rstudio · gadenbuie · Aug 25, 2026 · Aug 20, 2026 · Aug 20, 2026 · Aug 20, 2026
diff --git a/NEWS.md b/NEWS.md
@@ -1,5 +1,9 @@
 # bslib (development version)
 
+## Bug fixes
+
+* Fixed `input_dark_mode()` writing an invalid `"undefined"` value to the `data-bs-theme` attribute when it connected while the document was already set to `"light"`. (#1349)
+
 ## Breaking changes
 
 * `show_offcanvas()` now accepts a character `id` to reveal a panel already in the UI, in addition to a `bslib_offcanvas` object. Previously, a bare string was treated as body content for a new anonymous panel; it is now treated as an id lookup instead, and errors if it looks like body text (e.g. it contains whitespace or is empty). `htmltools::HTML()` continues to be treated as body content. (#1346)

diff --git a/R/sysdata.rda b/R/sysdata.rda
diff --git a/inst/components/dist/web-components.js b/inst/components/dist/web-components.js
diff --git a/inst/components/dist/web-components.js.map b/inst/components/dist/web-components.js.map
diff --git a/inst/components/dist/web-components.min.js b/inst/components/dist/web-components.min.js
diff --git a/inst/components/dist/web-components.min.js.map b/inst/components/dist/web-components.min.js.map
diff --git a/inst/lib/bsw3/yeti/font.css b/inst/lib/bsw3/yeti/font.css
diff --git a/man/figures/logo.png b/man/figures/logo.png
diff --git a/man/figures/navset-card-pill.png b/man/figures/navset-card-pill.png
diff --git a/man/figures/navset-card-underline.png b/man/figures/navset-card-underline.png
diff --git a/man/figures/navset-pill-list.png b/man/figures/navset-pill-list.png
diff --git a/man/figures/navset-pill.png b/man/figures/navset-pill.png
diff --git a/man/figures/navset-tab-basic.png b/man/figures/navset-tab-basic.png
diff --git a/man/figures/navset-tab-card.png b/man/figures/navset-tab-card.png
diff --git a/man/figures/navset-tab.png b/man/figures/navset-tab.png
diff --git a/man/figures/navset-underline.png b/man/figures/navset-underline.png
diff --git a/man/figures/navset_card_pill.png b/man/figures/navset_card_pill.png
diff --git a/man/figures/page-navbar.png b/man/figures/page-navbar.png
diff --git a/man/figures/value-box-background-color.png b/man/figures/value-box-background-color.png
diff --git a/man/figures/value-box-background-theme.png b/man/figures/value-box-background-theme.png
diff --git a/man/figures/value-box-custom.png b/man/figures/value-box-custom.png
diff --git a/man/figures/value-box-gradient-1.png b/man/figures/value-box-gradient-1.png
diff --git a/man/figures/value-box-named-color.png b/man/figures/value-box-named-color.png
diff --git a/man/figures/value-box-named-theme.png b/man/figures/value-box-named-theme.png
diff --git a/man/figures/value-box-showcase-bottom.png b/man/figures/value-box-showcase-bottom.png
diff --git a/man/figures/value-box-showcase-left-center.png b/man/figures/value-box-showcase-left-center.png
diff --git a/man/figures/value-box-showcase-top-right.png b/man/figures/value-box-showcase-top-right.png
diff --git a/man/figures/value-box-text-color.png b/man/figures/value-box-text-color.png
diff --git a/man/figures/value-box-text-theme.png b/man/figures/value-box-text-theme.png
diff --git a/man/figures/value-box-theme-class.png b/man/figures/value-box-theme-class.png
diff --git a/srcts/src/components/webcomponents/inputDarkMode.ts b/srcts/src/components/webcomponents/inputDarkMode.ts
@@ -229,7 +229,7 @@ export class BslibInputDarkMode extends LitElement {
       if (fromDom === "dark") {
         this.mode = "dark";
       } else if (fromDom === "light") {
-        this.mode == "light";
+        this.mode = "light";
       } else {
         this.mode = window.matchMedia("(prefers-color-scheme: dark)").matches
           ? "dark"

diff --git a/vignettes/any-project/rstudio-templates.png b/vignettes/any-project/rstudio-templates.png
diff --git a/vignettes/custom-components/person.png b/vignettes/custom-components/person.png
diff --git a/vignettes/theming/bootswatch.png b/vignettes/theming/bootswatch.png
diff --git a/vignettes/theming/custom-dark-mode.png b/vignettes/theming/custom-dark-mode.png
diff --git a/vignettes/theming/nes.png b/vignettes/theming/nes.png
diff --git a/vignettes/theming/progress-gray.png b/vignettes/theming/progress-gray.png
diff --git a/vignettes/theming/progress-orange.png b/vignettes/theming/progress-orange.png
diff --git a/vignettes/theming/themer-code.png b/vignettes/theming/themer-code.png
diff --git a/vignettes/utility-classes/DT-card-custom.png b/vignettes/utility-classes/DT-card-custom.png
diff --git a/vignettes/utility-classes/DT-card.png b/vignettes/utility-classes/DT-card.png
diff --git a/vignettes/utility-classes/pills.png b/vignettes/utility-classes/pills.png
diff --git a/vignettes/utility-classes/rmarkdown-tabs-source.png b/vignettes/utility-classes/rmarkdown-tabs-source.png
diff --git a/vignettes/utility-classes/rmarkdown-tabs.png b/vignettes/utility-classes/rmarkdown-tabs.png
diff --git a/vignettes/utility-classes/tab-after.png b/vignettes/utility-classes/tab-after.png
diff --git a/vignettes/utility-classes/tab-before.png b/vignettes/utility-classes/tab-before.png