diff --git a/docs/libs.rst b/docs/libs.rst
index e2a7dba0..ebec4f88 100644
--- a/docs/libs.rst
+++ b/docs/libs.rst
@@ -55,26 +55,21 @@ Explicit renaming macro family.
 (picrin regexp)
 ---------------
 
-(regexp ptrn [flags])
-^^^^^^^^^^^^^^^^^^^^^
+.. topic:: (regexp ptrn [flags])
 
 Compiles pattern string into a regexp object. A string flags may contain any of #\g, #\i, #\m.
 
-(regexp? obj)
-^^^^^^^^^^^^^
+.. topic:: (regexp? obj)
 
 Judges if obj is a regexp object or not.
 
-(regexp-match re input)
-^^^^^^^^^^^^^^^^^^^^^^^
+.. topic:: (regexp-match re input)
 
 Returns two values: a list of match strings, and a list of match indeces.
 
-(regexp-replace re input txt)
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+.. topic:: (regexp-replace re input txt)
 
-(regexp-split re input)
-^^^^^^^^^^^^^^^^^^^^^^^
+.. topic:: (regexp-split re input)
 
 (picrin control)
 ----------------