fix: add mobile menu to projects view and CSS

public/css/style.css

@@ -1959,3 +1959,63 @@ ul, ol {
   height: 28px;
   font-size: 0.875rem;
 }
+
+/* === Mobile Menu === */
+.mobile-menu {
+  display: none;
+  position: fixed;
+  top: 0;
+  left: 0;
+  right: 0;
+  bottom: 0;
+  background: var(--color-bg);
+  z-index: 1000;
+  padding: var(--space-4);
+}
+
+.mobile-menu.open {
+  display: block;
+}
+
+.mobile-menu-header {
+  display: flex;
+  justify-content: space-between;
+  align-items: center;
+  margin-bottom: var(--space-4);
+  padding-bottom: var(--space-4);
+  border-bottom: 1px solid var(--color-border);
+}
+
+.mobile-menu-header span {
+  font-weight: 600;
+  font-size: 1.125rem;
+}
+
+.mobile-menu-content {
+  display: flex;
+  flex-direction: column;
+  gap: var(--space-2);
+}
+
+.mobile-menu-content a {
+  display: block;
+  padding: var(--space-3);
+  background: var(--color-bg-secondary);
+  border-radius: var(--radius-md);
+  color: var(--color-text);
+  text-decoration: none;
+  font-size: 1rem;
+}
+
+.mobile-menu-content a:active {
+  background: var(--color-bg-tertiary);
+}
+
+@media (max-width: 768px) {
+  .mobile-menu {
+    display: none;
+  }
+  .mobile-menu.open {
+    display: block;
+  }
+}