:root{--bg: #f6f7f9;--surface: #ffffff;--text: #1c1f23;--muted: #6b7280;--border: #e5e7eb;--accent: #4f46e5;--accent-hover: #4338ca;--danger: #dc2626;--shadow: 0 1px 3px rgba(0, 0, 0, .08), 0 1px 2px rgba(0, 0, 0, .04);--radius: 12px}@media (prefers-color-scheme: dark){:root{--bg: #0f1115;--surface: #1a1d23;--text: #e8eaed;--muted: #9aa0a6;--border: #2c3038;--accent: #818cf8;--accent-hover: #a5b4fc;--danger: #f87171;--shadow: 0 1px 3px rgba(0, 0, 0, .4)}}*{box-sizing:border-box}body{margin:0;background:var(--bg);color:var(--text);font-family:system-ui,-apple-system,Segoe UI,Roboto,sans-serif;font-size:16px;line-height:1.5;-webkit-font-smoothing:antialiased}.app{max-width:560px;margin:0 auto;padding:2.5rem 1.25rem 4rem}.app-header{display:flex;align-items:baseline;justify-content:space-between;margin-bottom:1.75rem}.app-header h1{margin:0;font-size:1.6rem;font-weight:650;letter-spacing:-.02em}.card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);box-shadow:var(--shadow);padding:1.25rem}.auth-card{margin-top:2rem}.auth-card h2{margin:0 0 .5rem;font-size:1.25rem}h2{font-weight:600}.muted{color:var(--muted)}.empty{text-align:center;padding:1.5rem 0}.error{color:var(--danger);font-size:.9rem;margin:.75rem 0 0}input[type=text],input[type=email]{width:100%;padding:.6rem .75rem;font:inherit;color:var(--text);background:var(--surface);border:1px solid var(--border);border-radius:8px;outline:none;transition:border-color .15s,box-shadow .15s}input[type=text]:focus,input[type=email]:focus{border-color:var(--accent);box-shadow:0 0 0 3px color-mix(in srgb,var(--accent) 20%,transparent)}button{font:inherit;cursor:pointer;border:none;border-radius:8px;padding:.6rem 1rem;background:var(--accent);color:#fff;font-weight:550;transition:background .15s,opacity .15s}button:hover:not(:disabled){background:var(--accent-hover)}button:disabled{opacity:.5;cursor:not-allowed}.link-button{background:none;color:var(--accent);padding:0;font-weight:500}.link-button:hover:not(:disabled){background:none;text-decoration:underline}.auth-card form{display:flex;flex-direction:column;gap:.75rem;margin-top:1rem}.add-form{display:flex;gap:.6rem;margin-bottom:1rem}.add-form input{flex:1}.todo-list{list-style:none;margin:0;padding:0}.todo-item{display:flex;align-items:center;gap:.75rem;padding:.7rem .25rem;border-top:1px solid var(--border)}.todo-item:first-child{border-top:none}.todo-item input[type=checkbox]{width:1.15rem;height:1.15rem;accent-color:var(--accent);flex-shrink:0;cursor:pointer}.todo-title{flex:1;cursor:text;word-break:break-word}.todo-item.done .todo-title{color:var(--muted);text-decoration:line-through}.edit-form{flex:1}.todo-actions{display:flex;gap:.25rem;flex-shrink:0}.icon-button{background:none;color:var(--muted);padding:.3rem .5rem;font-size:.85rem;font-weight:500;border-radius:6px}.icon-button:hover:not(:disabled){background:var(--border);color:var(--text)}.icon-button.danger:hover:not(:disabled){color:var(--danger)}