Cleanup

CLAUDE.md

@@ -88,7 +88,8 @@ When building features, apply this order:
 ## Date Formatting
 
 - General UI dates (file listings, metadata): ISO `YYYY-MM-DD`
-- Diary long-form dates: German locale, e.g. `Mittwoch, 1. April 2026` — use `formatGermanDate` in `diary.go`; Go's `time.Format` is English-only so locale names are kept in maps keyed by `time.Weekday` / `time.Month`
+- Diary headings (year/month/day) are also ISO short form: `# 2026`, `## 2026-05`, `### 2026-05-28`. No long-form rendering.
+- Calendar widget month names are German; the `germanMonths` map in `diary.go` keeps the labels keyed by `time.Month` since Go's `time.Format` is English-only.
 
 ## What to Avoid
 

README.md

@@ -52,36 +52,45 @@ type = diary
 
 ### Diary
 
-Designed for a chronological photo diary. Expected structure:
+Designed for a chronological photo diary. The whole year lives in a single
+file as ISO-headed sections; photos are loose JPEGs named with a date prefix.
 
 ```
 FolderName/
   .page-settings        ← type = diary
   YYYY/
-    YYYY-MM-DD Desc.jpg ← photos named with date prefix
-    MM/
-      DD/
-        index.md        ← diary entry for that day
+    index.md            ← `# YYYY` + `## YYYY-MM` + `### YYYY-MM-DD` sections
+    YYYY-MM-DD Desc.jpg ← photos named with the date they belong to
 ```
 
-| View | What renders |
-|------|-------------|
-| Year (`YYYY/`) | Section per month with link and photo count |
-| Month (`MM/`) | Section per day with entry content and photo grid |
-| Day (`DD/`) | Entry content and photo grid |
+The year page (`YYYY/`) renders every section in the file with photos
+attached to each `### YYYY-MM-DD` heading. Months and days the file doesn't
+yet contain are rendered as **virtual** headings with an `[edit]` button that
+splices a new section into the year file at the right chronological position;
+virtual day headings still carry photos for that date. Past years render
+every month/day slot; the current year stops at today; future years skip
+virtual entries entirely. The file may contain non-date headings (e.g.
+`## Events` → `### Festival` between `# YYYY` and `## YYYY-01`); these keep
+their document position.
 
-Days with photos but no `index.md` still appear in the month view and can be created by clicking their heading link.
+A sidebar calendar widget shows one month grid at a time; the month-name
+button opens a dropdown of all twelve months, and a separate year dropdown
+jumps between years. Day cells link to the matching anchor on the year page
+regardless of whether the date has a real section yet.
 
 #### Persistent date links
 
-Each diary root exposes three stable paths intended for browser bookmarks. They redirect to the current dated URL on every visit:
+Each diary root exposes three stable paths intended for browser bookmarks.
+They resolve against the year page rather than separate per-day URLs:
 
 | Path | Redirects to |
 |------|-------------|
-| `<diary>/today/` | `<diary>/YYYY/MM/DD/` (or `…/?edit` if the day folder does not exist yet) |
-| `<diary>/this-month/` | `<diary>/YYYY/MM/` |
+| `<diary>/today/` | `<diary>/YYYY/#YYYY-MM-DD` (or the year file's insert-section editor when today's section doesn't exist yet) |
+| `<diary>/this-month/` | `<diary>/YYYY/#YYYY-MM` |
 | `<diary>/this-year/` | `<diary>/YYYY/` |
 
+Legacy `YYYY/MM/` and `YYYY/MM/DD/` URLs (no longer the canonical form) redirect to the matching anchor on the year page.
+
 ## Quick-Add Bookmarklet
 
 Replace `wiki.host` with your wiki host and `/Topics/Bookmarks/` with the destination page (one bookmarklet per target):

assets/diary/calendar.html

@@ -1,22 +1,24 @@
-<div class="diary-cal panel panel-sidebar">
+<div class="diary-cal panel panel-sidebar"
+     data-display-year="{{.DisplayYear}}"
+     data-display-month="{{.DisplayMonth}}">
   <div class="panel-header"><a href="{{.DiaryURL}}">Chronological</a></div>
   <div class="diary-cal-nav">
-    <a href="{{.MonthURL}}" class="diary-cal-heading">{{.MonthName}}</a>
     <div class="dropdown diary-cal-drop">
-      <button type="button" class="btn btn-small" data-action="cal-month-drop" aria-expanded="false" title="Monat wählen">▾</button>
+      <button type="button" class="btn" data-cal-month-link data-action="cal-month-drop" aria-expanded="false" title="Monat wählen"> {{.DisplayMonthName}} </button>
       <div class="dropdown-menu scrollable">
-        {{range .AllMonths}}<a class="btn btn-block{{if .IsCurrent}} cal-current{{end}}" href="{{.URL}}">{{.Name}}</a>{{end}}
+        {{range .Months}}<a class="btn btn-block" data-cal-month-jump="{{.Num}}" href="{{.AnchorURL}}">{{.Name}}</a>{{end}}
       </div>
     </div>
     <a href="{{.YearURL}}" class="diary-cal-heading">{{.DisplayYear}}</a>
     <div class="dropdown diary-cal-drop">
-      <button type="button" class="btn btn-small" data-action="cal-year-drop" aria-expanded="false" title="Jahr wählen">▾</button>
+      <button type="button" class="btn" data-action="cal-year-drop" aria-expanded="false" title="Jahr wählen">▾</button>
       <div class="dropdown-menu align-right scrollable">
         {{range .Years}}<a class="btn btn-block{{if .IsCurrent}} cal-current{{end}}" href="{{.URL}}">{{.Num}}</a>{{end}}
       </div>
     </div>
   </div>
-  <table class="diary-cal-grid">
+  {{range .Months}}
+  <table class="diary-cal-grid" data-cal-month="{{.Num}}"{{if ne .Num $.DisplayMonth}} hidden{{end}}>
     <thead>
       <tr><th>Mo</th><th>Di</th><th>Mi</th><th>Do</th><th>Fr</th><th>Sa</th><th>So</th></tr>
     </thead>
@@ -25,5 +27,6 @@
     {{end}}
     </tbody>
   </table>
+  {{end}}
 </div>
 <script src="/_/diary/calendar.js"></script>

assets/diary/calendar.js

@@ -2,4 +2,48 @@
   var cal = document.querySelector(".diary-cal");
   if (!cal) return;
   cal.querySelectorAll(".dropdown > button").forEach(wireDropdown);
+
+  var displayYear = parseInt(cal.dataset.displayYear, 10);
+  var current = parseInt(cal.dataset.displayMonth, 10);
+  var monthLabel = cal.querySelector("[data-cal-month-link]");
+  var months = {};
+  cal.querySelectorAll("[data-cal-month]").forEach(function (t) {
+    months[parseInt(t.dataset.calMonth, 10)] = t;
+  });
+  var jumpLinks = {};
+  cal.querySelectorAll("[data-cal-month-jump]").forEach(function (a) {
+    jumpLinks[parseInt(a.dataset.calMonthJump, 10)] = a;
+  });
+
+  function show(m) {
+    if (m === current) return;
+    if (!months[m]) return;
+    months[current].hidden = true;
+    months[m].hidden = false;
+    current = m;
+    if (monthLabel) {
+      var label = jumpLinks[m];
+      if (label) monthLabel.textContent = " " + label.textContent + " ";
+    }
+  }
+
+  // Dropdown month picks scroll via the href anchor; we also swap the grid
+  // so the calendar reflects what the user just navigated to.
+  Object.keys(jumpLinks).forEach(function (key) {
+    var a = jumpLinks[key];
+    a.addEventListener("click", function () { show(parseInt(key, 10)); });
+  });
+
+  // Any in-page anchor click (#YYYY-MM or #YYYY-MM-DD) updates the calendar
+  // so it tracks the user's focus through the year page.
+  function syncFromHash() {
+    var h = window.location.hash;
+    if (!h) return;
+    var m = h.match(/^#(\d{4})-(\d{2})(?:-\d{2})?$/);
+    if (!m) return;
+    if (parseInt(m[1], 10) !== displayYear) return;
+    show(parseInt(m[2], 10));
+  }
+  window.addEventListener("hashchange", syncFromHash);
+  syncFromHash();
 })();

assets/diary/content.html

@@ -0,0 +1,13 @@
+{{range .Sections}}
+{{if eq .Level 1}}<h1 id="{{.ID}}">{{.Heading}}{{if .EditURL}} <a href="{{.EditURL}}" class="btn btn-small">edit</a>{{end}}</h1>
+{{else if eq .Level 2}}<h2 id="{{.ID}}">{{.Heading}}{{if .EditURL}} <a href="{{.EditURL}}" class="btn btn-small">edit</a>{{end}}</h2>
+{{else}}<h3 id="{{.ID}}">{{.Heading}}{{if .EditURL}} <a href="{{.EditURL}}" class="btn btn-small">edit</a>{{end}}</h3>{{end}}
+{{if .Body}}{{.Body}}{{end}}
+{{if .Photos}}
+<div class="photo-grid">
+  {{range .Photos}}
+  <a href="{{.URL}}" target="_blank"><img src="{{.ThumbURL}}" alt="" loading="lazy"></a>
+  {{end}}
+</div>
+{{end}}
+{{end}}

assets/diary/day.html

@@ -1,7 +0,0 @@
-{{if .Photos}}
-<div class="photo-grid">
-  {{range .Photos}}
-  <a href="{{.URL}}" target="_blank"><img src="{{.ThumbURL}}" alt="" loading="lazy"></a>
-  {{end}}
-</div>
-{{end}}

assets/diary/month.html

@@ -1,13 +0,0 @@
-{{range .Days}}
-<h2 id="{{.ID}}">{{if .URL}}<a href="{{.URL}}">{{.Heading}}</a>{{else}}{{.Heading}}{{end}}
-  {{if .EditURL}}<a href="{{.EditURL}}" class="btn btn-small">edit</a>{{end}}
-</h2>
-{{if .Content}}{{.Content}}{{end}}
-{{if .Photos}}
-<div class="photo-grid">
-  {{range .Photos}}
-  <a href="{{.URL}}" target="_blank"><img src="{{.ThumbURL}}" alt="" loading="lazy"></a>
-  {{end}}
-</div>
-{{end}}
-{{end}}

assets/diary/year.html

@@ -1,11 +0,0 @@
-<h2 id="months">Monate</h2>
-{{range .Months}}
-<h3 id="{{.ID}}"><a href="{{.URL}}">{{.Name}}</a></h3>
-{{if .Photos}}
-<div class="photo-grid">
-  {{range .Photos}}
-  <a href="{{.URL}}" target="_blank"><img src="{{.ThumbURL}}" alt="" loading="lazy"></a>
-  {{end}}
-</div>
-{{end}}
-{{end}}

assets/editor/main.html

@@ -9,6 +9,7 @@
 </script>
 <form id="edit-form" class="edit-form" method="POST" action="{{.PostURL}}">
     {{if ge .SectionIndex 0}}<input type="hidden" name="section" value="{{.SectionIndex}}">{{end}}
+    {{if ge .InsertBefore 0}}<input type="hidden" name="insert_before" value="{{.InsertBefore}}">{{end}}
     <div class="editor-toolbar">
         <button type="button" class="btn btn-tool" data-action="bold"      data-key="B" title="Bold (B)">**</button>
         <button type="button" class="btn btn-tool" data-action="italic"    data-key="I" title="Italic (I)">*</button>

assets/page/main.html

@@ -28,7 +28,7 @@
 {{if or .Content .SpecialContent}}
 <script src="/_/page/content.js"></script>
 <script src="/_/page/anchors.js"></script>
-<script src="/_/page/toc.js"></script>
+{{if not .SuppressTOC}}<script src="/_/page/toc.js"></script>{{end}}
 <script src="/_/page/tasks.js"></script>
 {{end}}
 {{if .Content}}

assets/page/sections.js

@@ -6,7 +6,9 @@
 
     // Section 0 is pre-heading content, editable via full-page edit.
     // Sections 1..N each start at a heading; that is the index sent to the server.
+    // Skip headings that already carry a server-rendered edit link.
     headings.forEach(function (h, i) {
+        if (h.querySelector('a.btn')) return;
         var a = document.createElement('a');
         a.href = '?edit&section=' + (i + 1);
         a.className = 'btn btn-small';

assets/style.css

@@ -325,7 +325,7 @@ main > h2 {
 .dropdown-menu.align-right { left: auto; right: 0; }
 .dropdown-menu.open-up { top: auto; bottom: 100%; margin-bottom: 0.4rem; }
 .dropdown-menu.is-open { display: block; }
-.dropdown-menu.scrollable { max-height: 14rem; overflow-y: auto; }
+.dropdown-menu.scrollable { max-height: 23rem; overflow-y: auto; }
 
 /* === Suggestion dropdown (header search + editor link picker) ===
    Anchored to a position:relative host. Mirrors .dropdown-menu visuals with
@@ -449,7 +449,6 @@ button.fab { display: none; }
     top: var(--space-4);
     align-self: start;
     max-height: calc(100vh - 2rem);
-    overflow-y: auto;
     display: flex;
     flex-direction: column;
     gap: var(--space-4);
@@ -582,6 +581,12 @@ aside.sidebar:empty { display: none; }
     font-size: var(--font-sm);
 }
 .diary-cal-nav .diary-cal-drop + .diary-cal-heading { margin-left: var(--space-3); }
+/* Anchor the month/year dropdowns to the nav row instead of the ▾ button so
+   the menu spans the full panel width rather than overflowing the 14rem
+   sidebar with its default min-width: 9rem. */
+.diary-cal-nav { position: relative; }
+.diary-cal-nav .diary-cal-drop { position: static; }
+.diary-cal-nav .dropdown-menu { left: 0; right: 0; min-width: 0; }
 .diary-cal-heading { color: var(--link); }
 .diary-cal-heading:hover { color: var(--link-hover); }
 .diary-cal-grid {

diary.go

@@ -5,10 +5,12 @@ import (
 	"fmt"
 	"html/template"
 	"log"
+	"net/http"
 	"net/url"
 	"os"
 	"path"
 	"path/filepath"
+	"regexp"
 	"sort"
 	"strconv"
 	"strings"
@@ -21,9 +23,31 @@ func init() {
 
 type diaryHandler struct{}
 
-// redirect resolves the persistent date links (today, this-month, this-year)
-// inside any diary root to a dated URL. Returns ok=false otherwise.
-func (d *diaryHandler) redirect(root, fsPath, urlPath string) (string, bool) {
+// redirect handles diary-specific redirect cases. The year page is the only
+// real diary page; month and day URLs are aliases that collapse to a year
+// page anchor (or to the year-file editor when ?edit is set).
+//
+//  1. `today` / `this-month` / `this-year` shortcuts resolve directly to a
+//     year+anchor target (or insert flow when today's section is missing).
+//  2. A virtual month URL (/diary/<root>/YYYY/MM/) redirects to
+//     /diary/<root>/YYYY/#YYYY-MM (or to ?edit&section=N when ?edit is set).
+//  3. A virtual day URL (/diary/<root>/YYYY/MM/DD/) redirects to
+//     /diary/<root>/YYYY/#YYYY-MM-DD (or to the section / insert_before
+//     editor flow when ?edit is set).
+//
+// Returns ok=false when the request is not a diary-handled redirect.
+func (d *diaryHandler) redirect(root, fsPath, urlPath string, r *http.Request) (string, bool) {
+	if target, ok := d.dateShortcutRedirect(root, fsPath, urlPath); ok {
+		return target, true
+	}
+	if r.Method != http.MethodGet {
+		return "", false
+	}
+	_, edit := r.URL.Query()["edit"]
+	return d.virtualURLRedirect(root, fsPath, urlPath, edit)
+}
+
+func (d *diaryHandler) dateShortcutRedirect(root, fsPath, urlPath string) (string, bool) {
 	base := path.Base(strings.TrimSuffix(urlPath, "/"))
 	switch base {
 	case "today", "this-month", "this-year":
@@ -42,44 +66,97 @@ func (d *diaryHandler) redirect(root, fsPath, urlPath string) (string, bool) {
 	year := fmt.Sprintf("%d", now.Year())
 	month := fmt.Sprintf("%02d", int(now.Month()))
 	day := fmt.Sprintf("%02d", now.Day())
+	yearURL := path.Join(diaryRootURL, year) + "/"
 
 	switch base {
 	case "today":
-		target := path.Join(diaryRootURL, year, month, day) + "/"
-		dayFS := filepath.Join(diaryRootFS, year, month, day)
-		if _, err := os.Stat(dayFS); err != nil {
-			target += "?edit"
+		dayHeading := fmt.Sprintf("%s-%s-%s", year, month, day)
+		raw, _ := os.ReadFile(filepath.Join(diaryRootFS, year, "index.md"))
+		sections := splitSections(raw)
+		if _, found := findSectionIndex(sections, dayHeading); found {
+			return yearURL + "#" + dayHeading, true
 		}
-		return target, true
+		// Missing day: route through the insert flow so today's section
+		// is spliced in at the right chronological position.
+		insertIdx := computeInsertIndex(sections, dayHeading)
+		return fmt.Sprintf("%s?edit&insert_before=%d&heading=%s",
+			yearURL, insertIdx, url.QueryEscape(dayHeading)), true
 	case "this-month":
-		return path.Join(diaryRootURL, year, month) + "/", true
+		return yearURL + "#" + fmt.Sprintf("%s-%s", year, month), true
 	case "this-year":
-		return path.Join(diaryRootURL, year) + "/", true
+		return yearURL, true
 	}
 	return "", false
 }
 
-// defaultHeading returns the German long-form date as the editor pre-fill
-// heading for a diary day folder (depth 3 inside a diary root).
-func (d *diaryHandler) defaultHeading(root, fsPath, urlPath string) (string, bool) {
-	depth, _, _, ok := findDiaryContext(root, fsPath, urlPath)
-	if !ok || depth != 3 {
+// virtualURLRedirect collapses month/day URLs onto the year page. For
+// non-edit GETs the target is `/YYYY/#YYYY-MM[-DD]`. For ?edit GETs the
+// target is the year-file editor URL (section edit when the section exists,
+// otherwise insert_before+heading for new days, whole-year edit for new
+// months). Returns ok=false when fsPath is a real folder (preferring the
+// real folder over the virtual redirect lets users recover from an
+// unfinished migration).
+func (d *diaryHandler) virtualURLRedirect(root, fsPath, urlPath string, edit bool) (string, bool) {
+	depth, diaryRootFS, diaryRootURL, ok := findDiaryContext(root, fsPath, urlPath)
+	if !ok || (depth != 2 && depth != 3) {
 		return "", false
 	}
-	day, err := strconv.Atoi(filepath.Base(fsPath))
-	if err != nil {
+	if info, err := os.Stat(fsPath); err == nil && info.IsDir() {
 		return "", false
 	}
-	monthFS := filepath.Dir(fsPath)
-	month, err := strconv.Atoi(filepath.Base(monthFS))
-	if err != nil || month < 1 || month > 12 {
+
+	year, month, day, ok := parseDiaryURLParts(fsPath, depth)
+	if !ok {
 		return "", false
 	}
-	year, err := strconv.Atoi(filepath.Base(filepath.Dir(monthFS)))
-	if err != nil {
-		return "", false
+	yearFS := filepath.Join(diaryRootFS, year)
+	yearURL := path.Join(diaryRootURL, year) + "/"
+
+	if !edit {
+		anchor := fmt.Sprintf("%s-%s", year, month)
+		if depth == 3 {
+			anchor = fmt.Sprintf("%s-%s-%s", year, month, day)
 		}
-	return formatGermanDate(time.Date(year, time.Month(month), day, 0, 0, 0, 0, time.UTC)), true
+		return yearURL + "#" + anchor, true
+	}
+
+	raw, _ := os.ReadFile(filepath.Join(yearFS, "index.md"))
+	sections := splitSections(raw)
+
+	if depth == 2 {
+		target := fmt.Sprintf("%s-%s", year, month)
+		if idx, found := findSectionIndex(sections, target); found {
+			return fmt.Sprintf("%s?edit&section=%d", yearURL, idx), true
+		}
+		return yearURL + "?edit", true
+	}
+	target := fmt.Sprintf("%s-%s-%s", year, month, day)
+	if idx, found := findSectionIndex(sections, target); found {
+		return fmt.Sprintf("%s?edit&section=%d", yearURL, idx), true
+	}
+	insertIdx := computeInsertIndex(sections, target)
+	return fmt.Sprintf("%s?edit&insert_before=%d&heading=%s",
+		yearURL, insertIdx, url.QueryEscape(target)), true
+}
+
+// parseDiaryURLParts extracts year/month/day from fsPath based on depth.
+// depth=1 returns year only; depth=2 returns year+month; depth=3 returns all.
+func parseDiaryURLParts(fsPath string, depth int) (year, month, day string, ok bool) {
+	parts := []string{}
+	cur := fsPath
+	for i := 0; i < depth; i++ {
+		parts = append([]string{filepath.Base(cur)}, parts...)
+		cur = filepath.Dir(cur)
+	}
+	switch depth {
+	case 1:
+		return parts[0], "", "", true
+	case 2:
+		return parts[0], parts[1], "", true
+	case 3:
+		return parts[0], parts[1], parts[2], true
+	}
+	return "", "", "", false
 }
 
 func (d *diaryHandler) handle(root, fsPath, urlPath string) *specialPage {
@@ -89,18 +166,29 @@ func (d *diaryHandler) handle(root, fsPath, urlPath string) *specialPage {
 	}
 	widget := computeCalendarWidget(diaryRootFS, diaryRootURL, fsPath, depth)
 	if depth == 0 {
-		return &specialPage{Widget: widget}
+		return &specialPage{Widget: widget, SuppressTOC: true}
 	}
-	var content template.HTML
-	switch depth {
-	case 1:
-		content = renderDiaryYear(fsPath, urlPath)
-	case 2:
-		content = renderDiaryMonth(fsPath, urlPath)
-	case 3:
-		content = renderDiaryDay(fsPath, urlPath)
+	year, _, _, ok := parseDiaryURLParts(fsPath, depth)
+	if !ok {
+		return &specialPage{Widget: widget, SuppressTOC: true}
 	}
-	return &specialPage{Content: content, SuppressListing: true, Widget: widget}
+	if depth == 1 {
+		yearFS := filepath.Join(diaryRootFS, year)
+		yearURL := path.Join(diaryRootURL, year) + "/"
+		content := renderDiaryYear(yearFS, yearURL)
+		return &specialPage{
+			Content:         content,
+			SuppressContent: true,
+			SuppressListing: true,
+			SuppressTOC:     true,
+			Widget:          widget,
+		}
+	}
+	// depth 2/3 only reach here when a real folder exists at the path
+	// (unfinished migration). The virtual URL would have been redirected
+	// in `redirect()` otherwise. Render the folder normally; just add the
+	// calendar widget.
+	return &specialPage{Widget: widget, SuppressTOC: true}
 }
 
 // findDiaryContext walks up from fsPath toward root looking for a
@@ -128,6 +216,118 @@ func findDiaryContext(root, fsPath, urlPath string) (depth int, diaryRootFS, dia
 	return 0, "", "", false
 }
 
+// headingTextRe matches an ATX heading at the start of a section. The
+// heading text is everything after the `#`s and the required space, on the
+// first line.
+var headingTextRe = regexp.MustCompile(`^(#{1,6})\s+([^\n]*)`)
+
+// sectionHeading returns the heading level (1..6) and trimmed text of a
+// section produced by splitSections. Returns level=0 for the pre-heading
+// section (index 0).
+func sectionHeading(section []byte) (level int, text string) {
+	m := headingTextRe.FindSubmatch(section)
+	if m == nil {
+		return 0, ""
+	}
+	return len(m[1]), strings.TrimSpace(string(m[2]))
+}
+
+// findSectionIndex returns the absolute section index whose heading text
+// matches target (e.g. "2026-05" or "2026-05-28"). Returns the first match.
+func findSectionIndex(sections [][]byte, target string) (int, bool) {
+	for i := 1; i < len(sections); i++ {
+		_, text := sectionHeading(sections[i])
+		if text == target {
+			return i, true
+		}
+	}
+	return 0, false
+}
+
+// computeInsertIndex returns the section index at which a new date heading
+// (target = `YYYY-MM` or `YYYY-MM-DD`) should be spliced in to keep date
+// sections chronologically ordered. Only date-format headings participate in
+// the comparison; non-date headings (e.g. `## Events` in a year intro) are
+// skipped so the new section is placed relative to the surrounding date
+// sections, not the intro. Falls back to len(sections) when target is
+// greater than every date heading. ISO formatting means string comparison
+// is equivalent to chronological order.
+func computeInsertIndex(sections [][]byte, target string) int {
+	for i := 1; i < len(sections); i++ {
+		_, text := sectionHeading(sections[i])
+		if !isDateHeading(text) {
+			continue
+		}
+		if text > target {
+			return i
+		}
+	}
+	return len(sections)
+}
+
+// isDateHeading reports whether text is exactly a `YYYY`, `YYYY-MM`, or
+// `YYYY-MM-DD` token. Used by the insert-index search to ignore non-date
+// section headings.
+func isDateHeading(text string) bool {
+	switch len(text) {
+	case 4, 7, 10:
+	default:
+		return false
+	}
+	if _, err := time.Parse("2006", text[:4]); err != nil {
+		return false
+	}
+	if len(text) >= 7 {
+		if text[4] != '-' {
+			return false
+		}
+		if _, err := time.Parse("2006-01", text[:7]); err != nil {
+			return false
+		}
+	}
+	if len(text) == 10 {
+		if text[7] != '-' {
+			return false
+		}
+		if _, err := time.Parse("2006-01-02", text); err != nil {
+			return false
+		}
+	}
+	return true
+}
+
+// daysWithEntriesByMonth returns a `month → set[day]` map of `### YYYY-MM-DD`
+// sections in the year's index.md. Used by the calendar widget to populate
+// all 12 month grids in a single file read.
+func daysWithEntriesByMonth(yearFS string, year int) map[int]map[int]bool {
+	out := map[int]map[int]bool{}
+	raw, err := os.ReadFile(filepath.Join(yearFS, "index.md"))
+	if err != nil {
+		return out
+	}
+	yearPrefix := fmt.Sprintf("%d-", year)
+	sections := splitSections(raw)
+	for i := 1; i < len(sections); i++ {
+		level, text := sectionHeading(sections[i])
+		if level != 3 || !strings.HasPrefix(text, yearPrefix) || len(text) < 10 {
+			continue
+		}
+		m, err := strconv.Atoi(text[5:7])
+		if err != nil || m < 1 || m > 12 {
+			continue
+		}
+		d, err := strconv.Atoi(text[8:10])
+		if err != nil || d < 1 || d > 31 {
+			continue
+		}
+		if out[m] == nil {
+			out[m] = map[int]bool{}
+		}
+		out[m][d] = true
+	}
+	return out
+}
+
 type calDay struct {
 	Num       int
 	URL       string
@@ -142,32 +342,31 @@ type calYear struct {
 	IsCurrent bool
 }
 
-type calMonth struct {
+// calMonthGrid carries everything the template needs to render one month's
+// grid plus the dropdown / heading entry that targets it. The calendar
+// widget ships all 12 in the initial HTML; JS swaps which one is visible.
+type calMonthGrid struct {
 	Num       int
 	Name      string
-	URL       string
-	IsCurrent bool
+	AnchorURL string // "#YYYY-MM" on a year page, full URL otherwise
+	Weeks     [][]calDay
 }
 
 type calendarData struct {
 	DisplayYear      int
 	DisplayMonth     int
-	MonthName    string
+	DisplayMonthName string // pre-resolved so the template doesn't need arithmetic
 	DiaryURL         string
 	YearURL          string
-	MonthURL     string
-	PrevMonURL   string
-	NextMonURL   string
-	Weeks        [][]calDay
+	Months           []calMonthGrid
 	Years            []calYear
-	AllMonths    []calMonth
 }
 
 var diaryCalTmpl = template.Must(template.ParseFS(assets, "assets/diary/calendar.html"))
 
 func computeCalendarWidget(diaryRootFS, diaryRootURL, fsPath string, depth int) template.HTML {
 	today := time.Now()
-	var displayYear, displayMonth, currentDay int
+	var displayYear, displayMonth, currentDay, currentMonth int
 
 	switch depth {
 	case 0:
@@ -212,73 +411,55 @@ func computeCalendarWidget(diaryRootFS, diaryRootURL, fsPath string, depth int)
 		displayYear = y
 		displayMonth = m
 		currentDay = d
+		currentMonth = m
 	default:
 		return ""
 	}
 
-	// Which days in the display month have diary subfolders?
-	monthFSPath := filepath.Join(diaryRootFS,
-		fmt.Sprintf("%d", displayYear),
-		fmt.Sprintf("%02d", displayMonth))
-	dayEntries, _ := os.ReadDir(monthFSPath)
-	hasDayEntry := map[int]bool{}
-	for _, e := range dayEntries {
-		if !e.IsDir() {
-			continue
-		}
-		d, err := strconv.Atoi(e.Name())
-		if err != nil || d < 1 || d > 31 {
-			continue
-		}
-		hasDayEntry[d] = true
-	}
-
-	// Build calendar grid with Monday as first column.
-	firstDay := time.Date(displayYear, time.Month(displayMonth), 1, 0, 0, 0, 0, time.UTC)
-	startOffset := int(firstDay.Weekday()+6) % 7
-	daysInMonth := time.Date(displayYear, time.Month(displayMonth)+1, 0, 0, 0, 0, 0, time.UTC).Day()
-
-	monthURLBase := path.Join(diaryRootURL,
-		fmt.Sprintf("%d", displayYear),
-		fmt.Sprintf("%02d", displayMonth)) + "/"
-
-	var weeks [][]calDay
-	week := make([]calDay, 7)
-	col := startOffset
-	for d := 1; d <= daysInMonth; d++ {
-		dayURL := path.Join(monthURLBase, fmt.Sprintf("%02d", d)) + "/"
-		cell := calDay{Num: d, HasEntry: hasDayEntry[d]}
-		if cell.HasEntry {
-			cell.URL = dayURL
-		} else {
-			cell.URL = dayURL + "?edit"
-		}
-		cell.IsCurrent = d == currentDay
-		cell.IsToday = d == today.Day() &&
-			time.Month(displayMonth) == today.Month() &&
-			displayYear == today.Year()
-		week[col] = cell
-		col++
-		if col == 7 {
-			weeks = append(weeks, week)
-			week = make([]calDay, 7)
-			col = 0
-		}
-	}
-	if col > 0 {
-		weeks = append(weeks, week)
-	}
-
-	prev := time.Date(displayYear, time.Month(displayMonth)-1, 1, 0, 0, 0, 0, time.UTC)
-	next := time.Date(displayYear, time.Month(displayMonth)+1, 1, 0, 0, 0, 0, time.UTC)
-	prevMonURL := path.Join(diaryRootURL,
-		fmt.Sprintf("%d", prev.Year()),
-		fmt.Sprintf("%02d", int(prev.Month()))) + "/"
-	nextMonURL := path.Join(diaryRootURL,
-		fmt.Sprintf("%d", next.Year()),
-		fmt.Sprintf("%02d", int(next.Month()))) + "/"
+	yearFS := filepath.Join(diaryRootFS, fmt.Sprintf("%d", displayYear))
+	hasDayEntryByMonth := daysWithEntriesByMonth(yearFS, displayYear)
 	yearURL := path.Join(diaryRootURL, fmt.Sprintf("%d", displayYear)) + "/"
 
+	// On a year page, in-year month/day links collapse to anchors so the
+	// browser scrolls within the current page instead of navigating away.
+	// On the diary root (depth=0), all links remain full URLs.
+	pageYear := 0
+	if depth >= 1 {
+		pageYear = displayYear
+	}
+
+	monthAnchor := func(year, month int) string {
+		if pageYear == year {
+			return fmt.Sprintf("#%d-%02d", year, month)
+		}
+		return path.Join(diaryRootURL,
+			fmt.Sprintf("%d", year),
+			fmt.Sprintf("%02d", month)) + "/"
+	}
+	dayAnchor := func(year, month, day int) string {
+		if pageYear == year {
+			return fmt.Sprintf("#%d-%02d-%02d", year, month, day)
+		}
+		return path.Join(diaryRootURL,
+			fmt.Sprintf("%d", year),
+			fmt.Sprintf("%02d", month),
+			fmt.Sprintf("%02d", day)) + "/"
+	}
+
+	months := make([]calMonthGrid, 12)
+	for m := 1; m <= 12; m++ {
+		var cd int
+		if m == currentMonth {
+			cd = currentDay
+		}
+		months[m-1] = calMonthGrid{
+			Num:       m,
+			Name:      germanMonths[time.Month(m)],
+			AnchorURL: monthAnchor(displayYear, m),
+			Weeks:     buildMonthGrid(displayYear, m, today, cd, hasDayEntryByMonth[m], dayAnchor),
+		}
+	}
+
 	// Collect all year subdirectories in diary root (descending).
 	yearEntries, _ := os.ReadDir(diaryRootFS)
 	var years []calYear
@@ -307,31 +488,14 @@ func computeCalendarWidget(diaryRootFS, diaryRootURL, fsPath string, depth int)
 	}
 	sort.Slice(years, func(i, j int) bool { return years[i].Num > years[j].Num })
 
-	// All 12 months, ascending, linked to current display year.
-	allMonths := make([]calMonth, 12)
-	for m := 1; m <= 12; m++ {
-		allMonths[m-1] = calMonth{
-			Num:  m,
-			Name: germanMonths[time.Month(m)],
-			URL: path.Join(diaryRootURL,
-				fmt.Sprintf("%d", displayYear),
-				fmt.Sprintf("%02d", m)) + "/",
-			IsCurrent: m == displayMonth,
-		}
-	}
-
 	data := calendarData{
 		DisplayYear:      displayYear,
 		DisplayMonth:     displayMonth,
-		MonthName:    germanMonths[time.Month(displayMonth)],
+		DisplayMonthName: months[displayMonth-1].Name,
 		DiaryURL:         diaryRootURL,
 		YearURL:          yearURL,
-		MonthURL:     monthURLBase,
-		PrevMonURL:   prevMonURL,
-		NextMonURL:   nextMonURL,
-		Weeks:        weeks,
+		Months:           months,
 		Years:            years,
-		AllMonths:    allMonths,
 	}
 
 	var buf bytes.Buffer
@@ -342,6 +506,45 @@ func computeCalendarWidget(diaryRootFS, diaryRootURL, fsPath string, depth int)
 	return template.HTML(buf.String())
 }
 
+// buildMonthGrid renders one month's day cells as a Monday-first week grid.
+// hasDayEntry maps day-of-month → has a diary entry. dayAnchor produces the
+// in-page anchor (or full URL when crossing pages); empty days link to the
+// same anchor — every day exists on the year page as either a real or
+// virtual section, so navigation is enough. Page creation happens via the
+// [edit] button on the heading itself.
+func buildMonthGrid(year, month int, today time.Time, currentDay int, hasDayEntry map[int]bool, dayAnchor func(int, int, int) string) [][]calDay {
+	firstDay := time.Date(year, time.Month(month), 1, 0, 0, 0, 0, time.UTC)
+	startOffset := int(firstDay.Weekday()+6) % 7
+	daysInMonth := time.Date(year, time.Month(month)+1, 0, 0, 0, 0, 0, time.UTC).Day()
+
+	var weeks [][]calDay
+	week := make([]calDay, 7)
+	col := startOffset
+	for d := 1; d <= daysInMonth; d++ {
+		cell := calDay{
+			Num:      d,
+			HasEntry: hasDayEntry[d],
+			URL:      dayAnchor(year, month, d),
+		}
+		cell.IsCurrent = currentDay > 0 && d == currentDay
+		cell.IsToday = d == today.Day() &&
+			time.Month(month) == today.Month() &&
+			year == today.Year()
+		week[col] = cell
+		col++
+		if col == 7 {
+			weeks = append(weeks, week)
+			week = make([]calDay, 7)
+			col = 0
+		}
+	}
+	if col > 0 {
+		weeks = append(weeks, week)
+	}
+	return weeks
+}
+
+
 // diaryPhoto is a photo file whose name starts with a YYYY-MM-DD date prefix.
 type diaryPhoto struct {
 	Date     time.Time
@@ -350,41 +553,20 @@ type diaryPhoto struct {
 	ThumbURL string
 }
 
-type diaryMonthSummary struct {
-	ID     string
-	Name   string
-	URL    string
+// diarySection is one rendered section of the diary content (year, month, or
+// day). Edit URLs point back into the year file's section editor so per-day
+// editing works from any slice page.
+type diarySection struct {
+	Level   int           // 1, 2, or 3
+	ID      string        // anchor id (e.g. "2026-05-28")
+	Heading string        // displayed heading text
+	EditURL string        // year-file section edit URL ("" = no edit button)
+	Body    template.HTML // rendered markdown body (excludes the heading line)
 	Photos  []diaryPhoto
 }
 
-type diaryDaySection struct {
-	ID      string
-	Heading string
-	URL     string
-	EditURL string
-	Content template.HTML
-	Photos  []diaryPhoto
-}
-
-type diaryYearData struct {
-	Months []diaryMonthSummary
-	Year   int
-}
-type diaryMonthData struct{ Days []diaryDaySection }
-type diaryDayData struct{ Photos []diaryPhoto }
-
-var diaryYearTmpl = template.Must(template.ParseFS(assets, "assets/diary/year.html"))
-var diaryMonthTmpl = template.Must(template.ParseFS(assets, "assets/diary/month.html"))
-var diaryDayTmpl = template.Must(template.ParseFS(assets, "assets/diary/day.html"))
-
-var germanWeekdays = map[time.Weekday]string{
-	time.Sunday:    "Sonntag",
-	time.Monday:    "Montag",
-	time.Tuesday:   "Dienstag",
-	time.Wednesday: "Mittwoch",
-	time.Thursday:  "Donnerstag",
-	time.Friday:    "Freitag",
-	time.Saturday:  "Samstag",
+type diaryContentData struct {
+	Sections []diarySection
 }
 
 var germanMonths = map[time.Month]string{
@@ -402,15 +584,6 @@ var germanMonths = map[time.Month]string{
 	time.December:  "Dezember",
 }
 
-func formatGermanDate(t time.Time) string {
-	return fmt.Sprintf("%s, %d. %s %d",
-		germanWeekdays[t.Weekday()],
-		t.Day(),
-		germanMonths[t.Month()],
-		t.Year(),
-	)
-}
-
 var photoExts = map[string]bool{
 	".jpg": true, ".jpeg": true, ".png": true, ".gif": true, ".webp": true,
 }
@@ -453,196 +626,196 @@ func yearPhotos(yearFsPath, yearURLPath string) []diaryPhoto {
 	return photos
 }
 
-// renderDiaryYear renders month sections with photo counts for a year folder.
-func renderDiaryYear(fsPath, urlPath string) template.HTML {
-	year, err := strconv.Atoi(filepath.Base(fsPath))
+var diaryContentTmpl = template.Must(template.ParseFS(assets, "assets/diary/content.html"))
+
+// sectionBody strips the first heading line and returns the rendered body.
+// Used so the diary template can emit the heading explicitly (with edit URL)
+// while still rendering the section body via goldmark.
+func sectionBody(section []byte) template.HTML {
+	body := stripFirstHeading(section)
+	if len(bytes.TrimSpace(body)) == 0 {
+		return ""
+	}
+	return renderMarkdown(body)
+}
+
+// renderDiaryYear renders the year page: every section from the year file
+// (with photos attached to `### YYYY-MM-DD` headings) plus virtual entries
+// for every month/day slot the file doesn't yet contain.
+func renderDiaryYear(yearFS, yearURL string) template.HTML {
+	year, err := strconv.Atoi(filepath.Base(yearFS))
 	if err != nil {
 		return ""
 	}
+	raw, _ := os.ReadFile(filepath.Join(yearFS, "index.md"))
+	sections := splitSections(raw)
+	photos := yearPhotos(yearFS, yearURL)
 
-	photos := yearPhotos(fsPath, urlPath)
+	out := buildFileSections(sections, photos, yearURL)
+	out = appendVirtualEntries(out, sections, photos, year, yearURL)
+	return renderDiaryContent(out)
+}
 
-	// Collect month numbers from both subdirectories and photo filenames so
-	// years that contain only photos (no diary entries) still list months.
-	monthSet := map[int]bool{}
-	monthDirs := map[int]string{}
-	entries, _ := os.ReadDir(fsPath)
-	for _, e := range entries {
-		if !e.IsDir() {
+// buildFileSections converts the year file's sections (skipping the
+// pre-heading section 0) into rendered diarySection entries. Photos are
+// attached to level-3 headings whose text parses as `YYYY-MM-DD`.
+func buildFileSections(sections [][]byte, photos []diaryPhoto, yearURL string) []diarySection {
+	var out []diarySection
+	for i := 1; i < len(sections); i++ {
+		level, text := sectionHeading(sections[i])
+		if level == 0 {
 			continue
 		}
-		n, err := strconv.Atoi(e.Name())
-		if err != nil || n < 1 || n > 12 {
+		sec := diarySection{
+			Level:   level,
+			ID:      text,
+			Heading: text,
+			EditURL: fmt.Sprintf("%s?edit&section=%d", yearURL, i),
+			Body:    sectionBody(sections[i]),
+		}
+		if level == 3 {
+			if y, m, d, ok := parseISODate(text); ok {
+				sec.Photos = filterPhotos(photos, y, m, d)
+			}
+		}
+		out = append(out, sec)
+	}
+	return out
+}
+
+// appendVirtualEntries inserts virtual month and day sections for every
+// `## YYYY-MM` / `### YYYY-MM-DD` slot in `year` that lacks a real section.
+// Virtual day sections carry photos when present. Each virtual entry's
+// EditURL routes through the insert-before flow so clicking [edit] splices
+// the section into the year file at the right chronological position.
+//
+// Scope: past years get all 12 months / 365(6) days; the current year stops
+// at today; future years are returned unchanged.
+//
+// Interleave: real date sections (`## YYYY-MM`, `### YYYY-MM-DD`) keep their
+// document position; virtual entries are spliced in lexicographic ID order
+// before the next real date section. Non-date headings (e.g. `## Events` →
+// `### Festival` in a year intro) are left where the user wrote them.
+func appendVirtualEntries(existing []diarySection, sections [][]byte, photos []diaryPhoto, year int, yearURL string) []diarySection {
+	today := time.Now()
+	if year > today.Year() {
+		return existing
+	}
+
+	coveredMonth := map[string]bool{}
+	coveredDay := map[string]bool{}
+	for _, s := range existing {
+		switch {
+		case s.Level == 2 && len(s.ID) == 7 && isDateHeading(s.ID):
+			coveredMonth[s.ID] = true
+		case s.Level == 3 && len(s.ID) == 10 && isDateHeading(s.ID):
+			coveredDay[s.ID] = true
+		}
+	}
+
+	photoByDay := map[string][]diaryPhoto{}
+	for _, p := range photos {
+		if p.Date.Year() != year {
 			continue
 		}
-		monthSet[n] = true
-		monthDirs[n] = e.Name()
-	}
-	for _, p := range photos {
-		if p.Date.Year() == year {
-			monthSet[int(p.Date.Month())] = true
-		}
+		photoByDay[p.Date.Format("2006-01-02")] = append(photoByDay[p.Date.Format("2006-01-02")], p)
 	}
 
-	monthNums := make([]int, 0, len(monthSet))
-	for m := range monthSet {
-		monthNums = append(monthNums, m)
+	lastDay := time.Date(year, time.December, 31, 0, 0, 0, 0, time.UTC)
+	if year == today.Year() {
+		lastDay = time.Date(year, today.Month(), today.Day(), 0, 0, 0, 0, time.UTC)
 	}
-	sort.Ints(monthNums)
 
-	var months []diaryMonthSummary
-	for _, monthNum := range monthNums {
-		var monthPhotos []diaryPhoto
-		for _, p := range photos {
-			if p.Date.Year() == year && int(p.Date.Month()) == monthNum {
-				monthPhotos = append(monthPhotos, p)
-			}
-		}
-		monthDate := time.Date(year, time.Month(monthNum), 1, 0, 0, 0, 0, time.UTC)
-		dirName, ok := monthDirs[monthNum]
-		if !ok {
-			dirName = fmt.Sprintf("%02d", monthNum)
-		}
-		months = append(months, diaryMonthSummary{
-			ID:     monthDate.Format("2006-01"),
-			Name:   fmt.Sprintf("%s %d", germanMonths[monthDate.Month()], year),
-			URL:    path.Join(urlPath, dirName) + "/",
-			Photos: monthPhotos,
+	var virtual []diarySection
+	for d := time.Date(year, time.January, 1, 0, 0, 0, 0, time.UTC); !d.After(lastDay); d = d.AddDate(0, 0, 1) {
+		if d.Day() == 1 {
+			monthID := d.Format("2006-01")
+			if !coveredMonth[monthID] {
+				idx := computeInsertIndex(sections, monthID)
+				virtual = append(virtual, diarySection{
+					Level:   2,
+					ID:      monthID,
+					Heading: monthID,
+					EditURL: fmt.Sprintf("%s?edit&insert_before=%d&heading=%s&level=%s",
+						yearURL, idx, url.QueryEscape(monthID), url.QueryEscape("##")),
 				})
 			}
-
-	var buf bytes.Buffer
-	if err := diaryYearTmpl.Execute(&buf, diaryYearData{Months: months, Year: year}); err != nil {
-		log.Printf("diary year template: %v", err)
-		return ""
 		}
-	return template.HTML(buf.String())
-}
-
-// renderDiaryMonth renders a section per day, each with its markdown content
-// and photos sourced from the parent year folder.
-func renderDiaryMonth(fsPath, urlPath string) template.HTML {
-	yearFsPath := filepath.Dir(fsPath)
-	yearURLPath := parentURL(urlPath)
-
-	year, err := strconv.Atoi(filepath.Base(yearFsPath))
-	if err != nil {
-		return ""
-	}
-	monthNum, err := strconv.Atoi(filepath.Base(fsPath))
-	if err != nil || monthNum < 1 || monthNum > 12 {
-		return ""
-	}
-
-	allPhotos := yearPhotos(yearFsPath, yearURLPath)
-	var monthPhotos []diaryPhoto
-	for _, p := range allPhotos {
-		if p.Date.Year() == year && int(p.Date.Month()) == monthNum {
-			monthPhotos = append(monthPhotos, p)
-		}
-	}
-
-	// Collect day numbers from subdirectories and from photo filenames.
-	daySet := map[int]bool{}
-	dayDirs := map[int]string{} // day number → actual directory name
-	entries, _ := os.ReadDir(fsPath)
-	for _, e := range entries {
-		if !e.IsDir() {
-			continue
-		}
-		d, err := strconv.Atoi(e.Name())
-		if err != nil || d < 1 || d > 31 {
-			continue
-		}
-		daySet[d] = true
-		dayDirs[d] = e.Name()
-	}
-	for _, p := range monthPhotos {
-		daySet[p.Date.Day()] = true
-	}
-
-	days := make([]int, 0, len(daySet))
-	for d := range daySet {
-		days = append(days, d)
-	}
-	sort.Ints(days)
-
-	var sections []diaryDaySection
-	for _, dayNum := range days {
-		date := time.Date(year, time.Month(monthNum), dayNum, 0, 0, 0, 0, time.UTC)
-
-		heading := date.Format("2006-01-02")
-		dayURL := path.Join(urlPath, fmt.Sprintf("%02d", dayNum)) + "/"
-		var content template.HTML
-		if dirName, ok := dayDirs[dayNum]; ok {
-			dayURL = path.Join(urlPath, dirName) + "/"
-			dayFsPath := filepath.Join(fsPath, dirName)
-			if raw, err := os.ReadFile(filepath.Join(dayFsPath, "index.md")); err == nil && len(raw) > 0 {
-				raw = stripFirstHeading(raw)
-				content = renderMarkdown(raw)
-			}
-		}
-
-		var photos []diaryPhoto
-		for _, p := range monthPhotos {
-			if p.Date.Day() == dayNum {
-				photos = append(photos, p)
-			}
-		}
-
-		sections = append(sections, diaryDaySection{
-			ID:      date.Format("2006-01-02"),
-			Heading: heading,
-			URL:     dayURL,
-			EditURL: dayURL + "?edit",
-			Content: content,
-			Photos:  photos,
+		dayID := d.Format("2006-01-02")
+		if !coveredDay[dayID] {
+			idx := computeInsertIndex(sections, dayID)
+			virtual = append(virtual, diarySection{
+				Level:   3,
+				ID:      dayID,
+				Heading: dayID,
+				EditURL: fmt.Sprintf("%s?edit&insert_before=%d&heading=%s",
+					yearURL, idx, url.QueryEscape(dayID)),
+				Photos: photoByDay[dayID],
 			})
 		}
+	}
+	if len(virtual) == 0 {
+		return existing
+	}
 
+	out := make([]diarySection, 0, len(existing)+len(virtual))
+	vi := 0
+	for _, s := range existing {
+		if isRealDateSection(s) {
+			for vi < len(virtual) && virtual[vi].ID < s.ID {
+				out = append(out, virtual[vi])
+				vi++
+			}
+		}
+		out = append(out, s)
+	}
+	for vi < len(virtual) {
+		out = append(out, virtual[vi])
+		vi++
+	}
+	return out
+}
+
+// isRealDateSection reports whether a rendered diarySection is one of the
+// date-headed slots (`## YYYY-MM` or `### YYYY-MM-DD`) the virtual-entry
+// interleave sorts against.
+func isRealDateSection(s diarySection) bool {
+	switch s.Level {
+	case 2:
+		return len(s.ID) == 7 && isDateHeading(s.ID)
+	case 3:
+		return len(s.ID) == 10 && isDateHeading(s.ID)
+	}
+	return false
+}
+
+// parseISODate parses "YYYY-MM-DD" leading characters of s. Returns ok=false
+// if the prefix does not match.
+func parseISODate(s string) (year, month, day int, ok bool) {
+	if len(s) < 10 {
+		return 0, 0, 0, false
+	}
+	t, err := time.Parse("2006-01-02", s[:10])
+	if err != nil {
+		return 0, 0, 0, false
+	}
+	return t.Year(), int(t.Month()), t.Day(), true
+}
+
+func filterPhotos(photos []diaryPhoto, year, month, day int) []diaryPhoto {
+	var out []diaryPhoto
+	for _, p := range photos {
+		if p.Date.Year() == year && int(p.Date.Month()) == month && p.Date.Day() == day {
+			out = append(out, p)
+		}
+	}
+	return out
+}
+
+func renderDiaryContent(sections []diarySection) template.HTML {
 	var buf bytes.Buffer
-	if err := diaryMonthTmpl.Execute(&buf, diaryMonthData{Days: sections}); err != nil {
-		log.Printf("diary month template: %v", err)
-		return ""
-	}
-	return template.HTML(buf.String())
-}
-
-// renderDiaryDay renders the photo grid for a single day, sourcing photos
-// from the grandparent year folder.
-func renderDiaryDay(fsPath, urlPath string) template.HTML {
-	monthFsPath := filepath.Dir(fsPath)
-	yearFsPath := filepath.Dir(monthFsPath)
-	yearURLPath := parentURL(parentURL(urlPath))
-
-	year, err := strconv.Atoi(filepath.Base(yearFsPath))
-	if err != nil {
-		return ""
-	}
-	monthNum, err := strconv.Atoi(filepath.Base(monthFsPath))
-	if err != nil {
-		return ""
-	}
-	dayNum, err := strconv.Atoi(filepath.Base(fsPath))
-	if err != nil {
-		return ""
-	}
-
-	allPhotos := yearPhotos(yearFsPath, yearURLPath)
-	var photos []diaryPhoto
-	for _, p := range allPhotos {
-		if p.Date.Year() == year && int(p.Date.Month()) == monthNum && p.Date.Day() == dayNum {
-			photos = append(photos, p)
-		}
-	}
-
-	if len(photos) == 0 {
-		return ""
-	}
-
-	var buf bytes.Buffer
-	if err := diaryDayTmpl.Execute(&buf, diaryDayData{Photos: photos}); err != nil {
-		log.Printf("diary day template: %v", err)
+	if err := diaryContentTmpl.Execute(&buf, diaryContentData{Sections: sections}); err != nil {
+		log.Printf("diary content template: %v", err)
 		return ""
 	}
 	return template.HTML(buf.String())

main.go

@@ -27,29 +27,28 @@ var (
 
 // specialPage is the result returned by a pageTypeHandler.
 // Content is injected into the page after the standard markdown content.
+// SuppressContent hides the markdown-rendered content (handler owns rendering).
 // SuppressListing hides the default file/folder listing.
 // Widget is a persistent sidebar widget rendered outside the main content area.
 type specialPage struct {
 	Content         template.HTML
+	SuppressContent bool
 	SuppressListing bool
+	SuppressTOC     bool
 	Widget          template.HTML
 }
 
 // pageTypeHandler is implemented by each special folder type (diary, gallery, …).
 // handle returns nil when the handler does not apply to the given path.
 // redirect returns ok=true with an absolute URL when the request should be
-// short-circuited with a 302 redirect (e.g. persistent date links in a diary).
-// defaultHeading returns ok=true with custom pre-fill heading text for the
-// editor when no index.md exists yet (e.g. German long-form date for a diary
-// day). Handlers that don't need a hook should return the zero value.
+// short-circuited with a 302 redirect (e.g. persistent date links in a diary,
+// or virtual diary URLs in edit mode that delegate to the year file's editor).
 //
 // When adding a new hook, prefer a sibling method here over folding logic
-// into main.go or render.go. If this list grows much beyond three, consider
-// collapsing into a single overrides struct returned per request.
+// into main.go or render.go.
 type pageTypeHandler interface {
 	handle(root, fsPath, urlPath string) *specialPage
-	redirect(root, fsPath, urlPath string) (target string, ok bool)
-	defaultHeading(root, fsPath, urlPath string) (heading string, ok bool)
+	redirect(root, fsPath, urlPath string, r *http.Request) (target string, ok bool)
 }
 
 // pageTypeHandlers is the registry. Each type registers itself via init().
@@ -218,7 +217,7 @@ func (h *handler) serveDir(w http.ResponseWriter, r *http.Request, urlPath, fsPa
 	}
 
 	for _, ph := range pageTypeHandlers {
-		if target, ok := ph.redirect(h.root, fsPath, urlPath); ok {
+		if target, ok := ph.redirect(h.root, fsPath, urlPath, r); ok {
 			http.Redirect(w, r, target, http.StatusFound)
 			return
 		}
@@ -229,17 +228,18 @@ func (h *handler) serveDir(w http.ResponseWriter, r *http.Request, urlPath, fsPa
 
 	// Determine section index (-1 = whole page).
 	sectionIndex := -1
+	insertBefore := -1
 	if editMode {
 		if s := r.URL.Query().Get("section"); s != "" {
 			if n, err := strconv.Atoi(s); err == nil && n >= 0 {
 				sectionIndex = n
 			}
 		}
+		if s := r.URL.Query().Get("insert_before"); s != "" {
+			if n, err := strconv.Atoi(s); err == nil && n >= 0 {
+				insertBefore = n
+			}
 		}
-
-	var rendered template.HTML
-	if len(rawMD) > 0 && !editMode {
-		rendered = renderMarkdown(rawMD)
 	}
 
 	var special *specialPage
@@ -251,6 +251,11 @@ func (h *handler) serveDir(w http.ResponseWriter, r *http.Request, urlPath, fsPa
 		}
 	}
 
+	var rendered template.HTML
+	if len(rawMD) > 0 && !editMode && (special == nil || !special.SuppressContent) {
+		rendered = renderMarkdown(rawMD)
+	}
+
 	var entries []entry
 	if !editMode && (special == nil || !special.SuppressListing) {
 		entries = listEntries(fsPath, urlPath)
@@ -263,26 +268,32 @@ func (h *handler) serveDir(w http.ResponseWriter, r *http.Request, urlPath, fsPa
 
 	var specialContent template.HTML
 	var sidebarWidget template.HTML
+	suppressTOC := false
 	if special != nil {
 		specialContent = special.Content
 		sidebarWidget = special.Widget
+		suppressTOC = special.SuppressTOC
 	}
 
 	rawContent := string(rawMD)
-	if editMode && sectionIndex >= 0 {
+	if editMode && insertBefore >= 0 {
+		heading := r.URL.Query().Get("heading")
+		level := r.URL.Query().Get("level")
+		if level == "" {
+			level = "###"
+		}
+		if heading != "" {
+			rawContent = level + " " + heading + "\n\n"
+		} else {
+			rawContent = ""
+		}
+	} else if editMode && sectionIndex >= 0 {
 		sections := splitSections(rawMD)
 		if sectionIndex < len(sections) {
 			rawContent = string(sections[sectionIndex])
 		}
 	} else if editMode && rawContent == "" && urlPath != "/" {
-		heading := pageTitle(urlPath)
-		for _, ph := range pageTypeHandlers {
-			if custom, ok := ph.defaultHeading(h.root, fsPath, urlPath); ok {
-				heading = custom
-				break
-			}
-		}
-		rawContent = "# " + heading + "\n\n"
+		rawContent = "# " + pageTitle(urlPath) + "\n\n"
 	}
 
 	parent := ""
@@ -296,12 +307,14 @@ func (h *handler) serveDir(w http.ResponseWriter, r *http.Request, urlPath, fsPa
 		EditMode:       editMode,
 		IsRoot:         urlPath == "/",
 		SectionIndex:   sectionIndex,
+		InsertBefore:   insertBefore,
 		PostURL:        urlPath,
 		RawContent:     rawContent,
 		Content:        rendered,
 		Entries:        entries,
 		SpecialContent: specialContent,
 		SidebarWidget:  sidebarWidget,
+		SuppressTOC:    suppressTOC,
 	}
 
 	w.Header().Set("Content-Type", "text/html; charset=utf-8")
@@ -350,9 +363,33 @@ func (h *handler) handlePost(w http.ResponseWriter, r *http.Request, urlPath, fs
 	indexPath := filepath.Join(fsPath, "index.md")
 	redirectTarget := urlPath
 
-	// If a section index was submitted, splice the edited section back into
-	// the full file rather than replacing the whole document.
-	if s := r.FormValue("section"); s != "" {
+	// insert_before splices a new section into the file *at* index N rather
+	// than replacing index N (used by the diary "create new day" flow).
+	// section replaces the section at index N (used by per-section edits).
+	// Exactly one of insert_before / section should be set; insert_before
+	// wins if both are present.
+	if s := r.FormValue("insert_before"); s != "" {
+		insertIndex, err := strconv.Atoi(s)
+		if err != nil || insertIndex < 0 {
+			http.Error(w, "bad insert_before", http.StatusBadRequest)
+			return
+		}
+		rawMD, _ := os.ReadFile(indexPath)
+		sections := splitSections(rawMD)
+		if insertIndex > len(sections) {
+			insertIndex = len(sections)
+		}
+		newSection := []byte(content)
+		inserted := make([][]byte, 0, len(sections)+1)
+		inserted = append(inserted, sections[:insertIndex]...)
+		inserted = append(inserted, newSection)
+		inserted = append(inserted, sections[insertIndex:]...)
+		content = string(joinSections(inserted))
+		ids := headingIDs([]byte(content))
+		if insertIndex-1 >= 0 && insertIndex-1 < len(ids) {
+			redirectTarget = urlPath + "#" + ids[insertIndex-1]
+		}
+	} else if s := r.FormValue("section"); s != "" {
 		sectionIndex, err := strconv.Atoi(s)
 		if err != nil || sectionIndex < 0 {
 			http.Error(w, "bad section", http.StatusBadRequest)

render.go

@@ -40,12 +40,14 @@ type pageData struct {
 	EditMode       bool
 	IsRoot         bool
 	SectionIndex   int // -1 = whole page; >=0 = section being edited
+	InsertBefore   int // -1 = no insert; >=0 = splice new section at this index
 	PostURL        string
 	RawContent     string
 	Content        template.HTML
 	Entries        []entry
 	SpecialContent template.HTML
 	SidebarWidget  template.HTML
+	SuppressTOC    bool
 	RenderMS       int64
 }