CSS: remove remaining fixable inline styles across templates

- Suppress modal form groups: strip margin-bottom:12px (lt-form-group
  already has margin-bottom in TDS); use lt-form-group--last for the
  final group where zero margin is needed
- Keyboard shortcuts table: remove width:100% (lt-table is already full-
  width in base.css)
- Settings divider: replace style=margin override with .lt-divider--compact
- Topology bus section: move max-width:860px into .topo-bus-section rule

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

static/style.css

@@ -118,6 +118,12 @@
   padding: 0.2rem 0.45rem;
 }
 
+/* ── Form group modifiers ────────────────────────────────────────── */
+.lt-form-group--last { margin-bottom: 0; }
+
+/* ── Divider compact variant ─────────────────────────────────────── */
+.lt-divider--compact { margin: 1rem 0 0.75rem; }
+
 /* ── Topology section collapse toggle ────────────────────────────── */
 .topo-collapse-btn {
   margin-left: auto;
@@ -520,6 +526,7 @@
 /* Bus rails */
 .topo-bus-section {
   width: 100%;
+  max-width: 860px;
   display: flex;
   flex-direction: column;
   align-items: stretch;