diff --git a/_pkgdown.yml b/_pkgdown.yml
index a633bd4..2c58d85 100644
--- a/_pkgdown.yml
+++ b/_pkgdown.yml
@@ -1,6 +1,8 @@
 url: https://shikokuchuo.net/secretbase/
 template:
   bootstrap: 5
+  bslib:
+    primary: "#0043ce"
 navbar:
   right:
   - icon: fa-github
diff --git a/pkgdown/extra.css b/pkgdown/extra.css
deleted file mode 100644
index 1ae185d..0000000
--- a/pkgdown/extra.css
+++ /dev/null
@@ -1,32 +0,0 @@
-body {
-  font-family: system-ui, "Helvetica Neue", Helvetica, Arial, sans-serif;
-  min-height: 100vh;
-}
-a { color: #0043ce; }
-a:hover { text-decoration: underline; }
-.navbar-default {
-  background-color: #ffffff;
-}
-.label-default {
-  color: #001d6c;
-  background-color: #ffffff;
-}
-footer {
-  color: #02141c
-}
-.navbar-default .navbar-link,
-.navbar-default .navbar-nav>li>a {
-  color:#02141c
-}
-.navbar-default .navbar-nav>li>a:hover,
-.navbar-default .navbar-nav>li>a:focus {
-  color:#0043ce;
-  background-color:transparent
-}
-.navbar-default .navbar-nav>.active>a,
-.navbar-default .navbar-nav>.active>a:hover,
-.navbar-default .navbar-nav>.active>a:focus {
-  color:#0043ce;
-  background-color:transparent
-}
-