*,*:before,*:after{box-sizing:border-box;margin:0;padding:0}:root{--bg: #f7f7f5;--surface: #ffffff;--border: #e0e0e0;--text: #1a1a1a;--muted: #888;--accent: #4f46e5;--accent-hover: #4338ca;--danger: #dc2626;--done-text: #aaa;--radius: 8px;--font: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif}body{font-family:var(--font);background:var(--bg);color:var(--text);min-height:100vh}.hidden{display:none!important}#auth-screen{min-height:100vh;display:flex;align-items:center;justify-content:center;padding:1rem}.auth-card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:2rem;width:100%;max-width:360px}.auth-card h1{font-size:1.4rem;margin-bottom:1.5rem;text-align:center}#login-form{display:flex;flex-direction:column;gap:.75rem}input[type=email],input[type=password],input[type=text]{width:100%;padding:.6rem .75rem;border:1px solid var(--border);border-radius:var(--radius);font-size:.95rem;font-family:var(--font);background:var(--surface);color:var(--text)}input:focus{outline:2px solid var(--accent);outline-offset:-1px;border-color:transparent}button{cursor:pointer;font-family:var(--font);border-radius:var(--radius);border:none;font-size:.9rem;transition:background .15s}#login-btn{padding:.65rem;background:var(--accent);color:#fff;font-size:.95rem}#login-btn:hover{background:var(--accent-hover)}#login-btn:disabled{opacity:.6;cursor:not-allowed}.error{color:var(--danger);font-size:.85rem;text-align:center}.auth-toggle{display:flex;align-items:center;justify-content:center;gap:.4rem;font-size:.85rem;color:var(--muted)}.auth-toggle button{background:none;border:none;padding:0;color:var(--accent);font-size:.85rem;text-decoration:underline}.auth-toggle button:hover{color:var(--accent-hover)}header{display:flex;align-items:center;justify-content:space-between;padding:1rem 1.25rem;background:var(--surface);border-bottom:1px solid var(--border);position:sticky;top:0;z-index:10}header h1{font-size:1.15rem}#logout-btn{padding:.4rem .9rem;background:transparent;border:1px solid var(--border);color:var(--muted);font-size:.85rem}#logout-btn:hover{background:var(--bg);color:var(--text)}main{max-width:640px;margin:0 auto;padding:1.5rem 1rem 4rem}.add-heading-form{display:flex;gap:.5rem;margin-bottom:2rem}.add-heading-form input{flex:1}.add-heading-form button{padding:.6rem 1rem;background:var(--accent);color:#fff;white-space:nowrap}.add-heading-form button:hover{background:var(--accent-hover)}#groups{display:flex;flex-direction:column;gap:1.5rem}.group{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);overflow:hidden}.group-header{display:flex;align-items:center;justify-content:space-between;padding:.75rem 1rem;background:var(--bg);border-bottom:1px solid var(--border)}.group-title{font-weight:600;font-size:1rem}.item-list{list-style:none}.item{display:flex;align-items:center;gap:.75rem;padding:.6rem 1rem;border-bottom:1px solid var(--border)}.item:last-child{border-bottom:none}.item input[type=checkbox]{width:1.1rem;height:1.1rem;flex-shrink:0;accent-color:var(--accent);cursor:pointer}.item-task{flex:1;font-size:.95rem;word-break:break-word}.item.done .item-task{text-decoration:line-through;color:var(--done-text)}.item-delete{background:transparent;border:none;color:var(--muted);font-size:1.1rem;padding:0 .25rem;line-height:1;flex-shrink:0}.item-delete:hover{color:var(--danger)}.add-item-form{display:flex;gap:.5rem;padding:.6rem 1rem;border-top:1px solid var(--border)}.add-item-form input{flex:1;padding:.45rem .6rem;font-size:.9rem}.add-item-form button{padding:.45rem .85rem;background:var(--accent);color:#fff}.add-item-form button:hover{background:var(--accent-hover)}.empty-hint{text-align:center;color:var(--muted);font-size:.9rem;padding:3rem 1rem}@media (max-width: 480px){header{padding:.75rem 1rem}.add-heading-form{flex-direction:column}.add-heading-form button{width:100%}}