style.css

body {
    font-family: Verdana, Tahoma, Geneva, sans-serif;
    line-height: 140%;
    padding: 1rem 3rem;
}

#program, #macro {
    font-size: 250%;
    outline: none;
}

h1, .help {
    color: #999;
}

form {
    margin-bottom: 3cm;
}

#program_result, #macro_result {
    list-style: none;
    padding-left: 0;
    font-size: 150%;
}

#program_error, #macro_error {
    display: none;
    color: red;
    position: absolute;
    margin-top: -1rem;
}

#options {
    visibility: hidden;

    background: #ddd;
    padding: 1rem;

    width: 15rem;
    position: absolute;
    right: 0;
    top: 0;
    bottom: 0;
}
#options h3 {
    margin-top: 1.5rem;
    margin-bottom: 0.5rem;
}
#options p {
    margin: 0.5rem 0;
}

/* The visual AST displays. */
.graph {
    float: right;
    overflow: visible;
    width: 20%;
    max-width: 500px;
    height: 500px;
}

#show_options {
    position: absolute;
    right: 0;
    top: 0;
    border: none;
    background: transparent;
    padding: 0.5rem 1rem 1rem 1rem;
    font-size: 200%;
}
#share_link {
    width: 100%;
    margin-top: 0;
}

.active_abs {
    color : #0000CD;
}

.active_subst {
    color : #B31B1B;
}

#macrolist {
    overflow: auto;
    list-style: none;
    padding-left: 0;
    font-size: 150%;
    height: 500px;
}