*{  
    margin: 0;
    padding: 0;
    font-family: "Poppins",sans-serif;
    box-sizing: border-box;

}
.container{
    width:100%;
    min-height:100vh;
    background: linear-gradient(135deg,#153,#fff000);
    padding:10px;
}

.todo-app{
    width:100%;
    max-width:540px;
    background: white;
    margin: 100px auto 20px;
    padding: 40px 30px 70px; /*top, left right, bottom*/
    border-radius: 10px; /*round corners */
}

.todo-app h2{
color:#000000;
display:flex;
align-items:center;
margin: 20px;
}

.todo-app h2 img{
width: 100px;
margin-left: 10px;
}

.row{
    display: flex;
    align: center;
    justify-content:space-between;
    background: #edeef0;
    border-radius: 30px;
    padding-left: 20px;
    margin-bottom: 25px;
}
input{
    flex:1;
    border: none;
    outline: none;
    background: transparent;
    padding: 10px;

}
button{
    border:none;
    outline:none;
    padding: 16px 50px;
    background:#cecb20;
    color:#000000;
    font-size: 16px;
    cursor: pointer;
    border-radius: 40px;
}
ul li {
    list-style: none;
    font-size: 17px;
    padding: 12px 8px 12px 50px;
    user-select: none;
    cursor: pointer;
    position: relative;
}
ul li::before{
    content:" ";
    position:absolute;
    height: 28px;
    width: 28px;
    border-radius: 50%;
    background-image: url(unchecked.png);
    background-size: cover;
    background-position: center;
    top: 12px;
    left: 8px;
}
ul li.checked{
    color: #555;
    text-decoration: line-through;
}
ul li.checked::before{
    background-image: url(checked.jpeg);
}
ul li span{
    position: absolute;
    right: 0;
    top:5px;
    width: 40px;
    height:40px;
    font-size: 22px;
    color:#555;
    line-height: 40px;
    text-align: center;
    border-radius:50%;
}
ul li span:hover{
    background:#edeef0;
}