* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Hiragino Sans", sans-serif;
  background: #f5f5f7;
  color: #1d1d1f;
}

main {
  max-width: 480px;
  margin: 48px auto;
  padding: 0 16px;
}

h1 {
  font-size: 22px;
  margin-bottom: 16px;
}

#todo-form {
  display: flex;
  gap: 8px;
  margin-bottom: 16px;
}

#todo-input {
  flex: 1;
  padding: 10px 12px;
  border: 1px solid #d2d2d7;
  border-radius: 8px;
  font-size: 15px;
}

#todo-form button {
  padding: 10px 16px;
  border: none;
  border-radius: 8px;
  background: #0071e3;
  color: #fff;
  font-size: 15px;
  cursor: pointer;
}

#todo-form button:hover {
  background: #0077ed;
}

#todo-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

#todo-list li {
  display: flex;
  align-items: center;
  gap: 10px;
  background: #fff;
  border-radius: 8px;
  padding: 10px 12px;
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.06);
}

#todo-list li span {
  flex: 1;
  word-break: break-all;
}

#todo-list li.completed span {
  text-decoration: line-through;
  color: #86868b;
}

#todo-list li button {
  border: none;
  background: none;
  color: #ff3b30;
  cursor: pointer;
  font-size: 14px;
}