fix(pwa): improve install prompt visibility and styling

src/components/InstallPrompt.vue

@@ -1,5 +1,5 @@
 <template>
-  <div v-if="showInstallPrompt" class="install-prompt">
+  <div v-if="showInstallPrompt" class="install-prompt glass-panel unselectable">
     <div class="prompt-content">
       <span class="prompt-text">Zainstaluj aplikację dla szybszego dostępu</span>
       <div class="prompt-actions">
@@ -57,18 +57,15 @@ onBeforeUnmount(() => {
 <style scoped>
 .install-prompt {
   position: fixed;
-  bottom: 80px; /* Above footer */
+  bottom: calc(5rem + env(safe-area-inset-bottom)); /* Above footer with extra space */
   left: 50%;
   transform: translateX(-50%);
   width: 90%;
   max-width: 400px;
-  background-color: var(--card-bg);
-  border: 1px solid var(--accent-color);
-  border-radius: 12px;
   padding: 1rem;
-  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
-  z-index: 100;
+  z-index: 9999;
   animation: slideUp 0.3s ease-out;
+  border-radius: 12px;
 }
 
 .prompt-content {
@@ -81,7 +78,7 @@ onBeforeUnmount(() => {
 .prompt-text {
   font-size: 0.9rem;
   font-weight: 500;
-  color: var(--text-color);
+  color: var(--text-strong);
 }
 
 .prompt-actions {
@@ -91,8 +88,8 @@ onBeforeUnmount(() => {
 }
 
 .install-btn {
-  background-color: var(--accent-color);
-  color: white;
+  background-color: var(--primary-accent);
+  color: #000; /* Dark text on bright cyan accent for dark mode */
   border: none;
   padding: 0.5rem 1rem;
   border-radius: 6px;
@@ -141,4 +138,10 @@ onBeforeUnmount(() => {
     }
   }
 }
+
+/* Light theme overrides for better contrast */
+:global(:root[data-theme="light"]) .install-btn {
+  background-color: var(--accent-purple);
+  color: #fff;
+}
 </style>