:root {
    --bg: #ffffff;
    --fg: #1a1a1a;
    --muted: #5a5a5a;
    --border: #d8d8d8;
    --nav-bg: #f6f6f4;
    --link: #0b5fa5;
    --code-bg: #f2f2ef;
    --accent: #8a5a00;
    --nav-width: 280px;
    --measure: 42em;
}

@media (prefers-color-scheme: dark) {
    :root {
        --bg: #14171a;
        --fg: #e8e6e1;
        --muted: #a3a3a3;
        --border: #33383d;
        --nav-bg: #1b1f23;
        --link: #6cb2f0;
        --code-bg: #1e2226;
        --accent: #d1a34a;
    }
}

* {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    margin: 0;
    background: var(--bg);
    color: var(--fg);
    font-family: "Iowan Old Style", "Palatino Linotype", Palatino, Georgia, serif;
    line-height: 1.6;
}

a {
    color: var(--link);
}

/* Side navigation */

#TOC {
    position: fixed;
    top: 0;
    left: 0;
    bottom: 0;
    width: var(--nav-width);
    overflow-y: auto;
    background: var(--nav-bg);
    border-right: 1px solid var(--border);
    padding: 1.5rem 1rem;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
    font-size: 0.9rem;
}

#TOC .toc-title {
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    font-size: 0.75rem;
    color: var(--muted);
    margin-bottom: 0.75rem;
}

#TOC ul {
    list-style: none;
    margin: 0;
    padding-left: 0.9rem;
}

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

#TOC li {
    margin: 0.2rem 0;
}

#TOC a {
    color: var(--fg);
    text-decoration: none;
    display: block;
    padding: 0.1rem 0;
}

#TOC a:hover {
    color: var(--link);
    text-decoration: underline;
}

.nav-toggle {
    display: none;
}

.nav-toggle-label {
    display: none;
    position: fixed;
    top: 0.75rem;
    left: 0.75rem;
    z-index: 20;
    background: var(--nav-bg);
    border: 1px solid var(--border);
    border-radius: 4px;
    width: 2.25rem;
    height: 2.25rem;
    line-height: 2.25rem;
    text-align: center;
    cursor: pointer;
}

main#content {
    margin-left: var(--nav-width);
    padding: 2.5rem clamp(1rem, 4vw, 4rem);
    max-width: calc(var(--measure) + 4rem);
}

@media (max-width: 900px) {
    #TOC {
        transform: translateX(-100%);
        transition: transform 0.2s ease-in-out;
        z-index: 15;
        box-shadow: 2px 0 12px rgba(0, 0, 0, 0.2);
    }

    .nav-toggle:checked ~ #TOC {
        transform: translateX(0);
    }

    .nav-toggle-label {
        display: block;
    }

    main#content {
        margin-left: 0;
        padding-top: 4rem;
    }
}

/* Title block */

#title-block-header {
    margin-bottom: 2.5rem;
}

#title-block-header .title {
    font-size: 1.9rem;
    margin-bottom: 0.25rem;
}

#title-block-header .subtitle {
    display: block;
    font-size: 1.2rem;
    font-weight: 400;
    color: var(--muted);
}

#title-block-header .author {
    color: var(--muted);
    font-size: 0.95rem;
}

#title-block-header .affiliations {
    color: var(--muted);
    font-size: 0.85rem;
    padding-left: 1.2rem;
}

/* Headings */

h1, h2, h3, h4, h5, h6 {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
    line-height: 1.25;
    scroll-margin-top: 1.5rem;
}

.secnum {
    color: var(--accent);
    margin-right: 0.5em;
}

/* Figures */

.figure {
    margin: 2rem 0;
    text-align: center;
}

.figure img {
    max-width: 100%;
    height: auto;
}

.figure.wide {
    max-width: none;
    margin-left: calc(-1 * clamp(0px, (100% - var(--measure)) / 2, 8rem));
    margin-right: calc(-1 * clamp(0px, (100% - var(--measure)) / 2, 8rem));
}

.figure p {
    font-size: 0.9rem;
    color: var(--muted);
    text-align: left;
    margin-top: 0.5rem;
}

.fig-number,
.tbl-number {
    font-weight: 600;
    color: var(--fg);
}

/* Tables */

table {
    border-collapse: collapse;
    margin: 1.5rem 0;
    font-size: 0.9rem;
}

table.wide-table {
    width: 100%;
}

caption {
    caption-side: bottom;
    text-align: left;
    font-size: 0.9rem;
    color: var(--muted);
    margin-top: 0.5rem;
}

th, td {
    border: 1px solid var(--border);
    padding: 0.4rem 0.7rem;
    text-align: left;
}

th {
    background: var(--code-bg);
}

/* Equations */

.equation {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin: 1.5rem 0;
    scroll-margin-top: 1.5rem;
}

.eq-body {
    overflow-x: auto;
    flex: 1;
}

.eq-number {
    color: var(--muted);
    padding-left: 1rem;
    white-space: nowrap;
}

/* Code */

pre, code {
    font-family: "SF Mono", Menlo, Consolas, "Liberation Mono", monospace;
    font-size: 0.85em;
}

pre {
    background: var(--code-bg);
    border: 1px solid var(--border);
    border-radius: 6px;
    padding: 0.85rem 1rem;
    overflow-x: auto;
}

code {
    background: var(--code-bg);
    border-radius: 3px;
    padding: 0.1em 0.3em;
}

pre code {
    background: none;
    padding: 0;
}

details.hide-code {
    margin: 1.25rem 0;
    border: 1px solid var(--border);
    border-radius: 6px;
    padding: 0.5rem 0.85rem;
}

details.hide-code summary {
    cursor: pointer;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
    color: var(--muted);
}

details.hide-code[open] summary {
    margin-bottom: 0.5rem;
}

/* Special sections */

.abstract, .code-availability, .appendix, .author-contribution,
.competing-interests, .acknowledgements, .disclaimer {
    margin: 2rem 0;
}

.abstract {
    font-size: 0.95rem;
    color: var(--muted);
    border-left: 3px solid var(--border);
    padding-left: 1rem;
}

blockquote {
    border-left: 3px solid var(--border);
    margin-left: 0;
    padding-left: 1rem;
    color: var(--muted);
}