Fold the header menu into a button when its links do not fit

A long menu wrapped onto two or three lines on phones and narrow
windows. With the new Design switch the header menu folds into a ☰
button (an icon, the word Menu, or both) carried by the title or logo
block just above it, at the right end of its row, or by the menu bar
when nothing is above it; the button opens the links as a stacked list
with the search box on top.

The open/closed state is a hidden checkbox and the button its label,
so opening needs no script and works in old browsers. Whether to fold
is decided by a small inline script — any link on a second line means
the menu does not fit — re-checked on resize; without it blog.css folds
on phones only, and browsers too old for that keep the wrapping menu.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Sd8UPWrvyYCLj97JexNw3A

1 files changed, 9 insertions, 2 deletions

diff --git a/internal/web/theme.go b/internal/web/theme.go
index 031f8fd..a43603b 100644
--- a/internal/web/theme.go
+++ b/internal/web/theme.go
@@ -54,6 +54,10 @@ type Theme struct {
 	NavSize      string `json:"nav_size"`      // normal | small | large
 	NavGap       string `json:"nav_gap"`       // normal | tight | wide (space around each link)
 	NavActive    string `json:"nav_active"`    // underline | bold | box | none: how the current page's link is marked
+	// NavFold folds the header menu into a button when its links do not fit
+	// the bar (see Layout.BurgerAt); NavFoldLabel is what the button shows.
+	NavFold      bool   `json:"nav_fold"`
+	NavFoldLabel string `json:"nav_fold_label"` // icon | text | both
 	NavBg        string `json:"nav_bg"`
 	NavText      string `json:"nav_text"`
 	NavHover     string `json:"nav_hover"` // "" = same as NavText
@@ -118,7 +122,7 @@ func DefaultTheme() Theme {
 		ContentStyle: "card", ContentPadding: "normal",
 		Font: "sans", HeadingFont: "same", FontSize: "normal",
 		HeaderImageHeight: "medium", HeaderAlign: "left", HeaderBg: "#2f3a4a", HeaderText: "#ffffff", TitleSize: "normal", HeaderRule: "none",
-		NavAlign: "left", NavBold: true, NavUnderline: "hover", NavSize: "normal", NavGap: "normal", NavActive: "underline", NavBg: "#ffffff", NavText: "#222222",
+		NavAlign: "left", NavBold: true, NavUnderline: "hover", NavSize: "normal", NavGap: "normal", NavActive: "underline", NavFoldLabel: "icon", NavBg: "#ffffff", NavText: "#222222",
 		ShowDates: true, DateFormat: "long", PostsPerPage: postsPerPageChoices[0], ListStyle: "full", PostImage: "top", TitleRule: "none", PostNotices: true,
 		FooterBg: "#2f3a4a", FooterColor: "#d0d5dc", FooterAlign: "center",
 		LogoSize: "medium",
@@ -213,6 +217,7 @@ func (t *Theme) normalize() {
 	t.NavSize = pick(t.NavSize, "normal", "small", "large")
 	t.NavGap = pick(t.NavGap, "normal", "tight", "wide")
 	t.NavActive = pick(t.NavActive, "underline", "bold", "box", "none")
+	t.NavFoldLabel = pick(t.NavFoldLabel, "icon", "text", "both")
 	t.NavBg = color(t.NavBg, d.NavBg)
 	t.NavText = color(t.NavText, d.NavText)
 	t.NavHover = optColor(t.NavHover)
@@ -287,6 +292,8 @@ func ThemeFromForm(cur Theme, f url.Values) Theme {
 	t.NavSize = get("nav_size")
 	t.NavGap = get("nav_gap")
 	t.NavActive = get("nav_active")
+	t.NavFold = on("nav_fold")
+	t.NavFoldLabel = get("nav_fold_label")
 	t.NavBg = get("nav_bg")
 	t.NavText = get("nav_text")
 	t.NavHover = hover("nav_hover")
@@ -591,7 +598,7 @@ a:hover {{"{"}}{{if .LinkHover}} color:{{.LinkHover}};{{end}}{{if eq .LinkUnderl
 .site-header a { color:{{.HeaderText}}; }
 .header-image img { max-height:{{.HeaderImageMaxHeight}}; }
 .site-nav { background:{{.NavBg}}; }
-.site-nav a { color:{{.NavText}}; }
+.site-nav a, .site-nav .nav-burger { color:{{.NavText}}; }
 {{- if .NavHover}}
 .site-nav a:hover { color:{{.NavHover}}; }
 {{- end}}