body {
  background-image: url(https://external-content.duckduckgo.com/iu/?u=https%3A%2F%2Fwallpapercave.com%2Fwp%2Fwp3640574.gif&f=1&nofb=1&ipt=a7ef62a505dcb322d09b11126c557b8b32122eabc2fcb1102c7b033aa59b905f);
  background-size: cover;
  min-height: 100px;
  font-family: Arial, sans-serif;
  color: #2F4F4F;
}

h1 {
  text-align: center;
  color: #4682B4
}

a {
  text-decoration: none;
}

li {
  list-style-type: none;
}

.todo-list {
  background-color: #5F9EA0;
  border-radius: 25px;
  padding: 10px;
  max-width: 600px;
  margin: 0 auto;
}

.todo-list-item:not(:last-child) {
  margin-bottom: 20px;
}

.todo-list > li {
  list-style-type: none;
}

input[type="checkbox"]:checked + label {
  text-decoration: line-through;
  color: #888;
}

.todo-list-item {
  background-color: #FFFFFF;
  border-radius: 25px;
  margin: 20px 10px;
  padding: 10px;
}

.sub-item li {
  list-style-type: square ;
  padding: 10px 0px 10px 0px;
}

.sub-item-link:link {
  color: #1E90FF;
}

.sub-item-link:hover {
  color: #4682B4;
}

.sub-item-link:focus {
  outline: 2px solid #1E90FF; 
  outline-offset: 2px;
  border-radius: 4px;
}

.sub-item-link:visited {
  color: #6A5ACD;
}

.sub-item-link:active {
  color: #FF4500;
}