*{box-sizing:border-box;margin:0;padding:0}body{background-color:#f0f2f5;font-family:Arial,sans-serif;padding:20px}.board{display:flex;gap:20px;overflow-x:auto}.column{background:#ebecf0;border-radius:3px;max-width:270px;min-width:270px}.column-header{font-weight:700;padding:10px}.card-list{min-height:100px;padding:10px}.card{background:#fff;border-radius:3px;cursor:grab;margin-bottom:8px;padding:10px;position:relative}.card:hover .delete-btn{display:block}.delete-btn{cursor:pointer;display:none;font-size:16px;position:absolute;right:5px;top:5px}.add-card-btn{color:#6b7780;cursor:pointer;padding:10px;text-align:center}.add-card-btn:hover{color:#0079bf}.dragging{cursor:grabbing;opacity:.5}.drop-zone{background-color:rgba(0,121,191,.1);border:2px dashed #0079bf;height:40px;line-height:40px;margin:5px 0;text-align:center}