main
{
	font-size:1.2em;	
	margin-top:1.0em;	    
	margin-left:1.0em;	
  	margin-right: 1em;			

	border-left:solid 15px rgb(0, 0, 0,1);
	border-right:solid 15px rgb(0, 0, 0,1);						
	border-top:solid 2px rgb(0, 0, 0,0.8);
	border-bottom:solid 4px rgb(0, 0, 0,1);    
	border-radius:1.0em 1.0em 1.0em 1.0em;


	background-color: rgba(200,255,255,0.2);
	background-image:
		linear-gradient(90deg, transparent 97%, #abced4 97%, #abced4 99%,
         transparent 99%);


	box-shadow: 4px 8px 8px rgba(0, 0, 0, 0.5);	
/*opacity: 0.5;*/
    

}

main .lesson-block
{
	margin-top:0.5em;			
	margin-left:1em;	
	margin-right:5em;		
}

main h2 {

  	display: inline-block;
    position: relative;
  	margin: 0;	
  	margin-left: -1.5em;	      
	padding-top:0;	    			
	padding-bottom:.2em;	    			
	padding-top:.4em;	    				
  	padding-left: 1.0em;	
  	padding-right: 1.0em;	  	
  	font-weight: bold;
  	font-size: 1.4em;

	color: rgba(255,255,255,1);  


   	text-shadow: 1px 1px 0px black, 0 0 1px blue, 0 0 0.2em blue;				

  	border-left: solid 4px rgba(0,0,0);
	border-top:solid 1px rgb(0, 0, 0,1);        
	border-bottom:solid 1px rgb(0, 0, 0,1);        
  	border-radius: 0.2em 1.0em 0px 0px;	

  	font-family: "Courier New", monospace;

	background-color: #f0ffff;
    background: linear-gradient( to right, rgba(0, 100, 200,0.3), rgba(0, 200,200,0.05));	

	box-shadow: 2px 0px 2px rgba(100, 100, 200, 1);    
}

main h2::before {
    content: "";
    position: absolute;
    inset: 0;   /* top:0; right:0; bottom:0; left:0; */
    pointer-events: none;  /* ne gêne pas les clics */
    background-image: repeating-linear-gradient(
        45deg,
        rgba(255, 255, 255, 0.2),
        rgba(255, 255, 255, 0.2) 20px,
        transparent 20px,
        transparent 40px
    );
    z-index: 10;  /* au-dessus du fond mais en dessous du contenu */
}