style.css

body{
	background-color:#34495e;
	}

#container
{ 
 	width:350px;
 	height: auto;
 	margin:0 auto;
 	text-align: center; 
 	background: white;
 	height: 700px; 
 	overflow-y: auto; 
 	color:black;
 	border:10px
 	solid #01a3a4; 
 	border-radius: 10px; 
}

#container h1
{ 
	margin-top: 50px;
 	margin-bottom: 50px; 
 	text-transform: uppercase;
} 

#container ul
{
	margin-top: 50px; 
	padding-left: 0;
}

#container ul li
{
    list-style: none;
    border: 2px
    solid #b5c5dd;
    width: 80%;
    opacity: 50;
    transition: opacity 0.5s ease-in-out;
    height: 40px;
    margin: 5px auto;
    text-align: left;
}

#container ul li label
{
  	margin: 0 auto;
    vertical-align: middle;
    height: 100%;
    line-height: 40px;
    font-size: 18px;
}

#container ul li #check
{
	float: left;
	width: 30px;
	height: 30px;
	margin: 5px;
	-webkit-appearance: none;
	border: 2px solid #b5c5dd;
	position: relative;
	outline: 0;
}

#container ul li #check:checked::after
{
	content: '\2714';
    font-size: 20px;
    position: absolute;
    top: 0px;
    left: 7px;
    color:black;
}
 	            
#container ul li input[type="checkbox"]:checked+label
{
 	text-decoration: line-through;
 	color:rgba(0,0,0,0.3);
}
 	              
#container .controls
{
    width: 60%;
    margin: auto;
}
 	             
#container .controls #input
{   width: 100%;
    height: 30px;
    font-size: 20px;
    padding-left: 5px;
    box-sizing: border-box;
    margin-bottom: 20px;
    border:2px solid #b5c5dd;
    border-radius: 10px;
}
 	             
#container .controls #input:focus
{ 
	outline: 0;
}
#container .controls button
{ 
	width:100%;
	background: white;
	border: none;
	height: 30px;
	margin-top: 2px;
	cursor: pointer;
	color: white;
}

#container .controls button:focus
{
	outline: 0;
}

#container .controls button:hover
{ 
	transform: scale(1.25);
} 

#container .controls #add
{	
	background-color: #2980b9;
	border-radius: 130px;
}

#container .controls #remove
{ 
	background-color: #c0392b;
	border-radius: 130px;
}

#container .mycheck
{ 
	opacity: 1;
	border-radius: 10px;
}

.visual
{ 
	opacity: 1 !important;
	border-radius: 10px;
}