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HTML

              
                <header>  
  <h1>Flexbox Playground</h1>
    <a href="http://webdesignerwall.com/tutorials/master-css-flexbox-5-simple-steps" target="_blank">View Tutorial</a>
</header>

<!--Based on the lovely work by Gabi https://codepen.io/enxaneta, forked primarily for presentation, language and CSS adjustments -->
<section class="main" role="main">
  <div class="main-column">
  <h2>Flex Container Properties</h2>
  <!--flex-direction: controls -->  
  <div class="control">
    <h4><a href="https://developer.mozilla.org/en-US/docs/Web/CSS/flex-flow">flex-direction</a>   </h4>
  <div class="radio">
    <input name="flex-direction" type="radio"  class="flex-direction" id="R11" value="row" checked><label for="R11">row:</label>
  <input name="flex-direction"  type="radio" class="flex-direction" id="R12" value="row-reverse"><label for="R12">row-reverse:</label>
  <input name="flex-direction"  type="radio" class="flex-direction" id="R13" value="column"><label for="R13">column:</label>
  <input name="flex-direction"  type="radio" class="flex-direction" id="R14" value="column-reverse"><label for="R14">column-reverse:</label>
  </div>
</div>
<!--flex-direction: row | row-reverse | column | column-reverse;-->    
<div class="flex-container" id="direction">
  <div class="item" data-color="2a80b9">    
    <p>1</p></div>
  <div class="item" data-color="8f44ad">    
    <p>2</p></div>
  <div class="item" data-color="16a086">    
    <p>3</p></div>
  <div class="item" data-color="f1c40f">
    <p>4</p></div>
  <div class="item" data-color="e77e23">
    <p>5</p></div>
</div>

<!-- Flex Wrap: controls -->
  <div class="control">
    <h4><a href="https://developer.mozilla.org/en-US/docs/Web/CSS/flex-flow">flex-wrap</a></h4>
    <div class="radio">
      <input name="flex-wrap" type="radio"  class="flex-wrap" id="R21" value="nowrap" checked><label for="R21">nowrap:</label>
      <input name="flex-wrap" type="radio"  class="flex-wrap" id="R22" value="wrap">   
      <label for="R22">wrap:</label>
      <input name="flex-wrap" type="radio"  class="flex-wrap" id="R23" value="wrap-reverse"><label for="R23">wrap-reverse:</label>
    </div>
  </div>
    
 <!-- flex-wrap: nowrap | wrap | wrap-reverse -->   
<div class="flex-container" id="wrap">
  <div class="item" data-color="2a80b9">  
    <p>1</p></div>
  <div class="item" data-color="8f44ad">
    <p>2</p></div>
  <div class="item" data-color="16a086">
    <p>3</p></div>
  <div class="item" data-color="f1c40f">     
    <p>4</p></div>
  <div class="item" data-color="e77e23">
    <p>5</p></div>
</div>
<!-- Align Items: controls --> 
  <div class="control">
    <h4><a href="https://developer.mozilla.org/en-US/docs/Web/CSS/align-items">align-items</a></h4>
    <div class="radio">
      <input name="flex-align-items" type="radio"  class="flex-align-items" id="R31" value="align-items-start" ><label for="R31">flex-start:</label>
      <input name="flex-align-items" type="radio"  class="flex-align-items" id="R32" value="align-items-end"><label for="R32">flex-end:</label>
      <input name="flex-align-items" type="radio"  class="flex-align-items" id="R33" value="align-items-center"><label for="R33">center:</label>
      <input name="flex-align-items" type="radio"  class="flex-align-items" id="R34" value="align-items-baseline"><label for="R34">baseline:</label>
      <input name="flex-align-items" type="radio"  class="flex-align-items" id="R35" value="align-items-stretch" checked><label for="R35">stretch:</label>
    </div>
 </div>
<!-- align-items: flex-start | flex-end | center | baseline | stretch -->
<div class="flex-container" id="align">
  <div class="item" data-color="2a80b9"> 
    <p>1</p></div>
  <div class="item" data-color="8f44ad">
    <p>2</p></div>
  <div class="item" data-color="16a086">
    <p>3</p></div>
  <div class="item" data-color="f1c40f">
    <p>4</p></div>
  <div class="item" data-color="e77e23">
    <p>5</p></div>
</div>

<!-- Justify Content: controls-->
  <div class="control">
    <h4><a href="https://developer.mozilla.org/en-US/docs/Web/CSS/justify-content">justify-content</a>   </h4> 
    <div class="radio">
      <input name="justify-content" type="radio"  class="justify-content" id="R41" value="justify-start" checked >      <label for="R41">flex-start:</label>
      <input name="justify-content" type="radio"  class="justify-content" id="R42" value="justify-end" ><label for="R42">flex-end:</label>
      <input name="justify-content" type="radio"  class="justify-content" id="R43" value="justify-space-between" >    <label for="R43">space-between:</label>
      <input name="justify-content" type="radio"  class="justify-content" id="R44" value="justify-center" ><label for="R44">center:</label>
      <input name="justify-content" type="radio"  class="justify-content" id="R45" value="justify-space-around" ><label for="R45">space-around:</label>
    </div>
  </div>

<!--justify-content: flex-start | flex-end | center | space-between | space-around -->
<div class="flex-container" id="justify">
  <div class="item" data-color="2a80b9"> 
    <p>1</p></div>
  <div class="item" data-color="8f44ad">
    <p>2</p></div>
  <div class="item" data-color="16a086">
    <p>3</p></div>
  <div class="item" data-color="f1c40f">
    <p>4</p></div>
  <div class="item" data-color="e77e23">
    <p>5</p></div>
</div>

<!--Align Content: controls-->
  <div class="control">
    <h4><a href="https://developer.mozilla.org/en-US/docs/Web/CSS/align-content">align-content</a></h4> 
  <div class="radio">
    <input name="align-content" type="radio"  class="align-content" id="R51" value="align-content-start" ><label for="R51">flex-start:</label>
    <input name="align-content" type="radio"  class="align-content" id="R52" value="align-content-end" ><label for="R52">flex-end:</label>
    <input name="align-content" type="radio"  class="align-content" id="R53" value="align-content-center" ><label for="R53">center:</label>
    <input name="align-content" type="radio"  class="align-content" id="R54" value="align-content-space-between" ><label for="R54">space-between:</label>
    <input name="align-content" type="radio"  class="align-content" id="R55" value="align-content-space-around" ><label for="R55">space-around:</label>
    <input name="align-content" type="radio"  class="align-content" id="R56" value="align-content-stretch"  checked>  <label for="R56">stretch:</label>
    </div>
  </div>

<!--align-content: flex-start | flex-end | center | space-between | space-around; -->
<div class="flex-container" id="alignContent">
  <div class="item" data-color="1bbc9d">
    <p>1</p></div>
  <div class="item" data-color="2fcc71">
    <p>2</p></div>
  <div class="item" data-color="3598dc">
    <p>3</p></div>
  <div class="item" data-color="9c59b8">
    <p>4</p></div>
  <div class="item" data-color="34495e">
    <p>5</p></div>
  <div class="item" data-color="16a086">
    <p>6</p></div>
  <div class="item" data-color="27ae61">
    <p>7</p></div>
  <div class="item" data-color="2a80b9">
    <p>8</p></div>
  <div class="item" data-color="8f44ad">
    <p>9</p></div>
  <div class="item" data-color="2d3e50">
    <p>10</p></div>
  <div class="item" data-color="f1c40f">
    <p>11</p></div>
  <div class="item" data-color="e77e23">
    <p>12</p></div>
  <div class="item" data-color="e84c3d">
    <p>13</p></div>
  <div class="item" data-color="ecf0f1">
    <p>14</p></div>
  <div class="item" data-color="96a6a6">
    <p>15</p></div>
  <div class="item" data-color="f49c14">
    <p>16</p></div>
  <div class="item" data-color="d55401">
    <p>17</p></div>
  <div class="item" data-color="c1392b">
    <p>18</p></div>
  <div class="item" data-color="bec3c7">
    <p>19</p></div>
  <div class="item" data-color="808b8d">
    <p>20</p></div>
  </div>
    
</div><!-- End column -->

<!-- Flex Items -->
<div class="main-column">
  <h2>Flex Item Properties</h2>
  
  <!-- Align Self: controls -->
  <div class="control">
    <h4><a href="https://developer.mozilla.org/en-US/docs/Web/CSS/align-self">align-self</a></h4>
  <div class="radio">
    <input name="align-self" type="radio"  class="align-self" id="R61" value="align-self-auto"  checked ><label for="R61">auto:</label>
    <input name="align-self" type="radio"  class="align-self" id="R62" value="align-self-start" ><label for="R62">flex-start:</label>
    <input name="align-self" type="radio"  class="align-self" id="R63" value="align-self-end" ><label for="R63">flex-end:</label>
    <input name="align-self" type="radio"  class="align-self" id="R64" value="align-self-center" ><label for="R64">center:</label>
    <input name="align-self" type="radio"  class="align-self" id="R65" value="align-self-baseline" ><label for="R65">baseline: </label>
    <input name="align-self" type="radio"  class="align-self" id="R66" value="align-self-stretch"><label for="R66">stretch:</label>
   </div>
</div>
  
<!-- align-self: auto | flex-start | flex-end | center | baseline | stretch --> 
<div class="flex-container align-items-center" id="FCI1">
  <div class="item" data-color="f49c14">
    <p>1</p></div>
  <div class="item" data-color="d55401">
    <p>2</p></div>
  <div class="item" data-color="c1392b"  id="alignSelf"><p style="font-size:50px;">3</p></div>
  <div class="item" data-color="bec3c7">
    <p>4</p></div>
  <div class="item" data-color="808b8d">
    <p>5</p></div>
</div>

<!-- Flex Grow: Controls -->
<div class="control">
  <h4><a href="https://developer.mozilla.org/en-US/docs/Web/CSS/flex-grow">flex-grow</a></h4> 
  <div class="radio">
  <label for="R71">Item 1: </label>    
    <input type="number" class="flex-grow" id="R71" min="0" >
  <label for="R72">Item 2: </label>    
    <input type="number" class="flex-grow" id="R72" min="0" >
      <label for="R73">Item 3: </label>
    <input type="number" class="flex-grow" id="R73" min="0" >
      <label for="R74">Item 4: </label>    <input type="number" class="flex-grow" id="R74" min="0" >
    <label for="R75">Item 5: </label>   
  <input type="number" class="flex-grow" id="R75" min="0" >
    </div>
</div>
  
<!-- flex-grow: number -->  
<div class="flex-container align-items-center" id="FCI2">
  <div class="item" id="itemR71" data-color="f49c14"><p>1</p></div>
  <div class="item" id="itemR72" data-color="d55401"><p>2</p></div>
  <div class="item" id="itemR73" data-color="c1392b"><p>3</p></div>
  <div class="item" id="itemR74" data-color="bec3c7"><p>4</p></div>
  <div class="item" id="itemR75" data-color="808b8d"><p>5</p></div>
</div>

<!--Flex Shrink: controls -->
<div class="control">
  <h4><a href="https://developer.mozilla.org/en-US/docs/Web/CSS/flex-shrink">flex-shrink</a>   
  </h4> 
  <div class="radio">
    <label for="R81">Item 1: </label>        <input type="number"  class="flex-shrink" id="R81" min="0" >
    <label for="R82">Item 2: </label>        <input type="number" class="flex-shrink" id="R82" min="0" >
    <label for="R83">Item 3: </label>        <input type="number" class="flex-shrink" id="R83" min="0" >
    <label for="R84">Item 4: </label>        <input type="number" class="flex-shrink" id="R84" min="0" ><label for="R85">Item 5: </label>
    <input type="number" class="flex-shrink" id="R85" min="0">
  </div>
</div>
  
<!-- flex-shrink: number -->  
<div class="flex-container align-items-center" id="FCI3">
  <div class="item" id="itemR81" data-color="f49c14"><p>1</p></div>
  <div class="item" id="itemR82" data-color="d55401"><p>2</p></div>
  <div class="item" id="itemR83" data-color="c1392b"><p>3</p></div>
  <div class="item" id="itemR84" data-color="bec3c7"><p>4</p></div>
  <div class="item" id="itemR85" data-color="808b8d"><p>5</p></div>
</div>

<!-- Flex Basis: controls -->
<div class="control">
  <h4><a href="https://developer.mozilla.org/en-US/docs/Web/CSS/flex">flex</a>
  </h4> 
  <pre>.item { flex: flex-basis | flex-grow | flex-shrink; }</pre>
  <table id="flexBasis">
  <tr><td>Item 1</td><td>Item 2</td></tr>
  <tr><td>
    <input type="number" class="flex-basis" id="B1" min="0" value="50" ><label for="B1">flex-basis %</label></td><td><input type="number" class="flex-basis" id="B2" min="0" value="50" ><label for="B2">flex-basis %</label>
  </td></tr>
  <tr><td>
    <input type="number" class="flex-basis-grow" id="G1" min="0" value="0" >
    <label for="G1">flex-grow</label>
  </td><td>
    <input type="number" class="flex-basis-grow" id="G2" min="0" value="0" ><label for="G2">flex-grow</label></td></tr>
  <tr><td>
    <input type="number" class="flex-basis-shrink" id="S1" min="0" value="0" >
    <label for="S1">flex-shrink</label>
    </td>
    <td>
      <input type="number" class="flex-basis-shrink" id="S2" min="0" value="0" >
      <label for="S2">flex-shrink</label>
  </td></tr>
</table>
</div>

<!--flex: flex-grow | flex-shrink | flex-basis -->
<div class="flex-container align-items-center" id="FCI4">
  <div class="item" id="item1" data-color="f49c14"><p>1</p></div>
  <div class="item" id="item2" data-color="d55401"><p>2</p></div>
</div>

<!-- Order: controls -->
<div class="control">
  <h4><a href="https://developer.mozilla.org/en-US/docs/Web/CSS/order">order</a>
  </h4> 
  <div class="radio">
    <label for="R91">Item 1: </label>
      <input type="number" class="flex-order" id="R91" min="0" >
    <label for="R92">Item 2: </label>   
      <input type="number" class="flex-order" id="R92" min="0" >
    <label for="R93">Item 3: </label>   
      <input type="number" class="flex-order" id="R93" min="0" >
    <label for="R94">Item 4: </label>
      <input type="number" class="flex-order" id="R94" min="0" >
    <label for="R95">Item 5: </label>
      <input type="number" class="flex-order" id="R95" min="0" >
  </div>
</div>
  
   <!-- order: <integer>  -->
  <div class="flex-container align-items-center" id="FCI5">
    <div class="item" id="orderR91" data-color="f49c14"><p>1</p></div>
    <div class="item" id="orderR92" data-color="d55401"><p>2</p></div>
    <div class="item" id="orderR93" data-color="c1392b"><p>3</p></div>
    <div class="item" id="orderR94" data-color="bec3c7"><p>4</p></div>
    <div class="item" id="orderR95" data-color="808b8d"><p>5</p></div>
  </div>
  
  </div><!-- End column -->
</section>
              
            
!

CSS

              
                /*flex-direction: row | row-reverse | column | column-reverse;*/

.flex-container.row {
  -webkit-flex-direction: row;
  -ms-flex-direction: row;
  flex-direction: row;
}

.flex-container.row-reverse {
  -webkit-flex-direction: row-reverse;
  -ms-flex-direction: row-reverse;
  flex-direction: row-reverse;
}

.flex-container.column {
  -webkit-flex-direction: column;
  -ms-flex-direction: column;
  flex-direction: column;
}

.flex-container.column-reverse {
  -webkit-flex-direction: column;
  -ms-flex-direction: column;
  flex-direction: column-reverse;
}
#direction .item:nth-of-type(3),
#wrap .item:nth-of-type(3)
{
  height: 150px;
}

/*flex-wrap: nowrap | wrap | wrap-reverse;*/

.flex-container.nowrap {
  -webkit-flex-wrap: nowrap;
  -ms-flex-wrap: nowrap;
  flex-wrap: nowrap;
}

.flex-container.wrap {
  -webkit-flex-wrap: wrap;
  -ms-flex-wrap: wrap;
  flex-wrap: wrap;
}

.flex-container.wrap-reverse {
  -webkit-flex-wrap: wrap-reverse;
  -ms-flex-wrap: wrap-reverse;
  flex-wrap: wrap-reverse;
}


/*align-items: flex-start | flex-end | center | baseline | stretch;*/

.flex-container.align-items-start {
  -webkit-align-items: flex-start;
  -ms-flex-align: start;
  align-items: flex-start;
}

.flex-container.align-items-end {
  -webkit-align-items: flex-end;
  -ms-flex-align: end;
  align-items: flex-end;
}

.flex-container.align-items-center {
  -webkit-align-items: center;
  -ms-flex-align: center;
  align-items: center;
}

.flex-container.align-items-baseline {
  webkit-align-items: baseline;
  -ms-flex-align: baseline;
  align-items: baseline;
}

.flex-container.align-items-stretch {
  webkit-align-items: stretch;
  -ms-flex-align: stretch;
  align-items: stretch;
}


/*justify-content: flex-start | flex-end | center | space-between | space-around;*/

.flex-container.justify-start {
  -webkit-justify-content: flex-start;
  -ms-flex-pack: start;
  justify-content: flex-start;
}

.flex-container.justify-end {
  -webkit-justify-content: flex-end;
  -ms-flex-pack: end;
  justify-content: flex-end;
}

.flex-container.justify-center {
  -webkit-justify-content: center;
  -ms-flex-pack: center;
  justify-content: center;
}

.flex-container.justify-space-between {
  -webkit-justify-content: space-between;
  -ms-flex-pack: justify;
  justify-content: space-between;
}

.flex-container.justify-space-around {
  -webkit-justify-content: space-around;
  -ms-flex-pack: justify;
  justify-content: space-around;
}


/*align-content: flex-start | flex-end | center | space-between | space-around | stretch;*/

.flex-container.align-content-start {
  -webkit-align-content: flex-start;
  -ms-flex-line-pack: start;
  align-content: flex-start;
}

.flex-container.align-content-end {
  -webkit-align-content: flex-end;
  -ms-flex-line-pack: end;
  align-content: flex-end;
}

.flex-container.align-content-center {
  -webkit-align-content: center;
  -ms-flex-line-pack: center;
  align-content: center;
}

.flex-container.align-content-space-between {
  -webkit-align-content: space-between;
  -ms-flex-line-pack: justify;
  align-content: space-between;
}

.flex-container.align-content-space-around {
  -webkit-align-content: space-around;
  -ms-flex-line-pack: justify;
  /*distribute;*/
  align-content: space-around;
}

.flex-container.align-content-stretch {
  -webkit-align-content: stretch;
  -ms-flex-line-pack: stretch;
  align-content: stretch;
}


/*align-self: auto | flex-start | flex-end | center | baseline | stretch;*/

.item.align-self-auto {
  -webkit-align-self: auto;
  -ms-flex-item-align: auto;
  align-self: auto;
}

.item.align-self-start {
  -webkit-align-self: flex-start;
  -ms-flex-item-align: start;
  align-self: flex-start;
}

.item.align-self-end {
  -webkit-align-self: flex-end;
  -ms-flex-item-align: end;
  align-self: flex-end;
}

.item.align-self-center {
  -webkit-align-self: center;
  -ms-flex-item-align: center;
  align-self: center;
}

.item.align-self-baseline {
  -webkit-align-self: baseline;
  -ms-flex-item-align: baseline;
  align-self: baseline;
}

.item.align-self-stretch {
  -webkit-align-self: stretch;
  -ms-flex-item-align: stretch;
  align-self: stretch;
}

.item.flex-grow1 {
  flex-grow: 1;
}

.item.flex-grow2 {
  flex-grow: 2;
}

.item.flex-grow3 {
  flex-grow: 3;
}

.item.flex-grow4 {
  flex-grow: 4;
}

/* Flex Demos */

.flex-container {
 border: 0.25rem dashed #ccc;
 display : -webkit-flex;
 display : -ms-flexbox;
 display : flex;
 padding: 1rem;
 width: 100%; 
  overflow: hidden;
 }

.item{
	margin: 0; 
  display: inherit;
	padding: 1rem; 
	width: 100px; 
	height: 100px;
	-webkit-align-items: center;
	-ms-flex-align: center;
	align-items: center;
}

.item p{
  width: 70px;
  height: 70px;
  text-align:center;
  font-size: 2rem;
  line-height: 70px;
  color: #777;
  background-color: #FFF;
  border-radius: 100%;
}
#direction .item{
  flex-wrap: wrap;
}

#align .item{
  height:auto; 
  height:auto;
  flex-wrap:wrap;
}	
#align .item:nth-of-type(3) p{
  font-size: 5vw;
}
#justify{ 
  margin: 1rem 0; 
  padding: 1rem 0;
}

#alignContent{flex-wrap:wrap; height:600px;}
#alignContent .item{ height:auto;} 
/* General styles */

html,body{ 
  width: 100%; 
  min-height: 100%; 
  margin: 0; 
  padding: 0; 
  color: #555; 
  font-family: sans-serif;
  /* Permalink - use to edit and share this gradient: http://colorzilla.com/gradient-editor/#fcfff4+0,e9e9ce+100;Wax+3D+%232 */
background: #fcfff4; /* Old browsers */
background: -moz-linear-gradient(left,  #fcfff4 0%, #e9e9ce 100%); /* FF3.6-15 */
background: -webkit-linear-gradient(left,  #fcfff4 0%,#e9e9ce 100%); /* Chrome10-25,Safari5.1-6 */
background: linear-gradient(to right,  #fcfff4 0%,#e9e9ce 100%); /* W3C, IE10+, FF16+, Chrome26+, Opera12+, Safari7+ */
filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#fcfff4', endColorstr='#e9e9ce',GradientType=1 ); /* IE6-9 */

}

*{
	box-sizing : border-box; 
}
/* Main Layout */
.main{
  display: flex;
  flex-direction: row; 
  flex-wrap: wrap;
}
.main-column{ 
  width: calc(100% - 20px); 
  min-width: 300px; 
  margin: 20px; 
}

/* Controls */
.radio{ margin-bottom:20px;}
label{ line-height:200%;}
input[type=radio] { color:white; }
input[type=radio]:checked + label { color:orange; }
input[type=number]{ width:40px; margin-right:.5em;}
h1{ font-size: 2rem;margin:20px;}
h2{ font-size: 1.6rem;margin:0px;}
h4 a{  font-size: 1rem; color:#999; text-decoration:none;}
h4 small{font-variant: normal; font-size: .8rem; font-weight:normal; color:#57bcdb;}
table{ width:100%; margin-bottom:1em;}
table td{ width:50%; padding:3px;}
.principal:last-of-type h4 small{ color:#ff8080;}
#FCI1{ min-height:300px;}
#FCI1 .item{ height:auto;}
#FCI3 .item{ width:25%;}
#FCI4 .item{ width:50%;}
#FCI5 .item{ width:20%;}


@media only screen and (max-width:580px) {
  .item{ 
    width:70px;
    height:70px;
  }
  .main-column{ 
    width: calc(100% - 40px); 
    min-width: initial;
  }
  .flex-container{
    width:100vw;  
    min-width: initial;
  }	
  .item p{
    width: 40px;
    height: 40px;
    display: block;
    font-size: 4vw;
    line-height: 40px;
    color: #777;
    background-color: #FFF;
    border-radius: 100%;
  }
}

/* General style */
header{
  width: 100%;
  display: block;
  background: #FFF;
  height: 40px;
  margin-bottom: 2%;
  color: #ccc;
  font-family: sans-serif;
  font-weight: bold;
  box-shadow: 0px 2px 0px 0px rgba(125,121,125,0.3);
  overflow: hidden;
}
header h1, header a{
  display: inline-block;
  font-size: .8rem;
  margin: auto 10px;
  line-height: 40px;

}
header h1{
    text-transform: uppercase;
    letter-spacing: 1px;
}
header a{
  text-decoration: none;
  background-color: #eee;
  color: #999;
  padding: 0 20px;
  transition: all ease-in-out .3s;
}
header a:hover{
  background-color: rgb(42, 128, 185);
  color: #eee;
  margin-left: -3px;
}
              
            
!

JS

              
                function changeFlex(e, t) {
  for (var n = document.querySelectorAll("." + e), l = document.querySelector("#" + t), r = 0; r < n.length; r++) n[r].addEventListener("change", function() {
    var e = this.value;
    l.setAttribute("class", "flex-container " + e)
  }, !1)
}

function changeItemFlex(e, t) {
  for (var n = document.querySelectorAll("." + e), l = document.querySelector("#" + t), r = 0; r < n.length; r++) n[r].addEventListener("change", function() {
    var e = this.value;
    l.setAttribute("class", "item " + e)
  }, !1)
}

function changeFlexBasis(e, t) {
  var n = isNaN(e.value) ? 0 : e.value;
  console.log("B: " + n), document.querySelector("#" + t).style.WebkitFlexBasis = n + "%", document.querySelector("#" + t).style.flexBasis = n + "%"
}

function changeFlexGrow(e, t) {
  var n = isNaN(e.value) ? 0 : e.value;
  console.log("G: " + n), document.querySelector("#" + t).style.WebkitFlexGrow = n, document.querySelector("#" + t).style.flexGrow = n
}

function changeFlexShrink(e, t) {
  var n = isNaN(e.value) ? 0 : e.value;
  console.log("S: " + n), document.querySelector("#" + t).style.WebkitFlexShrink = n, document.querySelector("#" + t).style.flexShrink = n
}

function changeFlexOrder(e, t) {
  var n = isNaN(e.value) ? 0 : e.value;
  console.log("O: " + n), document.querySelector("#" + t).style.WebkitOrder = n, document.querySelector("#" + t).style.order = n
}

function changeAll(e, t, n, l) {
  changeFlexBasis(e, l), changeFlexGrow(t, l), changeFlexShrink(n, l)
}
for (var items = document.querySelectorAll(".item"), i = 0; i < items.length; i++)
  if (items[i].hasAttribute("data-color")) {
    var color = items[i].getAttribute("data-color");
    items[i].style.backgroundColor = "#" + color
  }
for (var flexO = document.querySelectorAll(".flex-order"), o = 0; o < flexO.length; o++) flexO[o].addEventListener("change", function() {
  changeFlexOrder(this, "order" + this.id)
}, !1);
changeFlex("flex-direction", "direction"), changeFlex("flex-wrap", "wrap"), changeFlex("flex-align-items", "align"), changeFlex("justify-content", "justify"), changeFlex("align-content", "alignContent"), changeItemFlex("align-self", "alignSelf");
for (var flexGrow = document.querySelectorAll(".flex-grow"), i = 0; i < flexGrow.length; i++) flexGrow[i].addEventListener("change", function() {
  var e = "item" + this.id;
  changeFlexGrow(this, e)
});
for (var flexShrink = document.querySelectorAll(".flex-shrink"), j = 0; j < flexShrink.length; j++) flexShrink[j].addEventListener("change", function() {
  var e = "item" + this.id;
  changeFlexShrink(this, e)
});
var B1 = document.querySelector("#B1"),
  G1 = document.querySelector("#G1"),
  S1 = document.querySelector("#S1"),
  B2 = document.querySelector("#B2"),
  G2 = document.querySelector("#G2"),
  S2 = document.querySelector("#S2");
B1.addEventListener("change", function() {
  changeAll(B1, G1, S1, "item1")
}), G1.addEventListener("change", function() {
  changeAll(B1, G1, S1, "item1")
}), S1.addEventListener("change", function() {
  changeAll(B1, G1, S1, "item1")
}), B2.addEventListener("change", function() {
  changeAll(B2, G2, S2, "item2")
}), G2.addEventListener("change", function() {
  changeAll(B2, G2, S2, "item2")
}), S2.addEventListener("change", function() {
  changeAll(B2, G2, S2, "item2")
});
              
            
!
999px

Console