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

body {
  font-family: "Apple SD Gothic Neo", "Segoe UI", sans-serif;
  background: linear-gradient(135deg, #667eea, #764ba2);
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: flex-start;
  padding: 40px 16px;
}

.container {
  background: #fff;
  width: 100%;
  max-width: 460px;
  border-radius: 16px;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
  padding: 28px;
}

h1 {
  text-align: center;
  color: #4a3f8f;
  margin-bottom: 20px;
  font-size: 1.6rem;
}

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

#todo-input {
  flex: 1;
  padding: 12px 14px;
  border: 2px solid #e0e0e0;
  border-radius: 10px;
  font-size: 1rem;
  outline: none;
  transition: border-color 0.2s;
}

#todo-input:focus {
  border-color: #667eea;
}

#todo-form button {
  padding: 12px 18px;
  background: #667eea;
  color: #fff;
  border: none;
  border-radius: 10px;
  font-size: 1rem;
  cursor: pointer;
  transition: background 0.2s;
}

#todo-form button:hover {
  background: #5568d3;
}

#todo-list {
  list-style: none;
}

.todo-item {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 12px 10px;
  border-bottom: 1px solid #f0f0f0;
}

.todo-item .text {
  flex: 1;
  font-size: 1rem;
  cursor: pointer;
  color: #333;
}

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

.todo-item input[type="checkbox"] {
  width: 20px;
  height: 20px;
  cursor: pointer;
  accent-color: #667eea;
}

.todo-item .delete-btn {
  background: #ff5c5c;
  color: #fff;
  border: none;
  border-radius: 8px;
  padding: 6px 10px;
  cursor: pointer;
  font-size: 0.85rem;
  transition: background 0.2s;
}

.todo-item .delete-btn:hover {
  background: #e03e3e;
}

.empty {
  text-align: center;
  color: #999;
  margin-top: 10px;
}