Add the Gizmo look for announcements: framed boxes that share a row

gizmolab's "next event" and "next assembly" boxes were hand-written HTML in
the home page's intro; they are announcements by nature, so now they can
be: a fourth style, a box framed in the theme's link colour with an italic
heading. Headed Gizmo boxes in the same spot share a row on wide screens
(the notices wrapper is a flex row, stacking on old browsers like .cols);
one without a heading takes the whole row, which is how a banner line goes
above a pair of boxes.

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

1 files changed, 10 insertions, 0 deletions

diff --git a/internal/db/migrations/blog/00009_gizmo_style.sql b/internal/db/migrations/blog/00009_gizmo_style.sql
new file mode 100644
index 0000000..1af8733
--- /dev/null
+++ b/internal/db/migrations/blog/00009_gizmo_style.sql
@@ -0,0 +1,10 @@
+-- +goose Up
+-- A fourth look for announcements: a box framed in the link colour, with
+-- boxes in the same spot sitting side by side on wide screens.
+ALTER TABLE sections DROP CONSTRAINT sections_style_check;
+ALTER TABLE sections ADD CONSTRAINT sections_style_check CHECK (style IN ('plain', 'note', 'warning', 'gizmo'));
+
+-- +goose Down
+UPDATE sections SET style = 'plain' WHERE style = 'gizmo';
+ALTER TABLE sections DROP CONSTRAINT sections_style_check;
+ALTER TABLE sections ADD CONSTRAINT sections_style_check CHECK (style IN ('plain', 'note', 'warning'));