fix(story): scrolly step cards — canvas surface + teal left accent bar

Card background was rgba(26,24,20,0.92) — identical to the page background
(--color-paper #1A1814), making cards invisible. Changed to --color-canvas
(#22201B) for a lifted surface. Added border-left: 3px solid --color-accent
as an editorial marker; other three sides keep the subtle --color-border.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Vgmzx8VTTTmCskSpQtsLTr

themes/intotheeast/css/style.css

@@ -1372,10 +1372,9 @@ body::after {
 .scrolly__steps-content { display: none; }
 .scrolly-step { min-height: 60vh; display: flex; align-items: center; padding: var(--space-16) var(--space-8); }
 .scrolly-step__inner {
-    background: rgba(26,24,20,0.92);
-    backdrop-filter: blur(4px);
-    -webkit-backdrop-filter: blur(4px);
+    background: var(--color-canvas);
     border: 1px solid var(--color-border);
+    border-left: 3px solid var(--color-accent);
     border-radius: var(--radius-sm);
     padding: var(--space-8) var(--space-8);
     opacity: 0;