Add storage-backed story history

public/css/style.css

@@ -421,6 +421,11 @@ ol.choice {
     overflow-anchor: none;
 }
 
+.story-block-archiving {
+    opacity: 0;
+    transition: opacity 320ms ease;
+}
+
 .story-image-block {
     box-sizing: border-box;
     margin: 0 auto;
@@ -484,9 +489,38 @@ ol.choice {
     scroll-behavior: smooth;
     overscroll-behavior: contain;
     overflow-anchor: none;
+    scrollbar-width: none;
     /* transform: translateX(-1%) translateY(2%) rotateX(0deg) rotateY(-1deg) rotateZ(0deg); */
 }
 
+#page_right::-webkit-scrollbar {
+    display: none;
+}
+
+#story_scrollbar {
+    position: sticky;
+    float: right;
+    top: 0.4rem;
+    width: 0.22rem;
+    height: calc(100% - 0.8rem);
+    margin-right: -1.5rem;
+    border-radius: 999px;
+    background: rgba(0, 0, 0, 0.12);
+    z-index: 12;
+    pointer-events: none;
+}
+
+#story_scrollbar_thumb {
+    position: absolute;
+    left: 0;
+    right: 0;
+    top: 0;
+    min-height: 1rem;
+    border-radius: inherit;
+    background: rgba(0, 0, 0, 0.72);
+    transition: top 260ms ease, height 260ms ease;
+}
+
 
 /* ===== Scrollbar CSS ===== */
   /* Firefox */