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

body {
  font-family: 'Roboto', sans-serif;
  background: linear-gradient(120deg, #89f7fe 0%, #66a6ff 100%);
  display: flex;
  justify-content: center;
  align-items: start;
  padding-top: 60px;
  min-height: 100vh;
}

.container {
  background: white;
  padding: 30px 25px;
  width: 100%;
  max-width: 400px;
  border-radius: 15px;
  box-shadow: 0 8px 20px rgba(0, 0, 0, 0.15);
}

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

.input-section {
  display: flex;
  gap: 10px;
  margin-bottom: 20px;
}

input[type="text"] {
  flex: 1;
  padding: 10px 15px;
  border-radius: 10px;
  border: 1px solid #ccc;
  font-size: 1rem;
}

button {
  padding: 10px 15px;
  background: #66a6ff;
  border: none;
  color: white;
  font-size: 1.1rem;
  border-radius: 10px;
  cursor: pointer;
  transition: background 0.3s;
}

button:hover {
  background: #4f8ef7;
}

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

li {
  background: #f9f9f9;
  margin-bottom: 12px;
  padding: 12px 16px;
  border-radius: 10px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  transition: background 0.3s;
}

li.completed {
  text-decoration: line-through;
  color: gray;
  background: #e2e2e2;
}

li:hover {
  background: #efefef;
}

li i {
  cursor: pointer;
  color: #ff6666;
  transition: color 0.3s;
}

li i:hover {
  color: #cc0000;
}