1 files changed, 14 insertions, 10 deletions
diff --git a/src/construct/heading_atx.rs b/src/construct/heading_atx.rs
index 22b93db..30c22f3 100644
--- a/src/construct/heading_atx.rs
+++ b/src/construct/heading_atx.rs
@@ -70,16 +70,20 @@ use crate::tokenizer::Tokenizer;
 pub fn start(tokenizer: &mut Tokenizer) -> State {
     if tokenizer.parse_state.constructs.heading_atx {
         tokenizer.enter(Name::HeadingAtx);
-        tokenizer.attempt(State::Next(StateName::HeadingAtxBefore), State::Nok);
-        State::Retry(space_or_tab_min_max(
-            tokenizer,
-            0,
-            if tokenizer.parse_state.constructs.code_indented {
-                TAB_SIZE - 1
-            } else {
-                usize::MAX
-            },
-        ))
+        if matches!(tokenizer.current, Some(b'\t' | b' ')) {
+            tokenizer.attempt(State::Next(StateName::HeadingAtxBefore), State::Nok);
+            State::Retry(space_or_tab_min_max(
+                tokenizer,
+                0,
+                if tokenizer.parse_state.constructs.code_indented {
+                    TAB_SIZE - 1
+                } else {
+                    usize::MAX
+                },
+            ))
+        } else {
+            State::Retry(StateName::HeadingAtxBefore)
+        }
     } else {
         State::Nok
     }