diff --git a/launcher/launcher/pom.xml b/launcher/launcher/pom.xml
index 61a702d..73cd02b 100644
--- a/launcher/launcher/pom.xml
+++ b/launcher/launcher/pom.xml
@@ -172,10 +172,12 @@
                                 <fileVersion>${project.version}.${hotfix}</fileVersion>
                                 <txtFileVersion>${project.version}.${hotfix}</txtFileVersion>
                                 <fileDescription>ZernMC Launcher</fileDescription>
+                                <copyright>Copyright (c) 2023-2026 ZernMC</copyright>
                                 <productVersion>${project.version}.${hotfix}</productVersion>
                                 <txtProductVersion>${project.version}.${hotfix}</txtProductVersion>
                                 <productName>ZernMC</productName>
                                 <companyName>ZernMC</companyName>
+                                <trademarks>ZernMC</trademarks>
                                 <internalName>zernmc</internalName>
                                 <originalFilename>zernmc.exe</originalFilename>
                             </versionInfo>
@@ -207,10 +209,12 @@
                                 <fileVersion>${project.version}.${hotfix}</fileVersion>
                                 <txtFileVersion>${project.version}.${hotfix}</txtFileVersion>
                                 <fileDescription>ZernMC Launcher CLI</fileDescription>
+                                <copyright>Copyright (c) 2023-2026 ZernMC</copyright>
                                 <productVersion>${project.version}.${hotfix}</productVersion>
                                 <txtProductVersion>${project.version}.${hotfix}</txtProductVersion>
                                 <productName>ZernMC CLI</productName>
                                 <companyName>ZernMC</companyName>
+                                <trademarks>ZernMC</trademarks>
                                 <internalName>zernmc-cli</internalName>
                                 <originalFilename>zernmc-cli.exe</originalFilename>
                             </versionInfo>
@@ -242,10 +246,12 @@
                                 <fileVersion>${project.version}.${hotfix}</fileVersion>
                                 <txtFileVersion>${project.version}.${hotfix}</txtFileVersion>
                                 <fileDescription>ZernMC Launcher CLI + JFX</fileDescription>
+                                <copyright>Copyright (c) 2023-2026 ZernMC</copyright>
                                 <productVersion>${project.version}.${hotfix}</productVersion>
                                 <txtProductVersion>${project.version}.${hotfix}</txtProductVersion>
                                 <productName>ZernMC CLI JFX</productName>
                                 <companyName>ZernMC</companyName>
+                                <trademarks>ZernMC</trademarks>
                                 <internalName>zernmc-cli-jfx</internalName>
                                 <originalFilename>zernmc-cli-jfx.exe</originalFilename>
                             </versionInfo>
diff --git a/launcher/launcher/src/resources/ui/index.html b/launcher/launcher/src/resources/ui/index.html
index a1da17b..f9ac99a 100644
--- a/launcher/launcher/src/resources/ui/index.html
+++ b/launcher/launcher/src/resources/ui/index.html
@@ -141,9 +141,12 @@
                             </div>
                         </nav>
 
-                        <div class="sidebar-section">
-                            <div class="section-header">
-                                <span class="section-title" data-i18n="sidebar.serverPacks">Server Packs</span>
+                        <div class="sidebar-section section-collapsible" id="server-packs-section">
+                            <div class="section-header" id="server-packs-header" title="Toggle">
+                                <span class="section-title-wrap">
+                                    <svg class="section-chevron" width="12" height="12" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2.5" stroke-linecap="round" stroke-linejoin="round"><polyline points="6 9 12 15 18 9"/></svg>
+                                    <span class="section-title" data-i18n="sidebar.serverPacks">Server Packs</span>
+                                </span>
                                 <button class="btn-icon" id="add-server-pack-btn" title="Install server pack">
                                     <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2"><line x1="12" y1="5" x2="12" y2="19"/><line x1="5" y1="12" x2="19" y2="12"/></svg>
                                 </button>
@@ -151,9 +154,12 @@
                             <div id="server-packs-list" class="pack-list"></div>
                         </div>
 
-                        <div class="sidebar-section" id="local-packs-section">
-                            <div class="section-header">
-                                <span class="section-title" data-i18n="sidebar.localPacks">Local Packs</span>
+                        <div class="sidebar-section section-collapsible" id="local-packs-section">
+                            <div class="section-header" id="local-packs-header" title="Toggle">
+                                <span class="section-title-wrap">
+                                    <svg class="section-chevron" width="12" height="12" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2.5" stroke-linecap="round" stroke-linejoin="round"><polyline points="6 9 12 15 18 9"/></svg>
+                                    <span class="section-title" data-i18n="sidebar.localPacks">Local Packs</span>
+                                </span>
                                 <button class="btn-icon" id="add-pack-btn" title="Add pack">
                                     <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2"><line x1="12" y1="5" x2="12" y2="19"/><line x1="5" y1="12" x2="19" y2="12"/></svg>
                                 </button>
diff --git a/launcher/launcher/src/resources/ui/launcher.js b/launcher/launcher/src/resources/ui/launcher.js
index 121ac31..daa3075 100644
--- a/launcher/launcher/src/resources/ui/launcher.js
+++ b/launcher/launcher/src/resources/ui/launcher.js
@@ -460,6 +460,7 @@ class ZernMCLauncher {
         this._playtimeAccumulated = 0;
         this._playtimeStartTime = null;
         this._currentPlaytimePack = null;
+        this._openSection = undefined;
         this.init();
     }
 
@@ -893,6 +894,20 @@ class ZernMCLauncher {
 
         document.getElementById('add-pack-btn').addEventListener('click', () => this.showInstallModal());
         document.getElementById('add-server-pack-btn').addEventListener('click', () => this.showInstallModal());
+
+        // Accordion sidebar sections: max one pack list open at a time
+        const serverHeader = document.getElementById('server-packs-header');
+        const localHeader = document.getElementById('local-packs-header');
+        [serverHeader, localHeader].forEach(header => {
+            if (!header) return;
+            header.addEventListener('click', (e) => {
+                if (e.target.closest('.btn-icon')) return;
+                const name = header.id === 'server-packs-header' ? 'server' : 'local';
+                this._openSection = this._openSection === name ? null : name;
+                this.syncOpenSections();
+            });
+        });
+
         document.getElementById('close-modal-btn').addEventListener('click', () => this.hideInstallModal());
         document.querySelectorAll('.modal-tab').forEach(t => {
             t.addEventListener('click', () => this.switchInstallTab(t.dataset.tab));
@@ -1044,6 +1059,13 @@ class ZernMCLauncher {
         return inst && inst.isServerPack && this.state.updateMap && this.state.updateMap[inst.name] === true;
     }
 
+    syncOpenSections() {
+        const serverSection = document.getElementById('server-packs-section');
+        const localSection = document.getElementById('local-packs-section');
+        if (serverSection) serverSection.classList.toggle('collapsed', this._openSection !== 'server');
+        if (localSection) localSection.classList.toggle('collapsed', this._openSection !== 'local');
+    }
+
     renderSidebar() {
         const serverList = document.getElementById('server-packs-list');
         const localList = document.getElementById('local-packs-list');
@@ -1085,6 +1107,13 @@ class ZernMCLauncher {
         if (localSection && localList.children.length > 0) {
             localSection.classList.remove('hidden');
         }
+
+        // Default: open the section that has packs (server list first)
+        if (this._openSection === undefined) {
+            this._openSection = serverList.children.length > 0 ? 'server'
+                : (localList.children.length > 0 ? 'local' : null);
+        }
+        this.syncOpenSections();
     }
 
     selectPack(inst) {
diff --git a/launcher/launcher/src/resources/ui/style.css b/launcher/launcher/src/resources/ui/style.css
index 75ec9f0..97c6021 100644
--- a/launcher/launcher/src/resources/ui/style.css
+++ b/launcher/launcher/src/resources/ui/style.css
@@ -219,7 +219,17 @@ body {
     display: flex; align-items: center; justify-content: space-between;
     margin-bottom: 8px; padding: 0 4px;
 }
-.section-title { font-size: 10px; font-weight: 600; text-transform: uppercase; letter-spacing: 1px; color: var(--text-muted); }
+.section-collapsible .section-header { cursor: pointer; user-select: none; }
+.section-collapsible .section-header:hover .section-title { color: var(--text-secondary); }
+.section-title-wrap {
+    display: flex; align-items: center; gap: 6px; min-width: 0;
+}
+.section-title { font-size: 10px; font-weight: 600; text-transform: uppercase; letter-spacing: 1px; color: var(--text-muted); transition: var(--transition); }
+.section-chevron { flex-shrink: 0; color: var(--text-muted); transition: transform .2s var(--ease, ease); }
+.section-collapsible.collapsed .section-chevron { transform: rotate(-90deg); }
+.section-collapsible.collapsed .pack-list { display: none; }
+.section-collapsible.collapsed .section-header { margin-bottom: 0; }
+.section-collapsible.collapsed .section-title { color: var(--text-muted); }
 
 .pack-list {
     display: flex; flex-direction: column; gap: 3px;
diff --git a/launcher/pom.xml b/launcher/pom.xml
index 70cd02a..cd39f99 100644
--- a/launcher/pom.xml
+++ b/launcher/pom.xml
@@ -20,7 +20,7 @@
 
     <properties>
         <revision>1.0.16</revision>
-        <hotfix>17</hotfix>
+        <hotfix>18</hotfix>
         <maven.compiler.source>21</maven.compiler.source>
         <maven.compiler.target>21</maven.compiler.target>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>