feat(FontListItem): refactor component to enhance UX with animations and move away from checkboxes to avoid scroll problems

src/app/styles/app.css

@@ -117,6 +117,8 @@
   }
   body {
     @apply bg-background text-foreground;
+    font-family: 'Karla', system-ui, sans-serif;
+    font-optical-sizing: auto;
   }
 }
 

src/app/ui/Layout.svelte

@@ -26,6 +26,13 @@ let { children } = $props();
     <link rel="icon" href={favicon} />
     <link rel="preconnect" href="https://api.fontshare.com" />
     <link rel="preconnect" href="https://cdn.fontshare.com" crossorigin="anonymous" />
+
+    <link rel="preconnect" href="https://fonts.googleapis.com">
+    <link rel="preconnect" href="https://fonts.gstatic.com" crossorigin="anonymous">
+    <link
+        href="https://fonts.googleapis.com/css2?family=Karla:ital,wght@0,200..800;1,200..800&display=swap"
+        rel="stylesheet"
+    >
 </svelte:head>
 
 <div id="app-root">

src/entities/Font/ui/FontApplicator/FontApplicator.svelte

@@ -6,9 +6,9 @@
     - Adds smooth transition when font appears
 -->
 <script lang="ts">
-import { motion } from '$shared/lib';
 import { cn } from '$shared/shadcn/utils/shadcn-utils';
 import type { Snippet } from 'svelte';
+import { prefersReducedMotion } from 'svelte/motion';
 import { appliedFontsManager } from '../../model';
 
 interface Props {
@@ -59,7 +59,7 @@ const status = $derived(appliedFontsManager.getFontStatus(id, weight, false));
 const shouldReveal = $derived(hasEnteredViewport && (status === 'loaded' || status === 'error'));
 
 const transitionClasses = $derived(
-    motion.reduced
+    prefersReducedMotion.current
         ? 'transition-none' // Disable CSS transitions if motion is reduced
         : 'transition-all duration-700 ease-[cubic-bezier(0.22,1,0.36,1)]',
 );
@@ -71,8 +71,9 @@ const transitionClasses = $derived(
     class={cn(
         transitionClasses,
         // If reduced motion is on, we skip the transform/blur entirely
-        !shouldReveal && !motion.reduced && 'opacity-0 translate-y-8 scale-[0.98] blur-sm',
+        !shouldReveal && !prefersReducedMotion.current
-        !shouldReveal && motion.reduced && 'opacity-0', // Still hide until font is ready, but no movement
+            && 'opacity-0 translate-y-8 scale-[0.98] blur-sm',
+        !shouldReveal && prefersReducedMotion.current && 'opacity-0', // Still hide until font is ready, but no movement
         shouldReveal && 'opacity-100 translate-y-0 scale-100 blur-0',
         className,
     )}

src/entities/Font/ui/FontListItem/FontListItem.svelte

@@ -4,8 +4,8 @@
 -->
 <script lang="ts">
 import { Badge } from '$shared/shadcn/ui/badge';
-import { Checkbox } from '$shared/shadcn/ui/checkbox';
+import { cn } from '$shared/shadcn/utils/shadcn-utils';
-import { Label } from '$shared/shadcn/ui/label';
+import { Spring } from 'svelte/motion';
 import {
     type UnifiedFont,
     selectedFontsStore,
@@ -17,32 +17,96 @@ interface Props {
      * Object with information about font
      */
     font: UnifiedFont;
+    /**
+     * Is element fully visible
+     */
+    isVisible: boolean;
+    /**
+     * From 0 to 1
+     */
+    proximity: number;
 }
 
-const { font }: Props = $props();
+const { font, isVisible, proximity }: Props = $props();
 
-const handleChange = (checked: boolean) => {
+let selected = $state(selectedFontsStore.has(font.id));
-    if (checked) {
+let timeoutId = $state<NodeJS.Timeout | null>(null);
-        selectedFontsStore.addOne(font);
+
-    } else {
+// Create a spring for smooth scale animation
-        selectedFontsStore.removeOne(font.id);
+const scale = new Spring(1, {
+    stiffness: 0.3,
+    damping: 0.7,
+});
+
+// Springs react to the virtualizer's computed state
+const bloom = new Spring(0, {
+    stiffness: 0.15,
+    damping: 0.6,
+});
+
+// Sync spring to proximity for a "Lens" effect
+$effect(() => {
+    bloom.target = isVisible ? 1 : 0;
+});
+
+$effect(() => {
+    selected = selectedFontsStore.has(font.id);
+});
+
+$effect(() => {
+    return () => {
+        if (timeoutId) {
+            clearTimeout(timeoutId);
         }
     };
+});
 
-const selected = $derived(selectedFontsStore.has(font.id));
+function handleClick() {
+    animateSelection();
+    selected ? selectedFontsStore.removeOne(font.id) : selectedFontsStore.addOne(font);
+}
+
+function animateSelection() {
+    scale.target = 0.98;
+
+    timeoutId = setTimeout(() => {
+        scale.target = 1;
+    }, 150);
+}
 </script>
 
-<div class="pb-1">
+<div
-    <Label
+    class={cn('pb-1 will-change-transform')}
-        for={font.id}
+    style:opacity={bloom.current}
-        class="
+    style:transform="
-            w-full hover:bg-accent/50 flex items-start gap-3 rounded-lg border border-transparent p-3
+		scale({0.92 + (bloom.current * 0.08)})
-            active:scale-[0.98] active:transition-transform active:duration-75
+		translateY({(1 - bloom.current) * 10}px)
-            has-aria-checked:border-blue-600
-            has-aria-checked:bg-blue-50
-            dark:has-aria-checked:border-blue-900
-            dark:has-aria-checked:bg-blue-950
 	"
+>
+    <div style:transform={`scale(${scale.current})`}>
+        <div
+            class={cn(
+                'w-full hover:bg-accent/50 flex items-start gap-3 rounded-lg border border-transparent p-3',
+                'active:transition-transform active:duration-150',
+                'border dark:border-slate-800',
+                'bg-white/10 border-white/20',
+                isVisible && 'bg-white/40 border-white/40',
+                selected && 'ring-2 ring-indigo-600 ring-inset bg-indigo-50/50 hover:bg-indigo-50',
+            )}
+            role="button"
+            tabindex="0"
+            onmousedown={(e => {
+                // Prevent browser focus-jump
+                if (e.currentTarget === document.activeElement) return;
+                e.preventDefault();
+                handleClick();
+            })}
+            onkeydown={(e => {
+                if (e.key === 'Enter' || e.key === ' ') {
+                    e.preventDefault();
+                    handleClick();
+                }
+            })}
         >
             <div class="w-full">
                 <div class="flex flex-row gap-1 w-full items-center justify-between">
@@ -63,22 +127,8 @@ const selected = $derived(selectedFontsStore.has(font.id));
                             {font.name}
                         </FontApplicator>
                     </div>
-
-                <Checkbox
-                    id={font.id}
-                    checked={selected}
-                    onCheckedChange={handleChange}
-                    class="
-                        transition-all duration-150 ease-out
-                        data-[state=checked]:scale-100
-                        data-[state=checked]:border-blue-600
-                        data-[state=checked]:bg-blue-600
-                        data-[state=checked]:text-white
-                        dark:data-[state=checked]:border-blue-700
-                        dark:data-[state=checked]:bg-blue-700
-                    "
-                />
                 </div>
             </div>
-    </Label>
+        </div>
+    </div>
 </div>

src/features/DisplayFont/ui/FontComparer/FontComparer.svelte

@@ -1,8 +1,9 @@
 <script lang="ts">
 import { appliedFontsManager } from '$entities/Font';
 import { controlManager } from '$features/SetupFont';
-import { Input } from '$shared/shadcn/ui/input';
 import { ComparisonSlider } from '$widgets/ComparisonSlider/ui';
+import { cubicOut } from 'svelte/easing';
+import { fly } from 'svelte/transition';
 import { displayedFontsStore } from '../../model';
 import PairSelector from '../PairSelector/PairSelector.svelte';
 
@@ -20,16 +21,17 @@ $effect(() => {
 {#if hasAnyPairs}
     <div class="flex flex-col gap-4">
         <div class="flex flex-row gap-4">
-            <Input bind:value={displayedText} />
             <PairSelector />
         </div>
 
         {#if fontA && fontB}
+            <div in:fly={{ y: 0, x: -50, duration: 300, easing: cubicOut, opacity: 0.2 }}>
                 <ComparisonSlider
                     fontA={fontA}
                     fontB={fontB}
                     bind:text={displayedText}
                 />
+            </div>
         {/if}
     </div>
 {/if}

src/features/GetFonts/ui/SuggestedFonts/SuggestedFonts.svelte

@@ -11,7 +11,7 @@ import {
 </script>
 
 <FontVirtualList items={fontshareStore.fonts}>
-    {#snippet children({ item: font })}
+    {#snippet children({ item: font, isVisible, proximity })}
-        <FontListItem {font} />
+        <FontListItem {font} {isVisible} {proximity} />
     {/snippet}
 </FontVirtualList>

src/features/SetupFont/model/const/const.ts

@@ -21,3 +21,11 @@ export const DEFAULT_LINE_HEIGHT = 1.5;
 export const MIN_LINE_HEIGHT = 1;
 export const MAX_LINE_HEIGHT = 2;
 export const LINE_HEIGHT_STEP = 0.05;
+
+/**
+ * Letter spacing constants
+ */
+export const DEFAULT_LETTER_SPACING = 0;
+export const MIN_LETTER_SPACING = -0.1;
+export const MAX_LETTER_SPACING = 0.5;
+export const LETTER_SPACING_STEP = 0.01;

src/features/SetupFont/model/state/manager.svelte.ts

@@ -3,15 +3,19 @@ import { createTypographyControlManager } from '../../lib';
 import {
     DEFAULT_FONT_SIZE,
     DEFAULT_FONT_WEIGHT,
+    DEFAULT_LETTER_SPACING,
     DEFAULT_LINE_HEIGHT,
     FONT_SIZE_STEP,
     FONT_WEIGHT_STEP,
+    LETTER_SPACING_STEP,
     LINE_HEIGHT_STEP,
     MAX_FONT_SIZE,
     MAX_FONT_WEIGHT,
+    MAX_LETTER_SPACING,
     MAX_LINE_HEIGHT,
     MIN_FONT_SIZE,
     MIN_FONT_WEIGHT,
+    MIN_LETTER_SPACING,
     MIN_LINE_HEIGHT,
 } from '../const/const';
 
@@ -49,6 +53,17 @@ const controlData: ControlModel[] = [
         decreaseLabel: 'Decrease Line Height',
         controlLabel: 'Line Height',
     },
+    {
+        id: 'letter_spacing',
+        value: DEFAULT_LETTER_SPACING,
+        max: MAX_LETTER_SPACING,
+        min: MIN_LETTER_SPACING,
+        step: LETTER_SPACING_STEP,
+
+        increaseLabel: 'Increase Letter Spacing',
+        decreaseLabel: 'Decrease Letter Spacing',
+        controlLabel: 'Letter Spacing',
+    },
 ];
 
 export const controlManager = createTypographyControlManager(controlData);

src/shared/lib/accessibility/motion.svelte.ts

@@ -1,32 +0,0 @@
-// Check if we are in a browser environment
-const isBrowser = typeof window !== 'undefined';
-
-// A class to manage motion preference and provide a single instance for use everywhere
-class MotionPreference {
-    // Reactive state
-    #reduced = $state(false);
-
-    constructor() {
-        if (isBrowser) {
-            const mediaQuery = window.matchMedia('(prefers-reduced-motion: reduce)');
-
-            // Set initial value immediately
-            this.#reduced = mediaQuery.matches;
-
-            // Simple listener that updates the reactive state
-            const handleChange = (e: MediaQueryListEvent) => {
-                this.#reduced = e.matches;
-            };
-
-            mediaQuery.addEventListener('change', handleChange);
-        }
-    }
-
-    // Getter allows us to use 'motion.reduced' reactively in components
-    get reduced() {
-        return this.#reduced;
-    }
-}
-
-// Export a single instance to be used everywhere
-export const motion = new MotionPreference();

src/shared/lib/helpers/createCharacterComparison/createCharacterComparison.svelte.ts

@@ -49,10 +49,6 @@ export function createCharacterComparison(
      * Matches the Tailwind breakpoints used in the component.
      */
     function getFontSize() {
-        // const fontSize = size();
-        // if (fontSize) {
-        //     return fontSize;
-        // }
         if (typeof window === 'undefined') {
             return 64;
         }

src/shared/lib/helpers/createVirtualizer/createVirtualizer.svelte.ts

@@ -14,6 +14,10 @@ export interface VirtualItem {
     end: number;
     /** Unique key for the item (for Svelte's {#each} keying) */
     key: string | number;
+    /** Whether the item is currently visible in the viewport */
+    isVisible: boolean;
+    /** Proximity of the item to the center of the viewport */
+    proximity: number;
 }
 
 /**
@@ -136,6 +140,8 @@ export function createVirtualizer<T>(
 
         let endIdx = startIdx;
         const viewportEnd = scrollOffset + containerHeight;
+        const viewportCenter = scrollOffset + (containerHeight / 2);
+
         while (endIdx < count && offsets[endIdx] < viewportEnd) {
             endIdx++;
         }
@@ -144,13 +150,31 @@ export function createVirtualizer<T>(
         const end = Math.min(count, endIdx + overscan);
 
         const result: VirtualItem[] = [];
+
         for (let i = start; i < end; i++) {
+            const itemStart = offsets[i];
+            const itemSize = measuredSizes[i] ?? options.estimateSize(i);
+            const itemEnd = itemStart + itemSize;
+
+            // Visibility check: Does the item overlap the viewport?
+            // const isVisible = itemStart < viewportEnd && itemEnd > scrollOffset;
+            // Fully visible
+            const isVisible = itemStart >= scrollOffset && itemEnd <= viewportEnd;
+
+            // Proximity calculation: 1.0 at center, 0.0 at edges
+            const itemCenter = itemStart + (itemSize / 2);
+            const distanceToCenter = Math.abs(viewportCenter - itemCenter);
+            const maxDistance = containerHeight / 2;
+            const proximity = Math.max(0, 1 - (distanceToCenter / maxDistance));
+
             result.push({
                 index: i,
-                start: offsets[i],
+                start: itemStart,
-                size: measuredSizes[i] ?? options.estimateSize(i),
+                size: itemSize,
-                end: offsets[i] + (measuredSizes[i] ?? options.estimateSize(i)),
+                end: itemEnd,
                 key: options.getItemKey?.(i) ?? i,
+                isVisible,
+                proximity,
             });
         }
 
@@ -207,23 +231,25 @@ export function createVirtualizer<T>(
             const index = parseInt(node.dataset.index || '', 10);
             const height = entry.borderBoxSize[0]?.blockSize ?? node.offsetHeight;
 
-            if (!isNaN(index) && measuredSizes[index] !== height) {
+            if (!isNaN(index)) {
-                // 1. Stuff the measurement into a temporary buffer
+                const oldHeight = measuredSizes[index];
+                // Only update if the height difference is significant (> 0.5px)
+                // This prevents "jitter" from focus rings or sub-pixel border changes
+                if (oldHeight === undefined || Math.abs(oldHeight - height) > 0.5) {
+                    // Stuff the measurement into a temporary buffer
                     measurementBuffer[index] = height;
 
-                // 2. Schedule a single update for the next animation frame
+                    // Schedule a single update for the next animation frame
                     if (frameId === null) {
                         frameId = requestAnimationFrame(() => {
-                        // 3. Update the state once for all collected measurements
-                        // We use spread to trigger a single fine-grained update
                             measuredSizes = { ...measuredSizes, ...measurementBuffer };
-
+                            // Reset the buffer
-                        // 4. Reset the buffer
                             measurementBuffer = {};
                             frameId = null;
                         });
                     }
                 }
+            }
         });
 
         resizeObserver.observe(node);

src/shared/lib/index.ts

@@ -19,5 +19,4 @@ export {
     type VirtualizerOptions,
 } from './helpers';
 
-export { motion } from './accessibility/motion.svelte';
 export { splitArray } from './utils';

src/shared/ui/CheckboxFilter/CheckboxFilter.svelte

@@ -9,7 +9,6 @@
 -->
 <script lang="ts">
 import type { Filter } from '$shared/lib';
-import { motion } from '$shared/lib';
 import { Badge } from '$shared/shadcn/ui/badge';
 import { buttonVariants } from '$shared/shadcn/ui/button';
 import { Checkbox } from '$shared/shadcn/ui/checkbox';
@@ -20,6 +19,7 @@ import {
 import { Label } from '$shared/shadcn/ui/label';
 import ChevronDownIcon from '@lucide/svelte/icons/chevron-down';
 import { cubicOut } from 'svelte/easing';
+import { prefersReducedMotion } from 'svelte/motion';
 import { slide } from 'svelte/transition';
 
 interface PropertyFilterProps {
@@ -37,7 +37,7 @@ let isOpen = $state(true);
 // Animation config respects user preferences - zero duration if reduced motion enabled
 // Local modifier prevents animation on initial render, only animates user interactions
 const slideConfig = $derived({
-    duration: motion.reduced ? 0 : 250,
+    duration: prefersReducedMotion.current ? 0 : 250,
     easing: cubicOut,
 });
 

src/shared/ui/SearchBar/SearchBar.svelte

@@ -70,7 +70,14 @@ function handleInputClick() {
                     bind:value={value}
                     onkeydown={handleKeyDown}
                     onclick={handleInputClick}
-                    class="flex flex-row flex-1"
+                    class="
+                        h-20 w-full md:text-2xl backdrop-blur-sm bg-white/60 dark:bg-slate-900/40
+                        border-2 border-slate-200/50 dark:border-slate-700/50
+                        focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-indigo-500/50
+                        hover:bg-white/70 dark:hover:bg-slate-900/50 text-slate-900 dark:text-slate-100
+                        placeholder:text-slate-400 px-6 py-4 rounded-2xl transition-all duration-300
+                        font-medium
+                    "
                 />
             </div>
         {/snippet}
@@ -83,7 +90,7 @@ function handleInputClick() {
                 e.preventDefault();
             }
         })}
-        class="w-(--bits-popover-anchor-width) min-w-(--bits-popover-anchor-width)"
+        class="w-(--bits-popover-anchor-width) min-w-(--bits-popover-anchor-width) md:rounded-2xl"
     >
         {@render children?.({ id: contentId })}
     </PopoverContent>

src/shared/ui/VirtualList/VirtualList.svelte

@@ -52,7 +52,7 @@ interface Props {
      *
      * @template T - The type of items in the list
      */
-    children: Snippet<[{ item: T; index: number }]>;
+    children: Snippet<[{ item: T; index: number; isVisible: boolean; proximity: number }]>;
 }
 
 let { items, itemHeight = 80, overscan = 5, class: className, onVisibleItemsChange, children }:
@@ -76,8 +76,13 @@ $effect(() => {
     class={cn(
         'relative overflow-auto rounded-md bg-background',
         'h-150 w-full',
+        'scroll-smooth',
         className,
     )}
+    onfocusin={(e => {
+        // Prevent the browser from jumping the scroll when an inner element gets focus
+        e.preventDefault();
+    })}
 >
     <div
         style:height="{virtualizer.totalSize}px"
@@ -92,7 +97,12 @@ $effect(() => {
             class="absolute top-0 left-0 w-full"
             style:transform="translateY({item.start}px)"
         >
-            {@render children({ item: items[item.index], index: item.index })}
+            {@render children({
+    item: items[item.index],
+    index: item.index,
+    isVisible: item.isVisible,
+    proximity: item.proximity,
+})}
         </div>
     {/each}
 </div>

src/widgets/ComparisonSlider/ui/ComparisonSlider/components/ControlsWrapper.svelte

@@ -171,7 +171,7 @@ $effect(() => {
             'animate-nudge relative transition-all',
             side === 'left' ? 'order-2' : 'order-0',
             isActive ? 'opacity-0' : 'opacity-100',
-            isDragging && 'opacity-40 grayscale-[0.2]',
+            isDragging && 'opacity-80 grayscale-[0.2]',
         )}
     >
         <AArrowUP class={cn('size-3', 'stroke-indigo-600')} />
@@ -183,7 +183,7 @@ $effect(() => {
             isActive
                 ? 'bg-white/95 border-indigo-400/40 shadow-[0_30px_70px_-10px_rgba(99,102,241,0.25)]'
                 : ' bg-white/25 border-white/40 shadow-[0_12px_40px_-12px_rgba(0,0,0,0.12)]',
-            isDragging && 'opacity-40 grayscale-[0.2]',
+            isDragging && 'opacity-80 grayscale-[0.2]',
         )}
         style:backdrop-filter="blur(24px)"
     >