:root{--bg:#f6f7f9;--card:#ffffff;--text:#1f2937;--muted:#6b7280;--border:#e5e7eb;--accent:#3b82f6;--accent-ink:#1e3a8a;--danger:#dc2626;font-family:ui-sans-serif,system-ui,-apple-system,Segoe UI,Roboto,Helvetica,Arial;color:var(--text);line-height:1.5;font-size:16px}*{box-sizing:border-box}body{margin:0;min-height:100vh;display:grid;place-items:center;background:var(--bg);padding:24px}h1{margin:0 0 .75rem;text-align:center;font-weight:700;font-size:1.65rem;letter-spacing:-.01em}button{border:1px solid var(--accent);background:linear-gradient(#fff,#f9fafb);color:var(--accent-ink);font-weight:600;padding:.6rem 1rem;border-radius:.55rem;cursor:pointer;transition:background-color .15s ease,box-shadow .15s ease,transform .05s ease}button:hover{background:#f3f4f6}button:active{transform:translateY(1px)}button:focus-visible{outline:3px solid #bfdbfe;outline-offset:2px}@media (prefers-color-scheme: dark){:root{--bg:#0b1220;--card:#0f172a;--text:#e5e7eb;--muted:#9ca3af;--border:#1f2937;--accent:#60a5fa;--accent-ink:#93c5fd;--danger:#ef4444}button{background:linear-gradient(#0f172a,#0b1424);border-color:#334155}button:hover{background:#111a2e}}.app-container{width:min(92vw,720px);background:var(--card);border:1px solid var(--border);border-radius:12px;padding:1.25rem 1.25rem .9rem;box-shadow:0 10px 28px #0000000f;display:flex;flex-direction:column;gap:1rem}.app-container h1{position:relative;padding-bottom:.8rem}.app-container h1:after{content:"";position:absolute;left:50%;transform:translate(-50%);bottom:0;width:120px;height:2px;background:linear-gradient(90deg,transparent,var(--accent),transparent);opacity:.5}.todo-form{display:flex;gap:.6rem}.todo-input{flex:1;padding:.75rem 1rem;border:1px solid var(--border);border-radius:.5rem;background:transparent;color:inherit;transition:border-color .15s ease,box-shadow .15s ease}.todo-input::placeholder{color:var(--muted)}.todo-input:focus{border-color:#bfdbfe;box-shadow:0 0 0 3px #e0f2fe;outline:none}.todo-list{list-style:none;margin:0;padding:0}.todo-item{display:flex;align-items:center;justify-content:space-between;gap:.75rem;padding:.65rem 0;border-bottom:1px solid var(--border)}.todo-item:last-child{border-bottom:none}.todo-item label{display:flex;align-items:center;gap:.6rem;cursor:pointer}.todo-item input[type=checkbox]{width:18px;height:18px;accent-color:var(--accent)}.todo-title{font-size:1rem}.todo-title.done{text-decoration:line-through;color:var(--muted)}.todo-remove{border:1px solid var(--danger);background:transparent;color:var(--danger);padding:.35rem .6rem;border-radius:.45rem;font-weight:700;cursor:pointer;transition:background-color .15s ease,transform .05s ease}.todo-remove:hover{background:color-mix(in oklab,var(--danger),#ffffff 88%)}.todo-remove:active{transform:translateY(1px)}.todo-empty{color:var(--muted);text-align:center;padding:.9rem 0}@media (max-width: 680px){.app-container{padding:1rem}.todo-form{flex-direction:column}}