diff --git a/sx/sxc/pages/__init__.py b/sx/sxc/pages/__init__.py
index 1380c13..7a19bc7 100644
--- a/sx/sxc/pages/__init__.py
+++ b/sx/sxc/pages/__init__.py
@@ -413,45 +413,104 @@ async def _docs_primitives_sx() -> str:
 
 
 def _docs_css_sx() -> str:
-    c1 = _code('# First page load:\n'
-               'GET / HTTP/1.1\n\n'
-               'HTTP/1.1 200 OK\n'
-               'Content-Type: text/html\n'
-               '# Full CSS in <style id="sx-css"> + hash in <meta name="sx-css-classes">\n\n'
-               '# Subsequent navigation:\n'
-               'GET /about HTTP/1.1\n'
-               'SX-Css: a1b2c3d4\n\n'
-               'HTTP/1.1 200 OK\n'
-               'Content-Type: text/sx\n'
-               'SX-Css-Hash: e5f6g7h8\n'
-               'SX-Css-Add: bg-blue-500,text-white,rounded-lg\n'
-               '# Only new rules in <style data-sx-css>', "bash")
+    c_css_basic = _code(';; Native style expressions\n'
+                        '(div :style (css :flex :gap-4 :p-2) "hello")\n'
+                        ';; => <div class="sx-faa0d2">hello</div>\n'
+                        ';; with .sx-faa0d2{display:flex;gap:1rem;padding:.5rem}\n\n'
+                        ';; Pseudo-class variants\n'
+                        '(button :style (css :bg-sky-500 :hover:bg-sky-600 :text-white :rounded) "Click")\n\n'
+                        ';; Responsive variants\n'
+                        '(div :style (css :flex :flex-col :sm:flex-row :gap-4) ...)\n\n'
+                        ';; Arbitrary values\n'
+                        '(div :style (css :w-[347px] :h-[60vh] :bg-[#f0f]) ...)')
+    c_defstyle = _code(';; Named styles with defstyle\n'
+                       '(defstyle card-base\n'
+                       '  (css :rounded-xl :bg-white :shadow :hover:shadow-md :transition))\n\n'
+                       '(div :style card-base "I am a card")\n\n'
+                       ';; Composition with merge-styles\n'
+                       '(div :style (merge-styles card-base (css :p-4 :border :border-stone-200))\n'
+                       '  "Card with extra styles")')
+    c_defkeyframes = _code(';; Custom keyframes\n'
+                           '(defkeyframes fade-in\n'
+                           '  (from (css :opacity-0))\n'
+                           '  (to (css :opacity-100)))\n\n'
+                           '(defkeyframes slide-up\n'
+                           '  ("0%" (css :translate-y-4 :opacity-0))\n'
+                           '  ("100%" (css :translate-y-0 :opacity-100)))\n\n'
+                           ';; Use with animate-{name}\n'
+                           '(div :style (css :animate-fade-in :duration-300) "Animated")')
+    c_protocol = _code('# First page load:\n'
+                       'GET / HTTP/1.1\n\n'
+                       'HTTP/1.1 200 OK\n'
+                       'Content-Type: text/html\n'
+                       '# Full CSS in <style id="sx-css"> + hash in <meta name="sx-css-classes">\n\n'
+                       '# Subsequent navigation:\n'
+                       'GET /about HTTP/1.1\n'
+                       'SX-Css: a1b2c3d4\n\n'
+                       'HTTP/1.1 200 OK\n'
+                       'Content-Type: text/sx\n'
+                       'SX-Css-Hash: e5f6g7h8\n'
+                       'SX-Css-Add: bg-blue-500,text-white,rounded-lg\n'
+                       '# Only new rules in <style data-sx-css>', "bash")
+    c_atoms = _code(';; The css primitive accepts keyword atoms\n'
+                    ';; Each atom maps to self-contained CSS declarations:\n'
+                    ';;   :flex        => display:flex\n'
+                    ';;   :gap-4       => gap:1rem\n'
+                    ';;   :bg-sky-100  => background-color:rgb(224 242 254)\n'
+                    ';;   :shadow      => box-shadow:0 1px 3px 0 rgba(0,0,0,.1),...\n\n'
+                    ';; Variant prefixes are split and wrapped automatically:\n'
+                    ';;   :hover:bg-sky-200  => .sx-xxx:hover{background-color:...}\n'
+                    ';;   :sm:flex-row       => @media (min-width:640px){.sx-xxx{...}}\n'
+                    ';;   :sm:hover:bg-sky-200 => compound variant (media + pseudo)')
     return (
-        f'(~doc-page :title "On-Demand CSS"'
+        f'(~doc-page :title "CSS"'
+        f'  (~doc-section :title "Native style expressions" :id "css-primitive"'
+        f'    (p :class "text-stone-600"'
+        f'      "The css primitive replaces Tailwind class strings with native SX expressions. '
+        f'Each keyword atom maps to self-contained CSS declarations. The result is a StyleValue '
+        f'with a content-addressed class name (sx-{{hash}}) and generated CSS rules.")'
+        f'    {c_css_basic})'
+        f'  (~doc-section :title "Style atoms" :id "atoms"'
+        f'    (p :class "text-stone-600"'
+        f'      "~500 atoms cover all standard utilities: display, position, flexbox, grid, spacing, '
+        f'sizing, typography, colors, borders, shadows, transitions, animations, and more. '
+        f'Atoms use the same names as Tailwind classes but resolve to self-contained CSS — '
+        f'no --tw-* custom properties needed.")'
+        f'    {c_atoms})'
+        f'  (~doc-section :title "Variants" :id "variants"'
+        f'    (p :class "text-stone-600"'
+        f'      "Pseudo-class variants: hover, focus, focus-within, focus-visible, active, disabled, '
+        f'first, last, odd, even, empty, open, placeholder, group-hover, group-open. '
+        f'Responsive breakpoints: sm (640px), md (768px), lg (1024px), xl (1280px), 2xl (1536px). '
+        f'Variants can be combined: sm:hover:bg-sky-200."))'
+        f'  (~doc-section :title "Named styles" :id "defstyle"'
+        f'    (p :class "text-stone-600"'
+        f'      "defstyle binds a css expression to a name for reuse. '
+        f'merge-styles combines multiple StyleValues into one, with later declarations winning.")'
+        f'    {c_defstyle})'
+        f'  (~doc-section :title "Keyframes" :id "defkeyframes"'
+        f'    (p :class "text-stone-600"'
+        f'      "defkeyframes defines custom CSS @keyframes animations. Each step takes a '
+        f'selector (from, to, or a percentage) and a css body. The keyframes are registered '
+        f'globally so animate-{{name}} atoms can reference them.")'
+        f'    {c_defkeyframes})'
+        f'  (~doc-section :title "On-demand delivery" :id "delivery"'
+        f'    (p :class "text-stone-600"'
+        f'      "Generated CSS rules flow through the same on-demand delivery pipeline as Tailwind classes. '
+        f'On the first page load, all used CSS is embedded in a <style> block. On subsequent navigations, '
+        f'the client sends a hash of known classes and the server sends only new rules.")'
+        f'    {c_protocol})'
         f'  (~doc-section :title "How it works" :id "how"'
         f'    (p :class "text-stone-600"'
-        f'      "sx scans every response for CSS class names used in :class attributes. '
-        f'It looks up only those classes in a pre-parsed Tailwind CSS registry and ships '
-        f'just the rules that are needed. No build step. No purging. No unused CSS.")'
+        f'      "Server-side: the css primitive resolves atoms to a StyleValue with declarations. '
+        f'The HTML renderer converts :style StyleValue to a class attribute and registers the CSS rule '
+        f'in the on-demand registry. Rules are delivered via the SX-Css delta protocol.")'
         f'    (p :class "text-stone-600"'
-        f'      "On the first page load, the full set of used classes is embedded in a <style> block. '
-        f'A hash of the class set is stored. On subsequent navigations, the client sends the hash '
-        f'in the SX-Css header. The server computes the diff and sends only new rules via '
-        f'SX-Css-Add and a <style data-sx-css> block."))'
-        f'  (~doc-section :title "The protocol" :id "protocol"'
-        f'    {c1})'
-        f'  (~doc-section :title "Advantages" :id "advantages"'
-        f'    (ul :class "space-y-2 text-stone-600"'
-        f'      (li "Zero build step — no Tailwind CLI, no PostCSS, no purging")'
-        f'      (li "Exact CSS — never ships a rule that isn\'t used on the page")'
-        f'      (li "Incremental — subsequent navigations only ship new rules")'
-        f'      (li "Component-aware — pre-scans component definitions at registration time")))'
-        f'  (~doc-section :title "Disadvantages" :id "disadvantages"'
-        f'    (ul :class "space-y-2 text-stone-600"'
-        f'      (li "Requires the full Tailwind CSS file loaded in memory at startup (~4MB parsed)")'
-        f'      (li "Regex-based class scanning — can miss dynamically constructed class names")'
-        f'      (li "No @apply support — classes must be used directly")'
-        f'      (li "Tied to Tailwind\'s utility class naming conventions"))))'
+        f'      "Client-side: the style dictionary is delivered as a JSON payload in a '
+        f'<script type=text/sx-styles> tag, cached in localStorage with the same hash+cookie pattern '
+        f'as components. The client-side css primitive mirrors the server resolver — same atoms, '
+        f'same variant splitting, same content-addressed class names. Generated CSS is injected '
+        f'into <style id=sx-css>.")))'
     )