added PageTop component, markdown styles, white background on logo svg, and documentation comments

assets/styles/app.css

@@ -1,4 +1,5 @@
 @import "~/assets/styles/color-pallet.css";
+@import "~/assets/styles/markdown.css";
 
 @font-face {
     font-family: "Noto Sans JP";
@@ -15,15 +16,20 @@
 
 .page-enter-active,
 .page-leave-active {
-    transition: all ease-in-out 0.6s;
+    transition: all ease-in-out 0.4s;
 }
 
 .page-enter-from,
 .page-leave-to {
     opacity: 0;
-    transform: translateY(100%);
 }
 
 body {
     margin: 0;
 }
+
+html {
+    font-size: 16px;
+    scrollbar-width: none;
+    scroll-behavior: smooth;
+}