#problems::-webkit-scrollbar {
  width: 12px;   
             /* width of the entire scrollbar */
}

#problems::-webkit-scrollbar-track {
  background: #343F3E;
	border-radius:10px;         /* color of the tracking area */
}

#problems::-webkit-scrollbar-thumb {
  background-color: #DCEDFF;    /* color of the scroll thumb */
  border-radius: 20px;       /* roundness of the scroll thumb */
  border: 3px solid #31343A;  /* creates padding around scroll thumb */
}



		 * {
           		box-sizing: border-box;
            		box-sizing: padding-box;
        		}

		body {
            		padding: 10px; 
            		background-color: #343F3E;
			}

		 header {
			width: 90%;
			margin-left:auto;
			margin-right:auto;
        		}
		
		nav {
        
            		width: 90%;
					margin-left:auto;
					margin-right:auto;
            		border: solid 4px #8F91A2;
            		border-top-right-radius: 5px;
            		border-top-left-radius: 5px;
            		border-bottom: none;
        		}
        
           	 nav ul {
                    	list-style-type: none;
                    	margin: 0;
                    	padding: 0;
                    	overflow: hidden;
                    	background-color: #343F3E;
                    	}

           	 nav li {
            	        float: left;
                     	border-right:1px solid #bbb;
                    	}


            	nav li a {
                    	display: block;
                    	color: white;
                   	 text-align: center;
                   	padding: 14px 16px;
                    	text-decoration: none;
                    	}

            	nav li a:hover:not(.active) {
                    	background-color: #111;
                    	}

            	nav .active {
                    	/* background-color: #94B0DA ; color:black;*/
			color:#e19964;
                    	}
        
            	nav .active li a:hover{
                    	background-color: white;
			color:black;
                    	}



		#wrapper {
				border: solid 4px #8F91A2;
				border-top:none;
				border-bottom-right-radius: 10px;
            			border-bottom-left-radius: 10px;
				width:90%;
				margin-left:auto;
					margin-right:auto;
			}
		#top {
			width:100%; float:none; 
			}
			
			

		#bottom {
			width: 100%; float:none;
			}
		
		#writeUp {
			background-color:#DCEDFF;
			width:100%;
			padding:10px;
			float:left;
			
			border-bottom-right-radius: 10px;
            		border-bottom-left-radius: 10px;
			}

		#priorConcepts{
			background-color:#DCEDFF;
			width:100%;
			padding:10px;
			float:right;
			
			border-top-right-radius: 10px;
            		border-top-left-radius: 10px;
			}

		 #video {
            		width:100%;
            		float: left;
            		background-color:#94B0DA;
            		padding: 20px;
			border-top-right-radius: 10px;
			
        		}

		#practice {
			background-color:#339966;
			/* background-color:#94B0DA; */
			width:100%;
			padding:10px;
			float:right;
					
			}

				#prac_left {width: 40%; float:left;}
				#prac_right {width: 40%; float:right;}


		#problems {
			
			background-color:white;
			
			padding-left: 30px;
			border-radius:10px;
			width:100%;	
			}

			
		footer { 
			color: white;
			text-align: center;
			}

		footer a {
				color: #94B0DA;
			}