feat(S02): modern UI design system — theme overhaul, skeletons, animations

- Redesigned theme.css: deeper darks (#0f1117), glassmorphism tokens,
  accent glow, softer borders (rgba), spring/slow transitions, new radii
- Added Inter + JetBrains Mono web fonts for premium typography
- Enhanced global.css: focus rings with box-shadow, skeleton shimmer animation,
  glass-card class, fade-in page transitions, slide-up animations, badge-glow pulse
- Created Skeleton component library: Skeleton, SkeletonRow, SkeletonTable,
  SkeletonChannelHeader, SkeletonChannelsList
- Replaced spinner-text loading states with skeleton placeholders
  (Channels page, ChannelDetail header and content table)
- Updated all card border-radius from radius-lg to radius-xl across all pages
- Added responsive breakpoint stub for mobile (768px)

src/frontend/src/components/Skeleton.tsx

@@ -0,0 +1,111 @@
+/**
+ * Skeleton loading placeholder components.
+ * Uses the .skeleton CSS class for shimmer animation.
+ */
+
+interface SkeletonProps {
+  width?: string | number;
+  height?: string | number;
+  borderRadius?: string;
+  style?: React.CSSProperties;
+}
+
+/** Generic skeleton block. */
+export function Skeleton({ width = '100%', height = 16, borderRadius, style }: SkeletonProps) {
+  return (
+    <div
+      className="skeleton"
+      style={{
+        width,
+        height,
+        borderRadius: borderRadius ?? 'var(--radius-md)',
+        ...style,
+      }}
+    />
+  );
+}
+
+/** Skeleton for a table row. */
+export function SkeletonRow({ columns = 6 }: { columns?: number }) {
+  return (
+    <tr>
+      {Array.from({ length: columns }).map((_, i) => (
+        <td key={i}>
+          <Skeleton
+            width={i === 0 ? 32 : i === 1 ? '70%' : '50%'}
+            height={i === 0 ? 32 : 14}
+            borderRadius={i === 0 ? '50%' : undefined}
+          />
+        </td>
+      ))}
+    </tr>
+  );
+}
+
+/** Skeleton for the full content table. */
+export function SkeletonTable({ rows = 8, columns = 6 }: { rows?: number; columns?: number }) {
+  return (
+    <div style={{ padding: 'var(--space-4)' }}>
+      <table style={{ width: '100%' }}>
+        <tbody>
+          {Array.from({ length: rows }).map((_, i) => (
+            <SkeletonRow key={i} columns={columns} />
+          ))}
+        </tbody>
+      </table>
+    </div>
+  );
+}
+
+/** Skeleton for the channel detail header. */
+export function SkeletonChannelHeader() {
+  return (
+    <div
+      style={{
+        display: 'flex',
+        gap: 'var(--space-5)',
+        padding: 'var(--space-5)',
+        backgroundColor: 'var(--bg-card)',
+        borderRadius: 'var(--radius-xl)',
+        border: '1px solid var(--border)',
+        marginBottom: 'var(--space-6)',
+      }}
+    >
+      <Skeleton width={80} height={80} borderRadius="50%" />
+      <div style={{ flex: 1, display: 'flex', flexDirection: 'column', gap: 'var(--space-3)' }}>
+        <Skeleton width={200} height={24} />
+        <Skeleton width={300} height={14} />
+        <div style={{ display: 'flex', gap: 'var(--space-3)', marginTop: 'var(--space-2)' }}>
+          <Skeleton width={120} height={32} borderRadius="var(--radius-md)" />
+          <Skeleton width={120} height={32} borderRadius="var(--radius-md)" />
+          <Skeleton width={100} height={32} borderRadius="var(--radius-md)" />
+        </div>
+      </div>
+    </div>
+  );
+}
+
+/** Skeleton for the channels list page. */
+export function SkeletonChannelsList({ rows = 4 }: { rows?: number }) {
+  return (
+    <div>
+      <div style={{ display: 'flex', justifyContent: 'space-between', marginBottom: 'var(--space-6)' }}>
+        <Skeleton width={120} height={28} />
+        <div style={{ display: 'flex', gap: 'var(--space-3)' }}>
+          <Skeleton width={110} height={34} borderRadius="var(--radius-md)" />
+          <Skeleton width={140} height={34} borderRadius="var(--radius-md)" />
+        </div>
+      </div>
+      <div
+        style={{
+          backgroundColor: 'var(--bg-card)',
+          borderRadius: 'var(--radius-xl)',
+          border: '1px solid var(--border)',
+          overflow: 'hidden',
+        }}
+      >
+        <SkeletonTable rows={rows} columns={7} />
+      </div>
+    </div>
+  );
+}

src/frontend/src/pages/ChannelDetail.tsx

@@ -28,6 +28,7 @@ import { PlatformBadge } from '../components/PlatformBadge';
 import { StatusBadge } from '../components/StatusBadge';
 import { QualityLabel } from '../components/QualityLabel';
 import { DownloadProgressBar } from '../components/DownloadProgressBar';
+import { SkeletonChannelHeader, SkeletonTable } from '../components/Skeleton';
 import { Pagination } from '../components/Pagination';
 import { Modal } from '../components/Modal';
 import { useDownloadProgress } from '../contexts/DownloadProgressContext';
@@ -667,9 +668,11 @@ export function ChannelDetail() {
 
   if (channelLoading) {
     return (
-      <div style={{ display: 'flex', alignItems: 'center', justifyContent: 'center', padding: 'var(--space-12)', color: 'var(--text-muted)' }}>
-        <Loader size={20} style={{ animation: 'spin 1s linear infinite', marginRight: 'var(--space-3)' }} />
-        Loading channel...
+      <div>
+        <SkeletonChannelHeader />
+        <div style={{ backgroundColor: 'var(--bg-card)', borderRadius: 'var(--radius-xl)', border: '1px solid var(--border)', overflow: 'hidden' }}>
+          <SkeletonTable rows={10} columns={8} />
+        </div>
       </div>
     );
   }
@@ -735,7 +738,7 @@ export function ChannelDetail() {
           gap: 'var(--space-5)',
           padding: 'var(--space-5)',
           backgroundColor: 'var(--bg-card)',
-          borderRadius: 'var(--radius-lg)',
+          borderRadius: 'var(--radius-xl)',
           border: '1px solid var(--border)',
           marginBottom: 'var(--space-6)',
           alignItems: 'flex-start',
@@ -1030,7 +1033,7 @@ export function ChannelDetail() {
       <div
         style={{
           backgroundColor: 'var(--bg-card)',
-          borderRadius: 'var(--radius-lg)',
+          borderRadius: 'var(--radius-xl)',
           border: '1px solid var(--border)',
           overflow: 'hidden',
         }}
@@ -1157,10 +1160,7 @@ export function ChannelDetail() {
           </div>
         ) : null}
         {contentLoading ? (
-          <div style={{ display: 'flex', alignItems: 'center', justifyContent: 'center', padding: 'var(--space-8)', color: 'var(--text-muted)' }}>
-            <Loader size={18} style={{ animation: 'spin 1s linear infinite', marginRight: 'var(--space-3)' }} />
-            Loading content...
-          </div>
+          <SkeletonTable rows={8} columns={8} />
         ) : hasPlaylistGroups ? (
           renderPlaylistGroups(playlistGroups!)
         ) : (
@@ -1196,7 +1196,7 @@ export function ChannelDetail() {
             padding: 'var(--space-3) var(--space-5)',
             backgroundColor: 'var(--bg-card)',
             border: '1px solid var(--border)',
-            borderRadius: 'var(--radius-lg)',
+            borderRadius: 'var(--radius-xl)',
             boxShadow: 'var(--shadow-lg)',
           }}
         >

src/frontend/src/pages/Channels.tsx

@@ -8,6 +8,7 @@ import { PlatformBadge } from '../components/PlatformBadge';
 import { StatusBadge } from '../components/StatusBadge';
 import { ProgressBar } from '../components/ProgressBar';
 import { AddChannelModal } from '../components/AddChannelModal';
+import { SkeletonChannelsList } from '../components/Skeleton';
 import type { ChannelWithCounts } from '@shared/types/api';
 
 // ── Helpers ──
@@ -184,12 +185,7 @@ export function Channels() {
   );
 
   if (isLoading) {
-    return (
-      <div style={{ display: 'flex', alignItems: 'center', justifyContent: 'center', padding: 'var(--space-12)', color: 'var(--text-muted)' }}>
-        <Loader size={20} style={{ animation: 'spin 1s linear infinite', marginRight: 'var(--space-3)' }} />
-        Loading channels...
-      </div>
-    );
+    return <SkeletonChannelsList />;
   }
 
   if (error) {
@@ -339,7 +335,7 @@ export function Channels() {
       <div
         style={{
           backgroundColor: 'var(--bg-card)',
-          borderRadius: 'var(--radius-lg)',
+          borderRadius: 'var(--radius-xl)',
           border: '1px solid var(--border)',
           overflow: 'hidden',
         }}

src/frontend/src/pages/Settings.tsx

@@ -725,7 +725,7 @@ export function SettingsPage() {
         <div
           style={{
             backgroundColor: 'var(--bg-card)',
-            borderRadius: 'var(--radius-lg)',
+            borderRadius: 'var(--radius-xl)',
             border: '1px solid var(--border)',
             overflow: 'hidden',
           }}
@@ -963,7 +963,7 @@ export function SettingsPage() {
         <div
           style={{
             backgroundColor: 'var(--bg-card)',
-            borderRadius: 'var(--radius-lg)',
+            borderRadius: 'var(--radius-xl)',
             border: '1px solid var(--border)',
             overflow: 'hidden',
           }}
@@ -1015,7 +1015,7 @@ export function SettingsPage() {
         <div
           style={{
             backgroundColor: 'var(--bg-card)',
-            borderRadius: 'var(--radius-lg)',
+            borderRadius: 'var(--radius-xl)',
             border: '1px solid var(--border)',
             overflow: 'hidden',
           }}
@@ -1068,7 +1068,7 @@ export function SettingsPage() {
         <div
           style={{
             backgroundColor: 'var(--bg-card)',
-            borderRadius: 'var(--radius-lg)',
+            borderRadius: 'var(--radius-xl)',
             border: '1px solid var(--border)',
             overflow: 'hidden',
           }}

src/frontend/src/styles/global.css

@@ -1,5 +1,6 @@
 /* ── Global Reset & Base Styles ── */
 @import './theme.css';
+@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&family=JetBrains+Mono:wght@400;500&display=swap');
 
 *,
 *::before,
@@ -13,6 +14,7 @@ html {
   font-size: 16px;
   -webkit-font-smoothing: antialiased;
   -moz-osx-font-smoothing: grayscale;
+  text-rendering: optimizeLegibility;
 }
 
 body {
@@ -22,6 +24,7 @@ body {
   background-color: var(--bg-main);
   line-height: 1.5;
   min-height: 100vh;
+  letter-spacing: -0.01em;
 }
 
 #root {
@@ -32,6 +35,7 @@ body {
 a {
   color: var(--text-link);
   text-decoration: none;
+  transition: color var(--transition-fast);
 }
 
 a:hover {
@@ -42,25 +46,26 @@ a:hover {
 :focus-visible {
   outline: 2px solid var(--accent);
   outline-offset: 2px;
+  border-radius: var(--radius-sm);
 }
 
 /* ── Scrollbar styling ── */
 ::-webkit-scrollbar {
-  width: 8px;
-  height: 8px;
+  width: 6px;
+  height: 6px;
 }
 
 ::-webkit-scrollbar-track {
-  background: var(--bg-main);
+  background: transparent;
 }
 
 ::-webkit-scrollbar-thumb {
-  background: var(--border-light);
-  border-radius: 4px;
+  background: rgba(255, 255, 255, 0.08);
+  border-radius: 3px;
 }
 
 ::-webkit-scrollbar-thumb:hover {
-  background: var(--text-muted);
+  background: rgba(255, 255, 255, 0.15);
 }
 
 /* ── Buttons base ── */
@@ -71,6 +76,7 @@ button {
   border: none;
   background: none;
   color: inherit;
+  transition: all var(--transition-fast);
 }
 
 /* ── Inputs base ── */
@@ -81,15 +87,17 @@ select {
   font-size: inherit;
   color: var(--text-primary);
   background-color: var(--bg-input);
-  border: 1px solid var(--border);
+  border: 1px solid var(--border-light);
   border-radius: var(--radius-md);
   padding: var(--space-2) var(--space-3);
+  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
 }
 
 input:focus,
 textarea:focus,
 select:focus {
   border-color: var(--accent);
+  box-shadow: 0 0 0 3px var(--accent-subtle);
   outline: none;
 }
 
@@ -106,10 +114,10 @@ table {
 th {
   text-align: left;
   font-weight: 600;
-  font-size: var(--font-size-sm);
-  color: var(--text-secondary);
+  font-size: var(--font-size-xs);
+  color: var(--text-muted);
   text-transform: uppercase;
-  letter-spacing: 0.03em;
+  letter-spacing: 0.06em;
   padding: var(--space-3) var(--space-4);
   border-bottom: 1px solid var(--border);
 }
@@ -136,6 +144,43 @@ tr:hover {
   border-width: 0;
 }
 
+/* ── Glassmorphism card ── */
+.glass-card {
+  background: var(--glass-bg);
+  backdrop-filter: blur(var(--glass-blur));
+  -webkit-backdrop-filter: blur(var(--glass-blur));
+  border: 1px solid var(--glass-border);
+  border-radius: var(--radius-xl);
+}
+
+/* ── Skeleton loader ── */
+.skeleton {
+  background: linear-gradient(
+    90deg,
+    var(--bg-input) 25%,
+    rgba(255, 255, 255, 0.04) 50%,
+    var(--bg-input) 75%
+  );
+  background-size: 200% 100%;
+  animation: skeleton-shimmer 1.8s ease-in-out infinite;
+  border-radius: var(--radius-md);
+}
+
+@keyframes skeleton-shimmer {
+  0% { background-position: 200% 0; }
+  100% { background-position: -200% 0; }
+}
+
+/* ── Status badge glow ── */
+.badge-pulse {
+  animation: badge-glow 2s ease-in-out infinite;
+}
+
+@keyframes badge-glow {
+  0%, 100% { box-shadow: none; }
+  50% { box-shadow: 0 0 8px var(--accent-glow); }
+}
+
 /* ── Animations ── */
 @keyframes pulse {
   0%, 100% { opacity: 1; }
@@ -146,3 +191,34 @@ tr:hover {
   from { transform: rotate(0deg); }
   to { transform: rotate(360deg); }
 }
+
+@keyframes fade-in {
+  from { opacity: 0; transform: translateY(4px); }
+  to { opacity: 1; transform: translateY(0); }
+}
+
+@keyframes slide-up {
+  from { opacity: 0; transform: translateY(12px); }
+  to { opacity: 1; transform: translateY(0); }
+}
+
+/* ── Page transition ── */
+main {
+  animation: fade-in 200ms ease-out;
+}
+
+/* ── Table row transitions ── */
+tbody tr {
+  transition: background-color var(--transition-fast);
+}
+
+tbody tr:hover {
+  background-color: var(--bg-hover);
+}
+
+/* ── Responsive ── */
+@media (max-width: 768px) {
+  :root {
+    --sidebar-width: 0px;
+  }
+}

src/frontend/src/styles/theme.css

@@ -1,56 +1,60 @@
 /* ── *arr Dark Theme ──
- * Color palette matching Sonarr/Radarr aesthetic.
+ * Color palette matching Sonarr/Radarr aesthetic with modern glassmorphism touches.
  * All UI components reference these custom properties.
  */
 
 :root {
   /* ── Backgrounds ── */
-  --bg-main: #1a1d23;
-  --bg-sidebar: #14161a;
-  --bg-card: #242731;
-  --bg-input: #2a2e38;
-  --bg-hover: #2f3341;
-  --bg-selected: #35394a;
-  --bg-header: #1e2029;
-  --bg-toolbar: #1e2129;
-  --bg-modal-overlay: rgba(0, 0, 0, 0.6);
+  --bg-main: #0f1117;
+  --bg-sidebar: #0a0c10;
+  --bg-card: rgba(30, 33, 44, 0.8);
+  --bg-card-solid: #1e212c;
+  --bg-input: #1a1d26;
+  --bg-hover: rgba(255, 255, 255, 0.04);
+  --bg-selected: rgba(255, 255, 255, 0.08);
+  --bg-header: #13151c;
+  --bg-toolbar: #13151c;
+  --bg-modal-overlay: rgba(0, 0, 0, 0.7);
+  --bg-glass: rgba(20, 22, 30, 0.6);
 
   /* ── Accent ── */
   --accent: #e05d44;
-  --accent-hover: #c94e38;
-  --accent-subtle: rgba(224, 93, 68, 0.12);
+  --accent-hover: #f06a51;
+  --accent-subtle: rgba(224, 93, 68, 0.1);
+  --accent-glow: rgba(224, 93, 68, 0.25);
 
   /* ── Text ── */
-  --text-primary: #e1e2e6;
+  --text-primary: #e8e9ed;
   --text-secondary: #8b8d97;
-  --text-muted: #5d5f69;
-  --text-inverse: #14161a;
+  --text-muted: #4d5060;
+  --text-inverse: #0f1117;
   --text-link: #e05d44;
 
   /* ── Status colors ── */
-  --success: #27c24c;
-  --success-bg: rgba(39, 194, 76, 0.12);
-  --warning: #ff902b;
-  --warning-bg: rgba(255, 144, 43, 0.12);
+  --success: #34d058;
+  --success-bg: rgba(52, 208, 88, 0.1);
+  --warning: #ff9f43;
+  --warning-bg: rgba(255, 159, 67, 0.1);
   --danger: #f05050;
-  --danger-bg: rgba(240, 80, 80, 0.12);
+  --danger-bg: rgba(240, 80, 80, 0.1);
   --info: #e05d44;
-  --info-bg: rgba(224, 93, 68, 0.12);
+  --info-bg: rgba(224, 93, 68, 0.1);
 
   /* ── Borders ── */
-  --border: #2d3040;
-  --border-light: #373b4e;
+  --border: rgba(255, 255, 255, 0.06);
+  --border-light: rgba(255, 255, 255, 0.1);
+  --border-accent: rgba(224, 93, 68, 0.3);
 
   /* ── Typography ── */
-  --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
-  --font-mono: 'SFMono-Regular', Consolas, 'Liberation Mono', Menlo, monospace;
-  --font-size-xs: 0.75rem;
+  --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
+  --font-mono: 'JetBrains Mono', 'SFMono-Regular', Consolas, 'Liberation Mono', Menlo, monospace;
+  --font-size-xs: 0.6875rem;
   --font-size-sm: 0.8125rem;
   --font-size-base: 0.875rem;
   --font-size-md: 1rem;
   --font-size-lg: 1.125rem;
-  --font-size-xl: 1.25rem;
-  --font-size-2xl: 1.5rem;
+  --font-size-xl: 1.375rem;
+  --font-size-2xl: 1.75rem;
 
   /* ── Spacing ── */
   --space-1: 0.25rem;
@@ -64,22 +68,32 @@
   --space-12: 3rem;
 
   /* ── Border Radius ── */
-  --radius-sm: 3px;
-  --radius-md: 4px;
-  --radius-lg: 6px;
-  --radius-xl: 8px;
+  --radius-sm: 4px;
+  --radius-md: 6px;
+  --radius-lg: 10px;
+  --radius-xl: 14px;
+  --radius-2xl: 20px;
+  --radius-full: 9999px;
 
   /* ── Shadows ── */
-  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
-  --shadow-md: 0 2px 8px rgba(0, 0, 0, 0.3);
-  --shadow-lg: 0 4px 16px rgba(0, 0, 0, 0.4);
+  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.4), 0 1px 2px rgba(0, 0, 0, 0.3);
+  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.4);
+  --shadow-lg: 0 8px 30px rgba(0, 0, 0, 0.5);
+  --shadow-glow: 0 0 20px rgba(224, 93, 68, 0.15);
 
   /* ── Layout ── */
-  --sidebar-width: 210px;
-  --sidebar-collapsed: 50px;
-  --header-height: 55px;
+  --sidebar-width: 220px;
+  --sidebar-collapsed: 56px;
+  --header-height: 56px;
 
   /* ── Transitions ── */
-  --transition-fast: 150ms ease;
-  --transition-normal: 250ms ease;
+  --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
+  --transition-normal: 250ms cubic-bezier(0.4, 0, 0.2, 1);
+  --transition-slow: 400ms cubic-bezier(0.4, 0, 0.2, 1);
+  --transition-spring: 500ms cubic-bezier(0.34, 1.56, 0.64, 1);
+
+  /* ── Glassmorphism ── */
+  --glass-blur: 12px;
+  --glass-bg: rgba(20, 22, 30, 0.6);
+  --glass-border: rgba(255, 255, 255, 0.08);
 }