body {
    font-family: sans-serif;
    background: #f5f5f5;
    padding: 40px;
  }
  
  h1 {
    text-align: center;
  }
  
  #todoInput {
    width: 70%;
    padding: 10px;
    font-size: 16px;
  }
  
  #addBtn {
    padding: 10px 16px;
    font-size: 16px;
    margin-left: 8px;
    cursor: pointer;
  }
  
  ul {
    list-style: none;
    padding: 0;
    margin-top: 20px;
  }
  
  li {
    background: white;
    padding: 10px;
    margin-bottom: 8px;
    display: flex;
    justify-content: space-between;
    align-items: center;
  }
  
  .delete-btn {
    background: red;
    color: white;
    border: none;
    padding: 4px 8px;
    cursor: pointer;
  }
  .done {
    text-decoration: line-through;
    color: gray;
  }
  
  #todoList {
    list-style: none;
    padding: 0;
    max-width: 400px;
    margin: 20px auto;
  }
  
  #todoList li {
    background: #fff;
    padding: 10px 12px;
    margin-bottom: 8px;
    border-radius: 6px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    cursor: grab;
  }
  
  #todoList li.dragging {
    opacity: 0.5;
  }
  
  #todoList li.done span {
    text-decoration: line-through;
    color: #aaa;
  }
  
  .delete-btn {
    background: #ff4d4f;
    border: none;
    color: white;
    border-radius: 4px;
    padding: 4px 8px;
    cursor: pointer;
  }
  
  .delete-btn:hover {
    opacity: 0.8;
  }
  .filter-btn {
    padding: 6px 12px;
    border: 1px solid #ccc;
    background: #fff;
    cursor: pointer;
    border-radius: 4px;
  }
  
  .filter-btn.active {
    background: #2563eb;
    color: #fff;
    border-color: #2563eb;
  }
  body.dark {
    background: #111827;
    color: #e5e7eb;
  }
  
  body.dark #todoList li {
    background: #1f2933;
  }
  
  body.dark .filter-btn {
    background: #1f2933;
    color: #e5e7eb;
    border-color: #374151;
  }
  
  body.dark .filter-btn.active {
    background: #3b82f6;
  }
  
  .dark-toggle {
    font-size: 20px;
    padding: 6px 10px;
    cursor: pointer;
    background: none;
    border: 1px solid #ccc;
    border-radius: 6px;
    margin-left: 10px;
    color: #333;   /* ← これを追加 */
  }
  body.dark .dark-toggle {
    color: #e5e7eb;
    border-color: #555;
  }
  body {
    font-family: system-ui, -apple-system, BlinkMacSystemFont, sans-serif;
    background: #f7f7f7;
  }
  
  .container {
    max-width: 640px;
    margin: 40px auto;
    background: #fff;
    padding: 24px;
    border-radius: 12px;
    box-shadow: 0 10px 25px rgba(0,0,0,0.08);
  }
  h1 {
    text-align: center;
    margin-bottom: 24px;
    font-size: 24px;
  }
  .input-area {
    display: flex;
    gap: 8px;
    margin-bottom: 16px;
  }
  
  input {
    flex: 1;
    padding: 10px;
    border-radius: 8px;
    border: 1px solid #ccc;
  }
  
  button.add {
    padding: 10px 16px;
    border-radius: 8px;
    border: none;
    background: #4f46e5;
    color: white;
  }
  .filters {
    display: flex;
    gap: 8px;
    margin-bottom: 20px;
  }
  
  .filters button {
    padding: 6px 12px;
    border-radius: 999px;
    border: 1px solid #ddd;
    background: white;
  }
  
  .filters button.active {
    background: #4f46e5;
    color: white;
    border-color: #4f46e5;
  }
  .todo {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 10px 12px;
    border-radius: 8px;
    background: #f9f9f9;
    margin-bottom: 8px;
  }
  
  .todo.completed span {
    text-decoration: line-through;
    color: #999;
  }
  .todo button {
    background: #ef4444;
    color: white;
    border: none;
    border-radius: 6px;
    padding: 4px 8px;
    font-size: 12px;
  }