First blog post, added theming

Coffee-themed, font changes and a first post.

template.html

@@ -4,48 +4,158 @@
 <meta charset="utf-8">
 <meta name="viewport" content="width=device-width, initial-scale=1">
 <title>Pascal Maas · Blog</title>
-<style>
-  :root {
-    --bg: #fbfaf7; --fg: #1d1d1b; --muted: #6b6a66; --line: #e4e1da;
-    --accent: #2f5d8a; --code-bg: #f1eee7;
-  }
-  @media (prefers-color-scheme: dark) {
-    :root {
-      --bg: #161616; --fg: #e8e6e1; --muted: #9a978f; --line: #2c2b29;
-      --accent: #8ab4dc; --code-bg: #222120;
+<script>
+  // Runs before the page is drawn, so a saved dark choice doesn't flash.
+  try {
+    if (localStorage.getItem("theme") === "dark") {
+      document.documentElement.dataset.theme = "dark";
     }
+  } catch (error) {}
+</script>
+<style>
+  /* Served from static/; Georgia shows until these have loaded. */
+  @font-face {
+    font-family: "Poltawski Nowy"; font-weight: 400; font-style: normal;
+    src: url("static/PoltawskiNowy-Regular.ttf"); font-display: swap;
+  }
+  @font-face {
+    font-family: "Poltawski Nowy"; font-weight: 400; font-style: italic;
+    src: url("static/PoltawskiNowy-Italic.ttf"); font-display: swap;
+  }
+  @font-face {
+    font-family: "Poltawski Nowy"; font-weight: 700; font-style: normal;
+    src: url("static/PoltawskiNowy-Bold.ttf"); font-display: swap;
+  }
+  @font-face {
+    font-family: "Poltawski Nowy"; font-weight: 700; font-style: italic;
+    src: url("static/PoltawskiNowy-BoldItalic.ttf"); font-display: swap;
+  }
+  :root {
+    --latte: #f4f2ee; --espresso: #231c15;
+    --espresso-button: #4a3326; --latte-button: #e3d9cb;
+    --bg: var(--latte); --fg: #1d1d1b; --muted: #6b6a66; --line: #dbd6cc;
+    --accent: #2f5d8a; --code-bg: #eae6e0;
+    /* Pinned header; the side list pins just below it. */
+    --header-height: 3.25rem; --header-bg: #ebe8e1;
+    --code-block-bg: #eae6e0; --code-text: #1d1d1b;
+    --code-comment: #7a7a7a; --code-keyword: #a85a1e; --code-string: #4f6b3f;
+    --code-number: #4a6f8f; --code-function: #8a6500;
+  }
+  :root[data-theme="dark"] {
+    --bg: var(--espresso); --fg: #e8e6e1; --muted: #9a978f; --line: #3d3227;
+    --accent: #8ab4dc; --code-bg: #2f261d; --header-bg: #2c231a;
+    --code-block-bg: #2e2822; --code-text: #d6d4cf;
+    --code-comment: #808080; --code-keyword: #cc7832; --code-string: #6a8759;
+    --code-number: #6897bb; --code-function: #ffc66d;
   }
   * { box-sizing: border-box; }
   body {
     margin: 0; background: var(--bg); color: var(--fg);
-    font: 17px/1.65 Georgia, "Iowan Old Style", "Times New Roman", serif;
+    font: 17px/1.65 "Poltawski Nowy", Georgia, "Iowan Old Style",
+      "Times New Roman", serif;
   }
-  .wrap { max-width: 44rem; margin: 0 auto; padding: 3rem 1rem 4rem; }
+  .wrap { max-width: 56rem; margin: 0 auto; padding: 0 1rem 4rem; }
   a { color: var(--accent); }
-  h1, h2, h3, .meta, nav, footer { font-family: system-ui, -apple-system, "Segoe UI", sans-serif; }
-  .site-header h1 { margin: 0; font-size: 1.6rem; letter-spacing: -0.01em; }
-  .site-header p { margin: .25rem 0 0; color: var(--muted); }
+  .site-header h1 {
+    margin: 0; font-size: 1.6rem; line-height: 1.2; letter-spacing: -0.01em;
+  }
+  .site-header p { display: none; margin: 0; color: var(--muted); }
+  .site-header {
+    display: flex; justify-content: space-between;
+    align-items: center; gap: 1rem;
+    position: sticky; top: 0; z-index: 2; background: var(--header-bg);
+    height: var(--header-height); padding: .5rem 0;
+    /* Stretches the colour and the line under it to the full window width
+       while the contents stay in the column. */
+    box-shadow: 0 0 0 100vmax var(--header-bg), 0 1px 0 100vmax var(--line);
+    clip-path: inset(0 -100vmax -1px);
+  }
+  .header-actions { display: flex; align-items: center; gap: .75rem; }
+  .site-header p, .header-actions { font-size: 15px; }
+  /* Same font as the tagline; buttons don't inherit it by default. */
+  .header-actions a, .theme-toggle { font: inherit; }
+  .header-actions a { color: var(--fg); text-decoration: none; }
+  .header-actions a:hover { text-decoration: underline; }
+  /* Espresso brown in light mode, latte beige in dark mode. */
+  .theme-toggle {
+    color: var(--latte); background: var(--espresso-button); cursor: pointer;
+    border: 1px solid var(--espresso-button); border-radius: 999px;
+    /* Fixed width fits "Espresso", so the Git link doesn't shift. */
+    width: 6em; padding: .2rem 0; text-align: center;
+  }
+  :root[data-theme="dark"] .theme-toggle {
+    color: var(--espresso); background: var(--latte-button);
+    border-color: var(--latte-button);
+  }
+  .theme-toggle:hover { opacity: .85; }
+  /* Wide enough for the tagline next to the name; hidden below this. */
+  @media (min-width: 52rem) {
+    .site-title { display: flex; align-items: baseline; gap: .75rem; }
+    .site-header p { display: block; }
+  }
 
-  nav { margin: 2.5rem 0 1rem; padding: 1rem 0; border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }
+  nav { margin: 2.5rem 0 1rem; padding: 1rem 0; border-bottom: 1px solid var(--line); }
   nav h2 { margin: 0 0 .5rem; font-size: .8rem; text-transform: uppercase; letter-spacing: .08em; color: var(--muted); }
   nav ol { margin: 0; padding: 0; list-style: none; }
   nav li { display: flex; justify-content: space-between; gap: 1rem; padding: .2rem 0; }
   nav li time { color: var(--muted); font-size: .85rem; white-space: nowrap; }
   nav a { text-decoration: none; }
   nav a:hover { text-decoration: underline; }
+  nav a.current { font-weight: 700; color: var(--fg); }
+
+  /* Side column (14rem) + gap (3rem) + posts (56rem) + padding (2rem). */
+  @media (min-width: 75rem) {
+    .wrap { max-width: 75rem; }
+    .layout { display: grid; grid-template-columns: 14rem 56rem; gap: 3rem; }
+    nav {
+      position: sticky; top: var(--header-height); align-self: start;
+      max-height: calc(100vh - var(--header-height)); overflow-y: auto;
+      margin: 0; padding: 2.5rem 0 1rem; border: none;
+    }
+    nav li, nav li time { display: block; }
+  }
 
   article { padding: 2.5rem 0; border-bottom: 1px solid var(--line); scroll-margin-top: 1rem; }
+  /* Keeps in-page jumps (footnotes) clear of the pinned header. */
+  html { scroll-padding-top: calc(var(--header-height) + 1rem); }
   article header h2 { margin: 0; font-size: 1.45rem; line-height: 1.25; }
   article header h2 a { color: inherit; text-decoration: none; }
   article header h2 a:hover { color: var(--accent); }
   .meta { margin: .35rem 0 1.25rem; font-size: .85rem; color: var(--muted); display: flex; gap: .75rem; align-items: center; }
   .tag { border: 1px solid var(--line); border-radius: 999px; padding: 0 .55rem; }
 
-  img { max-width: 100%; height: auto; }
+  /* Defined terms (Markdown "*[term]: definition"); the script below fills
+     data-definition with the text for the bubble. */
+  abbr[data-definition] {
+    position: relative; cursor: help;
+    text-decoration: underline dotted; text-underline-offset: .2em;
+  }
+  abbr[data-definition]:is(:hover, :focus)::after {
+    content: attr(data-definition);
+    position: absolute; left: 50%; bottom: 100%; z-index: 3;
+    transform: translateX(-50%); margin-bottom: .35rem;
+    width: max-content; max-width: 16rem; padding: .35rem .6rem;
+    background: var(--header-bg); color: var(--fg);
+    border: 1px solid var(--line); border-radius: 6px;
+    font-size: .85rem; line-height: 1.4;
+  }
+
+  img { display: block; margin: 0 auto; max-width: 100%; height: auto; }
   pre, code { font-family: ui-monospace, "Cascadia Code", Menlo, Consolas, monospace; font-size: .88em; }
   code { background: var(--code-bg); padding: .1em .3em; border-radius: 4px; }
-  pre { background: var(--code-bg); padding: 1rem; border-radius: 6px; overflow-x: auto; }
+  pre { background: var(--code-block-bg); color: var(--code-text); padding: 1rem; border-radius: 6px; overflow-x: auto; }
   pre code { background: none; padding: 0; }
+  /* Pygments token classes, Darcula colours: comments, keywords, strings,
+     numbers, function names. */
+  .codehilite :is(.c, .c1, .cm, .ch, .cs) {
+    color: var(--code-comment); font-style: italic;
+  }
+  .codehilite :is(.k, .kc, .kd, .kn, .kr, .kt) { color: var(--code-keyword); }
+  .codehilite :is(.s, .s1, .s2, .sa, .sd, .se, .si) {
+    color: var(--code-string);
+  }
+  .codehilite :is(.m, .mi, .mf, .mh, .il) { color: var(--code-number); }
+  .codehilite :is(.nf, .nb, .fm) { color: var(--code-function); }
   blockquote { margin: 1.25rem 0; padding-left: 1rem; border-left: 3px solid var(--line); color: var(--muted); }
   table { border-collapse: collapse; width: 100%; display: block; overflow-x: auto; }
   th, td { border: 1px solid var(--line); padding: .4rem .6rem; text-align: left; }
@@ -56,22 +166,102 @@
 <body>
 <div class="wrap">
   <header class="site-header">
-    <h1>Pascal Maas</h1>
-    <p>Notes and writing.</p>
+    <div class="site-title">
+      <h1>Pascal Maas</h1>
+      <p>A blog about bioinformatics in metabolomics</p>
+    </div>
+    <div class="header-actions">
+      <a href="https://git.pascal-maas.nl/pascalmaas" target="_blank"
+         rel="me noopener">Git</a>
+      <a href="mailto:contact@pascal-maas.nl">Contact</a>
+      <button class="theme-toggle" type="button"
+              title="Switch to dark mode">Espresso</button>
+    </div>
   </header>
 
-  <nav aria-label="Posts">
-    <h2>Posts</h2>
-    <ol>
+  <div class="layout">
+    <nav aria-label="Posts">
+      <h2>Posts</h2>
+      <ol>
 {{toc}}
-    </ol>
-  </nav>
+      </ol>
+    </nav>
 
-  <main>
+    <main>
 {{posts}}
-  </main>
+    </main>
+  </div>
 
   <footer>© {{year}} Pascal Maas</footer>
 </div>
+<script>
+  const root = document.documentElement;
+  const button = document.querySelector(".theme-toggle");
+
+  // The button names the mode it switches to, not the current one.
+  function applyTheme(theme) {
+    root.dataset.theme = theme;
+    if (theme === "dark") {
+      button.textContent = "Latte";
+      button.title = "Switch to light mode";
+    } else {
+      button.textContent = "Espresso";
+      button.title = "Switch to dark mode";
+    }
+  }
+
+  applyTheme(root.dataset.theme || "light");
+  button.addEventListener("click", function () {
+    const theme = root.dataset.theme === "dark" ? "light" : "dark";
+    applyTheme(theme);
+    try {
+      localStorage.setItem("theme", theme);
+    } catch (error) {}
+  });
+
+  const header = document.querySelector(".site-header");
+  const articles = Array.from(document.querySelectorAll("main article"));
+  const links = document.querySelectorAll("nav a");
+
+  // First use of each term per post keeps its definition, moved out of
+  // "title" so the browser's plain tooltip doesn't show beside the bubble.
+  for (const article of articles) {
+    const seen = new Set();
+    for (const term of article.querySelectorAll("abbr[title]")) {
+      if (seen.has(term.textContent)) {
+        term.replaceWith(term.textContent);
+        continue;
+      }
+      seen.add(term.textContent);
+      term.dataset.definition = term.title;
+      term.removeAttribute("title");
+      term.tabIndex = 0;
+    }
+  }
+
+  // The current post is the last one whose top has passed a line 3rem
+  // (48px) below the header; at the very bottom, it is always the last post.
+  function markCurrentPost() {
+    if (articles.length === 0) {
+      return;
+    }
+    const line = header.getBoundingClientRect().bottom + 48;
+    const viewBottom = window.innerHeight + window.scrollY;
+    const atBottom = viewBottom >= root.scrollHeight - 2;
+    let current = articles[0];
+    for (const article of articles) {
+      if (atBottom || article.getBoundingClientRect().top <= line) {
+        current = article;
+      }
+    }
+    for (const link of links) {
+      link.classList.toggle("current", link.hash === "#" + current.id);
+    }
+  }
+
+  markCurrentPost();
+  window.addEventListener("scroll", markCurrentPost, { passive: true });
+  window.addEventListener("resize", markCurrentPost);
+</script>
 </body>
 </html>