.lesson-content.theory 
{
  position: relative; /* nécessaire pour positionner le ::before */

  margin-top: 5px;    
  margin-left: 1.7em;    
  margin-right: .4em;    
  padding-top: 0px; 
  padding-left: .7em;


  font-family: Georgia, serif;
  font-size: 1.4em;


  color: rgb(50,50,50);  

  border-left: solid 1.1em rgba(100, 200,255, 1);   
  border-right: solid 5px rgba(100, 200,255, 1);  
  border-bottom: 2px solid rgba(100, 200,255, 1);
  border-radius: 5px 5px 5px 1em;    

  background-color: #fffdf6; 

  background-image: linear-gradient(
    to right,
    transparent 0px,
    transparent 10px,
    rgba(200,100,0) 10px,
    rgba(200,100,0) 12px,
    transparent 12px
  ),

  /* Trait vertical à gauche */
  linear-gradient(to right, rgba(0,0,0,1) 1px, transparent 1px),


  linear-gradient(to bottom, #d0e1ff 1px, transparent 2px);


  background-size: 100% 24px;  /* distance entre les lignes */

  text-shadow:
      -1px 0px 0px rgb(200,225,255),
      1px 0px 0px rgb(200,225,255),      
      0px -1px 0px rgb(200,255,255),      
       0px 1px 0px rgb(200,225,255);



  box-shadow: -2px -1px 1px rgba(0,0,0,1),
              0px 1px 1px rgba(0,0,0,1),  
              -6px 1px 0px rgba(0,100,255,1),                
              1px 0px 0px rgba(0,0,0,1),                              
              4px 2px 3px rgba(0,0,0,0.4);


}

.lesson-content.theory  p u {

  margin-top: 10px;
  padding-right: 0.5em;  
  padding-top: 0px;      
  padding-left: 2px;    
  padding-bottom: 10px;

  border-bottom: solid 1px;
  border-radius: 0px 10px 0px 10px;

  background-color: rgba(100,100,100,0.1); 

  background-image: linear-gradient(
    to bottom,
    rgba(255,255,255,0.0),
    rgba(255,255,255,0.0),    
    rgba(200,100,0,0.1)
  );


  box-shadow: 0px 1px 1px rgba(0, 0, 0, 1);    
}



.lesson-content.theory::before {
    content: "➤"; /*∴🧭ℹ️📘🔷📖➤🟩✦∴*/
    position: absolute;
    left: -50px; 
    top: 30%;  
    padding: 5px;
    font-size: 20px;
    align-self: flex-start;
    border: solid 1px;        
    border-bottom: solid 3px rgb(0,155,255);
    background-color: white;
    box-shadow: 2px 2px 4px rgba(0, 0, 0, 1);    

}