Buttons readable in every theme: filled controls use the strong accent pair (white on #3b82f6 failed AA on creator pages; browser check) (#69)

ddiff --git a/public/css/vip.css b/public/css/vip.css
iindex dd9ffac..16995f2 100644
---- a/public/css/vip.css
++++ b/public/css/vip.css
@@@ -6,6 +6,9 @@
    --vip-muted: var(--text-secondary, #9aa7bd);
    --vip-accent: var(--accent, #3b82f6);
    --vip-on-accent: var(--on-accent, #ffffff);
++  /* Filled controls carry text: the strong pair passes AA in every theme (white on #3b82f6 is 3.68:1). */
++  --vip-accent-strong: var(--accent-strong, var(--accent, #3472d8));
++  --vip-on-accent-strong: var(--on-accent-strong, var(--on-accent, #ffffff));
    --vip-border: var(--border, rgba(255, 255, 255, .1));
    --vip-bad: #f87171;
    --vip-good: #34d399;
@@@ -29,7 +32,7 @@ h3 { font-size: 1.05rem; margin: .8em 0 .3em; }
  .hero p { font-size: 1.08rem; }
  .card { background: var(--vip-card); border: 1px solid var(--vip-border); border-radius: 12px; padding: 16px 18px; margin: 16px 0; }
  .card.narrow { max-width: 560px; margin: 32px auto; }
--.button, button { display: inline-block; background: var(--vip-accent); color: var(--vip-on-accent); border: 0; border-radius: 8px; padding: 9px 16px; font: inherit; font-weight: 600; cursor: pointer; text-decoration: none; }
++.button, :where(main) button { display: inline-block; background: var(--vip-accent-strong); color: var(--vip-on-accent-strong); border: 0; border-radius: 8px; padding: 9px 16px; font: inherit; font-weight: 600; cursor: pointer; text-decoration: none; }
  .button-quiet { background: transparent; color: var(--vip-accent); border: 1px solid var(--vip-accent); }
  form label { display: block; margin: 10px 0; }
  form input:not([type=checkbox]):not([type=hidden]), form textarea, form select {