fix(planning): complete explanation and trace behavior (#46)

src/app/components/calendar-year/calendar-year.scss

@@ -496,6 +496,10 @@ code {
 	font-weight: 800;
 }
 
+.hypothetical-symbol {
+	width: 1.5rem;
+}
+
 .month-grid {
 	display: grid;
 	grid-template-columns: repeat(auto-fit, minmax(min(100%, 21rem), 1fr));