How to style a checkbox using CSS

Answer 1

Here is an example, with theme support. It is a modern approach with CSS transitions. There is absolutely no JavaScript required.

I derived the following code linked in this comment; on a related question.

Edit: I added radio buttons, as maxshuty suggests.

const selector = '.grid-container > .grid-row > .grid-col[data-theme="retro"]';
const main = () => {
  new CheckboxStyler().run(selector);
  new RadioStyler().run(selector);
};

/*
 * This is only used to add the wrapper class and checkmark span to an existing DOM,
 * to make this CSS work.
 */
class AbstractInputStyler {
  constructor(options) {
    this.opts = options;
  }
  run(parentSelector) {
    let wrapperClass = this.opts.wrapperClass;
    let parent = document.querySelector(parentSelector) || document.getElementsByTagName('body')[0];
    let labels = parent.querySelectorAll('label');
    if (labels.length) labels.forEach(label => {
      if (label.querySelector(`input[type="${this.opts._inputType}"]`)) {
        if (!label.classList.contains(wrapperClass)) {
          label.classList.add(wrapperClass);
          label.appendChild(this.__createDefaultNode());
        }
      }
    });
    return this;
  }
  /* @protected */
  __createDefaultNode() {
    let checkmark = document.createElement('span');
    checkmark.className = this.opts._activeClass;
    return checkmark;
  }
}

class CheckboxStyler extends AbstractInputStyler {
  constructor(options) {
    super(Object.assign({
      _inputType: 'checkbox',
      _activeClass: 'checkmark'
    }, CheckboxStyler.defaultOptions, options));
  }
}
CheckboxStyler.defaultOptions = {
  wrapperClass: 'checkbox-wrapper'
};

class RadioStyler extends AbstractInputStyler {
  constructor(options) {
    super(Object.assign({
      _inputType: 'radio',
      _activeClass: 'pip'
    }, RadioStyler.defaultOptions, options));
  }
}
RadioStyler.defaultOptions = {
  wrapperClass: 'radio-wrapper'
};

main();

/* Theming */

:root {
  --background-color: #FFF;
  --font-color: #000;
  --checkbox-default-background: #EEE;
  --checkbox-hover-background: #CCC;
  --checkbox-disabled-background: #AAA;
  --checkbox-selected-background: #1A74BA;
  --checkbox-selected-disabled-background: #6694B7;
  --checkbox-checkmark-color: #FFF;
  --checkbox-checkmark-disabled-color: #DDD;
}

[data-theme="dark"] {
  --background-color: #111;
  --font-color: #EEE;
  --checkbox-default-background: #222;
  --checkbox-hover-background: #444;
  --checkbox-disabled-background: #555;
  --checkbox-selected-background: #2196F3;
  --checkbox-selected-disabled-background: #125487;
  --checkbox-checkmark-color: #EEE;
  --checkbox-checkmark-disabled-color: #999;
}

[data-theme="retro"] {
  --background-color: #FFA;
  --font-color: #000;
  --checkbox-default-background: #EEE;
  --checkbox-hover-background: #FFF;
  --checkbox-disabled-background: #BBB;
  --checkbox-selected-background: #EEE;
  --checkbox-selected-disabled-background: #BBB;
  --checkbox-checkmark-color: #F44;
  --checkbox-checkmark-disabled-color: #D00;
}


/* General styles */

html {
  width: 100%;
  height: 100%;
}

body {
  /*background: var(--background-color); -- For demo, moved to column. */
  /*color:      var(--font-color);       -- For demo, moved to column. */
  background: #777;
  width: calc(100% - 0.5em);
  height: calc(100% - 0.5em);
  padding: 0.25em;
}

h1 {
  font-size: 1.33em !important;
}

h2 {
  font-size: 1.15em !important;
  margin-top: 1em;
}


/* Grid style - using flex */

.grid-container {
  display: flex;
  height: 100%;
  flex-direction: column;
  flex: 1;
}

.grid-row {
  display: flex;
  flex-direction: row;
  flex: 1;
  margin: 0.25em 0;
}

.grid-col {
  display: flex;
  flex-direction: column;
  height: 100%;
  padding: 0 1em;
  flex: 1;
  margin: 0 0.25em;
  /* If not demo, remove and uncomment the body color rules */
  background: var(--background-color);
  color: var(--font-color);
}

.grid-cell {
  width: 100%;
  height: 100%;
}


/* The checkbox wrapper */

.checkbox-wrapper,
.radio-wrapper {
  display: block;
  position: relative;
  padding-left: 1.5em;
  margin-bottom: 0.5em;
  cursor: pointer;
  -webkit-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  user-select: none;
}


/* Hide the browser's default checkbox and radio buttons */

.checkbox-wrapper input[type="checkbox"] {
  position: absolute;
  opacity: 0;
  cursor: pointer;
  height: 0;
  width: 0;
}

.radio-wrapper input[type="radio"] {
  position: absolute;
  opacity: 0;
  cursor: pointer;
  height: 0;
  width: 0;
}


/* Create a custom checkbox */

.checkbox-wrapper .checkmark {
  position: absolute;
  top: 0;
  left: 0;
  height: 1em;
  width: 1em;
  background-color: var(--checkbox-default-background);
  transition: all 0.2s ease-in;
}

.radio-wrapper .pip {
  position: absolute;
  top: 0;
  left: 0;
  height: 1em;
  width: 1em;
  border-radius: 50%;
  background-color: var(--checkbox-default-background);
  transition: all 0.2s ease-in;
}


/* Disabled style */

.checkbox-wrapper input[type="checkbox"]:disabled~.checkmark,
.radio-wrapper input[type="radio"]:disabled~.pip {
  cursor: not-allowed;
  background-color: var(--checkbox-disabled-background);
  color: var(--checkbox-checkmark-disabled-color);
}

.checkbox-wrapper input[type="checkbox"]:disabled~.checkmark:after,
.radio-wrapper input[type="radio"]:disabled~.pip:after {
  color: var(--checkbox-checkmark-disabled-color);
}

.checkbox-wrapper input[type="checkbox"]:disabled:checked~.checkmark,
.radio-wrapper input[type="radio"]:disabled:checked~.pip {
  background-color: var(--checkbox-selected-disabled-background);
}


/* On mouse-over, add a grey background color */

.checkbox-wrapper:hover input[type="checkbox"]:not(:disabled):not(:checked)~.checkmark,
.radio-wrapper:hover input[type="radio"]:not(:disabled):not(:checked)~.pip {
  background-color: var(--checkbox-hover-background);
}


/* When the checkbox is checked, add a blue background */

.checkbox-wrapper input[type="checkbox"]:checked~.checkmark,
.radio-wrapper input[type="radio"]:checked~.pip {
  background-color: var(--checkbox-selected-background);
}


/* Create the checkmark/indicator (hidden when not checked) */

.checkbox-wrapper .checkmark:after {
  display: none;
  width: 100%;
  position: absolute;
  text-align: center;
  content: "\2713";
  color: var(--checkbox-checkmark-color);
  line-height: 1.1em;
}

.radio-wrapper .pip:after {
  display: none;
  width: 100%;
  position: absolute;
  text-align: center;
  content: "\2022";
  color: var(--checkbox-checkmark-color);
  font-size: 1.5em;
  top: -0.2em;
}


/* Show the checkmark when checked */

.checkbox-wrapper input[type="checkbox"]:checked~.checkmark:after {
  display: block;
  line-height: 1.1em;
}

.radio-wrapper input[type="radio"]:checked~.pip:after {
  display: block;
  line-height: 1.1em;
}

  

    

      

        
Pure CSS
        
Checkbox
        One
          
          
        
        Two
          
          
        
        Three
          
          
        
        Four
          
          
        
        
Radio
        One
          
          
        
        Two
          
          
        
        Three
          
          
        
        Four
          
          
        
      
    
    

      

        
Pure CSS
        
Checkbox
        One
          
          
        
        Two
          
          
        
        Three
          
          
        
        Four
          
          
        
        
Radio
        One
          
          
        
        Two
          
          
        
        Three
          
          
        
        Four
          
          
        
      
    
    

      

        
JS + CSS
        
Checkbox
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        Two   
        Three 
        Four  
        
Radio
        One   
        Two   
        Three 
        Four