* {
  box-sizing: border-box;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background: #f4f5f7;
  color: #1f2933;
  display: flex;
  justify-content: center;
  padding: 40px 16px;
  margin: 0;
}

.app {
  width: 100%;
  max-width: 480px;
}

.app-header {
  display: flex;
  align-items: center;
  gap: 10px;
  color: #2563eb;
  margin-bottom: 12px;
}

.app-header h1 {
  font-size: 1.5rem;
  margin: 0;
  color: #1f2933;
}

main {
  background: #fff;
  border-radius: 8px;
  box-shadow: 0 1px 4px rgba(0, 0, 0, 0.1);
  padding: 24px;
}

.app-footer {
  text-align: center;
  color: #9aa5b1;
  font-size: 0.8rem;
  margin-top: 16px;
}

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

#todo-input {
  flex: 1;
  padding: 10px 12px;
  border: 1px solid #cbd2d9;
  border-radius: 6px;
  font-size: 1rem;
}

#todo-form button {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 10px 16px;
  border: none;
  border-radius: 6px;
  background: #2563eb;
  color: #fff;
  font-size: 1rem;
  cursor: pointer;
}

#todo-form button:hover {
  background: #1d4ed8;
}

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

#todo-list li {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 0;
  border-bottom: 1px solid #e4e7eb;
}

#todo-list li:last-child {
  border-bottom: none;
}

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

#todo-list li.completed span {
  text-decoration: line-through;
  color: #9aa5b1;
}

#todo-stats {
  margin: 16px 0 0;
  color: #616e7c;
  font-size: 0.85rem;
  text-align: center;
}

#todo-list li button {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  border: none;
  background: #ef4444;
  color: #fff;
  border-radius: 6px;
  padding: 6px 10px;
  cursor: pointer;
}

#todo-list li button:hover {
  background: #dc2626;
}