* {
  box-sizing: border-box;
  font-family: Arial, Helvetica, sans-serif;
}

.container {
  width: 600px;
  margin: 30px auto;
}

.form {
  display: flex;
}

.form,
.tasks {
  background-color: #EEE;
  padding: 20px;
  border-radius: 5px;
}

.form .input,
.form .add {
  padding: 10px;
  border: 1px solid #DDD;
  font-size: 15px;
  border-radius: 5px;
}

.form .input {
  outline: none;
  border-color: #CCC;
}

.form .add {
  background-color: #f44336;
  color: white;
  font-weight: bold;
  cursor: pointer;
}

.form .input {
  flex: 1;
  margin-right: 10px;
}

.form .add {
  width: 100px;
}

.delete-all {
  margin-top: 20px;
  padding: 20px;
  position: relative;
  opacity: 0.5;
}

.delete-all.active {
  opacity: 1;
}

.delete-all span {
  position: absolute;
  left: 0;
  top: 50%;
  transform: translateY(-50%);
  background-color: #f44336;
  color: white;
  padding: 11px;
  font-size: 16px;
  font-weight: bold;
  border-radius: 4px;
  cursor: pointer;
}


.tasks {
  margin-top: 20px;
}

.tasks .task {
  background-color: white;
  padding: 10px;
  padding-left: 50px;
  margin-top: 20px;
  font-size: 18px;
  border-radius: 5px;
  position: relative;
  cursor: pointer;
}

.tasks .task:hover {
  opacity: 0.9;
}

.tasks .task.done {
  opacity: 0.5;
}

.tasks .task:first-child {
  margin-top: 0;
}

.task input {
  position: absolute;
  margin: 0;
  top: 50%;
  left: 10px;
  transform: translateY(-50%);
  height: 25px;
  width: 25px;
  opacity: 0;
  cursor: pointer;
  z-index: 1;
}

.checkmark {
  position: absolute;
  top: 50%;
  left: 10px;
  transform: translateY(-50%);
  height: 25px;
  width: 25px;
  border-radius: 4px;
  background-color: #f44336;
  opacity: 0.6;
}

.task input:hover ~ .checkmark{
  opacity: 1;
}

.checkmark:after {
  content: "";
  position: absolute;
  display: none;
}

input:checked ~ .checkmark{
  opacity: 1;
}

input:checked ~ .checkmark:after {
  display: block;
}

.checkmark:after {
  left: 50%;
  top: 50%;
  width: 5px;
  height: 10px;
  border: solid white;
  border-width: 0 3px 3px 0;
  transform: translate(-50%, -50%) rotate(45deg);
}

.tasks .task .del {
  position: absolute;
  right: 10px;
  top: 50%;
  transform: translateY(-50%);
  background-color: #f44336;
  color: white;
  padding: 5px;
  font-size: 14px;
  border-radius: 4px;
  cursor: pointer;
}