feat: add mobile logo count display and responsive styles for header

src/components/Header.svelte

@@ -218,6 +218,10 @@
       </div>
     </div>
   </div>
+  <div class="logo-count-mobile mobile-only">
+    {displayLogos.length} of {logos.length} logos
+  </div>
+
   <div class="header-row header-controls">
     <div class="search-bar">
       <input
@@ -1217,4 +1221,119 @@
   .selected-brand .close:hover {
     opacity: 1;
   }
+
+  /* Mobile responsive styles for header elements */
+  .mobile-only {
+    display: none;
+  }
+
+  .desktop-only {
+    display: block;
+  }
+
+  .logo-count-mobile {
+    font-family: system-ui, Arial, sans-serif;
+    font-size: 0.6rem;
+    font-weight: normal;
+    color: var(--color-text);
+    opacity: 0.7;
+    padding: 0;
+    margin: 0;
+    text-align: left;
+  }
+
+  .theme-mobile-toggle {
+    position: relative;
+    display: none;
+  }
+
+  .theme-mobile-button {
+    background: var(--color-card);
+    color: var(--color-text);
+    border: 1px solid var(--color-border);
+    border-radius: 6px;
+    padding: 0.5rem;
+    cursor: pointer;
+    transition: background 0.2s, color 0.2s;
+    display: flex;
+    align-items: center;
+    justify-content: center;
+  }
+
+  .theme-mobile-button:hover {
+    background: var(--color-accent);
+    color: #fff;
+  }
+
+  .theme-mobile-dropdown {
+    position: absolute;
+    top: 100%;
+    right: 0;
+    margin-top: 0.5rem;
+    background: var(--color-card);
+    border: 1px solid var(--color-border);
+    border-radius: 6px;
+    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.1);
+    z-index: 1000;
+    min-width: 120px;
+    display: none;
+    flex-direction: column;
+    overflow: hidden;
+  }
+
+  .theme-mobile-dropdown.show {
+    display: flex;
+  }
+
+  .theme-mobile-dropdown button {
+    background: none;
+    border: none;
+    padding: 0.75rem 1rem;
+    cursor: pointer;
+    color: var(--color-text);
+    display: flex;
+    align-items: center;
+    gap: 0.5rem;
+    font-size: 0.9rem;
+    transition: background 0.2s;
+    text-align: left;
+  }
+
+  .theme-mobile-dropdown button:hover {
+    background: var(--color-border);
+  }
+
+  .theme-mobile-dropdown button.active {
+    background: var(--color-accent);
+    color: #fff;
+  }
+
+  @media (max-width: 700px) {
+    .mobile-only {
+      display: block;
+    }
+
+    .desktop-only {
+      display: none;
+    }
+
+    .theme-mobile-toggle {
+      display: block;
+    }
+
+    .header-row {
+      flex-direction: row;
+      align-items: center;
+      justify-content: space-between;
+      gap: 1rem;
+    }
+
+    .logo-count {
+      display: none;
+    }
+
+    .theme-switcher {
+      margin-left: 0;
+    }
+  }
 </style>