Center format toolbar buttons + fix dropdown z-index clipping (overflow visible)

src/css/components.css

@@ -364,12 +364,12 @@
   display: flex;
   flex-wrap: nowrap;
   align-items: center;
+  justify-content: center;
   gap: 3px;
   padding: 6px 10px;
   border-bottom: 1px solid var(--color-border);
   background: var(--color-surface);
-  overflow-x: auto;
-  overflow-y: hidden;
+  overflow: visible;
   position: relative;
   z-index: 50;
   flex-shrink: 0;