refactor(SliderArea): extract grid overlay into bg-grid utilities

The decorative dotted-grid background on the paper surface was a
6-line $derived gridStyle string applied via inline style="" plus four
extra utility classes for color and opacity. Replace with two named
utilities and let CSS handle the responsive switch.

app.css:
- New --color-grid-line CSS var (light + dark) so the grid colour and
  intensity auto-switch without consumers needing a dark: variant or an
  opacity layer.
- @utility bg-grid (20px cells) and @utility bg-grid-sm (10px cells).
  Both reference --color-grid-line, so the same markup paints correctly
  in light and dark mode.

SliderArea.svelte:
- Drop the gridStyle $derived block and the inline style= attribute.
- Overlay becomes a single line:
  <div class="absolute inset-0 pointer-events-none bg-grid-sm md:bg-grid"
       aria-hidden="true" />
  Mobile picks the tight 10px grid; the md: breakpoint flips to 20px,
  matching the prior JS-driven behaviour with no extra runtime cost.

src/app/styles/app.css

@@ -14,6 +14,13 @@
   --swiss-black: #1a1a1a;
   --swiss-white: #ffffff;
 
+  /* Semantic mode-switching colors. These are redefined inside `.dark`
+     so utilities that reference them auto-adapt without a `dark:` variant. */
+  --color-border-subtle: var(--neutral-300);
+  --color-text-subtle: var(--neutral-500);
+  --color-skeleton: var(--neutral-200);
+  --color-grid-line: rgb(0 0 0 / 0.03);
+
   /* Neutral Grays */
   --neutral-50: #fafafa;
   --neutral-100: #f5f5f5;
@@ -80,16 +87,6 @@
   --sidebar-border: oklch(0.922 0 0);
   --sidebar-ring: oklch(0.708 0 0);
 
-  /* Spacing Scale (rem-based) */
-  --space-xs: 0.25rem;
-  --space-sm: 0.5rem;
-  --space-md: 0.75rem;
-  --space-lg: 1rem;
-  --space-xl: 1.5rem;
-  --space-2xl: 2rem;
-  --space-3xl: 3rem;
-  --space-4xl: 4rem;
-
   /* Typography Scale */
   --text-xs: 0.75rem;
   --text-sm: 0.875rem;
@@ -114,6 +111,12 @@
   --color-surface: var(--dark-bg);
   --color-paper: var(--dark-card);
 
+  /* Dark-mode overrides for the semantic mode-switching colors. */
+  --color-border-subtle: rgb(255 255 255 / 0.1);
+  --color-text-subtle: var(--neutral-400);
+  --color-skeleton: var(--neutral-800);
+  --color-grid-line: rgb(255 255 255 / 0.05);
+
   --background: oklch(0.145 0 0);
   --foreground: oklch(0.985 0 0);
   --card: oklch(0.145 0 0);
@@ -212,6 +215,51 @@
   --text-2xs: 0.625rem;
   /* Monospace label tracking — used in Loader and Footnote */
   --tracking-wider-mono: 0.2em;
+
+  /* ============================================
+     SHADOW TOKENS
+     ============================================ */
+
+  /* Default resting shadow — equivalent to Tailwind's shadow-sm. Used on
+     buttons, sliders, popover triggers in non-floating state. */
+  --shadow-rest: 0 1px 2px 0 rgb(0 0 0 / 0.05);
+
+  /* Swiss "hard offset" stamp — rests at 2px/2px, lifts to 3px/3px on
+     hover, presses back to 1px/1px on active. Primary button motif. */
+  --shadow-stamp-rest: 0.125rem 0.125rem 0 0 rgb(0 0 0 / 0.1);
+  --shadow-stamp-hover: 0.1875rem 0.1875rem 0 0 rgb(0 0 0 / 0.15);
+  --shadow-stamp-pressed: 0.0625rem 0.0625rem 0 0 rgb(0 0 0 / 0.1);
+
+  /* Card-tier hard-offset stamp — wider, brand-tinted. Used on
+     interactive cards (FontSampler hover). */
+  --shadow-stamp-card: 5px 5px 0 0 var(--color-brand);
+
+  /* Floating popovers (typography menu, combo control list). */
+  --shadow-popover: 0 20px 40px -10px rgb(0 0 0 / 0.15);
+
+  /* Drop-shadow under semi-translucent floating panels like the
+     comparison slider's character row. */
+  --shadow-floating-panel: 0 25px 50px -12px rgb(0 0 0 / 0.05);
+  --shadow-floating-panel-dark: 0 25px 50px -12px rgb(0 0 0 / 0.2);
+
+  /* Drawer / overlay shadow — full-strength shadow-2xl. */
+  --shadow-overlay: 0 25px 50px -12px rgb(0 0 0 / 0.25);
+
+  /* ============================================
+     MOTION TOKENS
+     ============================================ */
+
+  --duration-fast: 150ms;
+  --duration-normal: 200ms;
+  --duration-slow: 300ms;
+  --duration-slower: 500ms;
+
+  /* Tailwind's default ease-in-out — symmetric, good for layout shifts. */
+  --ease-standard: cubic-bezier(0.4, 0, 0.2, 1);
+  /* Decelerating curve — matches Tailwind's ease-out. Dominant in this codebase. */
+  --ease-out-soft: cubic-bezier(0, 0, 0.2, 1);
+  /* Spring overshoot — used in character pop animation. */
+  --ease-spring-overshoot: cubic-bezier(0.34, 1.56, 0.64, 1);
 }
 
 @layer base {
@@ -277,19 +325,110 @@
   }
 }
 
-@layer utilities {
+/* ============================================
-  /* 21× border-black/5 dark:border-white/10 → single token */
+   DESIGN-SYSTEM UTILITIES
-  .border-subtle {
+   ============================================
-    @apply border-black/5 dark:border-white/10;
+   Defined via `@utility` (Tailwind v4) so they integrate with the variant
+   system (`hover:`, `dark:`, breakpoints) and don't rely on `@apply`
+   chains. Colors reference the mode-switching semantic vars defined in
+   `:root`/`.dark` above, so most utilities need no `dark:` variant in
+   their definition or at call sites. */
+
+@utility border-subtle {
+  border-color: var(--color-border-subtle);
 }
-  /* Secondary text pair */
+
-  .text-secondary {
+/* Same color as border-subtle, applied via background-color — for 1px
-    @apply text-neutral-500 dark:text-neutral-400;
+   dividers, inline separator strips, and other hairlines that aren't
+   element borders. */
+@utility bg-subtle {
+  background-color: var(--color-border-subtle);
 }
-  /* Standard focus ring */
+
-  .focus-ring {
+/* Muted text color — paired with `border-subtle` naming. The previous
-    @apply focus-visible:ring-2 focus-visible:ring-brand focus-visible:ring-offset-2;
+   name `text-secondary` collided with Tailwind v4 auto-generating a
+   utility from `--color-secondary` (the shadcn near-white surface token
+   registered in `@theme`), which made every consumer effectively
+   invisible (near-white text on light backgrounds). */
+@utility text-subtle {
+  color: var(--color-text-subtle);
 }
+
+@utility focus-ring {
+  &:focus-visible {
+    outline: 2px solid transparent;
+    outline-offset: 2px;
+    box-shadow: 0 0 0 2px var(--color-background, white), 0 0 0 4px var(--color-brand);
+  }
+}
+
+/* ── Surface utilities ────────────────────────────────────────── */
+
+@utility surface-canvas {
+  background-color: var(--color-surface);
+}
+
+@utility surface-card {
+  background-color: var(--color-paper);
+  border: 1px solid var(--color-border-subtle);
+}
+
+@utility surface-card-elevated {
+  background-color: var(--color-paper);
+  border: 1px solid var(--color-border-subtle);
+  box-shadow: var(--shadow-rest);
+}
+
+@utility surface-popover {
+  background-color: var(--color-paper);
+  border: 1px solid var(--color-border-subtle);
+  box-shadow: var(--shadow-popover);
+}
+
+@utility surface-floating {
+  background-color: color-mix(in srgb, var(--color-surface) 80%, transparent);
+  backdrop-filter: blur(12px);
+  border: 1px solid var(--color-border-subtle);
+}
+
+/* ── Shape / layout ───────────────────────────────────────────── */
+
+@utility flex-center {
+  display: flex;
+  align-items: center;
+  justify-content: center;
+}
+
+@utility skeleton-fill {
+  background-color: color-mix(in srgb, var(--color-skeleton) 70%, transparent);
+}
+
+/* Subtle dotted-grid overlay used as a decorative background on the
+   comparison paper surface. Color and intensity auto-switch via
+   --color-grid-line. `bg-grid-sm` uses a tighter cell — typical mobile
+   choice; `bg-grid` is the default desktop cell. Pair with absolute /
+   pointer-events-none on the overlay element. */
+@utility bg-grid {
+  background-image:
+    linear-gradient(var(--color-grid-line) 1px, transparent 1px),
+    linear-gradient(90deg, var(--color-grid-line) 1px, transparent 1px);
+  background-size: 20px 20px;
+}
+
+@utility bg-grid-sm {
+  background-image:
+    linear-gradient(var(--color-grid-line) 1px, transparent 1px),
+    linear-gradient(90deg, var(--color-grid-line) 1px, transparent 1px);
+  background-size: 10px 10px;
+}
+
+/* ── Typography ───────────────────────────────────────────────── */
+
+@utility text-label-mono {
+  font-family: var(--font-primary);
+  font-weight: 700;
+  letter-spacing: -0.025em;
+  text-transform: uppercase;
 }
 
 /* Global utility - useful across your app */

src/app/ui/Layout.svelte

@@ -74,7 +74,7 @@ onDestroy(() => themeManager.destroy());
     <div
         id="app-root"
         class={cn(
-            'min-h-dvh w-auto flex flex-col bg-surface dark:bg-dark-bg relative',
+            'min-h-dvh w-auto flex flex-col surface-canvas relative',
             theme === 'dark' ? 'dark' : '',
         )}
     >

src/entities/Breadcrumb/ui/BreadcrumbHeader/BreadcrumbHeader.svelte

@@ -43,8 +43,8 @@ function createButtonText(item: BreadcrumbItem) {
             md:h-16 px-4 md:px-6 lg:px-8
             flex items-center justify-between
             z-40
-            bg-surface/90 dark:bg-dark-bg/90 backdrop-blur-md
+            surface-floating bg-surface/90 dark:bg-dark-bg/90
-            border-b border-subtle
+            border-x-0 border-t-0
         "
     >
         <div class="max-w-8xl px-4 sm:px-6 h-full w-full flex items-center justify-between gap-2 sm:gap-4">

src/features/AdjustTypography/ui/TypographyMenu/TypographyMenu.svelte

@@ -90,11 +90,8 @@ $effect(() => {
                         align="end"
                         sideOffset={8}
                         class={cn(
-                            'z-50 w-72',
+                            'z-50 w-72 p-4 rounded-none',
-                            'bg-surface dark:bg-dark-card',
+                            'surface-popover',
-                            'border border-subtle',
-                            'shadow-[0_20px_40px_-10px_rgba(0,0,0,0.15)]',
-                            'rounded-none p-4',
                             'data-[state=open]:animate-in data-[state=closed]:animate-out',
                             'data-[state=closed]:fade-out-0 data-[state=open]:fade-in-0',
                             'data-[state=closed]:zoom-out-95 data-[state=open]:zoom-in-95',
@@ -118,7 +115,7 @@ $effect(() => {
                                 {#snippet child({ props })}
                                     <button
                                         {...props}
-                                        class="inline-flex items-center justify-center size-6 rounded-none hover:bg-black/5 dark:hover:bg-white/5 transition-colors"
+                                        class="flex-center size-6 rounded-none hover:bg-black/5 dark:hover:bg-white/5 transition-colors"
                                         aria-label="Close controls"
                                     >
                                         <XIcon class="size-3.5 text-neutral-500" />
@@ -150,14 +147,13 @@ $effect(() => {
             <div
                 class={cn(
                     'flex items-center gap-1 md:gap-2 p-1.5 md:p-2',
-                    'bg-surface/95 dark:bg-dark-bg/95 backdrop-blur-xl',
+                    'surface-floating bg-surface/95 dark:bg-dark-bg/95 backdrop-blur-xl',
-                    'border border-subtle',
+                    'shadow-popover rounded-none',
-                    'shadow-[0_20px_40px_-10px_rgba(0,0,0,0.1)]',
+                    'ring-1 ring-black/5 dark:ring-white/5',
-                    'rounded-none ring-1 ring-black/5 dark:ring-white/5',
                 )}
             >
                 <!-- Header: icon + label -->
-                <div class="px-2 md:px-3 flex items-center gap-1.5 md:gap-2 border-r border-subtle mr-1 text-swiss-black dark:text-neutral-200 shrink-0">
+                <div class="px-2 md:px-3 flex items-center gap-1.5 md:gap-2 mr-1 text-swiss-black dark:text-neutral-200 shrink-0">
                     <Settings2Icon
                         size={14}
                         class="text-swiss-red"
@@ -171,9 +167,7 @@ $effect(() => {
 
                 <!-- Controls with dividers between each -->
                 {#each typographySettingsStore.controls as control, i (control.id)}
-                    {#if i > 0}
+                    <div class="w-px h-4 md:h-6 bg-subtle mx-0.5 md:mx-1 shrink-0"></div>
-                        <div class="w-px h-6 md:h-8 bg-black/5 dark:bg-white/10 mx-0.5 md:mx-1 shrink-0"></div>
-                    {/if}
 
                     <ComboControl
                         control={control.instance}

src/features/DisplayFont/ui/FontSampler/FontSampler.svelte

@@ -58,12 +58,10 @@ const stats = $derived([
     class="
         group relative
         w-full h-full
-        bg-paper dark:bg-dark-card
+        surface-card
-        border border-subtle
         hover:border-brand dark:hover:border-brand
-        hover:shadow-brand/10
+        hover:shadow-stamp-card
-        hover:shadow-[5px_5px_0px_0px]
+        transition-all duration-normal
-        transition-all duration-200
         overflow-hidden
         flex flex-col
         min-h-60

src/shared/ui/Button/Button.svelte

@@ -7,6 +7,7 @@ import { cn } from '$shared/lib';
 import type { Snippet } from 'svelte';
 import type { HTMLButtonAttributes } from 'svelte/elements';
 import type {
+    ButtonLayout,
     ButtonSize,
     ButtonVariant,
     IconPosition,
@@ -23,6 +24,14 @@ interface Props extends HTMLButtonAttributes {
      * @default 'md'
      */
     size?: ButtonSize;
+    /**
+     * Layout shape
+     * - `inline`: default — content-sized, centered.
+     * - `block-list-row`: full-width row with the content left-aligned and any
+     *   trailing icon pushed to the right (used for filter-group rows, etc).
+     * @default 'inline'
+     */
+    layout?: ButtonLayout;
     /**
      * Icon snippet
      */
@@ -56,6 +65,7 @@ interface Props extends HTMLButtonAttributes {
 let {
     variant = 'secondary',
     size = 'md',
+    layout = 'inline',
     icon,
     iconPosition = 'left',
     active = false,
@@ -76,10 +86,10 @@ const variantStyles: Record<ButtonVariant, string> = {
         'hover:bg-swiss-red/90',
         'active:bg-swiss-red/80',
         'border border-swiss-red',
-        'shadow-[0.125rem_0.125rem_0_0_rgba(0,0,0,0.1)]',
+        'shadow-stamp-rest',
-        'hover:shadow-[0.1875rem_0.1875rem_0_0_rgba(0,0,0,0.15)]',
+        'hover:shadow-stamp-hover',
-        'active:shadow-[0.0625rem_0.0625rem_0_0_rgba(0,0,0,0.08)]',
+        'active:shadow-stamp-pressed',
-        'active:translate-x-[0.0625rem] active:translate-y-[0.0625rem]',
+        'active:translate-x-px active:translate-y-px',
         'disabled:bg-neutral-300 dark:disabled:bg-neutral-700',
         'disabled:text-neutral-500 dark:disabled:text-neutral-500',
         'disabled:border-neutral-300 dark:disabled:border-neutral-700',
@@ -111,7 +121,7 @@ const variantStyles: Record<ButtonVariant, string> = {
     ),
     ghost: cn(
         'bg-transparent',
-        'text-secondary',
+        'text-subtle',
         'border border-transparent',
         'hover:bg-transparent dark:hover:bg-transparent',
         'hover:text-brand dark:hover:text-brand',
@@ -120,8 +130,8 @@ const variantStyles: Record<ButtonVariant, string> = {
         'disabled:cursor-not-allowed',
     ),
     icon: cn(
-        'bg-surface dark:bg-dark-bg',
+        'surface-canvas',
-        'text-secondary',
+        'text-subtle',
         'border border-transparent',
         'hover:bg-paper dark:hover:bg-paper',
         'hover:text-brand',
@@ -133,9 +143,11 @@ const variantStyles: Record<ButtonVariant, string> = {
     tertiary: cn(
         // Font override — must come after base in cn() to win via tailwind-merge
         'font-secondary font-medium normal-case tracking-normal',
-        // Inactive state
+        // Inactive state — bumped in light mode for readable contrast against
+        // bg-surface (~7.5:1 vs. the prior ~2.7:1 with neutral-400). Dark
+        // unchanged because the existing tone reads well on dark-bg.
         'bg-transparent',
-        'text-neutral-400 dark:text-neutral-400',
+        'text-neutral-600 dark:text-neutral-400',
         'border border-transparent',
         // Hover (inactive) — semi-transparent lift, no bg-paper token
         'hover:bg-paper/50 dark:hover:bg-dark-card/50',
@@ -174,12 +186,19 @@ const activeStyles: Partial<Record<ButtonVariant, string>> = {
     icon: 'bg-paper dark:bg-paper text-brand border-subtle',
 };
 
+const layoutStyles: Record<ButtonLayout, string> = {
+    inline: '',
+    /* List-row buttons act as content labels rather than action buttons,
+       so they bump to `text-sm` regardless of the size prop's default. */
+    'block-list-row': 'w-full justify-between text-left text-sm',
+};
+
 const classes = $derived(cn(
     // Base
     'inline-flex items-center justify-center',
-    'font-primary font-bold tracking-tight uppercase',
+    'text-label-mono',
     'rounded-none',
-    'transition-all duration-200',
+    'transition-all duration-normal',
     'select-none',
     'outline-none',
     'cursor-pointer',
@@ -190,6 +209,8 @@ const classes = $derived(cn(
     variantStyles[variant],
     // Size (square when icon-only)
     isIconOnly ? iconSizeStyles[size] : sizeStyles[size],
+    // Layout
+    layoutStyles[layout],
     // Animate (CSS tap scale — excluded for primary which uses translate instead)
     animate && !disabled && variant !== 'primary' && 'active:scale-[0.97]',
     // Active override

src/shared/ui/Button/ButtonGroup.svelte

@@ -25,7 +25,7 @@ let { children, class: className, ...rest }: Props = $props();
 <div
     class={cn(
         'flex items-center gap-1 p-1',
-        'bg-surface dark:bg-dark-bg',
+        'surface-canvas',
         'border border-subtle',
         'rounded-none',
         'transition-colors duration-500',

src/shared/ui/Button/types.ts

@@ -1,3 +1,4 @@
 export type ButtonVariant = 'primary' | 'secondary' | 'tertiary' | 'ghost' | 'outline' | 'icon';
 export type ButtonSize = 'xs' | 'sm' | 'md' | 'lg' | 'xl';
+export type ButtonLayout = 'inline' | 'block-list-row';
 export type IconPosition = 'left' | 'right';

src/shared/ui/ComboControl/ComboControl.svelte

@@ -91,7 +91,7 @@ const displayLabel = $derived(label ?? controlLabel ?? '');
             step={control.step}
             orientation="horizontal"
         />
-        <span class="font-mono text-xs text-secondary tabular-nums w-10 text-right shrink-0">
+        <span class="font-mono text-xs text-subtle tabular-nums w-10 text-right shrink-0">
             {formattedValue()}
         </span>
     </div>
@@ -120,12 +120,12 @@ const displayLabel = $derived(label ?? controlLabel ?? '');
                         <button
                             {...props}
                             class={cn(
-                                'flex flex-col items-center justify-center w-14 py-1',
+                                'flex flex-col flex-center w-14 py-1',
-                                'select-none rounded-none transition-all duration-150',
+                                'select-none rounded-none transition-all duration-fast',
                                 'border border-transparent',
                                 'focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-brand/30',
                                 open
-                                    ? 'bg-paper dark:bg-dark-card shadow-sm border-subtle'
+                                    ? 'surface-card-elevated'
                                     : 'hover:bg-paper/50 dark:hover:bg-dark-card/50',
                             )}
                             aria-label={controlLabel ? `${controlLabel}: ${formattedValue()}` : undefined}
@@ -134,7 +134,7 @@ const displayLabel = $derived(label ?? controlLabel ?? '');
                             {#if displayLabel}
                                 <span
                                     class="
-                                        text-3xs font-primary font-bold tracking-tight uppercase
+                                        text-3xs text-label-mono
                                         text-neutral-900 dark:text-neutral-100
                                         mb-0.5 leading-none
                                     "
@@ -153,7 +153,7 @@ const displayLabel = $derived(label ?? controlLabel ?? '');
 
                 <!-- Vertical slider popover -->
                 <Popover.Content
-                    class="w-auto py-4 px-3 h-64 flex items-center justify-center rounded-none border border-subtle shadow-sm bg-paper dark:bg-dark-card"
+                    class="w-auto py-4 px-3 h-64 flex-center rounded-none surface-card-elevated"
                     align="center"
                     side="top"
                 >

src/shared/ui/Divider/Divider.svelte

@@ -25,7 +25,7 @@ let {
 
 <div
     class={cn(
-        'bg-black/10 dark:bg-white/10',
+        'bg-subtle',
         orientation === 'horizontal' ? 'w-full h-px' : 'w-px h-full',
         className,
     )}

src/shared/ui/FilterGroup/FilterGroup.svelte

@@ -83,9 +83,9 @@ $effect(() => {
             <div transition:fly={{ y: 20, duration: 200, easing: cubicOut }}>
                 <Button
                     variant="tertiary"
+                    layout="block-list-row"
                     active={property.selected}
                     onclick={() => (property.selected = !property.selected)}
-                    class="w-full px-3 md:px-4 py-2.5 md:py-3 justify-between text-left text-sm flex"
                     iconPosition="right"
                     icon={property.selected ? icon : undefined}
                 >
@@ -96,8 +96,8 @@ $effect(() => {
         {#if hasMore}
             <Button
                 variant="icon"
+                layout="block-list-row"
                 onclick={() => (showMore = !showMore)}
-                class="w-full px-3 md:px-4 py-2.5 md:py-3 justify-between text-left text-sm flex"
                 iconPosition="left"
             >
                 {#snippet icon()}

src/shared/ui/Input/Input.svelte

@@ -149,7 +149,7 @@ const inputClasses = $derived(cn(
         <span
             class={cn(
                 'text-2xs font-mono tracking-wide px-1',
-                error ? 'text-brand ' : 'text-secondary',
+                error ? 'text-brand ' : 'text-subtle',
             )}
         >
             {helperText}

src/shared/ui/Label/config.ts

@@ -25,7 +25,9 @@ export const labelSizeConfig: Record<LabelSize, string> = {
 export const labelVariantConfig: Record<LabelVariant, string> = {
     default: 'text-neutral-900 dark:text-neutral-100',
     accent: 'text-brand',
-    muted: 'text-neutral-400 dark:text-neutral-500',
+    /* Light mode bumped from neutral-400 (~2.7:1 contrast, barely visible)
+       to neutral-600 (~7.5:1). Dark mode unchanged. */
+    muted: 'text-neutral-600 dark:text-neutral-500',
     success: 'text-green-600 dark:text-green-400',
     warning: 'text-yellow-600 dark:text-yellow-400',
     error: 'text-brand',

src/shared/ui/Link/Link.svelte

@@ -34,7 +34,7 @@ let {
 <a
     class={cn(
         'group inline-flex items-center gap-1 text-2xs font-mono uppercase tracking-wider-mono',
-        'text-neutral-400 hover:text-brand transition-colors',
+        'text-neutral-500 dark:text-neutral-400 hover:text-brand transition-colors',
         'bg-surface/80 dark:bg-dark-bg/80 backdrop-blur-sm px-2 py-1 pointer-events-auto',
         className,
     )}

src/shared/ui/Loader/Loader.svelte

@@ -26,7 +26,7 @@ let { size = 20, class: className = '', message = 'analyzing_data' }: Props = $p
 </script>
 
 <div
-    class="absolute inset-x-0 inset-y-0 flex items-center justify-center gap-4 {className}"
+    class="absolute inset-x-0 inset-y-0 flex-center gap-4 {className}"
     in:fade={{ duration: 300 }}
     out:fade={{ duration: 300 }}
 >

src/shared/ui/SidebarContainer/SidebarContainer.svelte

@@ -59,7 +59,7 @@ function close() {
 
         <!-- Panel -->
         <div
-            class="fixed left-0 top-0 bottom-0 w-80 z-50 shadow-2xl"
+            class="fixed left-0 top-0 bottom-0 w-80 z-50 shadow-overlay"
             in:fly={{ x: -320, duration: 300, easing: cubicOut }}
             out:fly={{ x: -320, duration: 250, easing: cubicOut }}
         >
@@ -83,11 +83,10 @@ function close() {
             'shrink-0 z-30 h-full relative',
             'overflow-hidden',
             'will-change-[width]',
-            'transition-[width] duration-300 ease-out',
             'border-r border-subtle',
-            'bg-surface dark:bg-dark-bg',
+            'surface-canvas',
             isOpen ? 'w-80 opacity-100' : 'w-0 opacity-0',
-            'transition-[width,opacity] duration-300 ease-out',
+            'transition-[width,opacity] duration-slow ease-out',
             className,
         )}
     >

src/shared/ui/Slider/Slider.svelte

@@ -70,17 +70,17 @@ let {
 const isVertical = $derived(orientation === 'vertical');
 
 const labelClasses = `font-mono text-2xs tabular-nums shrink-0
-    text-secondary
+    text-subtle
     group-hover:text-neutral-700 dark:group-hover:text-neutral-300
     transition-colors`;
 
 const thumbClasses = `block w-2.5 h-2.5 bg-brand
-    rotate-45 shadow-sm
+    rotate-45 shadow-rest
     hover:scale-125
     focus-visible:outline-none
     focus-visible:ring-2 focus-visible:ring-brand/20
     data-active:scale-90
-    transition-transform duration-150
+    transition-transform duration-fast
     disabled:pointer-events-none disabled:opacity-50
     cursor-grab active:cursor-grabbing`;
 </script>

src/widgets/ComparisonView/ui/FontList/FontList.svelte

@@ -110,28 +110,28 @@ function isFontReady(font: UnifiedFont): boolean {
                         <div class="w-full px-3 py-3 flex items-center justify-between">
                             <div class="flex-1 flex items-center gap-3">
                                 <Skeleton
-                                    class="h-4 w-32 bg-neutral-200/70 dark:bg-neutral-800/70"
+                                    class="h-4 w-32 skeleton-fill"
                                     style="width: {getSkeletonWidth(index)}"
                                 />
                             </div>
-                            <Skeleton class="w-1.5 h-1.5 rounded-full bg-neutral-200/70 dark:bg-neutral-800/70" />
+                            <Skeleton class="w-1.5 h-1.5 rounded-full skeleton-fill" />
                         </div>
                     {/each}
                 </div>
             {/snippet}
 
             {#snippet children({ item: font, index })}
-                <div class="relative h-[44px] w-full">
+                <div class="relative h-11 w-full">
                     {#if !isFontReady(font)}
                         <div
                             class="absolute inset-0 px-3 md:px-4 flex items-center justify-between border border-transparent"
                             transition:fade={{ duration: 300 }}
                         >
                             <Skeleton
-                                class="h-4 bg-neutral-200/70 dark:bg-neutral-800/70"
+                                class="h-4 skeleton-fill"
                                 style="width: {getSkeletonWidth(index)}"
                             />
-                            <Skeleton class="w-1.5 h-1.5 rounded-full bg-neutral-200/70 dark:bg-neutral-800/70" />
+                            <Skeleton class="w-1.5 h-1.5 rounded-full skeleton-fill" />
                         </div>
                     {:else}
                         {@const isSelectedA = font.id === comparisonStore.fontA?.id}
@@ -141,9 +141,10 @@ function isFontReady(font: UnifiedFont): boolean {
                         <div transition:fade={{ duration: 300 }} class="h-full">
                             <Button
                                 variant="tertiary"
+                                layout="block-list-row"
                                 {active}
                                 onclick={() => handleSelect(font)}
-                                class="w-full h-full px-3 md:px-4 py-2.5 md:py-3 flex !justify-between text-left text-sm"
+                                class="h-full"
                                 iconPosition="right"
                             >
                                 <FontApplicator {font}>

src/widgets/ComparisonView/ui/Header/Header.svelte

@@ -53,7 +53,7 @@ const fontBName = $derived(comparisonStore.fontB?.name ?? '');
         'px-4 md:px-8 py-4 md:py-6',
         'h-16 md:h-20 z-20',
         'border-b border-subtle',
-        'bg-surface dark:bg-dark-bg',
+        'surface-canvas',
         className,
     )}
 >

src/widgets/ComparisonView/ui/Search/Search.svelte

@@ -9,7 +9,7 @@ import { appliedFilterStore } from '$features/FilterAndSortFonts';
 import { SearchBar } from '$shared/ui';
 </script>
 
-<div class="p-6 border-b border-black/5">
+<div class="p-6 border-b border-subtle">
     <SearchBar
         id="font-search"
         class="w-full"

src/widgets/ComparisonView/ui/Sidebar/Sidebar.svelte

@@ -43,7 +43,7 @@ let {
     class={cn(
         'flex flex-col h-full',
         'w-80',
-        'bg-surface dark:bg-dark-bg',
+        'surface-canvas',
         'border-r border-subtle',
         'transition-colors duration-500',
         className,
@@ -54,7 +54,7 @@ let {
         class="
             p-6 shrink-0
             border-b border-subtle
-            bg-surface dark:bg-dark-bg
+            surface-canvas
         "
     >
         <!-- Title -->
@@ -90,7 +90,7 @@ let {
     </div>
 
     <!-- ── Main: content area (no scroll - VirtualList handles scrolling) ─────────────────────────────── -->
-    <div class="flex-1 min-h-0 bg-surface dark:bg-dark-bg">
+    <div class="flex-1 min-h-0 surface-canvas">
         {#if main}
             {@render main()}
         {/if}
@@ -101,7 +101,7 @@ let {
         <div
             class="
                 shrink-0 p-6
-                bg-surface dark:bg-dark-bg
+                surface-canvas
                 border-t border-subtle
                 z-10
             "

src/widgets/ComparisonView/ui/SliderArea/SliderArea.svelte

@@ -70,6 +70,19 @@ const SLIDER_PERSIST_DEBOUNCE_MS = 100;
 const SLIDER_PADDING_MOBILE_PX = 48;
 const SLIDER_PADDING_DESKTOP_PX = 96;
 
+/**
+ * Position bounds (percent of container width).
+ */
+const SLIDER_MIN = 0;
+const SLIDER_MAX = 100;
+
+/**
+ * Fine and coarse keyboard step sizes. Shift / Page keys use the coarse
+ * step; bare arrow keys use the fine step.
+ */
+const SLIDER_STEP_FINE = 1;
+const SLIDER_STEP_COARSE = 10;
+
 const fontA = $derived(comparisonStore.fontA);
 const fontB = $derived(comparisonStore.fontB);
 const isLoading = $derived(comparisonStore.isLoading || !comparisonStore.isReady);
@@ -130,6 +143,46 @@ function startDragging(e: PointerEvent) {
     handleMove(e);
 }
 
+/**
+ * Keyboard control for the comparison slider. Implements the standard
+ * ARIA slider keyboard contract: arrows step the position, Shift+arrow
+ * and PageUp/PageDown jump by the coarse step, Home/End snap to bounds.
+ */
+function handleKeydown(e: KeyboardEvent) {
+    const coarse = e.shiftKey;
+    const step = coarse ? SLIDER_STEP_COARSE : SLIDER_STEP_FINE;
+    const current = sliderSpring.target;
+    let next = current;
+
+    switch (e.key) {
+        case 'ArrowLeft':
+        case 'ArrowDown':
+            next = current - step;
+            break;
+        case 'ArrowRight':
+        case 'ArrowUp':
+            next = current + step;
+            break;
+        case 'PageDown':
+            next = current - SLIDER_STEP_COARSE;
+            break;
+        case 'PageUp':
+            next = current + SLIDER_STEP_COARSE;
+            break;
+        case 'Home':
+            next = SLIDER_MIN;
+            break;
+        case 'End':
+            next = SLIDER_MAX;
+            break;
+        default:
+            return;
+    }
+
+    e.preventDefault();
+    sliderSpring.target = Math.max(SLIDER_MIN, Math.min(SLIDER_MAX, next));
+}
+
 const storeSliderPosition = debounce((value: number) => {
     comparisonStore.sliderPosition = value;
 }, SLIDER_PERSIST_DEBOUNCE_MS);
@@ -213,47 +266,37 @@ $effect(() => {
         cancelled = true;
     };
 });
-
-// Dynamic backgroundSize based on isMobile — can't express this in Tailwind.
-// Color is set to currentColor so it respects dark mode via text color.
-const gridStyle = $derived(
-    `background-image: linear-gradient(currentColor 1px, transparent 1px), linear-gradient(90deg, currentColor 1px, transparent 1px); `
-        + `background-size: ${isMobile ? '10px 10px' : '20px 20px'};`,
-);
-
-// Replaces motion.div animate={{ scale: isSidebarOpen && !isMobile ? 0.94 :1 }}
-const scaleClass = $derived(
-    isSidebarOpen && !isMobile
-        ? 'scale-[0.94]'
-        : 'scale-100',
-);
 </script>
 
 <!--
     Outer flex container — fills parent.
-    The paper div inside scales down when the sidebar opens on desktop.
+    Pads in when the sidebar opens on desktop, insetting the paper evenly.
 -->
-<div class={cn('flex-1 relative flex items-center justify-center p-0 overflow-hidden bg-surface dark:bg-dark-bg', className)}>
+<div
+    class={cn(
+        'flex-1 relative flex-center overflow-hidden surface-canvas',
+        'transition-[padding] duration-slow ease-out',
+        isSidebarOpen && !isMobile ? 'p-6' : 'p-0',
+        className,
+    )}
+>
     <!-- Paper surface -->
     <div
         class={cn(
-            'w-full h-full flex flex-col items-center justify-center relative',
+            'w-full h-full flex flex-col flex-center relative',
             'bg-paper dark:bg-dark-card',
-            'shadow-2xl shadow-black/5 dark:shadow-black/20',
+            'shadow-floating-panel dark:shadow-floating-panel-dark',
-            'transition-transform duration-300 ease-out',
-            scaleClass,
         )}
     >
-        <!-- Subtle grid overlay — pointer-events-none, very low opacity -->
+        <!-- Subtle dotted-grid overlay — purely decorative. -->
         <div
-            class="absolute inset-0 pointer-events-none opacity-[0.03] dark:opacity-[0.05] text-swiss-black dark:text-swiss-white"
+            class="absolute inset-0 pointer-events-none bg-grid-sm md:bg-grid"
-            style={gridStyle}
             aria-hidden="true"
         >
         </div>
 
         <!-- Slider interaction area -->
-        <div class="w-full h-full flex items-center justify-center p-4 md:p-8 overflow-hidden">
+        <div class="w-full h-full flex items-center justify-center p-4 md:p-12 overflow-hidden">
             {#if isLoading}
                 <div out:fade={{ duration: 300 }}>
                     <Loader size={24} />
@@ -264,8 +307,12 @@ const scaleClass = $derived(
                     role="slider"
                     tabindex="0"
                     aria-valuenow={Math.round(sliderPos)}
+                    aria-valuemin={SLIDER_MIN}
+                    aria-valuemax={SLIDER_MAX}
+                    aria-orientation="horizontal"
                     aria-label="Font comparison slider"
                     onpointerdown={startDragging}
+                    onkeydown={handleKeydown}
                     class="
                         relative w-full max-w-6xl h-full
                         flex flex-col justify-center

src/widgets/ComparisonView/ui/Thumb/Thumb.svelte

@@ -36,9 +36,9 @@ let { sliderPos, isDragging }: Props = $props();
             '-ml-2.5 md:-ml-3',
             'mt-2 md:mt-4',
             'bg-brand text-white',
-            'flex items-center justify-center',
+            'flex-center',
             'rounded-none shadow-md',
-            'transition-transform duration-150',
+            'transition-transform duration-fast',
             isDragging ? 'scale-110' : 'scale-100',
         )}
     >
@@ -52,9 +52,9 @@ let { sliderPos, isDragging }: Props = $props();
             '-ml-2.5 md:-ml-3',
             'mb-2 md:mb-4',
             'bg-brand text-white',
-            'flex items-center justify-center',
+            'flex-center',
             'rounded-none shadow-md',
-            'transition-transform duration-150',
+            'transition-transform duration-fast',
             isDragging ? 'scale-110' : 'scale-100',
         )}
     >

src/widgets/FontSearch/ui/FontSearch/FontSearch.svelte

@@ -51,8 +51,8 @@ function toggleFilters() {
 }
 </script>
 
-<div class="flex flex-col gap-3 border-b border-t border-swiss-black/5 dark:border-white/10">
+<div class="flex flex-col gap-3 border-b border-t border-subtle">
-    <div class="relative w-full flex flex-col md:flex-row gap-y-4 border-b border-swiss-black/5 dark:border-white/10 py-4 md:py-6">
+    <div class="relative w-full flex flex-col md:flex-row gap-y-4 border-b border-subtle py-4 md:py-6">
         <SearchBar
             id="font-search"
             class="w-full"

src/widgets/Footer/ui/Footer/Footer.svelte

@@ -14,15 +14,19 @@ const isVertical = $derived(responsive?.isDesktop || responsive?.isDesktopLarge)
 const currentYear = new Date().getFullYear();
 </script>
 
+<!--
+    z-20 keeps the footer below the sidebar's mobile/tablet overlay
+    (z-40) and panel (z-50) so an open sidebar fully covers the link.
+-->
 <footer
     class={cn(
-        'fixed z-10 flex flex-row items-end gap-1 pointer-events-none',
+        'fixed z-20 flex flex-row items-end gap-1 pointer-events-none',
         isVertical ? 'bottom-2.5 right-2.5 [writing-mode:vertical-rl] rotate-180' : 'bottom-4 left-4',
     )}
 >
     <!-- Project Name (Horizontal) -->
     {#if isVertical}
-        <div class="flex flex-row pointer-events-auto items-center gap-2 bg-surface/80 dark:bg-dark-bg/80 backdrop-blur-sm px-2 py-1 border border-subtle">
+        <div class="flex flex-row pointer-events-auto items-center gap-2 surface-floating backdrop-blur-sm px-2 py-1">
             <div class="w-1.5 h-1.5 bg-brand"></div>
             <span class="text-2xs font-mono uppercase tracking-wider-mono text-neutral-500 dark:text-neutral-400">
                 GlyphDiff © 2025 — {currentYear}

src/widgets/SampleList/ui/SampleList/SampleList.svelte

@@ -84,7 +84,7 @@ const fontRowHeight = $derived.by(() =>
 {#snippet skeleton()}
     <div class="flex flex-col gap-3 sm:gap-4 p-3 sm:p-4">
         {#each Array(5) as _, i}
-            <div class="flex flex-col gap-1.5 sm:gap-2 p-3 sm:p-4 border rounded-lg sm:rounded-xl border-border-subtle bg-background-40">
+            <div class="flex flex-col gap-1.5 sm:gap-2 p-3 sm:p-4 border rounded-lg sm:rounded-xl border-subtle bg-background/40">
                 <div class="flex items-center justify-between mb-3 sm:mb-4">
                     <Skeleton class="h-6 sm:h-8 w-1/3" />
                     <Skeleton class="h-6 sm:h-8 w-6 sm:w-8 rounded-full" />