body {
    background-color: gray;
}

.todo-list {
    color: black;
    background-color: rgba(0, 0, 0, 0.21) 
}

a {
    text-decoration: none;
}

a:link {
    text-decoration: none;
    color: red;
}

a:visited {
    text-decoration: none;
    color: green;
}

a:hover {
    text-decoration: none;
    color: hotpink;
}

a:active {
    text-decoration: outline;
    color: blue;
} 

a:focus {
    outline: 2px solid orange; 
    outline-offset: 2px;       
}