Add Calendar integration (read-only)

assets/style.css

@@ -389,6 +389,10 @@ main > h2 {
 .dropdown-menu.scrollable { max-height: 23rem; overflow-y: auto; }
 
 .actions-special > .btn {text-align: left;}
+/* Header actions carry an icon and a label: the mobile dropdown shows the
+   label, the inline desktop bar (see responsive block) the icon. */
+.btn-icon { display: none; }
+.btn-icon svg { display: block; }
 
 /* === Suggestion dropdown (header search + editor link picker) ===
    Anchored to a position:relative host. Mirrors .dropdown-menu visuals with
@@ -797,6 +801,37 @@ aside.sidebar:empty { display: none; }
 .diary-cal-grid td.cal-current,
 .diary-cal-grid td.cal-current a { color: var(--primary-hover); }
 .btn-block.cal-current { color: var(--primary-hover); }
+/* Calendar events and weight under a diary day heading. */
+.diary-day-cal { margin: var(--space-3) 0 0; }
+.diary-day-cal p { margin: 0; }
+
+/* === Calendars ===
+   Header maintenance chip + dropdown, and the calendars folder page. */
+.maint-toggle { display: inline-flex; align-items: center; }
+.maint-count { margin-left: 0.3rem; }
+.maint-toggle.is-idle { color: var(--text-muted); }
+.maint-menu {
+    min-width: 20rem;
+    max-width: calc(100vw - 2rem);
+    padding: var(--space-2) var(--space-3);
+    white-space: normal;
+}
+/* Two columns so dates line up; an empty when-cell keeps the grid intact. */
+.maint-list {
+    display: grid;
+    grid-template-columns: max-content 1fr;
+    column-gap: var(--space-2);
+    row-gap: 0.15rem;
+    font-size: var(--font-sm);
+}
+.maint-list > .muted { grid-column: 1 / -1; }
+.maint-list + .panel-header { margin-top: var(--space-3); }
+.maint-when { color: var(--text-muted); white-space: nowrap; }
+.maint-all { margin-top: var(--space-3); padding: 0.3rem 0 0; border-top: var(--border-dashed); }
+.cal-scroll { overflow-x: auto; }
+.cal-table .nowrap { white-space: nowrap; }
+.cal-error { color: var(--danger); font-size: var(--font-sm); }
+.cal-sync { margin-top: var(--space-3); }
 
 /* === Fitness dashboard ===
    Server-rendered inline SVG charts. Geometry comes precomputed from Go;
@@ -840,7 +875,9 @@ aside.sidebar:empty { display: none; }
 @media (min-width: 1101px) {
     .actions-toggle, .actions-special {display: none;}
     .actions, .actions-menu, .actions.dropdown-menu.is-open {display: contents;}
-    .actions-menu .btn-block { width: auto; padding: 0;}
+    .actions-menu .btn-block { width: auto; padding: 0; align-items: center; }
+    .actions-menu .btn-icon { display: inline-block; }
+    .actions-menu .btn-label { display: none; }
 }
 
 @media (max-width: 600px) {