vertical lines : centraliser en fixed dans App.svelte

- Retirer les lignes des views (Home, Expertise, About, Portfolio)
- Centraliser dans App.svelte en position:fixed, visibilité par slide
  via transition de hauteur 0→100vh selon slides.active.template
- Positions calculées depuis la golden-grid (1/6, 1/3, 1/2, 2/3, 5/6)
- Nettoyer layout.css (garder seulement les classes pour Menu.svelte)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/views/About.svelte

@@ -77,6 +77,7 @@
 </script>
 
 <div class="about golden-grid page-scrollable" bind:this={sectionEl} onscroll={() => navigation.setScrolled(sectionEl.scrollTop > 100)}>
+
   <div class="page-container">
     <!-- Intro -->
     <section class="about-intro">
@@ -182,12 +183,18 @@
   }
 
   .page-container {
+    align-items: center;
+    display: flex;
+    flex-direction: column;
+    font-size: 18px;
+    font-size: var(--font-size-paragraph);
     grid-area: 6/6/span 7/span 10;
     height: 100%;
     place-self: center;
     text-align: center;
     white-space: pre-line;
-    width: 100%;
+    width: 100%;  
+    overflow:visible;
   }
 
   /* ── Intro ── */

src/views/Expertise.svelte

@@ -284,13 +284,6 @@
     </video>
   </div>
 
-  <!-- Decorative vertical lines -->
-  <div class="vertical-line-start"               aria-hidden="true"></div>
-  <div class="vertical-line vertical-line-col8"  aria-hidden="true"></div>
-  <div class="vertical-line-center"              aria-hidden="true"></div>
-  <div class="vertical-line vertical-line-col14" aria-hidden="true"></div>
-  <div class="vertical-line-end"                 aria-hidden="true"></div>
-
   <!-- Title -->
   <h2 class="expertise-title">
     {@html data?.pageTitle ?? ''}
@@ -345,15 +338,6 @@
     opacity: 1;
   }
 
-  /* Custom vertical lines */
-  .vertical-line-col8 {
-    grid-area: 1/8 / span 20 / span 1;
-  }
-
-  .vertical-line-col14 {
-    grid-area: 1/14 / span 20 / span 1;
-  }
-
   /* Title */
   .expertise-title {
     grid-area: 8/6 / span 5 / span 5;

src/views/Home.svelte

@@ -87,10 +87,6 @@
     </figure>
   </div>
 
-  <div class="vertical-line-start"></div>
-  <div class="vertical-line-center"></div>
-  <div class="vertical-line-end"></div>
-
   <div class="home-text">
     <h2 class="font-face-danzza-light home-subtitle">
       {data.hero.subtitle}

src/views/Portfolio.svelte

@@ -156,10 +156,6 @@
   bind:this={sectionEl}
   aria-label="Portfolio"
 >
-  <!-- Decorative vertical lines -->
-  <div class="vertical-line-center" aria-hidden="true"></div>
-  <div class="vertical-line-end" aria-hidden="true"></div>
-
   {#if currentProject}
     <!-- Galerie animation (gauche desktop / plein écran mobile) -->
     <div class="portfolio-gallery desktop-only" aria-hidden="true">
@@ -243,15 +239,6 @@
     background-size: cover;
   }
 
-  /* Custom vertical lines */
-  .vertical-line-col8 {
-    grid-area: 1/8 / span 20 / span 1;
-  }
-
-  .vertical-line-col14 {
-    grid-area: 1/14 / span 20 / span 1;
-  }
-
   /* Desktop layout */
   .portfolio-gallery {
     grid-area: 1/1 / span 20 / span 7;