diff --git a/.beans/ATFS-dfm3--atfsdev-docs-split-into-a-multi-page-diataxis-site.md b/.beans/ATFS-dfm3--atfsdev-docs-split-into-a-multi-page-diataxis-site.md
index e76b1fa..5f8eec2 100644
--- a/.beans/ATFS-dfm3--atfsdev-docs-split-into-a-multi-page-diataxis-site.md
+++ b/.beans/ATFS-dfm3--atfsdev-docs-split-into-a-multi-page-diataxis-site.md
@@ -320,6 +320,19 @@ afterthought.
       `reference/error-codes/+page.svelte`'s local `ErrorCodeMeta` type
       updated to match. Both the field consolidation and the tense/voice
       rules are documented in CLAUDE.md's docs-conventions bullet.
+- [x] Required settings' `ATFS_DATA_DIR` paragraph mixed SBC and Docker
+      defaults into one ungated bullet list, missed by the original
+      platform-toggle pass — reported by the user directly off the built
+      page. Split into an `sbc`/`docker` `PlatformBlock` pair, same
+      pattern as the rest of the page. Swept every other `relevance:
+      common` page for the same problem (a paragraph stating different
+      per-platform facts inline, ungated) and found none — the one other
+      close call, `reference/settings/`'s `ATFS_DATA_DIR` row, is a
+      deliberately dense one-line-per-field comparison (matching
+      `ATFS_HTTP_PORT`'s own `2837 (80 in Docker)` aside) that also names
+      a third "bare binary" default the toggle has no state for, so it
+      stayed as-is rather than being forced into block-level
+      `PlatformBlock`s.
 
 ## Known gaps
 
diff --git a/web/src/routes/docs/configuration/required-settings/+page.md b/web/src/routes/docs/configuration/required-settings/+page.md
index 37e11bc..0f7df05 100644
--- a/web/src/routes/docs/configuration/required-settings/+page.md
+++ b/web/src/routes/docs/configuration/required-settings/+page.md
@@ -32,12 +32,21 @@ A fresh owner is not automatically an uploader. Add the owner's own DID to
 </Callout>
 
 **`ATFS_DATA_DIR`** is where blobs and the node's libp2p identity are
-stored. Its default differs by platform:
+stored. Its default differs by platform.
 
-- In Docker, it is `/data`, the image's working directory.
-- On an SBC with onboard eMMC, it is the eMMC, formatted automatically on
-  first boot.
-- On an SBC without onboard eMMC, it is the SD card's own `/data` partition.
+<PlatformBlock platform="sbc">
+
+With onboard eMMC, the default is the eMMC, formatted automatically on
+first boot. Without onboard eMMC, it is the SD card's own `/data`
+partition.
+
+</PlatformBlock>
+
+<PlatformBlock platform="docker">
+
+The default is `/data`, the image's working directory.
+
+</PlatformBlock>
 
 **`ATFS_IDENTITY_KEY`** is normally left empty. atfs generates a libp2p
 identity key on first run and keeps it in the data directory. Set this