diff --git a/README.md b/README.md
index 70b6347..d04783f 100644
--- a/README.md
+++ b/README.md
@@ -86,7 +86,7 @@ If a Shinylive app cannot be exported, the build fails. Move it to the server ru
 
 ## Input Help and Tooltips
 
-Use input tooltips conservatively. Add them only when a control represents a non-obvious statistical or mathematical concept, uses a confusing scale, changes the result conceptually, or needs context that does not fit naturally in its label.
+Use input tooltips conservatively across all apps, including drafts. Add them only when a control represents a non-obvious statistical or mathematical concept, uses a confusing scale, changes the result conceptually, or needs context that does not fit naturally in its label.
 
 - Treat two to four tooltips per app as an upper limit, not a target.
 - Do not add help to obvious controls such as the number of observations unless there is an important non-obvious consequence.
@@ -94,38 +94,32 @@ Use input tooltips conservatively. Add them only when a control represents a non
 - Do not repeat the general explanation already available in `readme.md`.
 - Preserve existing label wrappers such as `tags$small()` and the current sidebar spacing.
 - Use namespace-qualified calls instead of adding `library(bsicons)`.
-- Give icon-only triggers a short accessible `title`.
+- Do not set `title` on the icon trigger; browser-native title tooltips duplicate the `bslib` tooltip.
+- For an icon-only trigger, wrap the icon in an accessible span with `role = "button"` and an `aria-label`.
 - Add a small spacing utility such as `class = "ms-1"` so the icon remains visually separate from the label.
 - Support hover, keyboard focus, and click/touch with `options = list(trigger = "hover focus click")`.
-- Use a light tooltip theme with a white background, dark text, and a subtle border or shadow.
+- Use the repository tooltip background `#495057`; keep the rest of the appearance on Bootstrap defaults.
 - Test the icon at normal and narrow widths and verify the interaction directly in the running app.
 
-Configure the light tooltip appearance once in the app theme:
+Configure the tooltip appearance once in each app that uses tooltips:
 
 ```r
-apptheme <- bs_theme(
-  "tooltip-bg" = "$white",
-  "tooltip-color" = "$body-color",
-  "tooltip-opacity" = 1
-) |>
-  bs_add_rules(
-    ".tooltip-inner {
-      border: 1px solid $border-color;
-      box-shadow: $box-shadow-sm;
-    }"
-  )
+apptheme <- bs_theme("tooltip-bg" = "#495057")
 ```
 
+If the app already customizes `bs_theme()`, keep those settings and add `"tooltip-bg" = "#495057"` to the same call.
+
 Use this pattern, adapting the outer wrapper to the existing label:
 
 ```r
 label = tags$small(tagList(
   "Parameter name",
   bslib::tooltip(
-    bsicons::bs_icon(
-      "info-circle",
+    tags$span(
+      bsicons::bs_icon("info-circle"),
       class = "ms-1",
-      title = "About parameter name"
+      role = "button",
+      `aria-label` = "About parameter name"
     ),
     "Short explanation.",
     placement = "right",
diff --git a/app-template/app.R b/app-template/app.R
index 43d2cbc..6b61d44 100644
--- a/app-template/app.R
+++ b/app-template/app.R
@@ -3,7 +3,7 @@ library(shiny)
 library(bslib)
 
 # theme -------------------------------------------------------------------
-apptheme <- bs_theme()
+apptheme <- bs_theme("tooltip-bg" = "#495057")
 
 sidebar <- purrr::partial(bslib::sidebar, width = 300)
 
@@ -39,4 +39,4 @@ server <- function(input, output, session) {
   # Add server logic here.
 }
 
-shinyApp(ui, server)
\ No newline at end of file
+shinyApp(ui, server)
diff --git a/decision-tree/app.R b/decision-tree/app.R
index fb4beb0..297230d 100644
--- a/decision-tree/app.R
+++ b/decision-tree/app.R
@@ -12,7 +12,7 @@ library(risk3r)       # remotes::install_github("jbkunst/risk3r", force = TRUE)
 library(klassets)     # remotes::install_github("jbkunst/klassets", force = TRUE)
 
 # theme options -----------------------------------------------------------
-apptheme <- bs_theme()
+apptheme <- bs_theme("tooltip-bg" = "#495057")
 
 sidebar <- purrr::partial(bslib::sidebar, width = 300)
 
@@ -48,7 +48,20 @@ ui <- page_fillable(
         ),
       sliderInput(
         "percent_noise",
-        tags$small("Percent noise"),
+        tags$small(tagList(
+          "Percent noise",
+          bslib::tooltip(
+            tags$span(
+              bsicons::bs_icon("info-circle"),
+              class = "ms-1",
+              role = "button",
+              `aria-label` = "About percent noise"
+            ),
+            "Randomly flips this percentage of class labels, making the underlying relationship harder to learn.",
+            placement = "right",
+            options = list(trigger = "hover focus click")
+          )
+        )),
         min = 0,
         max = 50,
         step = 5,
@@ -253,4 +266,4 @@ server <- function(input, output, session) {
   
 }
 
-shinyApp(ui, server)
\ No newline at end of file
+shinyApp(ui, server)
diff --git a/lorenz-attractor/app.R b/lorenz-attractor/app.R
index 16159f1..27a6278 100644
--- a/lorenz-attractor/app.R
+++ b/lorenz-attractor/app.R
@@ -8,17 +8,7 @@ library(markdown)
 library(shinyWidgets)
 
 # theme options -----------------------------------------------------------
-apptheme <- bs_theme(
-  "tooltip-bg" = "$white",
-  "tooltip-color" = "$body-color",
-  "tooltip-opacity" = 1
-) |>
-  bs_add_rules(
-    ".tooltip-inner {
-      border: 1px solid $border-color;
-      box-shadow: $box-shadow-sm;
-    }"
-  )
+apptheme <- bs_theme("tooltip-bg" = "#495057")
 
 sidebar <- purrr::partial(bslib::sidebar, width = 300)
 
@@ -63,7 +53,12 @@ ui <- page_fillable(
         tagList(
           "\\( \\sigma \\) (sigma):",
           bslib::tooltip(
-            bsicons::bs_icon("info-circle", class = "ms-1", title = "About sigma"),
+            tags$span(
+              bsicons::bs_icon("info-circle"),
+              class = "ms-1",
+              role = "button",
+              `aria-label` = "About sigma"
+            ),
             "Controls how quickly x follows y.",
             placement = "right",
             options = list(trigger = "hover focus click")
@@ -79,7 +74,12 @@ ui <- page_fillable(
         tagList(
           "\\( \\rho \\) (rho):",
           bslib::tooltip(
-            bsicons::bs_icon("info-circle", class = "ms-1", title = "About rho"),
+            tags$span(
+              bsicons::bs_icon("info-circle"),
+              class = "ms-1",
+              role = "button",
+              `aria-label` = "About rho"
+            ),
             "Controls the system's driving strength and whether chaotic behavior emerges.",
             placement = "right",
             options = list(trigger = "hover focus click")
@@ -95,7 +95,12 @@ ui <- page_fillable(
         tagList(
           "\\( \\beta \\) (beta):",
           bslib::tooltip(
-            bsicons::bs_icon("info-circle", class = "ms-1", title = "About beta"),
+            tags$span(
+              bsicons::bs_icon("info-circle"),
+              class = "ms-1",
+              role = "button",
+              `aria-label` = "About beta"
+            ),
             "Controls damping in the z direction.",
             placement = "right",
             options = list(trigger = "hover focus click")
@@ -119,7 +124,12 @@ ui <- page_fillable(
         tagList(
           "Time step (dt):",
           bslib::tooltip(
-            bsicons::bs_icon("info-circle", class = "ms-1", title = "About time step"),
+            tags$span(
+              bsicons::bs_icon("info-circle"),
+              class = "ms-1",
+              role = "button",
+              `aria-label` = "About time step"
+            ),
             "Larger steps cover more time per point but reduce numerical accuracy.",
             placement = "right",
             options = list(trigger = "hover focus click")
diff --git a/pokemon-dimensionality-reduction/app.R b/pokemon-dimensionality-reduction/app.R
index fabab12..b035684 100644
--- a/pokemon-dimensionality-reduction/app.R
+++ b/pokemon-dimensionality-reduction/app.R
@@ -29,7 +29,8 @@ apptheme <- bs_theme(
   bg = "#f5f7fb",
   fg = "#172033",
   primary = "#2a75bb",
-  secondary = "#ffcb05"
+  secondary = "#ffcb05",
+  "tooltip-bg" = "#495057"
 )
 
 sidebar <- purrr::partial(bslib::sidebar, width = 305)
@@ -224,7 +225,20 @@ ui <- page_fillable(
         "input.method === 'tsne'",
         sliderInput(
           "perplexity",
-          "Perplexity",
+          tagList(
+            "Perplexity",
+            bslib::tooltip(
+              tags$span(
+                bsicons::bs_icon("info-circle"),
+                class = "ms-1",
+                role = "button",
+                `aria-label` = "About perplexity"
+              ),
+              "Controls the effective neighborhood size t-SNE tries to preserve; larger values emphasize broader structure.",
+              placement = "right",
+              options = list(trigger = "hover focus click")
+            )
+          ),
           min = 5,
           max = 100,
           value = 40,
@@ -243,7 +257,20 @@ ui <- page_fillable(
         "input.method === 'umap'",
         sliderInput(
           "n_neighbors",
-          "Neighbors",
+          tagList(
+            "Neighbors",
+            bslib::tooltip(
+              tags$span(
+                bsicons::bs_icon("info-circle"),
+                class = "ms-1",
+                role = "button",
+                `aria-label` = "About UMAP neighbors"
+              ),
+              "Controls how many nearby observations UMAP uses to define local structure; larger values emphasize broader patterns.",
+              placement = "right",
+              options = list(trigger = "hover focus click")
+            )
+          ),
           min = 2,
           max = 100,
           value = 30,
@@ -251,7 +278,20 @@ ui <- page_fillable(
         ),
         sliderInput(
           "min_dist",
-          "Minimum distance",
+          tagList(
+            "Minimum distance",
+            bslib::tooltip(
+              tags$span(
+                bsicons::bs_icon("info-circle"),
+                class = "ms-1",
+                role = "button",
+                `aria-label` = "About UMAP minimum distance"
+              ),
+              "Controls how tightly UMAP can pack nearby points in the embedding; smaller values form denser clusters.",
+              placement = "right",
+              options = list(trigger = "hover focus click")
+            )
+          ),
           min = 0,
           max = 0.95,
           value = 0.15,