main.css

body {
    background: lightcoral;
}

h2 {
    font-family: 'Oleo Script', Helvetica, sans-serif;
}

.note {
    width: 400px;
    height: 300px;
    margin: 0 auto 20px auto;
    padding: 20px;
    text-align: left;
}

#note1 {
    background-color: aquamarine;
    position: relative;
    overflow: hidden;
}

#note1:after {
    content: "";
    height: 0;
    position: absolute;
    bottom: 0;
    right: 0;
    border: solid;
    border-width: 0 0 30px 30px;
    border-color: transparent transparent lightcoral rgba(0, 0, 0, 0.3);
    -webkit-box-shadow: 0 2px 2px rgba(0, 0, 0, 0.6), -2px 2px 2px rgba(0, 0, 0, 0.3);
    -moz-box-shadow: 0 2px 2px rgba(0, 0, 0, 0.6), -2px 2px 2px rgba(0, 0, 0, 0.3);
    box-shadow: 0 2px 2px rgba(0, 0, 0, 0.6), -2px 2px 2px rgba(0, 0, 0, 0.3);
    /* Firefox 3.0 damage limitation */
    display: block;
    width: 0;
}

#note2 {
    background-color: indianred;
    position: relative;
    overflow: hidden;
}

#note3 {
    background-color: beige;
}