diff --git a/client/src/loading.ts b/client/src/loading.ts
new file mode 100644
index 0000000..e70c326
--- /dev/null
+++ b/client/src/loading.ts
@@ -0,0 +1,17 @@
+// Shared "Chargement..." placeholder - spinner + text, see .spinner in
+// styles/base.css for the actual CSS ring (no image/icon-font asset, just
+// a bordered circle animated with a plain @keyframes rotation). One
+// constant so every route/section that fetches before it has anything
+// real to show (Album/Artist/Library/Playlist/Series's own route entry,
+// Home's per-library carousels) renders the exact same markup instead of
+// each hand-typing a slightly different one - a plain-text .hide/.hint
+// mismatch is exactly the kind of drift a shared constant avoids.
+//
+// The sidebar's own library list (Shell.html) and Player.ts's video-
+// buffering notice (Player.html's #loadingNotice) don't use this: the
+// sidebar's markup is a static template with no JS import of its own
+// (see Shell.html directly - same spinner markup, just pasted once by
+// hand instead of imported), and the video notice is already a distinct,
+// separately-styled centered overlay with its own text ("Chargement du
+// flux..."), not a plain in-flow <p class="hint">.
+export const LOADING_HINT = '<p class="hint"><span class="spinner"></span>Chargement...</p>';
diff --git a/client/src/shell/Shell.html b/client/src/shell/Shell.html
index de9bd4e..9fa156a 100644
--- a/client/src/shell/Shell.html
+++ b/client/src/shell/Shell.html
@@ -4,7 +4,7 @@
     <nav class="sidebarNav" id="sidebarNav">
       <a href="#/home" class="navItem">Accueil</a>
       <div class="navSectionLabel">Bibliothèques</div>
-      <p class="hint" id="libStatus">Chargement...</p>
+      <p class="hint" id="libStatus"><span class="spinner"></span>Chargement...</p>
     </nav>
     <button class="linklike sidebarLogout" id="logout"></button>
   </aside>
diff --git a/client/src/styles/base.css b/client/src/styles/base.css
index 92e550d..5748950 100644
--- a/client/src/styles/base.css
+++ b/client/src/styles/base.css
@@ -51,6 +51,33 @@ h2 { font-size: 16px; margin: 0 0 12px; }
 .hint { color: var(--muted); font-size: 13px; margin: 0 0 16px; }
 .error { color: var(--danger); font-size: 13px; min-height: 18px; }
 
+/* Plain CSS ring, not an image/icon-font asset - `display: inline-block`
+   + `vertical-align` so it drops into an existing text node (a .hint's
+   "Chargement...", Player.css's own .loadingNotice) without needing to
+   restructure the element into a flex row - see loading.ts's LOADING_HINT
+   for the one shared constant most call sites use instead of hand-typing
+   this markup. `prefers-reduced-motion` gets a static ring instead of an
+   endless spin, same reasoning as this app avoiding motion elsewhere. */
+.spinner {
+  display: inline-block;
+  vertical-align: -3px;
+  width: 14px;
+  height: 14px;
+  margin-right: 8px;
+  border: 2px solid rgba(255, 255, 255, .25);
+  border-top-color: var(--accent);
+  border-radius: 50%;
+  animation: spin .7s linear infinite;
+}
+
+@keyframes spin {
+  to { transform: rotate(360deg); }
+}
+
+@media (prefers-reduced-motion: reduce) {
+  .spinner { animation: none; }
+}
+
 label {
   display: block;
   font-size: 13px;
diff --git a/client/src/views/album/Album.ts b/client/src/views/album/Album.ts
index eafdf1c..7876e3b 100644
--- a/client/src/views/album/Album.ts
+++ b/client/src/views/album/Album.ts
@@ -5,6 +5,7 @@ import { getAlbumTracks, getItem } from '../../api/embyApi';
 import { addTrackToQueue, createParty } from '../../api/party';
 import { getActiveMusicPartyId, joinMusicParty } from '../../musicBar/MusicBar';
 import { escapeHtml, formatDuration, wireSearchFilter } from '../../tiles';
+import { LOADING_HINT } from '../../loading';
 import type { ItemDto, MusicTrackInput } from '../../types';
 import type { RouteParams } from '../../router';
 
@@ -16,7 +17,7 @@ const TICKS_PER_SECOND = 10000000; // Emby/.NET convention: 1 tick = 100ns, same
  *  series' seasons do). */
 export async function renderAlbum(root: HTMLElement, params: RouteParams): Promise<void> {
   const albumId = params.id as string;
-  root.innerHTML = '<p class="hint">Chargement...</p>';
+  root.innerHTML = LOADING_HINT;
 
   let album: ItemDto;
   let tracks: ItemDto[];
diff --git a/client/src/views/artist/Artist.ts b/client/src/views/artist/Artist.ts
index 62a0d96..43e7644 100644
--- a/client/src/views/artist/Artist.ts
+++ b/client/src/views/artist/Artist.ts
@@ -2,6 +2,7 @@ import html from './Artist.html';
 import { getArtistAlbums, getItem } from '../../api/embyApi';
 import type { RouteParams } from '../../router';
 import { tileHtml, wireSearchFilter } from '../../tiles';
+import { LOADING_HINT } from '../../loading';
 
 /** Route `/artist/:id` - one artist's albums, reached from a music
  *  library's top-level grid (see views/library) via a MusicArtist tile's
@@ -12,7 +13,7 @@ import { tileHtml, wireSearchFilter } from '../../tiles';
  *  artist has nothing itself to start a party from). */
 export async function renderArtist(root: HTMLElement, params: RouteParams): Promise<void> {
   const artistId = params.id as string;
-  root.innerHTML = '<p class="hint">Chargement...</p>';
+  root.innerHTML = LOADING_HINT;
 
   let artist;
   let albums;
diff --git a/client/src/views/home/Home.ts b/client/src/views/home/Home.ts
index 45af6e7..9086edf 100644
--- a/client/src/views/home/Home.ts
+++ b/client/src/views/home/Home.ts
@@ -5,6 +5,7 @@ import { connectLobby, createParty, joinParty } from '../../api/party';
 import { getActiveMusicPartyId } from '../../musicBar/MusicBar';
 import { navigate } from '../../router';
 import { escapeHtml, tileHtml, wireTileButtons } from '../../tiles';
+import { LOADING_HINT } from '../../loading';
 import type { LobbyPartyDto } from '../../types';
 
 export function renderHome(root: HTMLElement): () => void {
@@ -148,7 +149,7 @@ async function loadRecentSections(root: HTMLElement): Promise<void> {
   for (const lib of libraries) {
     const section = document.createElement('section');
     section.className = 'section';
-    section.innerHTML = `<h2>Ajouts récents - ${escapeHtml(lib.name)}</h2><div class="carousel"><p class="hint">Chargement...</p></div>`;
+    section.innerHTML = `<h2>Ajouts récents - ${escapeHtml(lib.name)}</h2><div class="carousel">${LOADING_HINT}</div>`;
     container.appendChild(section);
 
     getRecentItems(lib.id)
diff --git a/client/src/views/library/Library.html b/client/src/views/library/Library.html
index 434a9df..69365c4 100644
--- a/client/src/views/library/Library.html
+++ b/client/src/views/library/Library.html
@@ -1,4 +1,4 @@
 <div class="pageHeader"><h1></h1></div>
 <input id="searchInput" class="searchBar" type="search" placeholder="Rechercher dans cette bibliothèque..." />
 <p class="hint searchEmpty hide">Aucun résultat.</p>
-<div id="grid" class="grid"><p class="hint">Chargement...</p></div>
+<div id="grid" class="grid"><p class="hint"><span class="spinner"></span>Chargement...</p></div>
diff --git a/client/src/views/library/Library.ts b/client/src/views/library/Library.ts
index bf43972..9d3d336 100644
--- a/client/src/views/library/Library.ts
+++ b/client/src/views/library/Library.ts
@@ -4,6 +4,7 @@ import { createParty } from '../../api/party';
 import { navigate } from '../../router';
 import type { RouteParams } from '../../router';
 import { tileHtml, wireSearchFilter, wireTileButtons } from '../../tiles';
+import { LOADING_HINT } from '../../loading';
 
 /**
  * Generic "one library" page, reached from the sidebar. What it renders
@@ -18,7 +19,7 @@ import { tileHtml, wireSearchFilter, wireTileButtons } from '../../tiles';
  *     level further in (views/artist, then views/album).
  */
 export async function renderLibrary(root: HTMLElement, params: RouteParams): Promise<void> {
-  root.innerHTML = '<p class="hint">Chargement...</p>';
+  root.innerHTML = LOADING_HINT;
 
   let libraries;
   try {
diff --git a/client/src/views/player/Player.html b/client/src/views/player/Player.html
index fa79e74..1cdc540 100644
--- a/client/src/views/player/Player.html
+++ b/client/src/views/player/Player.html
@@ -1,7 +1,7 @@
 <div class="playerWrap">
   <video id="video" playsinline></video>
 
-  <p id="loadingNotice" class="loadingNotice">Chargement du flux...</p>
+  <p id="loadingNotice" class="loadingNotice"><span class="spinner"></span>Chargement du flux...</p>
   <div id="playerError" class="playerError hide">
     <p id="playerErrorText"></p>
     <button id="playerErrorRetry" class="linklike">Réessayer</button>
diff --git a/client/src/views/player/Player.ts b/client/src/views/player/Player.ts
index ae37a15..b20c9a0 100644
--- a/client/src/views/player/Player.ts
+++ b/client/src/views/player/Player.ts
@@ -7,6 +7,7 @@ import type { PartyConnection } from '../../api/party';
 import { navigate } from '../../router';
 import type { CleanupFn, RouteParams } from '../../router';
 import { colorForName, escapeHtml, initialsFor } from '../../tiles';
+import { LOADING_HINT } from '../../loading';
 import type { BurnInChangedMsg, ItemChangedMsg, PartyPublicState, PauseRequestedMsg, PlaybackOptionsDto, ResumeRequestedMsg, SocketMember, StreamOptionsChangedMsg, TextSubtitleChangedMsg } from '../../types';
 import { joinMusicParty, leaveMusicParty } from '../../musicBar/MusicBar';
 
@@ -81,7 +82,7 @@ const PAUSE_ICON_SVG = `
  */
 export function renderPartyPlayer(root: HTMLElement, params: RouteParams): CleanupFn {
   const partyId = params.id as string;
-  root.innerHTML = '<p class="hint">Chargement...</p>';
+  root.innerHTML = LOADING_HINT;
 
   let cleanup: CleanupFn = () => {};
   let cancelled = false;
diff --git a/client/src/views/playlist/Playlist.ts b/client/src/views/playlist/Playlist.ts
index 0d3bb8d..73f85f3 100644
--- a/client/src/views/playlist/Playlist.ts
+++ b/client/src/views/playlist/Playlist.ts
@@ -6,6 +6,7 @@ import { joinMusicParty } from '../../musicBar/MusicBar';
 import { navigate } from '../../router';
 import type { RouteParams } from '../../router';
 import { escapeHtml, formatDuration } from '../../tiles';
+import { LOADING_HINT } from '../../loading';
 import type { ItemDto } from '../../types';
 
 const TICKS_PER_SECOND = 10000000; // Emby/.NET convention: 1 tick = 100ns, same as everywhere else this app touches durations
@@ -23,7 +24,7 @@ const TICKS_PER_SECOND = 10000000; // Emby/.NET convention: 1 tick = 100ns, same
  */
 export async function renderPlaylist(root: HTMLElement, params: RouteParams): Promise<void> {
   const playlistId = params.id as string;
-  root.innerHTML = '<p class="hint">Chargement...</p>';
+  root.innerHTML = LOADING_HINT;
 
   let playlist: ItemDto;
   let items: ItemDto[];
diff --git a/client/src/views/series/Series.ts b/client/src/views/series/Series.ts
index 146255f..63dc39c 100644
--- a/client/src/views/series/Series.ts
+++ b/client/src/views/series/Series.ts
@@ -5,11 +5,12 @@ import { createParty } from '../../api/party';
 import { navigate } from '../../router';
 import type { RouteParams } from '../../router';
 import { escapeHtml } from '../../tiles';
+import { LOADING_HINT } from '../../loading';
 import type { ItemDto, SeasonDto } from '../../types';
 
 export async function renderSeries(root: HTMLElement, params: RouteParams): Promise<void> {
   const seriesId = params.id as string;
-  root.innerHTML = '<p class="hint">Chargement...</p>';
+  root.innerHTML = LOADING_HINT;
 
   let series: ItemDto;
   let seasons: SeasonDto[];
@@ -57,7 +58,7 @@ export async function renderSeries(root: HTMLElement, params: RouteParams): Prom
 
 async function loadEpisodes(root: HTMLElement, seriesId: string, seasonId: string): Promise<void> {
   const listEl = root.querySelector('#episodeList')!;
-  listEl.innerHTML = '<p class="hint">Chargement...</p>';
+  listEl.innerHTML = LOADING_HINT;
 
   let episodes: ItemDto[];
   try {
diff --git a/docs/architecture.md b/docs/architecture.md
index 8ada078..63fa476 100644
--- a/docs/architecture.md
+++ b/docs/architecture.md
@@ -2336,6 +2336,48 @@ response with neither header (most proxied paths) doesn't choke or
 invent one; `EmbyClient.fetch` tests cover a 304 not hitting the
 failure log and the two new headers being sent only when given.
 
+## A spinner on every loading state
+
+Asked for directly - every "Chargement..." spot across the app (route
+entry for Album/Artist/Library/Playlist/Series, the sidebar's own
+library list, Home's per-library carousels, a season switch reloading
+its episode list, the player's video-buffering notice) was plain
+`.hint` text with no visual motion, easy to mistake for a stuck page
+rather than one still fetching. New `.spinner` in `styles/base.css` - a
+plain CSS ring (`border` + `border-top-color`, no image/icon-font
+asset), `display: inline-block` with a small negative `vertical-align`
+so it drops into an existing text node instead of needing the element
+restructured into a flex row; `@media (prefers-reduced-motion: reduce)`
+turns off the spin for a viewer who's asked for less motion, matching
+this app's existing carefulness about motion elsewhere.
+
+New `client/src/loading.ts` exports one shared `LOADING_HINT` constant
+(`<p class="hint"><span class="spinner"></span>Chargement...</p>`) so
+every dynamic call site renders identical markup instead of each
+hand-typing a slightly different one; the handful of *static* HTML
+templates that had their own inert copy of this same placeholder text
+(never actually paintable - immediately overwritten synchronously by
+the same script that just set it, so a viewer could never see the
+old, spinner-less version even for a frame) were left alone rather
+than churned for a change nobody could ever see; `Library.html`'s own
+`#grid` placeholder was the one exception - genuinely visible while
+its library's items load - and got the same markup pasted directly
+(a static template, no JS import of its own).
+
+Not touched: the brief button-label loading states elsewhere ("Ajout...",
+"Démarrage..." while a party/queue-add request is in flight) - a
+different, smaller UI element than a block-level `.hint`, and typically
+resolved within one REST round trip, low enough value to add a second
+spinner variant for.
+
+Verified: full typecheck/build on the client (no server changes at
+all - this is pure client markup/CSS). Visually confirmed in a real
+browser (the compiled bundle's own `app.css`) that the spinner renders
+correctly inline with text in both a plain `.hint` and the player's
+`.loadingNotice` context, and is genuinely animating (`getComputedStyle`
+sampled twice, 300ms apart, showed a different `transform` matrix each
+time).
+
 ## Known limitations
 
 - Playback always goes through `hls.js` against whatever Emby's