feat: Improved font sizes and overall cleanup, b=no-bug, c=folders, tabs

Author: mr-cheffy

src/zen/folders/zen-folders.css

@@ -308,7 +308,7 @@ zen-folder {
       border: none !important;
       color: var(--sidebar-text-color) !important;
       margin: 0 !important;
-      font-weight: 500;
+      font-weight: 600;
       display: flex;
       align-items: center;
       height: 100% !important;

src/zen/tabs/zen-tabs/vertical-tabs.css

@@ -258,32 +258,29 @@
 #tabbrowser-tabs {
   margin-inline-start: 0 !important;
   padding-inline-start: 0 !important;
-  overflow-y: unset !important; /* Critical: Prevents rendering issues on workspace changes */
-  overflow-x: clip; /* Clip horizontal overflow */
-  overflow-clip-margin: var(--zen-toolbox-padding); /* Add margin to clipping area */
+  overflow-y: unset !important;
+  overflow-x: clip;
+  overflow-clip-margin: var(--zen-toolbox-padding);
 
   --focus-outline-color: transparent;
 
   @media (-moz-platform: macos) {
-    font-size: 1.1rem; /* Slightly larger font on macOS */
+    font-size: 1.2rem; /* Slightly larger font on macOS */
   }
 
-  --tab-inner-inline-margin: 0; /* Reset default inner margin */
+  --tab-inner-inline-margin: 0;
 
   position: relative;
-  border-bottom: 0px solid transparent !important; /* Remove default bottom border */
+  border-bottom: 0px solid transparent !important;
 
-  /* Define tab variables */
   --tab-block-margin: 2px;
   --tab-selected-bgcolor: light-dark(rgba(255, 255, 255, 0.8), rgba(255, 255, 255, 0.12));
   --tab-selected-shadow: 0 1px 1px 1px light-dark(rgba(0, 0, 0, 0.09), rgba(0, 0, 0, 0.1)) !important;
-  grid-gap: 0 !important; /* Reset grid gap */
+  grid-gap: 0 !important;
 
-  /* Hide default overflow indicators and the provided separator */
   &[overflow]::after,
-  #vertical-tabs-newtab-button, /* Assuming this is a button *within* #tabbrowser-tabs, but it looks like it's outside */
+  #vertical-tabs-newtab-button,
   #vertical-pinned-tabs-splitter {
-    /* Selector targets the specific separator ID */
     display: none !important;
   }