diff --git a/src/browser/main/tab/page/content/text/gemini/reader/parser/header.rs b/src/browser/main/tab/page/content/text/gemini/reader/parser/header.rs
new file mode 100644
index 00000000..a440c642
--- /dev/null
+++ b/src/browser/main/tab/page/content/text/gemini/reader/parser/header.rs
@@ -0,0 +1,79 @@
+use gtk::glib::{markup_escape_text, GString, Regex, RegexCompileFlags, RegexMatchFlags};
+
+pub enum Level {
+    H1,
+    H2,
+    H3,
+}
+
+pub struct Header {
+    level: Level,
+    text: GString,
+    markup: GString,
+}
+
+impl Header {
+    pub fn from(line: &str) -> Option<Header> {
+        // Parse line
+        let parsed = Regex::split_simple(
+            r"^(#{1,3})\s*(.+)$",
+            line,
+            RegexCompileFlags::DEFAULT,
+            RegexMatchFlags::DEFAULT,
+        );
+
+        // Validate match results
+        if let Some(text) = parsed.get(2) {
+            if let Some(level) = parsed.get(1) {
+                // Init level
+                let level = match level.len() {
+                    1 => Level::H1,
+                    2 => Level::H2,
+                    3 => Level::H3,
+                    _ => return None,
+                };
+
+                // Init text
+                let text = GString::from(text.as_str());
+
+                if text.trim().is_empty() {
+                    return None;
+                }
+
+                // Init markup
+                let markup = match level {
+                    Level::H1 => GString::from(format!(
+                        "<span size=\"xx-large\">{}</span>\n",
+                        markup_escape_text(&text)
+                    )),
+                    Level::H2 => GString::from(format!(
+                        "<span size=\"x-large\">{}</span>\n",
+                        markup_escape_text(&text)
+                    )),
+                    Level::H3 => GString::from(format!(
+                        "<span size=\"large\">{}</span>\n",
+                        markup_escape_text(&text)
+                    )),
+                    _ => return None,
+                };
+
+                // Result
+                return Some(Header {
+                    level,
+                    text,
+                    markup,
+                });
+            }
+        }
+
+        None // not header line given
+    }
+
+    pub fn text(&self) -> &GString {
+        &self.text
+    }
+
+    pub fn markup(&self) -> &GString {
+        &self.markup
+    }
+}
diff --git a/src/browser/main/tab/page/content/text/gemini/reader/parser/mod.rs b/src/browser/main/tab/page/content/text/gemini/reader/parser/mod.rs
new file mode 100644
index 00000000..f505d688
--- /dev/null
+++ b/src/browser/main/tab/page/content/text/gemini/reader/parser/mod.rs
@@ -0,0 +1 @@
+pub mod header;