/* Element selector */
body {
    font-family: Arial, Helvetica, sans-serif;
    background-color: #f0f8ff;
    color: #222;
    margin: 40px;
    line-height: 1.6;
}

/* Class selector */
.reference {
    font-style: italic;
    color: #1a5fb4;
}

/* ID selector */
#treeImage {
    display: block;
    margin: 20px auto;
    border: 2px solid #444;
    border-radius: 10px;
}