:root{--bg-color:#0d1117;--card-bg:#161b22;--text-primary:#e6edf3;--text-secondary:#8b949e;--accent-color:#58a6ff;--accent-hover:#1f6feb;--danger-color:#f85149;--success-color:#3fb950;--border-color:#30363d;--font-family:"Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;--shadow:0 4px 12px #00000080;--transition:all .3s cubic-bezier(.4, 0, .2, 1)}*{box-sizing:border-box;margin:0;padding:0}body{background-color:var(--bg-color);color:var(--text-primary);font-family:var(--font-family);-webkit-font-smoothing:antialiased;justify-content:center;align-items:flex-start;min-height:100vh;padding-top:50px;display:flex}#root{width:100%;max-width:600px;padding:20px}h1{text-align:center;background:linear-gradient(90deg, var(--accent-color), #bc85ff);-webkit-text-fill-color:transparent;-webkit-background-clip:text;margin-bottom:2rem;font-size:2.5rem;font-weight:800}.card{background-color:var(--card-bg);border:1px solid var(--border-color);box-shadow:var(--shadow);border-radius:12px;padding:24px}input[type=text]{background-color:var(--bg-color);border:1px solid var(--border-color);width:100%;color:var(--text-primary);transition:var(--transition);border-radius:8px;margin-bottom:16px;padding:12px 16px;font-size:1rem}input[type=text]:focus{border-color:var(--accent-color);outline:none;box-shadow:0 0 0 3px #58a6ff33}button{cursor:pointer;transition:var(--transition);justify-content:center;align-items:center;gap:8px;font-weight:600;display:inline-flex}.btn-primary{background-color:var(--accent-color);color:#fff;border:none;border-radius:8px;width:100%;padding:12px 24px;font-size:1rem}.btn-primary:hover{background-color:var(--accent-hover);transform:translateY(-1px)}.todo-item{border-bottom:1px solid var(--border-color);transition:var(--transition);justify-content:space-between;align-items:center;padding:16px;display:flex}.todo-item:last-child{border-bottom:none}.todo-item:hover{background-color:#ffffff05}.todo-content{flex:1;align-items:center;gap:12px;display:flex}.todo-text{transition:var(--transition);font-size:1.05rem}.todo-text.completed{color:var(--text-secondary);text-decoration:line-through}.todo-actions{gap:8px;display:flex}.btn-icon{color:var(--text-secondary);background:0 0;border:none;border-radius:6px;padding:8px}.btn-icon:hover{color:var(--text-primary);background-color:var(--border-color)}.btn-icon.delete:hover{color:var(--danger-color);background-color:#f851491a}.checkbox-container{cursor:pointer;width:24px;height:24px;position:relative}.checkbox-container input{opacity:0;cursor:pointer;position:absolute}.checkmark{border:2px solid var(--border-color);width:24px;height:24px;transition:var(--transition);background-color:#0000;border-radius:6px;position:absolute;top:0;left:0}.checkbox-container:hover input~.checkmark{border-color:var(--accent-color)}.checkbox-container input:checked~.checkmark{background-color:var(--success-color);border-color:var(--success-color)}.checkmark:after{content:"";display:none;position:absolute}.checkbox-container input:checked~.checkmark:after{display:block}.checkbox-container .checkmark:after{border:2px solid #fff;border-width:0 2px 2px 0;width:5px;height:10px;top:4px;left:8px;transform:rotate(45deg)}.empty-state{text-align:center;color:var(--text-secondary);padding:40px 0}