1 files changed, 1 insertions, 1 deletions
diff --git a/src/values/length.rs b/src/values/length.rs
index 28a7156..556f8ff 100644
--- a/src/values/length.rs
+++ b/src/values/length.rs
@@ -50,7 +50,7 @@ impl Value for Length {
                 _ => Err(ParseLengthError::InvalidType),
             }
         } else {
-            if s.starts_with(|c: char| !c.is_alphabetic()) {
+            if s.starts_with(|c: char| c.is_ascii_digit()) {
                 return Err(ParseLengthError::MissingPrefix);
             }