:root{--brand: #0000ff;--bg: #f5f6fa;--surface: #ffffff;--text: #1a1a1a;--muted: #6b7280;--border: #e5e7eb}*{box-sizing:border-box}body{margin:0;font-family:system-ui,-apple-system,Segoe UI,Roboto,sans-serif;background:var(--bg);color:var(--text)}.app{max-width:640px;margin:0 auto;padding:2rem 1rem 4rem}.app__header{text-align:center;margin-bottom:1.5rem}.app__title{margin:0;font-size:1.75rem;color:var(--brand)}.app__subtitle{margin:.25rem 0 0;color:var(--muted);font-size:.95rem}.task-form{display:flex;gap:.5rem;margin-bottom:1.25rem}.task-form__input{flex:1;padding:.65rem .75rem;border:1px solid var(--border);border-radius:8px;font-size:1rem}.task-form__input:focus{outline:2px solid var(--brand);border-color:var(--brand)}.btn{border:none;border-radius:8px;padding:.65rem 1rem;font-size:.95rem;cursor:pointer;background:var(--brand);color:#fff}.btn:disabled{opacity:.5;cursor:not-allowed}.task-list{list-style:none;margin:0;padding:0;display:flex;flex-direction:column;gap:.5rem}.task-item{display:flex;align-items:center;gap:.75rem;background:var(--surface);border:1px solid var(--border);border-radius:8px;padding:.75rem}.task-item__checkbox{width:18px;height:18px;cursor:pointer}.task-item__title{flex:1;font-size:1rem}.task-item--done .task-item__title{text-decoration:line-through;color:var(--muted)}.task-item__delete{background:transparent;border:none;color:var(--muted);cursor:pointer;font-size:1.1rem;line-height:1;padding:.25rem .5rem}.task-item__delete:hover{color:#dc2626}.app__empty{text-align:center;color:var(--muted);padding:2rem 0}.app__footer{margin-top:1.25rem;text-align:center;color:var(--muted);font-size:.9rem}