Fix Swap Faces and Download buttons to match dark amber theme

Browser UA stylesheet was overriding custom CSS on disabled/button
elements. Added appearance:none resets and !important guards so the
themed amber styles render correctly instead of browser-default gray.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

static/app.css

@@ -174,6 +174,7 @@ footer{display:none!important}
     color:#ffffff!important;-webkit-text-fill-color:#ffffff!important;
     transition:all .2s ease;letter-spacing:-.2px;
     box-shadow:0 4px 16px rgba(217,119,6,.4),inset 0 1px 0 rgba(255,255,255,.1);
+    -webkit-appearance:none;appearance:none;
 }
 .btn-run:hover:not(:disabled){
     background:linear-gradient(135deg,#b45309,#f59e0b);transform:translateY(-1px);
@@ -181,11 +182,13 @@ footer{display:none!important}
 }
 .btn-run:active:not(:disabled){transform:translateY(0)}
 .btn-run:disabled{
-    background:linear-gradient(135deg,#292400,#361f00);
-    color:#9a7c2e!important;-webkit-text-fill-color:#9a7c2e!important;
+    background:rgba(217,119,6,.12)!important;
+    border:1px solid rgba(217,119,6,.2);
+    color:#7a5c1e!important;-webkit-text-fill-color:#7a5c1e!important;
     cursor:not-allowed;box-shadow:none;
 }
 .btn-run svg{width:18px;height:18px;flex-shrink:0}
+.btn-run:disabled svg polygon{fill:#7a5c1e}
 
 /* ── Output frame ─────────────────────────────────────────────────────────── */
 .output-frame{flex:1;display:flex;flex-direction:column}
@@ -203,9 +206,10 @@ footer{display:none!important}
 .out-placeholder{color:#f59e0b;font-size:13px;text-align:center;padding:20px}
 .out-download-btn{
     display:none;align-items:center;gap:5px;padding:3px 10px;height:24px;
-    background:rgba(217,119,6,.15);border:1px solid rgba(217,119,6,.3);border-radius:6px;
+    background:rgba(217,119,6,.15)!important;border:1px solid rgba(217,119,6,.3);border-radius:6px;
     color:#fbbf24!important;-webkit-text-fill-color:#fbbf24!important;
     font-size:11px;font-weight:500;cursor:pointer;transition:all .15s;
+    -webkit-appearance:none;appearance:none;
 }
 .out-download-btn:hover{background:rgba(217,119,6,.3);color:#fff!important;-webkit-text-fill-color:#fff!important}
 .out-download-btn.visible{display:inline-flex}