[doc] add a blank line
diff --git a/readme.md b/readme.md
index 1254d49..1f72b76 100644
--- a/readme.md
+++ b/readme.md
@@ -23,6 +23,7 @@
 - fully support AVX-512
 
 - support APX
+
 **Note**:
 Use `and_()`, `or_()`, ... instead of `and()`, `or()`.
 If you want to use them, then specify `-fno-operator-names` option to gcc/clang.