diff --git a/adapters/gitea.css b/adapters/gitea.css
new file mode 100644
index 0000000..3078f65
--- /dev/null
+++ b/adapters/gitea.css
@@ -0,0 +1,85 @@
+/**
+ * RSP Works - Gitea Theme Adapter
+ * Applies blog theme to Gitea interface
+ *
+ * Deploy to: /opt/gitea/data/gitea/custom/public/css/
+ * Then set CUSTOM_STYLE_URL in app.ini
+ */
+
+@import url('../css/core.css');
+
+/* Base */
+body {
+    background-color: var(--background) !important;
+    color: var(--text-primary) !important;
+    font-family: var(--font-family) !important;
+    font-size: var(--font-size-base) !important;
+}
+
+/* Links */
+a {
+    color: var(--link-color) !important;
+}
+a:hover, a:focus {
+    color: var(--link-hover) !important;
+}
+
+/* Top navigation bar */
+.ui.top.attached.header,
+.header .ui.menu {
+    background-color: var(--text-secondary) !important;
+    color: white !important;
+    border-color: var(--text-secondary) !important;
+}
+.ui.menu .item,
+.ui.menu a.item {
+    color: white !important;
+}
+.ui.menu .item:hover,
+.ui.menu a.item:hover {
+    background-color: var(--link-hover) !important;
+    color: white !important;
+}
+
+/* Buttons */
+.ui.primary.button {
+    background-color: var(--text-secondary) !important;
+    color: white !important;
+}
+.ui.primary.button:hover {
+    background-color: var(--link-hover) !important;
+}
+
+/* Repository list */
+.repository.list .item {
+    border-bottom: 1px solid #ddd !important;
+}
+
+/* Code blocks */
+.code-view .code-inner,
+.hljs {
+    background-color: var(--background) !important;
+    color: var(--text-primary) !important;
+}
+
+/* Headings */
+h1, h2, h3, h4, h5, h6 {
+    color: var(--text-primary) !important;
+}
+
+/* Cards / segments */
+.ui.segment {
+    background-color: white !important;
+    border-color: #ddd !important;
+}
+
+/* Footer */
+.footer {
+    color: var(--text-secondary) !important;
+}
+
+/* Selection */
+::selection {
+    background: var(--selection-bg);
+    color: var(--selection-text);
+}
diff --git a/adapters/nextcloud.css b/adapters/nextcloud.css
new file mode 100644
index 0000000..9ec233c
--- /dev/null
+++ b/adapters/nextcloud.css
@@ -0,0 +1,68 @@
+/**
+ * RSP Works - Nextcloud Theme Adapter
+ * Applies blog theme to Nextcloud interface
+ *
+ * Deploy to: Nextcloud container at /var/www/html/themes/custom/
+ */
+
+@import url('../css/core.css');
+
+/* Base */
+body {
+    background-color: var(--background) !important;
+    color: var(--text-primary) !important;
+    font-family: var(--font-family) !important;
+}
+
+/* Top header bar */
+#header {
+    background-color: var(--text-secondary) !important;
+}
+
+/* Links */
+a {
+    color: var(--link-color) !important;
+}
+a:hover, a:focus {
+    color: var(--link-hover) !important;
+}
+
+/* Buttons */
+.button.primary,
+button.primary,
+input[type="submit"] {
+    background-color: var(--text-secondary) !important;
+    color: white !important;
+    border-color: var(--text-secondary) !important;
+}
+.button.primary:hover,
+button.primary:hover {
+    background-color: var(--link-hover) !important;
+}
+
+/* Sidebar navigation */
+#app-navigation {
+    background-color: var(--background) !important;
+}
+#app-navigation a {
+    color: var(--text-secondary) !important;
+}
+#app-navigation a:hover {
+    color: var(--link-hover) !important;
+}
+
+/* Main content area */
+#app-content {
+    background-color: var(--background) !important;
+}
+
+/* Headings */
+h1, h2, h3, h4, h5, h6 {
+    color: var(--text-primary) !important;
+}
+
+/* Selection */
+::selection {
+    background: var(--selection-bg);
+    color: var(--selection-text);
+}
diff --git a/adapters/shlink.css b/adapters/shlink.css
new file mode 100644
index 0000000..cdfe54b
--- /dev/null
+++ b/adapters/shlink.css
@@ -0,0 +1,62 @@
+/**
+ * RSP Works - Shlink Theme Adapter
+ * Applies blog theme to Shlink URL shortener
+ *
+ * Note: Shlink is a React app - theming is limited.
+ * This works best injected via Nginx or a browser extension.
+ *
+ * Deploy to: FR1 Nginx config as a location block,
+ * or inject via browser extension on short.rspworks.tech
+ */
+
+@import url('../css/core.css');
+
+/* Base */
+body {
+    background-color: var(--background) !important;
+    color: var(--text-primary) !important;
+    font-family: var(--font-family) !important;
+}
+
+/* Links */
+a {
+    color: var(--link-color) !important;
+}
+a:hover, a:focus {
+    color: var(--link-hover) !important;
+}
+
+/* Shlink uses Bootstrap-style classes */
+.btn-primary {
+    background-color: var(--text-secondary) !important;
+    border-color: var(--text-secondary) !important;
+    color: white !important;
+}
+.btn-primary:hover {
+    background-color: var(--link-hover) !important;
+}
+
+/* Cards */
+.card {
+    background-color: white !important;
+    border-color: #ddd !important;
+}
+
+/* Navbar */
+.navbar {
+    background-color: var(--text-secondary) !important;
+}
+.navbar a, .navbar .nav-link {
+    color: white !important;
+}
+
+/* Headings */
+h1, h2, h3, h4, h5, h6 {
+    color: var(--text-primary) !important;
+}
+
+/* Selection */
+::selection {
+    background: var(--selection-bg);
+    color: var(--selection-text);
+}
diff --git a/adapters/ttrss.css b/adapters/ttrss.css
new file mode 100644
index 0000000..9302d88
--- /dev/null
+++ b/adapters/ttrss.css
@@ -0,0 +1,80 @@
+/**
+ * RSP Works - TT-RSS Theme Adapter
+ * Applies blog theme to Tiny Tiny RSS
+ *
+ * Deploy to: /var/www/tt-rss/themes/custom/ on FR1
+ * Or paste into TT-RSS Preferences > Interface > Custom CSS
+ */
+
+@import url('../css/core.css');
+
+/* Base */
+body {
+    background-color: var(--background) !important;
+    color: var(--text-primary) !important;
+    font-family: var(--font-family) !important;
+    font-size: var(--font-size-base) !important;
+}
+
+/* Links */
+a {
+    color: var(--link-color) !important;
+}
+a:hover, a:focus {
+    color: var(--link-hover) !important;
+}
+
+/* Toolbar */
+#toolbar {
+    background-color: var(--text-secondary) !important;
+    color: white !important;
+}
+#toolbar a {
+    color: white !important;
+}
+
+/* Feed list / headlines */
+#headlines-frame {
+    background-color: var(--background) !important;
+}
+
+/* Headline items */
+.hl {
+    border-bottom: 1px solid #ddd !important;
+    color: var(--text-primary) !important;
+}
+
+/* Selected headline */
+.hl.Selected {
+    background-color: var(--text-secondary) !important;
+    color: white !important;
+}
+.hl.Selected a {
+    color: white !important;
+}
+
+/* Read vs unread */
+.hl.read {
+    color: var(--text-secondary) !important;
+}
+.hl.unread {
+    color: var(--text-primary) !important;
+    font-weight: bold;
+}
+
+/* Article view */
+#content-frame {
+    background-color: white !important;
+    color: var(--text-primary) !important;
+}
+
+/* Headings */
+h1, h2, h3, h4, h5, h6 {
+    color: var(--text-primary) !important;
+}
+
+/* Selection */
+::selection {
+    background: var(--selection-bg);
+    color: var(--selection-text);
+}
diff --git a/css/core.css b/css/core.css
new file mode 100644
index 0000000..5fb7a77
--- /dev/null
+++ b/css/core.css
@@ -0,0 +1,54 @@
+/**
+ * RSP Works - Core Theme Variables
+ * Extracted from css/style.css
+ * Single source of truth for all service theming
+ *
+ * Usage: @import url('../css/core.css');
+ */
+
+:root {
+    /* Background */
+    --background: #f6f6e3;
+
+    /* Text */
+    --text-primary: black;
+    --text-secondary: #565;
+    --text-tertiary: #444;
+    --text-accent: #232;
+
+    /* Links */
+    --link-color: #565;
+    --link-hover: black;
+
+    /* Selection */
+    --selection-bg: #898;
+    --selection-text: white;
+
+    /* Typography */
+    --font-family: serif;
+    --font-size-base: 12pt;
+    --line-height: 1.5em;
+
+    /* Layout */
+    --max-width: 70em;
+    --padding-desktop: 2em 4em;
+    --padding-tablet: 1em 2em;
+    --padding-mobile: 1em 1em;
+
+    /* Breakpoints (for reference) */
+    --break-tablet: 720px;
+    --break-mobile: 53em;
+
+    /* Spacing */
+    --spacing-xs: 0.3em;
+    --spacing-sm: 0.5em;
+    --spacing-md: 1em;
+    --spacing-lg: 2em;
+    --spacing-xl: 4em;
+}
+
+/* Selection highlight */
+::selection {
+    background: var(--selection-bg);
+    color: var(--selection-text);
+}