Check out example codes for "formatting checkbox css". It will help you in understanding the concepts better.

Code Example 1

/* Customize the label (the container) */
.container {
  display: block;
  
  position: relative;
  padding-left: 35px;
  margin-bottom: 
  12px;
  cursor: pointer;
  font-size: 22px;
  -webkit-user-select: 
  none;
  -moz-user-select: none;
  -ms-user-select: none;
  
  user-select: none;
}

/* Hide the 
  browser's default checkbox */
.container input {
  position: absolute;
  
  opacity: 0;
  cursor: pointer;
  height: 0;
  width: 
  0;

  }

  
/* Create a custom checkbox */
.checkmark {
  position: 
  absolute;
  top: 0;
  left: 0;
  height: 25px;
  
  width: 25px;
  background-color: #eee;
}

/* On mouse-over, add a grey background color */
.container:hover 
  input ~ .checkmark {
  background-color: #ccc;
}

/* When the 
  checkbox is checked, add a blue background */
.container input:checked ~ 
  .checkmark {
  background-color: #2196F3;
}

/* Create the 
  checkmark/indicator (hidden when not checked) */
.checkmark:after {
  
  content: "";
  position: absolute;
  display: none;
}

/* Show the 
  checkmark when checked */
.container input:checked ~ .checkmark:after {
  
  display: block;
}

/* Style the checkmark/indicator */
.container 
  .checkmark:after {
  left: 9px;
  top: 5px;
  width: 
  5px;
  height: 10px;
  border: solid white;
  
  border-width: 0 3px 3px 0;
  -webkit-transform: rotate(45deg);
  
  -ms-transform: rotate(45deg);
  transform: rotate(45deg);
}

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