Move Why Sign Up section to sticky sidebar on study landing page

src/App.css

@@ -1084,10 +1084,6 @@
   padding: 0.5rem 0 0.25rem;
 }
 
-.section-study-signup-why {
-  padding: 1.5rem 0 2.5rem;
-}
-
 .study-signup-why-grid {
   display: grid;
   grid-template-columns: repeat(2, minmax(0, 1fr));
@@ -1182,6 +1178,65 @@
   padding: 1rem 0 0;
 }
 
+.study-tracks-with-sidebar {
+  display: grid;
+  grid-template-columns: 1fr 340px;
+  gap: 2.5rem;
+  align-items: start;
+}
+
+.study-tracks-main {
+  min-width: 0;
+}
+
+.study-signup-sidebar {
+  position: sticky;
+  top: 5.75rem;
+  background: rgba(20, 20, 18, 0.92);
+  border: 1px solid rgba(201, 168, 76, 0.2);
+  border-radius: 16px;
+  padding: 1.5rem;
+  height: fit-content;
+}
+
+.study-signup-sidebar-header {
+  margin-bottom: 1rem;
+}
+
+.study-signup-sidebar-label {
+  margin: 0 0 0.3rem;
+  color: var(--brand-gold);
+  text-transform: uppercase;
+  letter-spacing: 0.12em;
+  font-size: 0.72rem;
+  font-weight: 600;
+}
+
+.study-signup-sidebar-header h3 {
+  margin: 0;
+  font-family: var(--brand-font-heading);
+  font-size: 1.35rem;
+  color: var(--brand-warm-white);
+}
+
+.study-signup-sidebar-cards {
+  display: flex;
+  flex-direction: column;
+  gap: 0.8rem;
+}
+
+.study-signup-sidebar .study-signup-why-card {
+  padding: 1rem;
+  margin: 0;
+}
+
+.study-signup-sidebar .study-signup-why-card h4 {
+  margin: 0.35rem 0 0.25rem;
+  font-family: var(--brand-font-heading);
+  font-size: 0.95rem;
+  color: var(--brand-warm-white);
+}
+
 .study-module-header {
   margin-bottom: 0.85rem;
 }
@@ -1518,6 +1573,16 @@
     flex-basis: 100%;
   }
 
+  .study-tracks-with-sidebar {
+    grid-template-columns: 1fr;
+    gap: 1.5rem;
+  }
+
+  .study-signup-sidebar {
+    position: static;
+    top: auto;
+  }
+
   .study-hub-flow-grid {
     grid-template-columns: 1fr;
   }