diff --git a/profile/README.md b/profile/README.md
index fa0a4bd..520a40b 100644
--- a/profile/README.md
+++ b/profile/README.md
@@ -1,8 +1,22 @@
+<!-- The h1 sits below the brand lockup by design: the mark leads the hero.
+     The a11y requirement MD041 protects — a top-level heading naming the
+     document — is satisfied at "# Answers with receipts" below. MD041 stays
+     enforced for every other file in the repo. -->
+<!-- markdownlint-disable-next-line MD041 -->
 <div align="center">
 
-<img alt="citature — answers with receipts" src="https://raw.githubusercontent.com/citature/.github/main/profile/assets/mark.svg" width="112" height="112">
+<picture>
+  <source
+    media="(prefers-color-scheme: dark)"
+    srcset="https://raw.githubusercontent.com/citature/.github/main/profile/assets/mark-dark.svg">
+  <img
+    alt="citature"
+    src="https://raw.githubusercontent.com/citature/.github/main/profile/assets/mark.svg"
+    width="112"
+    height="112">
+</picture>
 
-### Answers with receipts
+# Answers with receipts
 
 **Agent-native tools over public US federal records.**
 
@@ -11,16 +25,16 @@ upstream government source, retrieval timestamps, coverage caveats, and match
 provenance on every cross-source join. Nothing is asserted without a locator you
 can re-fetch yourself.
 
-[citature.com](https://citature.com) &nbsp;·&nbsp; [Apify Store](https://apify.com/citature)
+[citature.com](https://citature.com) · [Apify Store](https://apify.com/citature)
 
 </div>
 
 ---
 
-### The data &nbsp;·&nbsp; primary sources only
+## The data
 
-Public-domain US federal records, refreshed nightly from the source of record —
-never an aggregator.
+Primary sources only. Public-domain US federal records, refreshed nightly from
+the source of record — never an aggregator.
 
 - **FEC** — campaign finance: 217M+ itemized contribution records across the
   2020–2026 cycles, plus committees and candidates
@@ -28,7 +42,9 @@ never an aggregator.
 - **SAM.gov** — contract opportunities and solicitations
 - **Grants.gov** — grant opportunities
 
-### The tools &nbsp;·&nbsp; on [Apify Store](https://apify.com/citature)
+## The tools
+
+Delivered on the [Apify Store](https://apify.com/citature).
 
 - **Money** — FEC contributions by state and committee type, federal awards by
   agency/state/recipient, follow-the-money committee inflows, and funding-entity
@@ -37,7 +53,7 @@ never an aggregator.
   contractor award lineage by agency, and agency buying patterns by year
 - **MCP** — every tool above delivered as agent-native calls from one MCP server
 
-### The rules
+## The rules
 
 Research over public records — never legal, financial, or eligibility advice.
 Entity-level data only; no individual-person products. citature reports what the
@@ -46,5 +62,8 @@ record says and never renders a verdict.
 ---
 
 <div align="center">
-  <sub><b><a href="https://citature.com">citature.com</a></b> &nbsp;·&nbsp; answers with receipts, from primary sources</sub>
+  <sub>
+    <b><a href="https://citature.com">citature.com</a></b>
+    · answers with receipts, from primary sources
+  </sub>
 </div>
diff --git a/profile/assets/mark-dark.svg b/profile/assets/mark-dark.svg
new file mode 100644
index 0000000..8490227
--- /dev/null
+++ b/profile/assets/mark-dark.svg
@@ -0,0 +1,5 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 1024 1024">
+  <rect width="1024" height="1024" fill="#141414"/>
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+  <g transform="translate(650.764 664.291) scale(0.594 -0.594)"><path d="M36 374L36 426L95 435Q110 437 114.5 445Q119 453 119 467L119 714Q119 735 114.5 742.5Q110 750 88 753L29 758L35 810L219 835L232 825L232 465Q232 450 236.5 443.5Q241 437 257 435L313 426L313 374Z" fill="#2FA37E"/></g>
+</svg>