cmd/build/main.go

@@ -8,6 +8,7 @@ import (
 	"io/fs"
 	"os"
 	"path/filepath"
+	"regexp"
 	"sort"
 	"strings"
 
@@ -26,6 +27,152 @@ func floatToIn(v float64) string {
 	return strings.TrimRight(strings.TrimRight(fmt.Sprintf("%.4fin", v), "0"), ".")
 }
 
+func min(a, b int) int {
+	if a < b {
+		return a
+	}
+	return b
+}
+
+// extractAndScopeCSS extracts <style> blocks from HTML content and scopes them to a page-specific selector
+func extractAndScopeCSS(content string, pageID string) (string, string) {
+	styleRegex := regexp.MustCompile(`(?s)<style[^>]*>(.*?)</style>`)
+	matches := styleRegex.FindAllStringSubmatch(content, -1)
+	
+	var scopedCSS strings.Builder
+	contentWithoutCSS := content
+	
+	// Remove all <style> blocks from content
+	contentWithoutCSS = styleRegex.ReplaceAllString(contentWithoutCSS, "")
+	
+	// Process each CSS block and scope it
+	for _, match := range matches {
+		cssContent := strings.TrimSpace(match[1])
+		if cssContent == "" {
+			continue
+		}
+		
+		// Scope the CSS rules to the page
+		scopedCSS.WriteString(scopeCSS(cssContent, pageID))
+		scopedCSS.WriteString("\n\n")
+	}
+	
+	return contentWithoutCSS, scopedCSS.String()
+}
+
+// scopeCSS wraps CSS rules with a page-specific selector
+func scopeCSS(css string, pageID string) string {
+	// Simple CSS scoping - wrap all rules with the page selector
+	lines := strings.Split(css, "\n")
+	var scopedLines []string
+	var inRule bool
+	var ruleBuffer strings.Builder
+	
+	for _, line := range lines {
+		trimmed := strings.TrimSpace(line)
+		
+		// Skip comments and empty lines
+		if trimmed == "" || strings.HasPrefix(trimmed, "/*") {
+			scopedLines = append(scopedLines, line)
+			continue
+		}
+		
+		// Handle @-rules (like @font-face, @media) - don't scope these
+		if strings.HasPrefix(trimmed, "@") {
+			if inRule {
+				// Finish current rule first
+				scopedLines = append(scopedLines, scopeRuleBuffer(ruleBuffer.String(), pageID))
+				ruleBuffer.Reset()
+				inRule = false
+			}
+			scopedLines = append(scopedLines, line)
+			continue
+		}
+		
+		// Detect start of CSS rule
+		if strings.Contains(trimmed, "{") && !inRule {
+			inRule = true
+			ruleBuffer.WriteString(line)
+			ruleBuffer.WriteString("\n")
+		} else if inRule {
+			ruleBuffer.WriteString(line)
+			ruleBuffer.WriteString("\n")
+			
+			// Check if rule ends
+			if strings.Contains(trimmed, "}") {
+				scopedLines = append(scopedLines, scopeRuleBuffer(ruleBuffer.String(), pageID))
+				ruleBuffer.Reset()
+				inRule = false
+			}
+		} else {
+			// Standalone line - might be a selector
+			if strings.Contains(trimmed, "{") {
+				ruleBuffer.WriteString(line)
+				ruleBuffer.WriteString("\n")
+				inRule = true
+			} else {
+				scopedLines = append(scopedLines, line)
+			}
+		}
+	}
+	
+	// Handle any remaining rule
+	if inRule && ruleBuffer.Len() > 0 {
+		scopedLines = append(scopedLines, scopeRuleBuffer(ruleBuffer.String(), pageID))
+	}
+	
+	return strings.Join(scopedLines, "\n")
+}
+
+func scopeRuleBuffer(rule string, pageID string) string {
+	lines := strings.Split(strings.TrimSpace(rule), "\n")
+	if len(lines) == 0 {
+		return rule
+	}
+	
+	// Find the selector line (first line before {)
+	for i, line := range lines {
+		if strings.Contains(line, "{") {
+			// Extract selector part
+			parts := strings.Split(line, "{")
+			if len(parts) >= 2 {
+				selector := strings.TrimSpace(parts[0])
+				rest := "{" + strings.Join(parts[1:], "{")
+				
+				// Scope the selector
+				scopedSelector := scopeSelector(selector, pageID)
+				lines[i] = scopedSelector + " " + rest
+			}
+			break
+		}
+	}
+	
+	return strings.Join(lines, "\n")
+}
+
+func scopeSelector(selector string, pageID string) string {
+	// Split multiple selectors by comma
+	selectors := strings.Split(selector, ",")
+	var scopedSelectors []string
+	
+	for _, sel := range selectors {
+		sel = strings.TrimSpace(sel)
+		if sel == "" {
+			continue
+		}
+		
+		// Don't scope selectors that already include the page ID or are body/html
+		if strings.Contains(sel, "#"+pageID) || sel == "body" || sel == "html" {
+			scopedSelectors = append(scopedSelectors, sel)
+		} else {
+			// Scope to page
+			scopedSelectors = append(scopedSelectors, "#"+pageID+" "+sel)
+		}
+	}
+	
+	return strings.Join(scopedSelectors, ", ")
+}
+
 type PageData struct {
 	Title   string
 	Content template.HTML
@@ -37,7 +184,9 @@ type IndexPage struct {
 }
 
 type PrintPage struct {
-	Content template.HTML
+	Content   template.HTML
+	PageID    string
+	ScopedCSS template.HTML
 }
 
 type TwoUpSheet struct {
@@ -164,15 +313,47 @@ func main() {
 	printTplPath := filepath.Join(templatesDir, "print.gohtml")
 	printTpl := template.Must(template.New("print").Parse(mustReadFile(printTplPath)))
 	var printPages []PrintPage
+	var allScopedCSS strings.Builder
+	
 	for _, pagePath := range pageFiles {
 		content := strings.TrimSpace(mustReadFile(pagePath))
-		printPages = append(printPages, PrintPage{Content: template.HTML(content)})
+		
+		// Generate unique page ID based on filename
+		base := filepath.Base(pagePath)
+		pageID := strings.TrimSuffix(base, filepath.Ext(base)) + "-page"
+		
+		// Extract and scope CSS
+		contentWithoutCSS, scopedCSS := extractAndScopeCSS(content, pageID)
+		
+		// Collect all scoped CSS
+		if scopedCSS != "" {
+			allScopedCSS.WriteString(scopedCSS)
+			allScopedCSS.WriteString("\n")
+		}
+		
+		printPages = append(printPages, PrintPage{
+			Content: template.HTML(contentWithoutCSS),
+			PageID:  pageID,
+			ScopedCSS: template.HTML(scopedCSS),
+		})
 	}
 	var outPrint bytes.Buffer
-	if err := printTpl.Execute(&outPrint, map[string]any{"Pages": printPages, "PageSizeAttr": pageSizeStyleAttr(config.PageWidthIn, config.PageHeightIn)}); err != nil {
+	if err := printTpl.Execute(&outPrint, map[string]any{
+		"Pages": printPages, 
+		"PageSizeAttr": pageSizeStyleAttr(config.PageWidthIn, config.PageHeightIn),
+	}); err != nil {
 		panic(err)
 	}
-	if err := writeFile(filepath.Join(outDir, "print.html"), outPrint.Bytes()); err != nil {
+	
+	// Inject scoped CSS into the output
+	cssToInject := allScopedCSS.String()
+	finalOutput := strings.ReplaceAll(
+		outPrint.String(), 
+		"PLACEHOLDER_FOR_SCOPED_CSS",
+		cssToInject,
+	)
+	
+	if err := writeFile(filepath.Join(outDir, "print.html"), []byte(finalOutput)); err != nil {
 		panic(err)
 	}
 
@@ -190,10 +371,20 @@ func main() {
 	print2TplPath := filepath.Join(templatesDir, "print_2up.gohtml")
 	print2Tpl := template.Must(template.New("print2up").Parse(mustReadFile(print2TplPath)))
 	var outPrint2 bytes.Buffer
-	if err := print2Tpl.Execute(&outPrint2, map[string]any{"Sheets": sheets}); err != nil {
+	if err := print2Tpl.Execute(&outPrint2, map[string]any{
+		"Sheets": sheets,
+	}); err != nil {
 		panic(err)
 	}
-	if err := writeFile(filepath.Join(outDir, "print_2up.html"), outPrint2.Bytes()); err != nil {
+	
+	// Inject scoped CSS into the 2-up output
+	finalOutput2Up := strings.ReplaceAll(
+		outPrint2.String(), 
+		"PLACEHOLDER_FOR_SCOPED_CSS",
+		cssToInject,
+	)
+	
+	if err := writeFile(filepath.Join(outDir, "print_2up.html"), []byte(finalOutput2Up)); err != nil {
 		panic(err)
 	}
 }

templates/print.gohtml

@@ -13,15 +13,17 @@
       @media print {
         html, body { width: auto !important; height: auto !important; overflow: visible !important; margin: 0 !important; padding: 0 !important; background: white !important; }
       }
-      /* Each #page is a fixed-size sheet */
-      #page { width: var(--page-w, 5.5in); height: var(--page-h, 8.5in); background: white; box-shadow: none !important; overflow: hidden; }
-      #page { page-break-after: always; break-after: page; }
-      #page:last-child { page-break-after: auto; break-after: auto; }
+      /* Each .page-container is a fixed-size sheet */
+      .page-container { width: var(--page-w, 5.5in); height: var(--page-h, 8.5in); background: white; box-shadow: none !important; overflow: hidden; }
+      .page-container { page-break-after: always; break-after: page; }
+      .page-container:last-child { page-break-after: auto; break-after: auto; }
+
+      PLACEHOLDER_FOR_SCOPED_CSS
     </style>
   </head>
   <body {{ .PageSizeAttr }}>
     {{ range .Pages }}
-      <div id="page">{{ .Content }}</div>
+      <div class="page-container" id="{{ .PageID }}">{{ .Content }}</div>
     {{ end }}
   </body>
 </html>

templates/print_2up.gohtml

@@ -14,16 +14,18 @@
       /* Each .sheet is one letter-sized page */
       .sheet { display: flex; gap: 0; margin: 0; padding: 0; width: 11in; height: 8.5in; }
       .cell { width: 5.5in; height: 8.5in; overflow: hidden; }
-      .cell > #page { width: 5.5in; height: 8.5in; box-shadow: none !important; }
+      .cell > .page-content { width: 5.5in; height: 8.5in; box-shadow: none !important; }
       .sheet { page-break-after: always; break-after: page; }
       .sheet:last-child { page-break-after: auto; break-after: auto; }
+
+      PLACEHOLDER_FOR_SCOPED_CSS
     </style>
   </head>
   <body>
     {{ range .Sheets }}
       <div class="sheet">
-        <div class="cell"><div id="page">{{ .Left.Content }}</div></div>
-        {{ if .Right }}<div class="cell"><div id="page">{{ .Right.Content }}</div></div>{{ end }}
+        <div class="cell"><div class="page-content" id="{{ .Left.PageID }}">{{ .Left.Content }}</div></div>
+        {{ if .Right }}<div class="cell"><div class="page-content" id="{{ .Right.PageID }}">{{ .Right.Content }}</div></div>{{ end }}
       </div>
     {{ end }}
   </body>