fix(theseus/light): darker --acid in light mode so brand green stays legible

#d6ff3d on a #ffffff / #f6f8fb background sits at ~1.3:1 contrast — the
acid green went almost invisible any time the user flipped Settings >
Theme to light. Override --acid to #4d7300 in every chrome page's
prefers-color-scheme: light block. Same hue family, ~5.5:1 contrast
on white, still reads as the same brand color.

Also: chrome.html was missing --acid: #d6ff3d in :root entirely (every
site used var(--acid, #d6ff3d) fallbacks). Adding the real declaration
means the light override can actually take effect.

Files touched: chrome.html, home.html, settings.html, error.html,
approval.html, messages.html. downloads.html is a dark-only overlay
(hardcoded), collision.html already had a proper light-mode --bcdn.
Tint fills (rgba(214,255,61,X) at low alpha) stay as-is — the specific
hue barely matters through 8% opacity.

Verified live via CDP: getComputedStyle(--acid) returned #d6ff3d in
dark, #4d7300 after cfg.set('theme','light').

approval.html

@@ -9,7 +9,9 @@
           --ink:#e7eaf1; --mut:#8b98a9; --dim:#5e6678; --acid:#d6ff3d; --danger:#f6768a; }
   @media (prefers-color-scheme: light) {
     :root { --surface:#ffffff; --surface2:#f1f4fa; --line:rgba(0,0,0,.12);
-            --ink:#1a1f2b; --mut:#5c6577; --dim:#8a93a5; }
+            --ink:#1a1f2b; --mut:#5c6577; --dim:#8a93a5;
+            /* Darker acid for light backgrounds — ~5.5:1 on white. */
+            --acid:#4d7300; }
   }
   * { box-sizing: border-box; }
   html, body { margin: 0; height: 100%; background: transparent; }

chrome.html

@@ -7,12 +7,20 @@
     --bg:#0f1420; --surface:#1b2330; --surface2:#171e2a; --active:#263041cc;
     --ink:#e7eaf1; --mut:#b9c2d0; --dim:#8b98a9; --faint:#5e6678;
     --line:rgba(255,255,255,.20); --line2:rgba(255,255,255,.13); --hover:rgba(255,255,255,.08);
+    /* Brand acid green. #d6ff3d reads ~10:1 on the dark ground; a darker
+       variant kicks in for light mode below so it stays legible. */
+    --acid:#d6ff3d;
   }
   @media (prefers-color-scheme: light) {
     :root {
       --bg:#e9ecf1; --surface:#ffffff; --surface2:#f1f3f7; --active:#dbe1ec;
       --ink:#1a1f28; --mut:#3c4453; --dim:#697280; --faint:#98a1b0;
       --line:rgba(0,0,0,.18); --line2:rgba(0,0,0,.11); --hover:rgba(0,0,0,.06);
+      /* Darker acid for light backgrounds — same hue family, ~5.5:1
+         contrast on #ffffff so text and single-pixel accents stay
+         readable. Tint fills (rgba(214,255,61,.08) etc.) stay as-is:
+         at low alpha the specific hue barely matters. */
+      --acid:#4d7300;
     }
   }
   [hidden] { display: none !important; }

error.html

@@ -10,7 +10,9 @@
           --warn:#ffc75f; --err:#f6768a; --info:#4b7bec; }
   @media (prefers-color-scheme: light) {
     :root { --bg:#f6f8fb; --panel:#ffffff; --panel2:#f0f4f9; --line:rgba(0,0,0,.10);
-            --ink:#1a1f2b; --mut:#5c6577; --dim:#8a93a5; }
+            --ink:#1a1f2b; --mut:#5c6577; --dim:#8a93a5;
+            /* Darker acid for light backgrounds — ~5.5:1 on white. */
+            --acid:#4d7300; }
   }
   * { box-sizing: border-box }
   html, body { margin: 0; height: 100% }

home.html

@@ -105,8 +105,10 @@
   @media (prefers-color-scheme: light) {
     :root { --bg1: #dce6f2; --bg2: #eef0f4;
             --card: #ffffff; --card-hi: #f4f7fb; --line: rgba(0,0,0,.10); --line2: rgba(0,0,0,.14);
-            --ink: #1a1f28; --mut: #4a5262; --dim: #8a93a2; }
-    h1 .g { color: #4a8a00; }
+            --ink: #1a1f28; --mut: #4a5262; --dim: #8a93a2;
+            /* Darker acid for light backgrounds — ~5.5:1 on white. */
+            --acid: #4d7300; }
+    h1 .g { color: var(--acid); }
     .modal { background: #ffffff; }
   }
 </style></head>

messages.html

@@ -9,6 +9,14 @@
     --ink:#e7eaf1; --mut:#8b98a9; --dim:#5e6678; --acid:#d6ff3d;
     --ok:#4fd1a5; --err:#f6768a; --warn:#ffc75f;
   }
+  @media (prefers-color-scheme: light) {
+    :root{
+      --bg:#f6f8fb; --panel:#ffffff; --panel2:#f0f4f9; --line:rgba(0,0,0,.10);
+      --ink:#1a1f28; --mut:#3c4453; --dim:#697280;
+      /* Darker acid for light backgrounds — ~5.5:1 on white. */
+      --acid:#4d7300;
+    }
+  }
   *{box-sizing:border-box}
   html,body{height:100%}
   body{

settings.html

@@ -38,7 +38,7 @@
      nativeTheme.themeSource, which drives prefers-color-scheme — so pinning
      color-scheme via that media query keeps the popup in sync automatically. */
   :root { color-scheme: dark; }
-  @media (prefers-color-scheme: light) { :root { color-scheme: light; } }
+  @media (prefers-color-scheme: light) { :root { color-scheme: light; --acid:#4d7300; } }
   /* Explicit option styling — Chromium respects it in the popup on Windows. */
   select option { background: #1b2330; color: var(--ink); }
   @media (prefers-color-scheme: light) { select option { background: #f1f3f7; color: #1a1f28; } }