html {
    background-color: #6d676e;
}

body {
    background-color: #fbfffe;
    margin: 0 auto;
    margin-top: 0;
    max-width: 1000px;
}

nav {
    background-color: #1b1b1e;
    overflow: hidden;
}

nav li {
    list-style-type: none;
}

nav a {
    float: left;
    color: #fbfffe;
    text-align: center;
    padding: 12px 12px;
    text-decoration: none;
    font-size: 17px;
}

nav a:hover {
    background-color: #fbfffe;
    color: black;
}

article {
    margin: 0 auto;
    padding-top: 10px;
    padding-left: 5px;
    padding-right: 5px;
    max-width: 800px;
}

section {
    margin: 0 auto;
    padding-top: 10px;
    padding-left: 5px;
    padding-right: 5px;
    max-width: 800px;
}

img {
    display: block;
    margin-left: auto;
    margin-right: auto;
    max-width: calc(min(650px, 100%));
    width: auto;
    height: auto;
    mix-blend-mode: multiply;
}

iframe {
    display: block;
    margin: 0 auto;
    max-width: 560px;
    width: 100%;
    height: 315px;
    /*width="560" height="315" */
}

footer {
    text-align: center;
    padding-top: 40px;
}

table,
th,
td {
    margin-left: auto;
    margin-right: auto;
    border: 1px solid;
}