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


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

.container {
  background: white;
  padding: 30px;
  border-radius: 15px;
  width: 350px;
  box-shadow: 0 10px 25px rgba(0,0,0,0.2);
  text-align: center;
}


h1 {
  margin-bottom: 20px;
  color: #333;
}

input {
  width: 90%;
  padding: 10px;
  margin: 8px 0;
  border: 1px solid #ddd;
  border-radius: 8px;
  outline: none;
  transition: 0.3s;
}

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


button {
  padding: 10px 15px;
  margin-top: 10px;
  border: none;
  background: #667eea;
  color: white;
  border-radius: 8px;
  cursor: pointer;
  transition: 0.3s;
}

button:hover {
  background: #5a67d8;
}


ul {
  list-style: none;
  margin-top: 20px;
}


li {
  background: #f4f4f4;
  margin: 10px 0;
  padding: 10px;
  border-radius: 8px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}


li button {
  margin-left: 5px;
  padding: 5px 8px;
  font-size: 12px;
}


.completed {
  text-decoration: line-through;
  color: gray;
}