spec/style.css

* {
    box-sizing: border-box;
}

body {
    font-size: 18px;
    line-height: 1.5;
    color: #333;
    background: #ffffff;
    font-family: Constantia, "Lucida Bright", Lucidabright, "Lucida Serif", Lucida, "DejaVu Serif," "Bitstream Vera Serif", "Liberation Serif", Georgia, serif;
    /* font-family: -apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Oxygen-Sans,Ubuntu,Cantarell,"Helvetica Neue",sans-serif; */
}

main {
    margin: 40px auto;
    max-width: 1000px;
    padding: 0 10px;
}

#content {
}

.toc {
    height: 100%;
    width: 300px;
    position: absolute;
    right: 0;
    padding-left: 20px;
    padding-top: 20px;
    background-color: rgba(255,255,255,0.95);
    transition: all 300ms ease-in-out;
    transform: translateX(100%);
}
.toc.open {
    box-shadow: 0 0 5px #c8c8c8;
    transform: translateX(0);
}
@media (min-width: 1000px) {
    #content {
        margin-right: 300px;
    }
    .toc {
        right: calc((100% - 1000px) / 2);
        transform: translateX(0);
    }
    .toc-menu {
        display: none;
    }
}
.toc .is-active-link::before {
    background-color: #0074D9;
}
.is-position-fixed {
    position: fixed !important;
    top: 0;
}
.toc-menu {
    position: fixed;
    top: 0;
    right: 0;
    z-index: 2;
    margin: .25rem;
    padding: .25rem;
    background-color: #f4f4f4;
    line-height: 1;
    border-radius: .125rem;
    border-color: #999;
    border-style: solid;
    border-width: 1px;
}
h1::before, h2::before, h3::before, h4::before, h5::before, h6::before {
    display: block;
    content: " ";
    height: 40px;
    margin-top: -40px;
    visibility: hidden;
}

p {
    margin-bottom: 1.4rem;
}

h1, h2, h3, h4, h5, h6 {
    line-height: 1.2;
}
h1:focus, h2:focus, h3:focus, h4:focus, h5:focus, h6:focus {
    /* fix weird outline when clicking a TOC link */
    outline: 0;
}

h1 {
    margin-top: 0;
    font-size: 4rem;
}

h2 {
    font-size: 3rem;
}

h3 {
    font-size: 2.25rem;
}

h4 {
    font-size: 1.5rem;
    margin-bottom: 1.5rem;
}

h5 {
    font-size: 1.25rem;
    font-variant: small-caps;
    margin-bottom: 1rem;
}

h6 {
    font-size: 1.125rem;
    font-variant: small-caps;
    margin-bottom: 1rem;
}

small {
    font-size: 0.8rem;
}

a {
    color: #0074D9;
}

code {
    /* font-family: Consolas, "Andale Mono WT", "Andale Mono", "Lucida Console", "Lucida Sans Typewriter", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Liberation Mono", "Nimbus Mono L", Monaco, "Courier New", Courier, monospace; */
    font-family: SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace;
    font-size: 0.9rem;
    color: #B10DC9;
}

pre {
    display: block;
    color: #212529;
    overflow: auto;
    margin-top: 0;
    margin-bottom: 1rem;
}

.notice {
    position: relative;
    padding: .75rem 1.25rem;
    margin-bottom: 1rem;
    border: 1px solid transparent;
    border-radius: .25rem;
    color: #0c5460;
    background-color: #d1ecf1;
    border-color: #bee5eb;
}

.notice p:first-child {
    margin-top: 0;
}

.notice p:last-child {
    margin-bottom: 0;
}

ol ol {
    list-style-type: lower-alpha;
}

#toc ul {
    list-style-type: none;
}

#toc>ul {
    padding-left: 0;
}

table {
    border-collapse: collapse;
    width: 100%;
}
table tr {
    border-top: 1px solid #dee2e6;
}
table thead tr {
    border-bottom: 2px solid #dee2e6;
}
table tbody tr:nth-child(odd) {
    background-color: rgba(0,0,0,.05);
}

figure {
    margin-left: 0;
    margin-right: 0;
}
figcaption {
    color: #888;
    font-size: 90%;
    padding-left: 10px;
    padding-right: 10px;
}