body {
  margin: 0;
  padding: 0;
  min-width: 250px;
  font-family: Arial, sans-serif;
  background-color: #f2f2f2;
}

* {
  box-sizing: border-box;
}

ul {
  margin: 0;
  padding: 0;
}

ul li {
  cursor: pointer;
  position: relative;
  padding: 12px 8px 12px 40px;
  list-style-type: none;
  background: #eee;
  font-size: 18px;
  transition: 0.2s;

  /* make the list items unselectable */
  -webkit-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  user-select: none;
}

ul li:nth-child(even) {
  background: #f5f2f2;
}

ul li:last-child {
  border-bottom: none;
}

ul li:hover {
  background-color: #d4d1d1;
}

ul li.checked {
  background-color: #f2f2f2;
  color: #888;
  text-decoration: line-through;
}

ul li.checked::before {
  content: "";
  position: absolute;
  top: 23px;
  left: 7px;
  border-color: #65a2a3;
  border-style: solid;
  border-width: 0 2px 2px 0;
  transform: rotate(45deg);
  height: 10px;
  width: 5px;
}

.close {
  position: absolute;
  right: 10px;
  top: 15px;
  color: #797575;
  font-size: 28px;
  font-weight: bold;
  transition: color 0.3s ease;
}

.close:hover {
  color: #000;
}

.header {
  background-color: #65a2a3;
  padding: 30px;
  color: #fff;
  text-align: center;
}

.header h1 {
  margin: 0;
  font-size: 36px;
}

.header input {
  border: none;
  border-radius: 50px;
  width: 60%;
  padding: 10px;
  font-size: 18px;
  margin-top: 20px;
  margin-right: 10px;
}

.addBtn {
  display: inline-block;
  padding: 10px;
  width: 20%;
  background-color: #5e8e8f;
  color: #fff;
  text-align: center;
  font-size: 18px;
  border-radius: 50px;
  cursor: pointer;
  transition: background-color 0.3s ease;
}

.addBtn:hover {
  background-color: #4c7475;
}

.todo-list {
  max-width: 90%;
  margin: 5px auto;
  padding: 20px 20px 20px 20px;
  background-color: #fff;
  border-radius: 5px;
  box-shadow: 0 0 10px rgba(0, 0, 0, 0.2);
  position: relative;
  overflow: hidden;
}

.todo-list::after {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 5px;
  background-color: #71aeaf;
}