diff --git a/.prettierrc.js b/.prettierrc.js
deleted file mode 100644
index 7aca5df..0000000
--- a/.prettierrc.js
+++ /dev/null
@@ -1,6 +0,0 @@
-export default {
-	semi: true,
-	trailingComma: 'all',
-	singleQuote: true,
-	useTabs: true,
-};
diff --git a/biome.json b/biome.json
new file mode 100644
index 0000000..f340327
--- /dev/null
+++ b/biome.json
@@ -0,0 +1,34 @@
+{
+	"$schema": "https://biomejs.dev/schemas/2.2.5/schema.json",
+	"vcs": {
+		"enabled": false,
+		"clientKind": "git",
+		"useIgnoreFile": true
+	},
+	"files": {
+		"ignoreUnknown": false
+	},
+	"formatter": {
+		"enabled": true,
+		"indentStyle": "tab"
+	},
+	"linter": {
+		"enabled": true,
+		"rules": {
+			"recommended": true
+		}
+	},
+	"javascript": {
+		"formatter": {
+			"quoteStyle": "double"
+		}
+	},
+	"assist": {
+		"enabled": true,
+		"actions": {
+			"source": {
+				"organizeImports": "on"
+			}
+		}
+	}
+}
diff --git a/package-lock.json b/package-lock.json
index 98ccc84..f5ca9f9 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -12,6 +12,7 @@
 				"@11ty/eleventy": "^3.1.2"
 			},
 			"devDependencies": {
+				"@biomejs/biome": "2.2.5",
 				"autoprefixer": "^10.4.21",
 				"postcss": "^8.5.6",
 				"postcss-csso": "^6.0.1",
@@ -199,6 +200,169 @@
 				"node": ">=18"
 			}
 		},
+		"node_modules/@biomejs/biome": {
+			"version": "2.2.5",
+			"resolved": "https://registry.npmjs.org/@biomejs/biome/-/biome-2.2.5.tgz",
+			"integrity": "sha512-zcIi+163Rc3HtyHbEO7CjeHq8DjQRs40HsGbW6vx2WI0tg8mYQOPouhvHSyEnCBAorfYNnKdR64/IxO7xQ5faw==",
+			"dev": true,
+			"license": "MIT OR Apache-2.0",
+			"bin": {
+				"biome": "bin/biome"
+			},
+			"engines": {
+				"node": ">=14.21.3"
+			},
+			"funding": {
+				"type": "opencollective",
+				"url": "https://opencollective.com/biome"
+			},
+			"optionalDependencies": {
+				"@biomejs/cli-darwin-arm64": "2.2.5",
+				"@biomejs/cli-darwin-x64": "2.2.5",
+				"@biomejs/cli-linux-arm64": "2.2.5",
+				"@biomejs/cli-linux-arm64-musl": "2.2.5",
+				"@biomejs/cli-linux-x64": "2.2.5",
+				"@biomejs/cli-linux-x64-musl": "2.2.5",
+				"@biomejs/cli-win32-arm64": "2.2.5",
+				"@biomejs/cli-win32-x64": "2.2.5"
+			}
+		},
+		"node_modules/@biomejs/cli-darwin-arm64": {
+			"version": "2.2.5",
+			"resolved": "https://registry.npmjs.org/@biomejs/cli-darwin-arm64/-/cli-darwin-arm64-2.2.5.tgz",
+			"integrity": "sha512-MYT+nZ38wEIWVcL5xLyOhYQQ7nlWD0b/4mgATW2c8dvq7R4OQjt/XGXFkXrmtWmQofaIM14L7V8qIz/M+bx5QQ==",
+			"cpu": [
+				"arm64"
+			],
+			"dev": true,
+			"license": "MIT OR Apache-2.0",
+			"optional": true,
+			"os": [
+				"darwin"
+			],
+			"engines": {
+				"node": ">=14.21.3"
+			}
+		},
+		"node_modules/@biomejs/cli-darwin-x64": {
+			"version": "2.2.5",
+			"resolved": "https://registry.npmjs.org/@biomejs/cli-darwin-x64/-/cli-darwin-x64-2.2.5.tgz",
+			"integrity": "sha512-FLIEl73fv0R7dI10EnEiZLw+IMz3mWLnF95ASDI0kbx6DDLJjWxE5JxxBfmG+udz1hIDd3fr5wsuP7nwuTRdAg==",
+			"cpu": [
+				"x64"
+			],
+			"dev": true,
+			"license": "MIT OR Apache-2.0",
+			"optional": true,
+			"os": [
+				"darwin"
+			],
+			"engines": {
+				"node": ">=14.21.3"
+			}
+		},
+		"node_modules/@biomejs/cli-linux-arm64": {
+			"version": "2.2.5",
+			"resolved": "https://registry.npmjs.org/@biomejs/cli-linux-arm64/-/cli-linux-arm64-2.2.5.tgz",
+			"integrity": "sha512-5DjiiDfHqGgR2MS9D+AZ8kOfrzTGqLKywn8hoXpXXlJXIECGQ32t+gt/uiS2XyGBM2XQhR6ztUvbjZWeccFMoQ==",
+			"cpu": [
+				"arm64"
+			],
+			"dev": true,
+			"license": "MIT OR Apache-2.0",
+			"optional": true,
+			"os": [
+				"linux"
+			],
+			"engines": {
+				"node": ">=14.21.3"
+			}
+		},
+		"node_modules/@biomejs/cli-linux-arm64-musl": {
+			"version": "2.2.5",
+			"resolved": "https://registry.npmjs.org/@biomejs/cli-linux-arm64-musl/-/cli-linux-arm64-musl-2.2.5.tgz",
+			"integrity": "sha512-5Ov2wgAFwqDvQiESnu7b9ufD1faRa+40uwrohgBopeY84El2TnBDoMNXx6iuQdreoFGjwW8vH6k68G21EpNERw==",
+			"cpu": [
+				"arm64"
+			],
+			"dev": true,
+			"license": "MIT OR Apache-2.0",
+			"optional": true,
+			"os": [
+				"linux"
+			],
+			"engines": {
+				"node": ">=14.21.3"
+			}
+		},
+		"node_modules/@biomejs/cli-linux-x64": {
+			"version": "2.2.5",
+			"resolved": "https://registry.npmjs.org/@biomejs/cli-linux-x64/-/cli-linux-x64-2.2.5.tgz",
+			"integrity": "sha512-fq9meKm1AEXeAWan3uCg6XSP5ObA6F/Ovm89TwaMiy1DNIwdgxPkNwxlXJX8iM6oRbFysYeGnT0OG8diCWb9ew==",
+			"cpu": [
+				"x64"
+			],
+			"dev": true,
+			"license": "MIT OR Apache-2.0",
+			"optional": true,
+			"os": [
+				"linux"
+			],
+			"engines": {
+				"node": ">=14.21.3"
+			}
+		},
+		"node_modules/@biomejs/cli-linux-x64-musl": {
+			"version": "2.2.5",
+			"resolved": "https://registry.npmjs.org/@biomejs/cli-linux-x64-musl/-/cli-linux-x64-musl-2.2.5.tgz",
+			"integrity": "sha512-AVqLCDb/6K7aPNIcxHaTQj01sl1m989CJIQFQEaiQkGr2EQwyOpaATJ473h+nXDUuAcREhccfRpe/tu+0wu0eQ==",
+			"cpu": [
+				"x64"
+			],
+			"dev": true,
+			"license": "MIT OR Apache-2.0",
+			"optional": true,
+			"os": [
+				"linux"
+			],
+			"engines": {
+				"node": ">=14.21.3"
+			}
+		},
+		"node_modules/@biomejs/cli-win32-arm64": {
+			"version": "2.2.5",
+			"resolved": "https://registry.npmjs.org/@biomejs/cli-win32-arm64/-/cli-win32-arm64-2.2.5.tgz",
+			"integrity": "sha512-xaOIad4wBambwJa6mdp1FigYSIF9i7PCqRbvBqtIi9y29QtPVQ13sDGtUnsRoe6SjL10auMzQ6YAe+B3RpZXVg==",
+			"cpu": [
+				"arm64"
+			],
+			"dev": true,
+			"license": "MIT OR Apache-2.0",
+			"optional": true,
+			"os": [
+				"win32"
+			],
+			"engines": {
+				"node": ">=14.21.3"
+			}
+		},
+		"node_modules/@biomejs/cli-win32-x64": {
+			"version": "2.2.5",
+			"resolved": "https://registry.npmjs.org/@biomejs/cli-win32-x64/-/cli-win32-x64-2.2.5.tgz",
+			"integrity": "sha512-F/jhuXCssPFAuciMhHKk00xnCAxJRS/pUzVfXYmOMUp//XW7mO6QeCjsjvnm8L4AO/dG2VOB0O+fJPiJ2uXtIw==",
+			"cpu": [
+				"x64"
+			],
+			"dev": true,
+			"license": "MIT OR Apache-2.0",
+			"optional": true,
+			"os": [
+				"win32"
+			],
+			"engines": {
+				"node": ">=14.21.3"
+			}
+		},
 		"node_modules/@csstools/selector-resolve-nested": {
 			"version": "3.1.0",
 			"resolved": "https://registry.npmjs.org/@csstools/selector-resolve-nested/-/selector-resolve-nested-3.1.0.tgz",
diff --git a/package.json b/package.json
index 933f19a..d7f19ca 100644
--- a/package.json
+++ b/package.json
@@ -24,6 +24,7 @@
 		"@11ty/eleventy": "^3.1.2"
 	},
 	"devDependencies": {
+		"@biomejs/biome": "2.2.5",
 		"autoprefixer": "^10.4.21",
 		"postcss": "^8.5.6",
 		"postcss-csso": "^6.0.1",
diff --git a/src/content/_data/metadata.js b/src/content/_data/metadata.js
index 237676d..1283b4b 100644
--- a/src/content/_data/metadata.js
+++ b/src/content/_data/metadata.js
@@ -1,8 +1,25 @@
 export default {
+    // Basic site identity
     siteUrl: 'https://j-m.es',
     siteName: 'James Loveridge',
     jobTitle: 'Software Engineer',
-    bluesky: 'j-m.es',
-    github: 'j-mes',
-    linkedin: 'j-mes'
+
+    // Short description used in meta description and social previews
+    description: 'Intermittent notes written by James Loveridge',
+
+    // Social / federated profiles (fill with full profile URLs if you prefer)
+    bluesky: 'https://bsky.app/profile/j-m.es',
+    mastodon: '',
+    github: 'https://github.com/j-mes',
+    linkedin: 'https://www.linkedin.com/in/j-mes',
+
+    // Social embed / sharing defaults
+    // socialImage: '/images/social-share.png',
+    // twitterHandle: '', // include @ if you wish, e.g. '@jmes'
+    // fbAppId: '',
+
+    // Misc
+    robots: 'index, follow',
+    // themeColor: '#0a0a0a',
+    // manifest: '/manifest.json'
 };
diff --git a/src/layouts/archive.njk b/src/layouts/archive.njk
index 0aca519..1a675ef 100644
--- a/src/layouts/archive.njk
+++ b/src/layouts/archive.njk
@@ -1,12 +1,12 @@
 {% extends "main.njk" %}
 {% block content %}
-<main class="archive">
-	<h1>{{ entries.title }}</h1>
+<main role="main" aria-labelledby="archive-title">
+	<h1 id="archive-title">{{ entries.title }}</h1>
 
 	{% if content %}
-	<div class="archive-intro">
+	<section>
 		{{ content | safe }}
-	</div>
+	</section>
 	{% endif %}
 
 	{% if collectionKey %}
@@ -15,12 +15,14 @@
 	{% if items and items | length > 0 %}
 	{% if groupByYear %}
 		{% for year in items | groupByYear %}
-			<section id="year-{{ year.year }}">
-			<h2>{{ year.year }}</h2>
+			<section id="year-{{ year.year }}" aria-labelledby="year-{{ year.year }}-heading">
+			<h2 id="year-{{ year.year }}-heading">{{ year.year }}</h2>
 			<ul>
 				{% for entry in year.items %}
 				<li>
-					<a href="{{ entry.url }}">{{ entry.data.title }}</a> &ndash; <time>{{ entry.date.toLocaleDateString('en-GB', { day: "numeric", month: "long" }) }}</time>
+					<a href="{{ entry.url }}">{{ entry.data.title }}</a>
+					&ndash;
+					<time datetime="{{ entry.date.toISOString() }}">{{ entry.date.toLocaleDateString('en-GB', { day: "numeric", month: "long" }) }}</time>
 				</li>
 				{% endfor %}
 			</ul>
@@ -30,16 +32,20 @@
 		<ul>
 			{% for entry in items %}
 			<li>
-				<a href="{{ entry.url }}">{{ entry.data.title }}</a> &ndash; <time>{{ entry.date.toLocaleDateString('en-GB', { day: "numeric", month: "long" }) }}</time>
+				<a href="{{ entry.url }}">{{ entry.data.title }}</a>
+				&ndash;
+				<time datetime="{{ entry.date.toISOString() }}">{{ entry.date.toLocaleDateString('en-GB', { day: "numeric", month: "long" }) }}</time>
 			</li>
 			{% endfor %}
 		</ul>
 		{% endif %}
 	{% else %}
-		<p>No entries found.</p>
+		<p role="status">No entries found.</p>
 	{% endif %}
 	{% else %}
-		<pre><code>No collectionKey set in frontmatter or data file for this archive page.</code></pre>
+		<section aria-live="polite">
+			<pre><code>No collectionKey set in frontmatter or data file for this archive page.</code></pre>
+		</section>
 	{% endif %}
 
 </main>
diff --git a/src/layouts/home.njk b/src/layouts/home.njk
index 848e7e7..2687947 100644
--- a/src/layouts/home.njk
+++ b/src/layouts/home.njk
@@ -1,7 +1,7 @@
 {# src/layouts/home.njk #}
 {% extends "main.njk" %}
 {% block content %}
-<article class="post">
+<article>
 	{{ content | safe }}
 
 	{%- if collections.notes -%}
@@ -12,17 +12,17 @@
 	{%- endif -%}
 
 	{% if latest %}
-	<section class="latest-intermittent-note">
-		<h2>Latest intermittent note</h2>
+	<section aria-labelledby="latest-heading">
+		<h2 id="latest-heading">Latest intermittent note</h2>
 		<h3><a href="{{ latest.url }}">{{ latest.data.title or latest.data.page.title or latest.fileSlug }}</a></h3>
-		<div class="note-content">
-			{{ latest.templateContent | striptags(true) | truncateWords(80)| safe }}
+		<div aria-describedby="latest-excerpt">
+			<p id="latest-excerpt">{{ latest.templateContent | striptags(true) | truncateWords(80)| safe }}</p>
 		</div>
 	</section>
 	{% endif %}
 
-	<section class="archives">
-		<h2>Here's the other things for intermittent notes</h2>
+	<section aria-labelledby="archives-heading">
+		<h2 id="archives-heading">Here's the other things for intermittent notes</h2>
 		<ul>
 			{% if collections.notes %}
 				<li><a href="/notes/">Archives</a></li>
diff --git a/src/layouts/main.njk b/src/layouts/main.njk
index c16bbb0..f26e379 100644
--- a/src/layouts/main.njk
+++ b/src/layouts/main.njk
@@ -2,16 +2,24 @@
 <html lang="en-GB">
 	<head>
 		<meta charset="utf-8" />
+		<meta name="viewport" content="width=device-width, initial-scale=1" />
 		<title>{{ title }} | {{ metadata.siteName }} &ndash; {{ metadata.jobTitle }}</title>
-		<link rel="stylesheet" href="/style.css" />
+		{% include 'meta-tags.njk' %}
 	</head>
 	<body>
-		<header>
-			<a href="/" title="{{ metadata.siteName }} &ndash; {{ metadata.jobTitle }}">{{ metadata.siteName }} &ndash; {{ metadata.jobTitle }}</a>
-			<h1>{{ title }}</h1>
+		<a href="#main-content">Skip to main content</a>
+		<header role="banner" aria-label="Site header">
+			<div>
+				<a href="/" title="{{ metadata.siteName }} &ndash; {{ metadata.jobTitle }}">{{ metadata.siteName }} &ndash; {{ metadata.jobTitle }}</a>
+			</div>
+			<h1 id="page-title">{{ title }}</h1>
 		</header>
+
+		<main id="main-content" role="main" aria-labelledby="page-title">
 			{% block content %}{% endblock %}
-		<footer>
+		</main>
+
+		<footer role="contentinfo" aria-label="Site footer">
 			{# Do something nice here? #}
 		</footer>
 	</body>
diff --git a/src/layouts/meta-tags.njk b/src/layouts/meta-tags.njk
new file mode 100644
index 0000000..58122d3
--- /dev/null
+++ b/src/layouts/meta-tags.njk
@@ -0,0 +1,55 @@
+{# Reusable head meta partial used by layouts/main.njk #}
+<meta name="description" content="{{ page.data.description or metadata.description or '' }}" />
+<link rel="canonical" href="{{ (metadata.siteUrl or '') ~ page.url }}" />
+<link rel="stylesheet" href="/style.css" />
+
+{# Open Graph / Facebook / generic social #}
+<meta property="og:site_name" content="{{ metadata.siteName }}" />
+<meta property="og:title" content="{{ title }}" />
+<meta property="og:description" content="{{ page.data.description or metadata.description or '' }}" />
+<meta property="og:type" content="{{ page.data.ogType or 'website' }}" />
+<meta property="og:url" content="{{ (metadata.siteUrl or '') ~ page.url }}" />
+{% if page.data.image or metadata.socialImage %}
+<meta property="og:image" content="{{ (metadata.siteUrl or '') ~ (page.data.image or metadata.socialImage) }}" />
+{% endif %}
+{% if metadata.fbAppId %}
+<meta property="fb:app_id" content="{{ metadata.fbAppId }}" />
+{% endif %}
+
+{# Twitter card #}
+<meta name="twitter:card" content="{{ page.data.twitterCard or 'summary_large_image' }}" />
+{% if metadata.twitterHandle %}
+<meta name="twitter:site" content="{{ metadata.twitterHandle }}" />
+<meta name="twitter:creator" content="{{ metadata.twitterHandle }}" />
+{% endif %}
+<meta name="twitter:title" content="{{ title }}" />
+<meta name="twitter:description" content="{{ page.data.description or metadata.description or '' }}" />
+{% if page.data.image or metadata.socialImage %}
+<meta name="twitter:image" content="{{ (metadata.siteUrl or '') ~ (page.data.image or metadata.socialImage) }}" />
+{% endif %}
+
+{# oEmbed discovery (JSON and XML) - some platforms may use this for rich embeds #}
+{% if page.data.oembed or metadata.oembed %}
+<link rel="alternate" type="application/json+oembed" href="{{ (metadata.siteUrl or '') ~ (page.data.oembed or metadata.oembed) }}" title="{{ title }} oEmbed JSON" />
+<link rel="alternate" type="text/xml+oembed" href="{{ (metadata.siteUrl or '') ~ (page.data.oembedXml or metadata.oembedXml) }}" title="{{ title }} oEmbed XML" />
+{% endif %}
+
+{# rel-me links for decentralised identity (Bluesky, Mastodon, etc.) #}
+{% if metadata.bluesky %}
+<link rel="me" href="{{ metadata.bluesky }}" />
+{% endif %}
+{% if metadata.mastodon %}
+<link rel="me" href="{{ metadata.mastodon }}" />
+{% endif %}
+
+{# Robots / PWA hints #}
+<meta name="robots" content="{{ page.data.robots or metadata.robots or 'index, follow' }}" />
+{% if metadata.themeColor %}
+<meta name="theme-color" content="{{ metadata.themeColor }}" />
+{% endif %}
+{% if metadata.manifest %}
+<link rel="manifest" href="{{ metadata.manifest }}" />
+{% endif %}
+
+{# Generic RSS/feed link for discoverability #}
+<link rel="alternate" type="application/rss+xml" title="{{ metadata.siteName }} RSS" href="/feed.xml" />
diff --git a/src/layouts/post.njk b/src/layouts/post.njk
index 2d79c3c..4c6a574 100644
--- a/src/layouts/post.njk
+++ b/src/layouts/post.njk
@@ -1,9 +1,17 @@
-{# src/layouts/post.njk #} 
-{% extends "main.njk" %} 
+{# src/layouts/post.njk #}
+{% extends "main.njk" %}
 {% block content %}
-<article class="post">
-	{{ content | safe }}
-	<span><em>{{ date.toLocaleDateString('en-GB', { day: "numeric", month: "long", year: "numeric" }) }}</em></span>
-	<p><a href="/notes" aria-label="Back to notes">&larrhk; Back to notes</a></p>
+<article role="article" aria-labelledby="post-title">
+	<header>
+		<h2 id="post-title">{{ title }}</h2>
+		<time datetime="{{ date.toISOString() }}">{{ date.toLocaleDateString('en-GB', { day: "numeric", month: "long", year: "numeric" }) }}</time>
+	</header>
+
+	<section>{{ content | safe }}</section>
+
+	<nav aria-label="Post navigation">
+		<p><a href="/notes" rel="up">&larrhk; Back to notes</a></p>
+	</nav>
+
 </article>
 {% endblock %}
diff --git a/src/styles/index.css b/src/styles/index.css
index b83d99f..9a0d32f 100644
--- a/src/styles/index.css
+++ b/src/styles/index.css
@@ -84,3 +84,34 @@ footer li {
 		fill: var(--colour-link-alt);
 	}
 }
+
+/* Accessible skip-to-content link (classless) */
+/* Target the page anchor used in templates: href="#main-content" */
+a[href="#main-content"] {
+	position: absolute;
+	left: -999px;
+	width: 1px;
+	height: 1px;
+	overflow: hidden;
+	clip: rect(1px, 1px, 1px, 1px); /* legacy */
+	white-space: nowrap;
+	border: 0;
+	padding: 0;
+}
+
+a[href="#main-content"]:focus,
+a[href="#main-content"]:focus-visible {
+	position: fixed;
+	top: 1rem;
+	left: 1rem;
+	width: auto;
+	height: auto;
+	overflow: visible;
+	clip: auto;
+	background: var(--colour-dark);
+	color: var(--colour-light);
+	padding: 0.25rem 0.5rem;
+	border-radius: 4px;
+	z-index: 1000;
+	text-decoration: none;
+}