* {
  box-sizing: border-box;
}

body {
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  background: #e8e4df;
  min-height: 100vh;
  margin: 0;
  padding: 2rem;
}

.container {
  max-width: 500px;
  margin: 0 auto;
  background: white;
  border-radius: 12px;
  padding: 2rem;
  box-shadow: 0 10px 40px rgba(0, 0, 0, 0.2);
}

h1 {
  margin-top: 0;
  color: #333;
  text-align: center;
}

.add-todo {
  display: flex;
  gap: 0.5rem;
  margin-bottom: 1.5rem;
}

#todo-input {
  flex: 1;
  padding: 0.75rem 1rem;
  font-size: 1rem;
  border: 2px solid #e0e0e0;
  border-radius: 8px;
  outline: none;
}

#todo-input:focus {
  border-color: #2c5f4f;
}

#save-btn {
  padding: 0.75rem 1.5rem;
  font-size: 1rem;
  font-weight: 600;
  color: white;
  background: #2c5f4f;
  border: none;
  border-radius: 8px;
  cursor: pointer;
}

#save-btn:hover {
  background: #234a3e;
}

.stats {
  display: flex;
  gap: 1.5rem;
  margin-bottom: 1.5rem;
  padding: 0.75rem;
  background: #f5f5f5;
  border-radius: 8px;
  font-size: 0.9rem;
  color: #555;
}

.stats strong {
  color: #333;
}

#todo-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.todo-item {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.75rem 1rem;
  margin-bottom: 0.5rem;
  background: #f9f9f9;
  border-radius: 8px;
  border: 1px solid #eee;
}

.todo-item.completed .todo-text {
  text-decoration: line-through;
  color: #999;
}

.todo-item input[type="checkbox"] {
  width: 20px;
  height: 20px;
  cursor: pointer;
  flex-shrink: 0;
}

.todo-text {
  flex: 1;
  font-size: 1rem;
}

.todo-actions {
  display: flex;
  gap: 0.25rem;
}

.todo-actions button {
  padding: 0.35rem 0.75rem;
  font-size: 0.85rem;
  border: none;
  border-radius: 6px;
  cursor: pointer;
}

.todo-actions button:hover {
  opacity: 0.8;
}

.edit-btn {
  background: #ffc107;
  color: #333;
}

.delete-btn {
  background: #f44336;
  color: white;
}

.save-edit-btn {
  background: #4caf50;
  color: white;
}

/* 編集モード: テキストがフォームに変わる */
.todo-item.editing .todo-text {
  display: none;
}

.todo-item.editing {
  flex-wrap: wrap;
}

.todo-item.editing .edit-form {
  display: flex;
  flex: 1;
  min-width: 0;
  gap: 0.5rem;
}

.edit-form {
  display: none;
}

.edit-form input {
  flex: 1;
  padding: 0.5rem;
  font-size: 1rem;
  border: 2px solid #2c5f4f;
  border-radius: 6px;
  outline: none;
}

/* 削除確認モーダル */
.modal-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.4);
  backdrop-filter: blur(4px);
  align-items: center;
  justify-content: center;
  z-index: 1000;
  animation: fadeIn 0.2s ease;
}

.modal-overlay.is-open {
  display: flex;
}

.modal-dialog {
  background: white;
  border-radius: 12px;
  padding: 1.5rem 2rem;
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
  min-width: 320px;
  animation: slideUp 0.25s ease;
}

.modal-message {
  margin: 0 0 1.5rem;
  font-size: 1.1rem;
  color: #333;
}

.modal-actions {
  display: flex;
  gap: 0.75rem;
  justify-content: flex-end;
}

.modal-btn {
  padding: 0.6rem 1.25rem;
  font-size: 1rem;
  font-weight: 600;
  border: none;
  border-radius: 8px;
  cursor: pointer;
}

.modal-btn:hover {
  opacity: 0.9;
}

.modal-btn:active {
  transform: scale(0.98);
}

.modal-cancel {
  background: #e0e0e0;
  color: #333;
}

.modal-confirm {
  background: #f44336;
  color: white;
}

@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

@keyframes slideUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* 編集入力が不正（空）だったときの見た目 */
.edit-input.is-invalid {
  border-color: #f44336;
}

/* 編集時のエラーメッセージ */
.edit-error {
  flex-basis: 100%;
  margin: 0.25rem 0 0;
  padding-left: 28px; /* checkbox幅 + gap でインデント */
  font-size: 0.85rem;
  color: #f44336;
}