Improve drawing symbols and sample popup

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

랜딩페이지/landing-page.ts

@@ -5,6 +5,7 @@ import { createLandingGuide } from './landing-guide';
 import { createHeroMotion, heroMotionMarkup } from './landing-motion';
 import './landing-white.css';
 import './landing-typography.css';
+import './sample-library-popup.css';
 import { createDrawingPopup, drawingPopupMarkup } from './drawing-popup';
 
 const appRoot = document.querySelector<HTMLDivElement>('.app');
@@ -81,6 +82,10 @@ const landingPanelMarkup = `
         </div>
       </article>
 
+      <article class="landing-card" data-card="sample">
+        <div><div class="landing-card-top"><div class="landing-card-icon"><svg viewBox="0 0 24 24" aria-hidden="true"><path d="M3 20V8l6-4 6 4 6-4v16H3zM9 4v16M15 8v12"/></svg></div><span class="landing-card-number">03 / EXPLORE</span></div><span class="landing-card-eyebrow">Design Library</span><h3>기설계교량 라이브러리</h3><p>기존 설계 프로젝트의 교각·지형·지도를 살펴보고 불러옵니다.</p></div>
+        <div class="landing-card-actions"><span class="landing-card-note">12개 설계 프로젝트</span><button class="landing-primary" type="button" aria-haspopup="dialog">설계 라이브러리 불러오기</button></div>
+      </article>
 
     </section>
     <footer class="landing-footer">
@@ -89,7 +94,7 @@ const landingPanelMarkup = `
     </footer>
     </section>
 
-    ${sampleExplorerMarkup}
+    <dialog class="sample-library-popup" aria-label="기설계교량 라이브러리"><button type="button" class="sample-library-close" aria-label="설계 라이브러리 닫기">×</button>${sampleExplorerMarkup}</dialog>
     <section id="landing-excel-panel" class="landing-panel" aria-label="엑셀 입력 패널">
       <div class="landing-panel-head">
         <h3>엑셀 입력</h3>
@@ -135,6 +140,7 @@ const closePanels = (): void => {
 };
 
 const showApp = (): void => {
+  landingOverlay.querySelector<HTMLDialogElement>('.sample-library-popup')?.close();
   landingGuide.close(false);
   if (appRoot) {
     appRoot.hidden = false;
@@ -262,6 +268,10 @@ document.querySelectorAll<HTMLButtonElement>('[data-pick-file]').forEach((button
 
 bindFilePicker(document.querySelector('[data-pick-file="excel"]') as HTMLButtonElement, 'landing-excel-input', 'landing-excel-name');
 
+const libraryPopup=landingOverlay.querySelector<HTMLDialogElement>('.sample-library-popup')!;
+landingOverlay.querySelector<HTMLButtonElement>('[data-card="sample"] button')!.addEventListener('click',()=>{landingGuide.close(false);landingGuide.dismissHint();if(!libraryPopup.open)libraryPopup.showModal();});
+libraryPopup.querySelector('.sample-library-close')!.addEventListener('click',()=>libraryPopup.close());
+libraryPopup.addEventListener('close',()=>{requestAnimationFrame(()=>{landingOverlay.querySelectorAll<HTMLElement>('.landing-shell,.landing-hero').forEach(element=>element.scrollTo(0,0));landingOverlay.querySelector<HTMLButtonElement>('[data-card=sample] button')?.focus({preventScroll:true});});});
 createSampleExplorer(landingOverlay,(sample:Sample)=>loadSampleIntoApp(sample,showApp,showLanding));
 
 if (homeButton) {