html {
    background: rgba(1, 130, 255, 0.5);
    background: -webkit-linear-gradient(bottom, rgba(1, 130, 255, 0.5), rgba(232, 241, 249, 0.5));
    background: -moz-linear-gradient(bottom, rgba(1, 130, 255, 0.5), rgba(232, 241, 249, 0.5));
    background: linear-gradient(to top, rgba(1, 130, 255, 0.5), rgba(232, 241, 249, 0.5));
    background-repeat: no-repeat;
    background-size: cover;
    width: 100%;
    height: 100%;
}

body {
    font-family: 'Quicksand', sans-serif;
}

#container {
    background-color: #f7f7f7;
    width: 40%;
    margin: 10% 30%;
}

h1 {
    background-color: dodgerblue;
    color: whitesmoke;
    text-transform: uppercase;
    padding: 10px 20px;
    margin: 0;
}

.add-input {
    float: right;
}

input {
    color: gray;
    font-family: inherit;
    font-size: 17px;
    font-weight: bolder;
    letter-spacing: 1px;
    border: none;
    width: 100%;
    padding: 20px 20px;
    margin: 0 0;
    box-sizing: border-box;
    outline: none;
}

ul {
    list-style: none;
    padding: 0;
    margin: 0;
}

li {
    color: gray;
    font-size: 18px;
    height: 60px;
    line-height: 60px;
    padding: 0;
}

li:nth-child(2n) {
    background-color: white;
}

.done {
    color: grey;
    text-decoration: line-through;
}

span {
    background-color: red;
    height: 100%;
    width: 0;
    display: inline-block;
    text-align: center;
    margin-right: 20px;
    opacity: 0;
    transition: 0.2s linear;
}

li:hover span {
    width: 60px;
    opacity: 1;
}

.delete-todo {
    color: white;
    font-size: 25px;
    border: none;
    padding: 10px;
}

@media only screen and (max-width: 767px) {
    #container {
        width: 80%;
        margin: 20% 10%;
    }
}