chore: add back-to-top button planning and design docs, update local settings

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

1 files changed, 133 insertions, 0 deletions

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+# Back-to-Top Button — Design Spec
+
+**Date:** 2026-04-20
+**Status:** Approved
+
+---
+
+## Context
+
+The TODO list includes "add back-to-top button". Article pages can be long and users currently have no quick way to return to the top. The button should integrate cleanly with the existing hacker-aesthetic theme, follow Alpine.js patterns already in use, and meet WCAG 2.1 AA accessibility standards.
+
+---
+
+## Design Decisions
+
+| Decision | Choice | Rationale |
+|---|---|---|
+| Position | Fixed bottom-right | Conventional, expected UX |
+| Shape | Circle solid | Consistent with theme energy; always-visible purple matches accent |
+| Trigger | 33% scroll depth | Balanced — not too early, not too late |
+| Animation | Slide up + fade (300ms) | Reuses existing `slideUp` keyframe |
+| Pages | `.Kind "page"` only | Articles and singles — same condition as reading progress bar |
+| Implementation | Inline Alpine.js in a partial | Consistent with `social-share.html`, `header.html` patterns |
+
+---
+
+## Behaviour
+
+- **Appears** when `window.scrollY / (document.documentElement.scrollHeight - window.innerHeight) >= 0.33`
+- **Disappears** when scroll drops back below 33%
+- **On click**: smooth-scrolls to top (`window.scrollTo({ top: 0, behavior: 'smooth' })`)
+- **Reduced motion**: CSS global `prefers-reduced-motion` rule already suppresses all animations; the button still appears/disappears (via Alpine `x-show`) but without the slide animation. The `smooth` scroll behavior should also be skipped — handled in the click handler by checking `window.matchMedia('(prefers-reduced-motion: reduce)').matches`.
+- **z-index**: `z-40` — sits below toasts (`z-50`), modals (`z-50`), and reading progress bar (`z-9999`). Toasts stack above it naturally.
+
+---
+
+## Visual Spec
+
+```
+Position:  fixed bottom-6 right-6  (24px from edges)
+Size:      44×44px circle
+Default:   bg: var(--accent) #a855f7, glow: box-shadow 0 0 12px rgba(168,85,247,0.4)
+Hover:     bg: #9333ea (one shade darker), glow: box-shadow 0 0 20px var(--accent)
+Icon:      Feather Icons `chevron-up` (already loaded globally via CDN)
+Entrance:  slideUp keyframe, 300ms ease-out
+Exit:      opacity fade (Alpine x-show transition), 200ms
+```
+
+---
+
+## Accessibility
+
+- `aria-label="Back to top"` on the button element
+- `role="button"` implicit (native `<button>`)
+- Keyboard accessible: Tab-focusable, Enter/Space triggers scroll
+- Focus ring: `focus-visible` outline using `var(--accent)` (already defined globally in CSS)
+- Button is removed from tab order when hidden via Alpine `x-show` (Alpine removes from DOM flow when not visible)
+- WCAG 2.1 AA contrast: white `↑` icon on `#a855f7` purple background — passes AA for UI components
+
+---
+
+## Implementation
+
+### New files
+- `themes/danix-xyz-hacker/layouts/partials/back-to-top.html` — the button partial
+
+### Modified files
+- `themes/danix-xyz-hacker/layouts/_default/baseof.html` — include partial + JS, conditionally on `.Kind "page"`
+- `themes/danix-xyz-hacker/assets/css/main.css` — add `.back-to-top` component class
+
+### No new JS file needed
+Logic is simple enough for inline Alpine `x-data` — consistent with `social-share.html`. No separate `.js` asset required.
+
+---
+
+## Component Structure
+
+**`back-to-top.html` partial:**
+```html
+<div
+  x-data="{ visible: false }"
+  @scroll.window="visible = (window.scrollY / (document.documentElement.scrollHeight - window.innerHeight)) >= 0.33"
+>
+  <button
+    x-show="visible"
+    x-transition:enter="..."
+    x-transition:enter-start="..."
+    x-transition:enter-end="..."
+    x-transition:leave="..."
+    x-transition:leave-start="..."
+    x-transition:leave-end="..."
+    class="back-to-top"
+    aria-label="Back to top"
+    @click="window.scrollTo({ top: 0, behavior: window.matchMedia('(prefers-reduced-motion: reduce)').matches ? 'auto' : 'smooth' })"
+  >
+    <!-- feather chevron-up icon -->
+  </button>
+</div>
+```
+
+**`.back-to-top` CSS class** (added to `main.css` `@layer components`):
+```css
+.back-to-top {
+  @apply fixed bottom-6 right-6 z-40 w-11 h-11 rounded-full flex items-center justify-center;
+  background: var(--accent);
+  box-shadow: 0 0 12px rgba(168, 85, 247, 0.4);
+  transition: background 200ms ease, box-shadow 200ms ease;
+  color: #fff;
+}
+.back-to-top:hover {
+  background: #9333ea;
+  box-shadow: 0 0 20px var(--accent);
+}
+.back-to-top:focus-visible {
+  outline: 2px solid var(--accent);
+  outline-offset: 2px;
+}
+```
+
+---
+
+## Verification
+
+1. Start Hugo dev server (`hugo server`)
+2. Open any article page
+3. Scroll past 33% — button slides up from bottom-right
+4. Scroll back up — button disappears
+5. Click button — smooth scroll to top
+6. Tab to button — focus ring visible
+7. Press Enter while focused — smooth scroll to top
+8. Test with `prefers-reduced-motion: reduce` in browser devtools — button appears without animation, click scrolls instantly
+9. Confirm toasts (if triggered) render above the button
+10. Check on mobile (narrow viewport) — button sits at bottom-right without overlapping content