* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Hiragino Sans",
    "Noto Sans JP", sans-serif;
  background: #f4f5f7;
  color: #1f2933;
  display: flex;
  justify-content: center;
  padding: 40px 16px;
  min-height: 100vh;
}

.app {
  width: 100%;
  max-width: 480px;
  background: #fff;
  border-radius: 16px;
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.08);
  padding: 28px;
}

h1 {
  font-size: 1.6rem;
  margin-bottom: 20px;
  text-align: center;
}

.todo-form {
  display: flex;
  gap: 8px;
  margin-bottom: 20px;
}

.todo-form input {
  flex: 1;
  padding: 12px 14px;
  border: 1px solid #d2d6dc;
  border-radius: 10px;
  font-size: 1rem;
  outline: none;
  transition: border-color 0.15s;
}

.todo-form input:focus {
  border-color: #4f86f7;
}

.todo-form button {
  padding: 0 18px;
  border: none;
  border-radius: 10px;
  background: #4f86f7;
  color: #fff;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.15s;
}

.todo-form button:hover {
  background: #3a6fd6;
}

.todo-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.todo-item {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 14px;
  background: #f9fafb;
  border: 1px solid #eceef1;
  border-radius: 10px;
}

.sort-bar {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 16px;
}

.sort-bar .sort-label {
  font-size: 0.85rem;
  color: #7b8794;
  margin-right: auto;
}

.sort-bar button {
  padding: 6px 12px;
  border: 1px solid #d2d6dc;
  border-radius: 8px;
  background: #fff;
  color: #3e4c59;
  font-size: 0.85rem;
  cursor: pointer;
  transition: background 0.15s, border-color 0.15s;
}

.sort-bar button:hover {
  background: #f0f4ff;
  border-color: #4f86f7;
}

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

.todo-item .text {
  flex: 1;
  word-break: break-word;
}

.todo-item.done .text {
  text-decoration: line-through;
  color: #9aa5b1;
}

.todo-item .delete-btn {
  border: none;
  background: transparent;
  color: #cbd2d9;
  font-size: 1.3rem;
  line-height: 1;
  cursor: pointer;
  padding: 0 4px;
  transition: color 0.15s;
}

.todo-item .delete-btn:hover {
  color: #e74c3c;
}

.empty-message {
  text-align: center;
  color: #9aa5b1;
  padding: 24px 0;
}