/* Rainbow animated background */
body {
  margin: 0;
  padding: 0;
  height: 100vh;
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  display: flex;
  justify-content: center;
  align-items: center;
  background: linear-gradient(-45deg, #ff9a9e, #fad0c4, #a18cd1, #fbc2eb, #f6d365, #96e6a1);
  background-size: 400% 400%;
  animation: gradient 15s ease infinite;
}

@keyframes gradient {
  0% { background-position: 0% 50%; }
  50% { background-position: 100% 50%; }
  100% { background-position: 0% 50%; }
}

.todo-container {
  background: rgba(255, 255, 255, 0.9);
  padding: 40px 30px;
  border-radius: 20px;
  box-shadow: 0 15px 30px rgba(0, 0, 0, 0.25);
  width: 500px;
  text-align: center;
}

h1 {
  color: #ff4e50;
  margin-bottom: 25px;
  font-size: 32px;
}

.input-section {
  display: flex;
  margin-bottom: 25px;
}

.input-section input {
  flex: 1;
  padding: 15px;
  font-size: 18px;
  border: 2px solid #ccc;
  border-radius: 10px 0 0 10px;
  outline: none;
}

.input-section button {
  padding: 15px 25px;
  background: #28a745;
  color: white;
  border: none;
  font-size: 18px;
  cursor: pointer;
  border-radius: 0 10px 10px 0;
  transition: background 0.3s;
}

.input-section button:hover {
  background: #218838;
}

ul {
  list-style: none;
  padding: 0;
}

li {
  background: #ffffff;
  padding: 12px 15px;
  margin-bottom: 10px;
  border-radius: 10px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 18px;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

li.completed {
  text-decoration: line-through;
  color: #888;
}

li button {
  background: #ff3e3e;
  border: none;
  color: white;
  padding: 7px 12px;
  border-radius: 5px;
  font-size: 14px;
  cursor: pointer;
  transition: background 0.3s;
}

li button:hover {
  background: #d63031;
}