*{
    margin: 0;
    padding: 0;
    font-family: 'Poppins', sans-serif;
    box-sizing: border-box;  /*check*/
}
 .container{
    width: 100%;
    height: 100vh;
    background: radial-gradient(circle at center, rgb(238, 134, 134) 0, rgb(194, 12, 12) 100%);
    padding: 10px;
 }

 .todo{
    width: 100%;
    background: #fff;
    max-width: 540px;
    margin: 100px auto 20px;
    padding: 40px 30px 70px;
    border-radius: 10px;
 }

 .todo h2 img{
    width: 30px;
    margin-left: 10px;
 }

 .todo h2{
    color: #002765;
    display: flex; /*check*/
    align-items: center;
    margin-bottom: 20px;
 }

 .row{
    display: flex;  /*check*/
    align-items: center;
    justify-content: space-between;
    background: #edeef0;
    border-radius: 30px;
    padding-left: 20px;
    margin-bottom: 25px;
 }

 input{
    flex: 1;
    border: none;
    outline: none;  /*check*/
    background: transparent;  /*check*/
    padding: 10px;
 }

 button{
    border: none;
    outline: none;
    padding: 16px 50px;
    background: rgb(234, 30, 30);
    color: #fff;
    font-size: 16px;
    cursor: pointer;
    border-radius: 40px;
 }

 ul li{
    list-style: none;
    font-size: 17px;
    user-select: none;  /*check*/
    cursor: pointer;
    padding: 12px 8px 12px 50px;
    position: relative; /*check*/
 }

 ul li::before{ /*check*/
    content: '';    /*check*/
    position: absolute; /*check*/
    height: 28px;
    width: 28px;
    border-radius: 50%; /*check*/
    background-image: url(../images/unchecked.png);
    background-size: cover; /*check*/
    background-position: center;    /*check*/
    top: 12px;  /*check*/
    left: 8px;
 }

 ul li.checked{
    color: #555;
    text-decoration: line-through;
 }

 ul li.checked::before{
    background-image: url(../images/checked.png);
 }

 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;
 }