header h1 {
  font-size: 2.2rem;
  margin-bottom: 20px;
  color: #2d3748;
}

section {
  background: #fff;
  padding: 20px 25px;
  width: 100%;
  max-width: 450px;
  border-radius: 12px;
  box-shadow: 0 8px 20px rgba(0,0,0,0.08);
}

section input[type="text"] {
  width: 100%;
  padding: 12px 15px;
  border-radius: 8px;
  border: 1px solid #ccc;
  outline: none;
  margin-bottom: 15px;
  font-size: 1rem;
  transition: 0.2s;
}

section input[type="text"]:focus {
  border-color: #3182ce;
  box-shadow: 0 0 0 2px rgba(49,130,206,0.2);
}

ul {
  list-style: none;
  margin-top: 10px;
}

li {
  background: #f8fafc;
  padding: 12px;
  border-radius: 10px;
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 10px;
  transition: 0.2s;
}

li:hover {
  background: #edf2f7;
}

input[type="checkbox"] {
  width: 18px;
  height: 18px;
  cursor: pointer;
}

li label {
  flex: 1;
  font-size: 1rem;
  cursor: pointer;
}

button {
  background: #e53e3e;
  border: none;
  color: #fff;
  padding: 6px 10px;
  border-radius: 6px;
  cursor: pointer;
  transition: 0.2s;
  font-size: 0.9rem;
}

button:hover {
  background: #c53030;
}

.complete label {
  text-decoration: line-through;
  color: #718096;
  opacity: 0.7;
}