Custom checkbox using only CSS and HTML

Answer 1

Custom checkbox using only HTML and CSS along with three checkbox states (checked, unchecked and half checked or unchecked(if it's used in a group of checkboxes))

 one
  
  


.checkboxcontainer input {
  display: none;
}

.checkboxcontainer {
  display: inlin-block;
  padding-left: 30px;
  position: relative;
  cursor: pointer;
  user-select: none;
}

.checkboxcontainer .checkmark {
  display: inlin-block;
  width: 25px;
  height: 25px;
  background: #eee;
  position: absolute;
  left: 0;
  top: 0;
}

.checkboxcontainer input:checked+.checkmark {
  background-color: #2196fc;
}

.checkboxcontainer input:checked+.checkmark:after {
  content: "";
  position: absolute;
  height: 4px;
  width: 9px;
  border-left: 3px solid white;
  border-bottom: 3px solid white;
  top: 45%;
  left: 50%;
  transform: translate(-50%, -50%) rotate(-45deg);
}

.checkboxcontainer input:indeterminate+.checkmark:after {
  content: "";
  position: absolute;
  height: 0px;
  width: 9px;
  border-left: 3px solid white;
  border-bottom: 3px solid white;
  top: 45%;
  left: 50%;
  transform: translate(-50%, -50%) rotate(180deg);
  }

Jsfiddle: Demo