style.css

body {
    margin: 0;
    padding: 0;
    font-size: 100%;
    color: #ddd;
    background: #344;
    line-height: 2.0;
    font-family: Verdana, Geneva, sans-serif
}

table, th, td {
    border: 1px solid black;
    }
    th, td {
            padding: 15px;
    }

p {
    font-size: 1.2em;
    margin: .6em 6em .6em 5em;
    padding: 0;
    line-height: 140%;
}

hr {
    margin: 2em 12em 2em 12em;
}

ol, ul, dl, li {
    margin: 1.6em 8em .6em 3em;
}

ul.centered {
    list-style-position: inside;
}
.menu {
    color: #312;
    margin: 1.6em 12em 0em 12em;
    list-style: none;
    padding: 0;
    margin: 0;
    display: flex;
    justify-content: space-between;
    background-image: url("https://upload.wikimedia.org/wikipedia/commons/2/21/Dewy_spider_web.jpg");
}

a {
    text-decoration: none;
    color: #aaf;
}
a.menu  {
    font-size: 1.3em;
    font-weight: 600;
    background: transparent;
    color: #312;
}
a:link {
    color: #caf;
}
a.menu:link {
    background: transparent;
    color: #312;
}
a:visited {
    color: #fac;
}
a.menu:visited {
    background: transparent;
    color: #312;
}

p.model {
/*    text-align: center; */
}

p.menu {
    text-align: center;
    margin: .4em 4em .8em 4em;
    font-size: 1.4em;
}

figure {
    margin: 1.4em 1em 1.4em 1em;
    text-align: center;
}
figure.logo {
    margin: 0em 0em .6em 0em;
}

figure figcaption {
    color: #69c;
    font-style: italic;
    margin: .8em 1em .8em 1em;
}

h1,h2,h3,h4,h5 {
    font-weight: 400;
}

h1 {
    margin: 1em 8em 1.4em 8em;
    text-align: center;
    font-size: 2em;
    color: #339;
    background-image: url("graphics/water.jpg");
    background-color: #cad;
}

h2 {
    font-size: 1.8em;
    margin: 1.4em .6em 1.3em .6em;
    color: #9cc;
}

h2.subhead {
    font-weight: normal;
    margin-top: 0;
}

h3 {
    font-size: 1.6em;
    margin: 1.4em .6em 1.3em .6em;
    color: #ecb;
}

h4 {
    font-size: 1.5em;
    margin: 1.4em .6em 1.2em 4em;
    color: #caf;
/*	text-align: center */
}

h5 {
    font-size: 1.4em;
    margin: 1.4em .6em 1.2em .6em;
    color: #faa;
}

summary.sum1 {
    font-size: 1.6em;
    color: #e69;
    margin: .8em 1.2em .8em 1.2em;
}

summary.sum2 {
    font-size: 1.5em;
    color: #acf;
    margin: .6em 1.2em .6em 2em;
}

summary.sum3 {
    font-size: 1.4em;
    color: #aac;
    margin: .4em 1.2em .4em 2.8em;
}

summary.sum4 {
    font-size: 1.3em;
    color: #fac;
    margin: .4em 1.2em .4em 2.8em;
}

summary.menu_sum {
    font-size: 1.4em;
    color: #fac;
    margin: .5em 0em .5em 0em;
}