add highlight-left/right modifiers for column emphasis

1 files changed, 17 insertions, 0 deletions

diff --git a/acarp.css b/acarp.css
index ed10edb..2e4c05a 100644
--- a/acarp.css
+++ b/acarp.css
@@ -598,6 +598,23 @@ section.layout-2col-center img {
 }
 
 /* ============================================================================
+   LAYOUT: highlight-left / highlight-right
+
+   Modifiers that fade out one column of a two-column slide to draw
+   attention to the other. Combine with layout-2col or layout-2col-center:
+
+   <!-- _class: layout-2col-center highlight-left -->
+
+   Use across consecutive slides to build up a two-sided comparison,
+   introducing one half first, then the other.
+   ============================================================================ */
+
+section.highlight-left .right-column,
+section.highlight-right .left-column {
+  opacity: 0.35;
+}
+
+/* ============================================================================
    SYNTAX HIGHLIGHTING OVERRIDE
    
    Override highlight.js theme colors for consistent academic styling.