diff --git a/internal/action/edit.go b/internal/action/edit.go
index 7e4ce90..d34e7c0 100644
--- a/internal/action/edit.go
+++ b/internal/action/edit.go
@@ -23,7 +23,7 @@ func View(cfg *config.Config, w http.ResponseWriter, r *http.Request, params *Pa
 
 	tmpl := util.NewTemplate("view.html")
 	title, _, plain, rendered := format.Apply(cfg, params.DbName, content)
-	summary := format.Summarize(plain, 144)
+	summary := format.TrimForSummary(plain, 144)
 
 	subAction := r.URL.Query().Get("b")
 	diffText := ""
diff --git a/internal/format/creole.go b/internal/format/creole.go
index a7e4069..8f16ae2 100644
--- a/internal/format/creole.go
+++ b/internal/format/creole.go
@@ -1,6 +1,6 @@
 package format
 
 // TODO
-func creole(cfg formatConfig, title string, text string) (string, string, string, string) {
-	return nomark(cfg, title, text) // fallback
+func creole(fc formatConfig, title string, text string) (string, string, string, string) {
+	return nomark(fc, title, text) // fallback
 }
diff --git a/internal/format/format.go b/internal/format/format.go
index de2f2db..83c060d 100644
--- a/internal/format/format.go
+++ b/internal/format/format.go
@@ -6,40 +6,49 @@ import (
 	"github.com/akikareha/himewiki/internal/config"
 )
 
-// Returns title, wiki text, plain text, HTML
+// Apply applies wiki formatting on input text
+// and returns title, wiki text, plain text, HTML.
 func Apply(cfg *config.Config, title string, text string) (string, string, string, string) {
 	if len(text) < 1 {
-		return title, text, text, ""
+		return title, "", "", ""
 	}
 	head := text[0]
 
-	fcfg := toFormatConfig(cfg)
+	fc := toFormatConfig(cfg)
 
 	// Detect markup by very first character of input text.
 	// * '=' : Creole
 	// * '#' : Markdown
 	// * Others : Nomark
 	if head == '=' {
-		return creole(fcfg, title, text)
+		return creole(fc, title, text)
 	} else if head == '#' {
-		return markdown(fcfg, title, text)
+		return markdown(fc, title, text)
 	} else {
-		return nomark(fcfg, title, text)
+		return nomark(fc, title, text)
 	}
 }
 
-func Summarize(s string, n int) string {
-	if n < 2 {
+// TrimForSummary trims text to specified length with ellipsis.
+// Spaces are compressed.
+func TrimForSummary(text string, length int) string {
+	if length < 0 {
+		panic("program error")
+	}
+	if length < 1 {
+		return ""
+	}
+	if length < 2 {
 		return "."
 	}
 
-	var b strings.Builder
-	long := false
+	var buf strings.Builder
+	overflowed := false
 	space := false
 	i := 0
-	for _, r := range s {
-		if i >= n-2 {
-			long = true
+	for _, r := range text {
+		if i >= length-2 {
+			overflowed = true
 			break
 		}
 		if r == '\r' || r == '\n' || r == '\t' {
@@ -52,13 +61,13 @@ func Summarize(s string, n int) string {
 		} else {
 			space = false
 		}
-		b.WriteRune(r)
+		buf.WriteRune(r)
 		i++
 	}
 
-	if long {
-		return b.String() + ".."
+	if overflowed {
+		return buf.String() + ".."
 	} else {
-		return b.String()
+		return buf.String()
 	}
 }
diff --git a/internal/format/markdown.go b/internal/format/markdown.go
index f558b6a..b84f790 100644
--- a/internal/format/markdown.go
+++ b/internal/format/markdown.go
@@ -1,6 +1,6 @@
 package format
 
 // TODO
-func markdown(cfg formatConfig, title string, text string) (string, string, string, string) {
-	return nomark(cfg, title, text) // fallback
+func markdown(fc formatConfig, title string, text string) (string, string, string, string) {
+	return nomark(fc, title, text) // fallback
 }
diff --git a/internal/format/nomark.go b/internal/format/nomark.go
index 41fbb17..c487e1f 100644
--- a/internal/format/nomark.go
+++ b/internal/format/nomark.go
@@ -203,7 +203,7 @@ func ensureBlock(s *state, block blockMode) {
 	openBlock(s, block)
 }
 
-func math(cfg formatConfig, s *state) bool {
+func math(fc formatConfig, s *state) bool {
 	line := s.input[s.index:s.lineEnd]
 	if !strings.HasPrefix(line, "%%") {
 		return false
@@ -231,7 +231,7 @@ func math(cfg formatConfig, s *state) bool {
 	return true
 }
 
-func strong(cfg formatConfig, s *state) bool {
+func strong(fc formatConfig, s *state) bool {
 	line := s.input[s.index:s.lineEnd]
 	if !strings.HasPrefix(line, "**") {
 		return false
@@ -266,7 +266,7 @@ func strong(cfg formatConfig, s *state) bool {
 	}
 	s.index += 2
 
-	markup(cfg, s)
+	markup(fc, s)
 
 	if s.innerDeco == decoStrong {
 		s.html.WriteString("</strong>")
@@ -287,7 +287,7 @@ func strong(cfg formatConfig, s *state) bool {
 	return true
 }
 
-func em(cfg formatConfig, s *state) bool {
+func em(fc formatConfig, s *state) bool {
 	line := s.input[s.index:s.lineEnd]
 	if !strings.HasPrefix(line, "//") {
 		return false
@@ -322,7 +322,7 @@ func em(cfg formatConfig, s *state) bool {
 	}
 	s.index += 2
 
-	markup(cfg, s)
+	markup(fc, s)
 
 	if s.innerDeco == decoEm {
 		s.html.WriteString("</em>")
@@ -477,7 +477,7 @@ func nonURLIndex(line string) int {
 	return len(line)
 }
 
-func link(cfg formatConfig, s *state) bool {
+func link(fc formatConfig, s *state) bool {
 	line := s.input[s.index:s.lineEnd]
 	if !strings.HasPrefix(line, "https:") {
 		return false
@@ -496,7 +496,7 @@ func link(cfg formatConfig, s *state) bool {
 		ext = ext[1:]
 	}
 	extFound := false
-	for _, extension := range cfg.image.extensions {
+	for _, extension := range fc.image.extensions {
 		if ext == extension {
 			extFound = true
 			break
@@ -504,7 +504,7 @@ func link(cfg formatConfig, s *state) bool {
 	}
 	domainFound := false
 	if extFound {
-		for _, domain := range cfg.image.domains {
+		for _, domain := range fc.image.domains {
 			if u.Host == domain {
 				domainFound = true
 				break
@@ -616,19 +616,19 @@ func parseHeading(s *state, line string) (int, string, bool) {
 	return level, title, true
 }
 
-func markup(cfg formatConfig, s *state) {
+func markup(fc formatConfig, s *state) {
 	for s.index < s.lineEnd {
-		if math(cfg, s) {
+		if math(fc, s) {
 			continue
-		} else if strong(cfg, s) {
+		} else if strong(fc, s) {
 			continue
-		} else if em(cfg, s) {
+		} else if em(fc, s) {
 			continue
 		} else if camel(s) {
 			continue
 		} else if wikiLink(s) {
 			continue
-		} else if link(cfg, s) {
+		} else if link(fc, s) {
 			continue
 		} else if html(s) {
 			continue
@@ -640,7 +640,7 @@ func markup(cfg formatConfig, s *state) {
 	}
 }
 
-func nomarkLine(cfg formatConfig, s *state) {
+func nomarkLine(fc formatConfig, s *state) {
 	line := s.input[s.index:s.lineEnd]
 
 	if s.block == blockCode {
@@ -696,6 +696,13 @@ func nomarkLine(cfg formatConfig, s *state) {
 		return
 	}
 
+	if line == "" {
+		ensureBlock(s, blockNone)
+		s.text.WriteString("\n")
+		nextLine(s)
+		return
+	}
+
 	prevBlock := s.block
 	ensureBlock(s, blockParagraph)
 	for s.index < s.lineEnd {
@@ -707,7 +714,7 @@ func nomarkLine(cfg formatConfig, s *state) {
 		s.html.WriteString("&nbsp;")
 		s.index += 1
 	}
-	markup(cfg, s)
+	markup(fc, s)
 	nextLine(s)
 
 	if s.index < len(s.input) {
@@ -723,7 +730,7 @@ func nomarkLine(cfg formatConfig, s *state) {
 	skipLastBlanks(s)
 }
 
-func nomark(cfg formatConfig, title string, text string) (string, string, string, string) {
+func nomark(fc formatConfig, title string, text string) (string, string, string, string) {
 	s := state{
 		input:     text,
 		index:     0,
@@ -768,7 +775,7 @@ func nomark(cfg formatConfig, title string, text string) (string, string, string
 		} else if s.block == blockCode && s.prevLine == "" && line == "}}}" {
 			closeBlock(&s, blockParagraph)
 			ensureBlock(&s, blockParagraph)
-			nomarkLine(cfg, &s)
+			nomarkLine(fc, &s)
 		} else if s.block != blockMath && s.block != blockRaw && s.block != blockCode && line == "%%%" {
 			ensureBlock(&s, blockMath)
 			nextLine(&s)
@@ -776,8 +783,13 @@ func nomark(cfg formatConfig, title string, text string) (string, string, string
 			closeBlock(&s, blockParagraph)
 			nextLine(&s)
 		} else if level, title, ok := parseHeading(&s, line); ok {
-			s.text.WriteString("\n" + line + "\n")
-			s.plain.WriteString("\n" + title + "\n")
+			s.text.WriteString("\n")
+			s.text.WriteString(line)
+			s.text.WriteString("\n")
+
+			s.plain.WriteString("\n")
+			s.plain.WriteString(title)
+			s.plain.WriteString("\n")
 			if level == 1 && s.title == "" {
 				s.title = title
 				nextLine(&s)
@@ -791,11 +803,21 @@ func nomark(cfg formatConfig, title string, text string) (string, string, string
 					buf.WriteRune('!')
 				}
 				mark := buf.String()
-				s.html.WriteString("<h" + levelStr + ">" + "<span class=\"markup\">" + mark + "</span> " + titleHTML + " <span class=\"markup\">" + mark + "</span>" + "</h" + levelStr + ">\n")
+				s.html.WriteString("<h")
+				s.html.WriteString(levelStr)
+				s.html.WriteString("><span class=\"markup\">")
+				s.html.WriteString(mark)
+				s.html.WriteString("</span> ")
+				s.html.WriteString(titleHTML)
+				s.html.WriteString(" <span class=\"markup\">")
+				s.html.WriteString(mark)
+				s.html.WriteString("</span></h")
+				s.html.WriteString(levelStr)
+				s.html.WriteString(">\n")
 				nextLine(&s)
 			}
 		} else {
-			nomarkLine(cfg, &s)
+			nomarkLine(fc, &s)
 		}
 	}
 	closeBlock(&s, blockNone)