent-strong)}.notes{width:100%;height:100%;color:var(--text-tertiary);grid-template-rows:repeat(3,1fr);grid-template-columns:repeat(3,1fr);font-size:10px;font-weight:400;line-height:1;display:grid}.notes span{justify-content:center;align-items:center;display:flex}.board{background:var(--bg);border:1.5px solid var(--border-strong);border-radius:var(--radius-md);grid-template-columns:repeat(9,1fr);display:grid;overflow:hidden}.board>.cell:nth-child(3n){border-right:1.5px solid var(--border-strong)}.board>.cell:nth-child(9n){border-right:none}.board>.cell:nth-child(n+19):nth-child(-n+27),.board>.cell:nth-child(n+46):nth-child(-n+54){border-bottom:1.5px solid var(--border-strong)}.board>.cell:nth-child(n+73){border-bottom:none}.numpad{grid-template-columns:repeat(9,1fr);gap:4px;margin-top:12px;display:grid}.numpad-key{background:var(--bg);border:.5px solid var(--border);border-radius:var(--radius-md);cursor:pointer;padding:12px 0;font-size:18px;font-weight:500;transition:background .15s}.numpad-key:hover:not(:disabled){background:var(--bg-secondary)}.numpad-key.done{color:var(--text-tertiary);background:var(--bg-secondary);cursor:default}.numpad-key:focus-visible{outline:2px solid var(--accent);outline-offset:2px}.controls{grid-template-columns:repeat(2,1fr);gap:6px;margin-top:8px;display:grid}.control{background:var(--bg);border:.5px solid var(--border);border-radius:var(--radius-md);cursor:pointer;padding:10px;font-size:13px;transition:background .15s}.control:hover{background:var(--bg-secondary)}.control.active{background:var(--accent-soft);color:var(--accent);border-color:var(--accent)}.control:focus-visible{outline:2px solid var(--accent);outline-offset:2px}.timer{font-family:var(--font-mono);background:var(--bg-secondary);border-radius:var(--radius-md);text-align:center;font-variant-numeric:tabular-nums;min-width:62px;padding:6px 12px;font-size:16px;font-weight:500}.menu{gap:8px;display:grid}.menu-item{background:var(--bg);border:.5px solid var(--border);border-radius:var(--radius-lg);cursor:pointer;text-align:left;flex-direction:column;align-items:flex-start;padding:14px 16px;font-size:15px;transition:background .15s;display:flex}.menu-item:hover{background:var(--bg-secondary)}.menu-item.continue{border:2px solid var(--accent)}.menu-label{font-weight:500}.menu-desc{color:var(--text-secondary);text-transform:capitalize;margin-top:2px;font-size:13px}.menu-item:focus-visible{outline:2px solid var(--accent);outline-offset:2px}.win{flex-direction:column;gap:1rem;display:flex}.win-card{text-align:center;background:var(--accent-soft);border-radius:var(--radius-lg);padding:2rem 1rem}.win-card h2{margin:0 0 8px;font-size:22px;font-weight:500}.win-card p{margin:0;font-size:14px}.win-actions{gap:8px;display:flex}.win-action{background:var(--bg);border:.5px solid var(--border);border-radius:var(--radius-md);cursor:pointer;flex:1;padding:12px;font-size:14px;font-weight:500;transition:background .15s}.win-action:hover{background:var(--bg-secondary)}.win-action.primary{background:var(--text);color:var(--bg);border-color:var(--text)}.history{flex-direction:column;gap:1.25rem;display:flex}.history-header{justify-content:space-between;align-items:center;gap:12px;display:flex}.history-header h1{margin:0;font-size:22px;font-weight:500}.history-header .spacer{width:56px}.best-row{grid-template-columns:repeat(3,1fr);gap:8px;display:grid}.best{background:var(--bg-secondary);border-radius:var(--radius-md);text-align:center;padding:12px}.best-label{color:var(--text-secondary);text-transform:capitalize;margin-bottom:4px;font-size:12px}.best-time{font-size:18px;font-weight:500;font-family:var(--font-mono);font-variant-numeric:tabular-nums}.entry-list{flex-direction:column;gap:6px;margin:0;padding:0;list-style:none;display:flex}.entry{background:var(--bg);border:.5px solid var(--border);border-radius:var(--radius-md);justify-content:space-between;align-items:center;padding:12px 14px;display:flex}.entry-diff{text-transform:capitalize;font-size:14px;font-weight:500}.entry-date{color:var(--text-tertiary);margin-top:2px;font-size:12px}.entry-time{font-family:var(--font-mono);font-variant-numeric:tabular-nums;font-size:14px}.empty{text-align:center;color:var(--text-secondary);padding:3rem 0;font-size:14px;line-height:1.7}.login-screen{justify-content:center;align-items:center;min-height:80vh;display:flex}.login-card{background:var(--bg);border:.5px solid var(--border);border-radius:var(--radius-lg);text-align:center;max-width:360px;padding:2.5rem 2rem}.login-card h1{margin:0 0 12px;font-size:28px;font-weight:500}.login-card p{color:var(--text-secondary);margin:0 0 1.5rem;font-size:14px;line-height:1.6}.login-btn{background:var(--text);color:var(--bg);border-radius:var(--radius-md);cursor:pointer;border:none;padding:12px 24px;font-family:inherit;font-size:15px;font-weight:500}.login-btn:hover{opacity:.9}.user-menu{color:var(--text-secondary);align-items:center;gap:12px;font-size:13px;display:flex}.user-name{color:var(--text);font-weight:500}.logout-btn{border:.5px solid var(--border);border-radius:var(--radius-md);cursor:pointer;color:var(--text-secondary);background:0 0;padding:4px 10px;font-family:inherit;font-size:12px}.logout-btn:hover{background:var(--bg-secondary);color:var(--text)}