Mobile home: show only first banner pane; expand callouts to single line

- .home-banner mobile: background-size auto 100% -> auto 200%, position
  top-left. logo_home.png is two carousel panes stacked vertically; at
  200% height the top pane fills the 200px container exactly and the
  bottom (cloud biochemistry) is offscreen below.
- Add class='callout-break' to all <br> tags inside .home-callout-left
  and .home-callout-right; hide them on mobile via media query so the
  text flows across the page as a single line instead of multiple lines.
- .home-callout-right font-weight 700 -> 400 (regular); strong inside
  drops to 700 — so only 'biomolecule sequences' is bold; the rest of
  the line is regular weight.

Author: rhiju

assets/css/style.scss

@@ -227,11 +227,11 @@ hr { border: 0; border-top: 1px dotted $text-faint; margin: 2rem 0; }
 }
 .home-callout-right {
   font-size: 1.5rem;
-  font-weight: 700;
+  font-weight: 400;
   text-align: left;
   line-height: 1.1;
   color: $text;
-  strong { color: inherit; font-weight: 800; }
+  strong { color: inherit; font-weight: 700; }
   .accent { color: $accent-hover; }
 }
 
@@ -351,6 +351,10 @@ hr { border: 0; border-top: 1px dotted $text-faint; margin: 2rem 0; }
   }
   .home-callout-left,
   .home-callout-right { text-align: center; }
+
+  /* Collapse the multi-line line breaks so the callouts flow as a single
+     line across the page on phone/tablet widths. */
+  .callout-break { display: none; }
 }
 
 /* ---------- people ---------- */
@@ -846,8 +850,12 @@ details.show-more {
   .home-banner {
     aspect-ratio: auto;
     height: 200px;
-    background-size: auto 100%;
-    background-position: 100% 50%;
+    /* logo_home.png is two carousel panes stacked (1022x696 = 1022x348 +
+       1022x348). Scale the image so its full height = 2x container,
+       making each pane exactly the container height; then anchor at the
+       top-left so only the FIRST pane (RNA fold & function) is visible. */
+    background-size: auto 200%;
+    background-position: 0 0;
   }
   /* Drop the desktop 5% breakout — at narrow viewports it caused horizontal
      overflow / scroll. */

index.md

@@ -15,9 +15,9 @@ slug: home
 </div>
 
 <div class="home-callouts">
-  <p class="home-callout-left">what<br><span class="accent">we do</span></p>
+  <p class="home-callout-left">what<br class="callout-break"><span class="accent">we do</span></p>
   <p class="home-mission">
     Our lab seeks an agile and predictive understanding of how RNAs code for information processing and replication in living systems. We are creating new computational and chemical tools to enable the precise modeling and design of these RNAs.
   </p>
-  <p class="home-callout-right">we strive to predict<br>how <strong>biomolecule<br><span class="accent">sequences</span></strong> code<br>for their behavior.</p>
+  <p class="home-callout-right">we strive to predict<br class="callout-break">how <strong>biomolecule<br class="callout-break"><span class="accent">sequences</span></strong> code<br class="callout-break">for their behavior.</p>
 </div>