*{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body{
    font-family:Arial, Helvetica, sans-serif;
}
.container{
    width: 100%;
    min-height: 100vh;
    background: linear-gradient(135deg, #153677, #4e085f);
    padding: 10px;
    display: flex;
    justify-content: center;
    align-items: center;
}
.todo-app{
    width: 100%;
    max-width: 540px;
    background-color: #fff;
    padding: 40px 30px;
    border-radius: 10px;
    flex-direction: column;
}
.app-title h2, .app-title i{
    display: flex;
    color: #002765;
}
.app-title{
    font-size: 26px;
}
.row{
    display: flex;
    align-items: center;
    justify-items: center;
    background-color: #edeef0;
    border-radius: 30px;
}
input{
    width: 100%;
    border: none;
    outline: none;
    padding: 12px;
    font-size: 17px;
    background-color: transparent;
    padding-left: 20px;
}
button{
    border: none;
    cursor: pointer;
    outline: none;
    padding: 15px 50px;
    border-radius: 30px;
    background-color: #ff5945;
    color: #fff;
    font-size: 18px;
    transition: all .25s ease;
}
button:hover{
    filter: brightness(.8);
}

@media screen and (max-width: 400px) {
    button{
        padding: 15px;
        border-radius: 0 30px 0;
    }
}

ul{
    list-style: none;
}

ul li{
    font-size: 17px;
    padding: 12px 8px 12px 50px;
    margin-top: 5px;
    user-select: none;
    cursor: pointer;
    position: relative;
}

ul li::before{
    position: absolute;
    content: '';
    width: 24px;
    height: 24px;
    border-radius: 50%;
    left: 0;
    border: 2px solid #ff5945;
}

ul .checked{
    color: #555;
    text-decoration: line-through;
}
span{
    position: absolute;
    right: 0;
    top: 50%;
    transform: translateY(-50%);
    width: 30px;
    height: 30px;
    border-radius: 50%;
    display: flex;
    justify-content: center;
    align-items: center;
    color: #555;
    font-size: 18px;
    transition: all .2s ease;
}
span:hover{
    background-color: #c9c9c9;
    color: #fff;
}