style phone section nav like the light/dark toggle

agents.md

@@ -177,8 +177,10 @@ Themes: `web` = default frosted-glass website (sidebar + content, light/dark),
   top panel it's just noise; the desktop/tablet sidebar keeps it.
 - On phones (`max-width: 640px`) the section nav (`.web-nav`) stops being the
   sideways-scrolling row it is on tablets and becomes a wrapping **grid**
-  (3-up, 2-up below `375px`) of button tiles, so every section fits with no
-  horizontal scroll — the collapsed top panel must never scroll sideways.
+  (3-up, 2-up below `375px`) styled to match the Light/Dark toggle (`.web-ctl`):
+  same `--btn-*` surface / radius / shadow and `0.82rem` / `600` type. Every
+  section fits with no horizontal scroll — the collapsed top panel must never
+  scroll sideways.
 - Under `max-width: 640px` the year-grid heatmap (`.heatmap-container`) and its
   legend/hover row (`.heatmap-status-row`) are `display: none` — the grid is
   unreadable at phone widths. The contribution total and the commit history

src/app/web.css

@@ -1116,19 +1116,22 @@ html[data-theme="web"][data-scheme="dark"] .heatmap-legend-cell[data-level="4"]
   }
   /* Section nav: fit every link on screen instead of a sideways-scrolling row,
      so the collapsed top panel never scrolls horizontally — a 3-up button
-     grid (2-up on very narrow phones, see the 374px block below). */
+     grid (2-up on very narrow phones, see the 374px block below) styled like
+     the Light/Dark toggle (.web-ctl): same surface, radius, shadow and type. */
   .web-nav {
     display: grid;
     grid-template-columns: repeat(3, minmax(0, 1fr));
-    gap: 6px;
+    gap: 8px;
     overflow: visible;
     padding-bottom: 0;
   }
   .web-nav a {
-    justify-content: center;
-    padding: 9px 8px;
     border: 1px solid var(--btn-border, var(--glass-border));
     background: var(--btn-bg, var(--glass-lo));
+    box-shadow: var(--btn-shadow, none);
+    color: var(--fg);
+    font-size: 0.82rem;
+    font-weight: 600;
   }
   .project-grid {
     columns: 1;