Using pseudo element before to realize equal scaling of elements

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       <
       
       style
       
       >
       
       
             
       
       /* Scale proportionally */
       
       
                    
       
       .box{
       
       
                    
       
       position: 
       
       relative;
       
       
                    
       
       width: 
       
       100%;     
       
       /* desired width */
       
       
                    
       
       background: 
       
       #000;
       
       
                    
       
       color: 
       
       #fff;
       
       
                }
       
       
                
       
       .box:
       
       before{
       
       
                    
       
       content: 
       
       "";
       
       
                    
       
       display: 
       
       block;
       
       
                    
       
       padding-top: 
       
       30%; 
       
       
                    
       
       background: 
       
       #f00;
       
       
                }
       
       
                
       
       .content{
       
       
                    
       
       position:  
       
       absolute;
       
       
                    
       
       top: 
       
       0;
       
       
                    
       
       left: 
       
       0;
       
       
                    
       
       bottom: 
       
       0;
       
       
                    
       
       right: 
       
       0;
       
       
                }
       
       
        
       
       </
       
       style
       
       >
       
       
     
       
       
     
       
       
        
       
       <
       
       div 
       
       class=
       
       'box'
       
       >
       
       
              
       
       <
       
       div 
       
       class=
       
       'content'
       
       >1:1
       
       </
       
       div
       
       >
       
       
            
       
       </
       
       div
       
       >
      
      
      
      

       
       
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