diff --git a/crates/treehouse/src/html/highlight/tokenize.rs b/crates/treehouse/src/html/highlight/tokenize.rs
index 3ced033..30865ce 100644
--- a/crates/treehouse/src/html/highlight/tokenize.rs
+++ b/crates/treehouse/src/html/highlight/tokenize.rs
@@ -24,7 +24,38 @@ impl CompiledSyntax {
                             break;
                         }
                     }
-                    CompiledTokenTypes::Captures(types) => { /* TODO */ }
+                    CompiledTokenTypes::Captures(types) => {
+                        if let Some(captures) = pattern.regex.captures(&text[i..]) {
+                            let whole_match = captures.get(0).unwrap();
+                            let mut last_match_end = 0;
+                            for (index, capture) in captures
+                                .iter()
+                                .skip(1)
+                                .enumerate()
+                                .filter_map(|(i, m)| m.map(|m| (i, m)))
+                            {
+                                let id = types
+                                    .captures
+                                    .get(index)
+                                    .copied()
+                                    .unwrap_or(TOKEN_ID_DEFAULT);
+                                push_token(
+                                    &mut tokens,
+                                    types.default,
+                                    i + last_match_end..i + capture.range().start,
+                                );
+                                push_token(
+                                    &mut tokens,
+                                    id,
+                                    i + capture.range().start..i + capture.range().end,
+                                );
+                                last_match_end = capture.range().end;
+                            }
+                            i += whole_match.range().end;
+                            had_match = true;
+                            break;
+                        }
+                    }
                 }
             }
 
@@ -47,6 +78,10 @@ impl CompiledSyntax {
 }
 
 fn push_token(tokens: &mut Vec<Token>, id: TokenId, range: Range<usize>) {
+    if range.is_empty() {
+        return;
+    }
+
     if let Some(previous_token) = tokens.last_mut() {
         if previous_token.id == id {
             previous_token.range.end = range.end;
diff --git a/crates/treehouse/src/html/markdown.rs b/crates/treehouse/src/html/markdown.rs
index 4415419..308b66f 100644
--- a/crates/treehouse/src/html/markdown.rs
+++ b/crates/treehouse/src/html/markdown.rs
@@ -23,7 +23,6 @@
 
 //! HTML renderer that takes an iterator of events as input.
 
-use std::borrow::Borrow;
 use std::collections::HashMap;
 use std::io;