*{margin:0;padding:0;box-sizing:border-box}body{font-family:-apple-system,BlinkMacSystemFont,'Segoe UI',Roboto,Oxygen,Ubuntu,Cantarell,sans-serif;background:linear-gradient(135deg,#667eea 0,#764ba2 100%);min-height:100vh;padding:20px}#app{-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale}.todo-app{max-width:1200px;margin:0 auto}.todo-app h1{color:#fff;text-align:center;margin-bottom:30px;font-size:2.5rem;text-shadow:2px 2px 4px rgba(0,0,0,.2)}.add-list-section{display:flex;gap:10px;margin-bottom:30px;max-width:600px;margin-left:auto;margin-right:auto}.input-field{flex:1;padding:12px 16px;border:none;border-radius:8px;font-size:16px;outline:0;box-shadow:0 2px 4px rgba(0,0,0,.1);transition:box-shadow .3s}.input-field:focus{box-shadow:0 4px 8px rgba(0,0,0,.2)}.btn{padding:12px 24px;border:none;border-radius:8px;font-size:14px;font-weight:600;cursor:pointer;transition:.3s;white-space:nowrap}.btn:hover{transform:translateY(-2px);box-shadow:0 4px 8px rgba(0,0,0,.2)}.btn-primary{background:#667eea;color:#fff}.btn-primary:hover{background:#5568d3}.btn-secondary{background:#48bb78;color:#fff}.btn-secondary:hover{background:#38a169}.btn-danger{background:#f56565;color:#fff}.btn-danger:hover{background:#e53e3e}.btn-sm{padding:8px 16px;font-size:13px}.btn:not(.btn-primary):not(.btn-secondary):not(.btn-danger){background:#e2e8f0;color:#2d3748}.btn:not(.btn-primary):not(.btn-secondary):not(.btn-danger):hover{background:#cbd5e0}.lists-container{display:grid;grid-template-columns:repeat(auto-fill,minmax(350px,1fr));gap:20px}.list-card{background:#fff;border-radius:12px;padding:20px;box-shadow:0 4px 6px rgba(0,0,0,.1);display:flex;flex-direction:column;height:fit-content}.list-header{display:flex;justify-content:space-between;align-items:center;margin-bottom:20px;padding-bottom:15px;border-bottom:2px solid #e2e8f0}.list-header h2{color:#2d3748;font-size:1.5rem;margin:0;word-break:break-word}.add-task-section{display:flex;gap:8px;margin-bottom:20px}.tasks-container{display:flex;flex-direction:column;gap:10px}.task-item{display:flex;gap:12px;padding:12px;background:#f7fafc;border-radius:8px;border:1px solid #e2e8f0;transition:.3s}.task-item:hover{box-shadow:0 2px 4px rgba(0,0,0,.1);border-color:#cbd5e0}.task-item.completed{opacity:.6}.task-item.completed .task-title{text-decoration:line-through}.task-checkbox{display:flex;align-items:center}.task-checkbox input[type=checkbox]{width:20px;height:20px;cursor:pointer}.task-content{flex:1;min-width:0}.task-view-mode{display:flex;flex-direction:column;gap:4px}.task-title{color:#2d3748;font-size:15px;word-break:break-word}.task-datetime{color:#718096;font-size:12px;display:flex;align-items:center;gap:4px}.task-datetime::before{content:"📅"}.task-edit-mode{display:flex;gap:8px;flex-wrap:wrap}.task-edit-mode .input-field{flex:1;min-width:150px}.task-actions{display:flex;gap:6px;flex-wrap:wrap;align-items:flex-start}.empty-state{text-align:center;color:#a0aec0;padding:30px;font-style:italic}.empty-state-main{grid-column:1/-1;text-align:center;color:#fff;font-size:1.2rem;padding:60px;background:rgba(255,255,255,.1);border-radius:12px;backdrop-filter:blur(10px)}.modal-overlay{position:fixed;top:0;left:0;right:0;bottom:0;background:rgba(0,0,0,.5);display:flex;align-items:center;justify-content:center;z-index:1000;padding:20px}.modal-content{background:#fff;border-radius:12px;padding:30px;max-width:400px;width:100%;box-shadow:0 10px 25px rgba(0,0,0,.3)}.modal-content h3{color:#2d3748;margin-bottom:20px;font-size:1.5rem}.modal-content .input-field{width:100%;margin-bottom:20px}.modal-actions{display:flex;gap:10px;flex-wrap:wrap}@media (max-width:768px){.lists-container{grid-template-columns:1fr}.todo-app h1{font-size:2rem}.add-list-section{flex-direction:column}.task-actions{width:100%}.task-item{flex-direction:column;gap:10px}.task-checkbox{order:-1}}