Improved appearance of back-to-top button

material/base.html

@@ -39,7 +39,7 @@
       {% endif %}
     {% endblock %}
     {% block styles %}
-      <link rel="stylesheet" href="{{ 'assets/stylesheets/main.ca7ac06f.min.css' | url }}">
+      <link rel="stylesheet" href="{{ 'assets/stylesheets/main.48b295f8.min.css' | url }}">
       {% if config.theme.palette %}
         {% set palette = config.theme.palette %}
         <link rel="stylesheet" href="{{ 'assets/stylesheets/palette.f1a3b89f.min.css' | url }}">
@@ -180,6 +180,7 @@
         {% if "navigation.top" in features %}
           <a href="#" class="md-top md-icon" title="{{ lang.t('top.title') }}" data-md-component="top" data-md-state="hidden">
             {% include ".icons/material/arrow-up.svg" %}
+            {{ lang.t('top.title') }}
           </a>
         {% endif %}
       </main>
@@ -222,7 +223,7 @@
       </script>
     {% endblock %}
     {% block scripts %}
-      <script src="{{ 'assets/javascripts/bundle.5d86c58f.min.js' | url }}"></script>
+      <script src="{{ 'assets/javascripts/bundle.70097392.min.js' | url }}"></script>
       {% for path in config["extra_javascript"] %}
         <script src="{{ path | url }}"></script>
       {% endfor %}

material/overrides/main.html

@@ -35,5 +35,5 @@
 {% endblock %}
 {% block scripts %}
   {{ super() }}
-  <script src="{{ 'overrides/assets/javascripts/bundle.9f7670a0.min.js' | url }}"></script>
+  <script src="{{ 'overrides/assets/javascripts/bundle.cdc3d82f.min.js' | url }}"></script>
 {% endblock %}

mkdocs.yml

@@ -55,6 +55,7 @@ theme:
     # - navigation.instant
     - navigation.sections
     - navigation.tabs
+    - navigation.top
     - navigation.tracking
     - search.highlight
     - search.share

src/assets/javascripts/actions/top/index.ts

@@ -46,3 +46,28 @@ export function resetBackToTopState(
 ): void {
   el.removeAttribute("data-md-state")
 }
+
+/* ------------------------------------------------------------------------- */
+
+/**
+ * Set back-to-top offset
+ *
+ * @param el - Back-to-top element
+ * @param value - Back-to-top offset
+ */
+ export function setBackToTopOffset(
+  el: HTMLElement, value: number
+): void {
+  el.style.top = `${value}px`
+}
+
+/**
+ * Reset back-to-top offset
+ *
+ * @param el - Back-to-top element
+ */
+export function resetBackToTopOffset(
+  el: HTMLElement
+): void {
+  el.style.top = ""
+}

src/assets/javascripts/bundle.ts

@@ -216,7 +216,7 @@ const content$ = defer(() => merge(
 
   /* Back-to-top button */
   ...getComponentElements("top")
-    .map(el => mountBackToTop(el, { viewport$, main$ }))
+    .map(el => mountBackToTop(el, { viewport$, header$, main$ }))
 ))
 
 /* Set up component observables */

src/assets/javascripts/components/top/index.ts

@@ -33,13 +33,20 @@ import {
   finalize,
   map,
   observeOn,
-  tap
+  tap,
+  withLatestFrom
 } from "rxjs/operators"
 
-import { resetBackToTopState, setBackToTopState } from "~/actions"
+import {
+  resetBackToTopOffset,
+  resetBackToTopState,
+  setBackToTopOffset,
+  setBackToTopState
+} from "~/actions"
 import { Viewport } from "~/browser"
 
 import { Component } from "../_"
+import { Header } from "../header"
 import { Main } from "../main"
 
 /* ----------------------------------------------------------------------------
@@ -62,6 +69,7 @@ export interface BackToTop {
  */
 interface WatchOptions {
   viewport$: Observable<Viewport>      /* Viewport observable */
+  header$: Observable<Header>          /* Header observable */
   main$: Observable<Main>              /* Main area observable */
 }
 
@@ -70,6 +78,7 @@ interface WatchOptions {
  */
 interface MountOptions {
   viewport$: Observable<Viewport>      /* Viewport observable */
+  header$: Observable<Header>          /* Header observable */
   main$: Observable<Main>              /* Main area observable */
 }
 
@@ -127,17 +136,23 @@ export function watchBackToTop(
  * @returns Back-to-top component observable
  */
 export function mountBackToTop(
-  el: HTMLElement, options: MountOptions
+  el: HTMLElement, { viewport$, header$, main$ }: MountOptions
 ): Observable<Component<BackToTop>> {
   const internal$ = new Subject<BackToTop>()
   internal$
     .pipe(
-      observeOn(animationFrameScheduler)
+      observeOn(animationFrameScheduler),
+      withLatestFrom(header$
+        .pipe(
+          distinctUntilKeyChanged("height")
+        )
+      )
     )
       .subscribe({
 
         /* Update state */
-        next({ hidden }) {
+        next([{ hidden }, { height }]) {
+          setBackToTopOffset(el, height + 16)
           if (hidden)
             setBackToTopState(el, "hidden")
           else
@@ -146,12 +161,13 @@ export function mountBackToTop(
 
         /* Reset on complete */
         complete() {
+          resetBackToTopOffset(el)
           resetBackToTopState(el)
         }
       })
 
   /* Create and return component */
-  return watchBackToTop(el, options)
+  return watchBackToTop(el, { viewport$, header$, main$ })
     .pipe(
       tap(internal$),
       finalize(() => internal$.complete()),

src/assets/stylesheets/main/layout/_top.scss

@@ -26,20 +26,20 @@
 
 // Back-to-top button
 .md-top {
-  position: sticky;
+  position: fixed;
-  bottom: px2rem(8px);
+  top: px2rem(48px + 16px);
   z-index: 1;
-  float: right;
+  margin-left: 50%;
-  margin: px2rem(-56px) px2rem(8px) px2rem(8px);
+  padding: px2rem(8px) px2rem(16px);
-  padding: px2rem(8px);
+  color: var(--md-default-fg-color--light);
-  color: var(--md-primary-bg-color);
+  font-size: px2rem(14px);
-  background: var(--md-primary-fg-color);
+  background: var(--md-default-bg-color);
-  border-radius: 100%;
+  border-radius: px2rem(32px);
   outline: none;
   box-shadow:
-    0 px2rem(4px)   px2rem(10px) hsla(0, 0%, 0%, 0.1),
+    0 px2rem(4px) px2rem(10px) hsla(0, 0%, 0%, 0.1),
-    0 px2rem(0.5px) px2rem(1px)  hsla(0, 0%, 0%, 0.1);
+    0 0           px2rem(1px)  hsla(0, 0%, 0%, 0.25);
-  transform: translateY(0);
+  transform: translate(-50%, 0);
   transition:
     opacity          125ms,
     transform        125ms cubic-bezier(0.4, 0, 0.2, 1),
@@ -52,7 +52,7 @@
 
   // Back-to-top button in hidden state
   &[data-md-state="hidden"] {
-    transform: translateY(px2rem(-4px));
+    transform: translate(-50%, px2rem(+4px));
     opacity: 0;
     pointer-events: none;
   }
@@ -60,7 +60,13 @@
   // Back-to-top button on focus/hover
   &:focus,
   &:hover {
+    color: var(--md-accent-bg-color);
     background: var(--md-accent-fg-color);
-    transform: scale(1.1);
+  }
+
+  // Inline icon
+  svg {
+    display: inline-block;
+    vertical-align: -0.5em;
   }
 }

src/base.html

@@ -344,6 +344,7 @@
             data-md-state="hidden"
           >
             {% include ".icons/material/arrow-up.svg" %}
+            {{ lang.t('top.title') }}
           </a>
         {% endif %}
       </main>