style.css

body {
    font-family: 'Roboto', sans-serif;
    background: #BE93C5;  /* fallback for old browsers */
    background: -webkit-linear-gradient(to right, #7BC6CC, #BE93C5);  /* Chrome 10-25, Safari 5.1-6 */
    background: linear-gradient(to right, #7BC6CC, #BE93C5); /* W3C, IE 10+/ Edge, Firefox 16+, Chrome 26+, Opera 12+, Safari 7+ */
}

#container {
    width: 360px;
    margin: 100px auto;
    background: #f0f0f0;
    box-shadow: 0 0 3px rgba(0, 0, 0, 0.1);
}

h1 {
    background: #2980b9;
    color: #fff;
    text-transform: uppercase;
    margin: 0;
    padding: 10px 20px;
    font-size: 24;
    font-weight: 400;
}

#new_note_input {
    color: #2980b9;
    background: #f0f0f0;
    border: none;
    font-size: 18px;
    width: 100%;
    padding: 13px 13px 13px 20px;
    box-sizing: border-box;
}

#new_note_input:focus {
    background: #fff;
    border: 3px solid steelblue;
    outline: none;
}

.hide {
    display: none;
}

#notes_list {
    list-style: none;
    padding: 0;
    margin: 0;
}

li {
    background: #fff;
    height: 40px;
    line-height: 40px;
    color: #666;
    font-weight: 600;
}

li:nth-of-type(2n) {
    background: #f0f0f0;
}

span {
    opacity: 0;
    background: #e70323;
    height: 40px;
    margin-right: 20px;
    text-align: center;
    display: inline-block;
    width: 0px;
    transition: 0.2s linear;
}

li:hover span {
    width: 40px;
    color: white;
    opacity: 1;
}

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