UI improvements, merge

src/styles.css

@@ -126,9 +126,59 @@ button.secondary {
   gap: 0.5rem;
 }
 
+.app-root {
+  min-height: 100vh;
+  background-color: #f3f4f6;
+}
+
+.app-header {
+  position: sticky;
+  top: 0;
+  z-index: 10;
+  background: #111827;
+  color: #e5e7eb;
+  padding: 0.6rem 1rem;
+  box-shadow: 0 1px 3px rgba(15, 23, 42, 0.4);
+}
+
+.app-header-title {
+  display: flex;
+  align-items: center;
+  gap: 0.6rem;
+}
+
+.app-header h1 {
+  font-size: 1rem;
+  margin: 0;
+}
+
+.app-header small {
+  color: #9ca3af;
+  font-size: 0.8rem;
+}
+
+.app-logo {
+  font-size: 1.4rem;
+}
+
+.app-main {
+  padding: 0.75rem;
+  max-width: 900px;
+  margin: 0 auto;
+  display: flex;
+  flex-direction: column;
+  gap: 0.75rem;
+}
+
+/* Make cards full-width on mobile */
+.card {
+  width: 100%;
+}
+
+/* Slightly less rounded page pills so they look like rectangles */
 .page-pill {
   padding: 0.2rem 0.5rem;
-  border-radius: 0.5rem;
+  border-radius: 0.5rem; /* was 999px */
   border: 1px solid #e5e7eb;
   font-size: 0.8rem;
   background: #f9fafb;