diff --git a/public/fonts/fraunces-OFL.txt b/public/fonts/v1/fraunces-OFL.txt
similarity index 100%
rename from public/fonts/fraunces-OFL.txt
rename to public/fonts/v1/fraunces-OFL.txt
diff --git a/public/fonts/fraunces-latin-ext-wght-normal.woff2 b/public/fonts/v1/fraunces-latin-ext-wght-normal.woff2
similarity index 100%
rename from public/fonts/fraunces-latin-ext-wght-normal.woff2
rename to public/fonts/v1/fraunces-latin-ext-wght-normal.woff2
diff --git a/public/fonts/fraunces-latin-wght-normal.woff2 b/public/fonts/v1/fraunces-latin-wght-normal.woff2
similarity index 100%
rename from public/fonts/fraunces-latin-wght-normal.woff2
rename to public/fonts/v1/fraunces-latin-wght-normal.woff2
diff --git a/public/fonts/inter-OFL.txt b/public/fonts/v1/inter-OFL.txt
similarity index 100%
rename from public/fonts/inter-OFL.txt
rename to public/fonts/v1/inter-OFL.txt
diff --git a/public/fonts/inter-latin-ext-wght-normal.woff2 b/public/fonts/v1/inter-latin-ext-wght-normal.woff2
similarity index 100%
rename from public/fonts/inter-latin-ext-wght-normal.woff2
rename to public/fonts/v1/inter-latin-ext-wght-normal.woff2
diff --git a/public/fonts/inter-latin-wght-normal.woff2 b/public/fonts/v1/inter-latin-wght-normal.woff2
similarity index 100%
rename from public/fonts/inter-latin-wght-normal.woff2
rename to public/fonts/v1/inter-latin-wght-normal.woff2
diff --git a/public/fonts/jetbrains-mono-OFL.txt b/public/fonts/v1/jetbrains-mono-OFL.txt
similarity index 100%
rename from public/fonts/jetbrains-mono-OFL.txt
rename to public/fonts/v1/jetbrains-mono-OFL.txt
diff --git a/public/fonts/jetbrains-mono-latin-ext-wght-normal.woff2 b/public/fonts/v1/jetbrains-mono-latin-ext-wght-normal.woff2
similarity index 100%
rename from public/fonts/jetbrains-mono-latin-ext-wght-normal.woff2
rename to public/fonts/v1/jetbrains-mono-latin-ext-wght-normal.woff2
diff --git a/public/fonts/jetbrains-mono-latin-wght-normal.woff2 b/public/fonts/v1/jetbrains-mono-latin-wght-normal.woff2
similarity index 100%
rename from public/fonts/jetbrains-mono-latin-wght-normal.woff2
rename to public/fonts/v1/jetbrains-mono-latin-wght-normal.woff2
diff --git a/public/fonts/source-sans-3-OFL.txt b/public/fonts/v1/source-sans-3-OFL.txt
similarity index 100%
rename from public/fonts/source-sans-3-OFL.txt
rename to public/fonts/v1/source-sans-3-OFL.txt
diff --git a/public/fonts/source-sans-3-latin-ext-wght-normal.woff2 b/public/fonts/v1/source-sans-3-latin-ext-wght-normal.woff2
similarity index 100%
rename from public/fonts/source-sans-3-latin-ext-wght-normal.woff2
rename to public/fonts/v1/source-sans-3-latin-ext-wght-normal.woff2
diff --git a/public/fonts/source-sans-3-latin-wght-normal.woff2 b/public/fonts/v1/source-sans-3-latin-wght-normal.woff2
similarity index 100%
rename from public/fonts/source-sans-3-latin-wght-normal.woff2
rename to public/fonts/v1/source-sans-3-latin-wght-normal.woff2
diff --git a/public/fonts/source-serif-4-OFL.txt b/public/fonts/v1/source-serif-4-OFL.txt
similarity index 100%
rename from public/fonts/source-serif-4-OFL.txt
rename to public/fonts/v1/source-serif-4-OFL.txt
diff --git a/public/fonts/source-serif-4-latin-ext-wght-normal.woff2 b/public/fonts/v1/source-serif-4-latin-ext-wght-normal.woff2
similarity index 100%
rename from public/fonts/source-serif-4-latin-ext-wght-normal.woff2
rename to public/fonts/v1/source-serif-4-latin-ext-wght-normal.woff2
diff --git a/public/fonts/source-serif-4-latin-wght-normal.woff2 b/public/fonts/v1/source-serif-4-latin-wght-normal.woff2
similarity index 100%
rename from public/fonts/source-serif-4-latin-wght-normal.woff2
rename to public/fonts/v1/source-serif-4-latin-wght-normal.woff2
diff --git a/public/fonts/space-grotesk-OFL.txt b/public/fonts/v1/space-grotesk-OFL.txt
similarity index 100%
rename from public/fonts/space-grotesk-OFL.txt
rename to public/fonts/v1/space-grotesk-OFL.txt
diff --git a/public/fonts/space-grotesk-latin-ext-wght-normal.woff2 b/public/fonts/v1/space-grotesk-latin-ext-wght-normal.woff2
similarity index 100%
rename from public/fonts/space-grotesk-latin-ext-wght-normal.woff2
rename to public/fonts/v1/space-grotesk-latin-ext-wght-normal.woff2
diff --git a/public/fonts/space-grotesk-latin-wght-normal.woff2 b/public/fonts/v1/space-grotesk-latin-wght-normal.woff2
similarity index 100%
rename from public/fonts/space-grotesk-latin-wght-normal.woff2
rename to public/fonts/v1/space-grotesk-latin-wght-normal.woff2
diff --git a/scripts/copy-studio.mjs b/scripts/copy-studio.mjs
index ddebc14..57034f5 100644
--- a/scripts/copy-studio.mjs
+++ b/scripts/copy-studio.mjs
@@ -9,7 +9,10 @@ const from = path.join(cli, "dist/assets/studio");
 const pub = new URL("../public/", import.meta.url).pathname;
 await rm(path.join(pub, "assets"), { recursive: true, force: true });
 await cp(from, pub, { recursive: true, filter: (src) => !src.endsWith(".map") });
-// Studio's own headers (CSP etc.) for its files; the site's pages set their own.
-const headers = await readFile(path.join(from, "_headers"), "utf8").catch(() => "");
-if (headers) await writeFile(path.join(pub, "_headers"), headers);
+// Studio's own headers (CSP etc.) for its files; the site's pages set their own. The theme's
+// fonts never change under a path (a new set gets /fonts/v2/): cached for a year, so a reload
+// draws the text in its font from the first paint instead of swapping it in later.
+const studio = await readFile(path.join(from, "_headers"), "utf8").catch(() => "");
+const fonts = "/fonts/v1/*\n  Cache-Control: public, max-age=31536000, immutable\n";
+await writeFile(path.join(pub, "_headers"), `${studio.trimEnd()}\n\n${fonts}`.trimStart());
 console.log(`Studio copied from ${from}`);
diff --git a/src/fonts.ts b/src/fonts.ts
index a75d746..a48cca9 100644
--- a/src/fonts.ts
+++ b/src/fonts.ts
@@ -4,12 +4,18 @@
  * (Turkish and other accented letters) load on demand through fonts.css's unicode ranges.
  */
 export const PAIRING_PRELOADS: Readonly<Record<string, readonly string[]>> = {
-  editorial: ["/fonts/fraunces-latin-wght-normal.woff2", "/fonts/inter-latin-wght-normal.woff2"],
-  modern: ["/fonts/space-grotesk-latin-wght-normal.woff2", "/fonts/inter-latin-wght-normal.woff2"],
-  humanist: ["/fonts/source-sans-3-latin-wght-normal.woff2"],
+  editorial: [
+    "/fonts/v1/fraunces-latin-wght-normal.woff2",
+    "/fonts/v1/inter-latin-wght-normal.woff2",
+  ],
+  modern: [
+    "/fonts/v1/space-grotesk-latin-wght-normal.woff2",
+    "/fonts/v1/inter-latin-wght-normal.woff2",
+  ],
+  humanist: ["/fonts/v1/source-sans-3-latin-wght-normal.woff2"],
   technical: [
-    "/fonts/jetbrains-mono-latin-wght-normal.woff2",
-    "/fonts/inter-latin-wght-normal.woff2",
+    "/fonts/v1/jetbrains-mono-latin-wght-normal.woff2",
+    "/fonts/v1/inter-latin-wght-normal.woff2",
   ],
-  classic: ["/fonts/source-serif-4-latin-wght-normal.woff2"],
+  classic: ["/fonts/v1/source-serif-4-latin-wght-normal.woff2"],
 };
diff --git a/src/styles/features/tokens.css b/src/styles/features/tokens.css
index 5eb4c95..7d65a1f 100644
--- a/src/styles/features/tokens.css
+++ b/src/styles/features/tokens.css
@@ -55,29 +55,41 @@
   font-family: ui-monospace, "Cascadia Code", "Source Code Pro", Menlo, Consolas, monospace;
 }
 /*
- * Font pairings (RFC-0023 §2): the families come from fonts.css and load only when used. They win
+ * Font pairings (RFC-0023 §2): the families come from fonts.css and load only when used; each is
+ * followed by its metric-matched fallback (font-fallbacks.css), so the swap does not move the
+ * text. They win
  * over the older typeface setting; `system` keeps it.
  */
 [data-ch-type-pairing="editorial"] {
-  --ch-font-display: "Fraunces Variable", ui-serif, Georgia, serif;
-  --ch-font-text: "Inter Variable", ui-sans-serif, system-ui, sans-serif;
+  --ch-font-display: "Fraunces Variable", "Fraunces Variable Fallback", ui-serif, Georgia, serif;
+  --ch-font-text: "Inter Variable", "Inter Variable Fallback", ui-sans-serif, system-ui, sans-serif;
 }
 [data-ch-type-pairing="modern"] {
-  --ch-font-display: "Space Grotesk Variable", ui-sans-serif, system-ui, sans-serif;
-  --ch-font-text: "Inter Variable", ui-sans-serif, system-ui, sans-serif;
+  --ch-font-display:
+    "Space Grotesk Variable", "Space Grotesk Variable Fallback", ui-sans-serif, system-ui,
+    sans-serif;
+  --ch-font-text: "Inter Variable", "Inter Variable Fallback", ui-sans-serif, system-ui, sans-serif;
 }
 [data-ch-type-pairing="humanist"] {
-  --ch-font-display: "Source Sans 3 Variable", ui-sans-serif, system-ui, sans-serif;
-  --ch-font-text: "Source Sans 3 Variable", ui-sans-serif, system-ui, sans-serif;
+  --ch-font-display:
+    "Source Sans 3 Variable", "Source Sans 3 Variable Fallback", ui-sans-serif, system-ui,
+    sans-serif;
+  --ch-font-text:
+    "Source Sans 3 Variable", "Source Sans 3 Variable Fallback", ui-sans-serif, system-ui,
+    sans-serif;
 }
 [data-ch-type-pairing="technical"] {
-  --ch-font-display: "JetBrains Mono Variable", ui-monospace, monospace;
-  --ch-font-text: "Inter Variable", ui-sans-serif, system-ui, sans-serif;
-  --ch-font-code: "JetBrains Mono Variable", ui-monospace, monospace;
+  --ch-font-display:
+    "JetBrains Mono Variable", "JetBrains Mono Variable Fallback", ui-monospace, monospace;
+  --ch-font-text: "Inter Variable", "Inter Variable Fallback", ui-sans-serif, system-ui, sans-serif;
+  --ch-font-code:
+    "JetBrains Mono Variable", "JetBrains Mono Variable Fallback", ui-monospace, monospace;
 }
 [data-ch-type-pairing="classic"] {
-  --ch-font-display: "Source Serif 4 Variable", ui-serif, Georgia, serif;
-  --ch-font-text: "Source Serif 4 Variable", ui-serif, Georgia, serif;
+  --ch-font-display:
+    "Source Serif 4 Variable", "Source Serif 4 Variable Fallback", ui-serif, Georgia, serif;
+  --ch-font-text:
+    "Source Serif 4 Variable", "Source Serif 4 Variable Fallback", ui-serif, Georgia, serif;
 }
 [data-ch-type-pairing]:not([data-ch-type-pairing="system"]) .ch-body {
   font-family: var(--ch-font-text);
diff --git a/src/styles/font-fallbacks.css b/src/styles/font-fallbacks.css
new file mode 100644
index 0000000..495c7e8
--- /dev/null
+++ b/src/styles/font-fallbacks.css
@@ -0,0 +1,53 @@
+/*
+ * Generated by scripts/font-fallbacks.ts: do not edit. Metric-matched fallback faces for the
+ * pairings' web fonts (tokens.css lists each right after its web font), so the swap to the web
+ * font does not move the text.
+ */
+@font-face {
+  font-family: "Fraunces Variable Fallback";
+  src: local("Times New Roman"), local("TimesNewRomanPSMT");
+  size-adjust: 113.62%;
+  ascent-override: 86.08%;
+  descent-override: 22.44%;
+  line-gap-override: 0.00%;
+}
+@font-face {
+  font-family: "Inter Variable Fallback";
+  src: local("Arial"), local("ArialMT");
+  size-adjust: 107.12%;
+  ascent-override: 90.44%;
+  descent-override: 22.52%;
+  line-gap-override: 0.00%;
+}
+@font-face {
+  font-family: "Space Grotesk Variable Fallback";
+  src: local("Arial"), local("ArialMT");
+  size-adjust: 109.47%;
+  ascent-override: 89.89%;
+  descent-override: 26.67%;
+  line-gap-override: 0.00%;
+}
+@font-face {
+  font-family: "Source Sans 3 Variable Fallback";
+  src: local("Arial"), local("ArialMT");
+  size-adjust: 92.42%;
+  ascent-override: 110.80%;
+  descent-override: 43.28%;
+  line-gap-override: 0.00%;
+}
+@font-face {
+  font-family: "Source Serif 4 Variable Fallback";
+  src: local("Times New Roman"), local("TimesNewRomanPSMT");
+  size-adjust: 117.91%;
+  ascent-override: 87.87%;
+  descent-override: 28.41%;
+  line-gap-override: 0.00%;
+}
+@font-face {
+  font-family: "JetBrains Mono Variable Fallback";
+  src: local("Courier New"), local("CourierNewPSMT");
+  size-adjust: 99.98%;
+  ascent-override: 102.02%;
+  descent-override: 30.00%;
+  line-gap-override: 0.00%;
+}
diff --git a/src/styles/fonts.css b/src/styles/fonts.css
index fea61f8..3317914 100644
--- a/src/styles/fonts.css
+++ b/src/styles/fonts.css
@@ -8,7 +8,7 @@
   font-style: normal;
   font-display: swap;
   font-weight: 100 900;
-  src: url(/fonts/fraunces-latin-ext-wght-normal.woff2) format("woff2-variations");
+  src: url(/fonts/v1/fraunces-latin-ext-wght-normal.woff2) format("woff2-variations");
   unicode-range:
     U+0100-02BA, U+02BD-02C5, U+02C7-02CC, U+02CE-02D7, U+02DD-02FF, U+0304, U+0308, U+0329, U+1D00-1DBF, U+1E00-1E9F, U+1EF2-1EFF, U+2020, U+20A0-20AB, U+20AD-20C0, U+2113, U+2C60-2C7F, U+A720-A7FF;
 }
@@ -17,7 +17,7 @@
   font-style: normal;
   font-display: swap;
   font-weight: 100 900;
-  src: url(/fonts/fraunces-latin-wght-normal.woff2) format("woff2-variations");
+  src: url(/fonts/v1/fraunces-latin-wght-normal.woff2) format("woff2-variations");
   unicode-range:
     U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
 }
@@ -26,7 +26,7 @@
   font-style: normal;
   font-display: swap;
   font-weight: 100 900;
-  src: url(/fonts/inter-latin-ext-wght-normal.woff2) format("woff2-variations");
+  src: url(/fonts/v1/inter-latin-ext-wght-normal.woff2) format("woff2-variations");
   unicode-range:
     U+0100-02BA, U+02BD-02C5, U+02C7-02CC, U+02CE-02D7, U+02DD-02FF, U+0304, U+0308, U+0329, U+1D00-1DBF, U+1E00-1E9F, U+1EF2-1EFF, U+2020, U+20A0-20AB, U+20AD-20C0, U+2113, U+2C60-2C7F, U+A720-A7FF;
 }
@@ -35,7 +35,7 @@
   font-style: normal;
   font-display: swap;
   font-weight: 100 900;
-  src: url(/fonts/inter-latin-wght-normal.woff2) format("woff2-variations");
+  src: url(/fonts/v1/inter-latin-wght-normal.woff2) format("woff2-variations");
   unicode-range:
     U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
 }
@@ -44,7 +44,7 @@
   font-style: normal;
   font-display: swap;
   font-weight: 100 800;
-  src: url(/fonts/jetbrains-mono-latin-ext-wght-normal.woff2) format("woff2-variations");
+  src: url(/fonts/v1/jetbrains-mono-latin-ext-wght-normal.woff2) format("woff2-variations");
   unicode-range:
     U+0100-02BA, U+02BD-02C5, U+02C7-02CC, U+02CE-02D7, U+02DD-02FF, U+0304, U+0308, U+0329, U+1D00-1DBF, U+1E00-1E9F, U+1EF2-1EFF, U+2020, U+20A0-20AB, U+20AD-20C0, U+2113, U+2C60-2C7F, U+A720-A7FF;
 }
@@ -53,7 +53,7 @@
   font-style: normal;
   font-display: swap;
   font-weight: 100 800;
-  src: url(/fonts/jetbrains-mono-latin-wght-normal.woff2) format("woff2-variations");
+  src: url(/fonts/v1/jetbrains-mono-latin-wght-normal.woff2) format("woff2-variations");
   unicode-range:
     U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
 }
@@ -62,7 +62,7 @@
   font-style: normal;
   font-display: swap;
   font-weight: 200 900;
-  src: url(/fonts/source-sans-3-latin-ext-wght-normal.woff2) format("woff2-variations");
+  src: url(/fonts/v1/source-sans-3-latin-ext-wght-normal.woff2) format("woff2-variations");
   unicode-range:
     U+0100-02BA, U+02BD-02C5, U+02C7-02CC, U+02CE-02D7, U+02DD-02FF, U+0304, U+0308, U+0329, U+1D00-1DBF, U+1E00-1E9F, U+1EF2-1EFF, U+2020, U+20A0-20AB, U+20AD-20C4, U+2113, U+2C60-2C7F, U+A720-A7FF;
 }
@@ -71,7 +71,7 @@
   font-style: normal;
   font-display: swap;
   font-weight: 200 900;
-  src: url(/fonts/source-sans-3-latin-wght-normal.woff2) format("woff2-variations");
+  src: url(/fonts/v1/source-sans-3-latin-wght-normal.woff2) format("woff2-variations");
   unicode-range:
     U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
 }
@@ -80,7 +80,7 @@
   font-style: normal;
   font-display: swap;
   font-weight: 200 900;
-  src: url(/fonts/source-serif-4-latin-ext-wght-normal.woff2) format("woff2-variations");
+  src: url(/fonts/v1/source-serif-4-latin-ext-wght-normal.woff2) format("woff2-variations");
   unicode-range:
     U+0100-02BA, U+02BD-02C5, U+02C7-02CC, U+02CE-02D7, U+02DD-02FF, U+0304, U+0308, U+0329, U+1D00-1DBF, U+1E00-1E9F, U+1EF2-1EFF, U+2020, U+20A0-20AB, U+20AD-20C4, U+2113, U+2C60-2C7F, U+A720-A7FF;
 }
@@ -89,7 +89,7 @@
   font-style: normal;
   font-display: swap;
   font-weight: 200 900;
-  src: url(/fonts/source-serif-4-latin-wght-normal.woff2) format("woff2-variations");
+  src: url(/fonts/v1/source-serif-4-latin-wght-normal.woff2) format("woff2-variations");
   unicode-range:
     U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
 }
@@ -98,7 +98,7 @@
   font-style: normal;
   font-display: swap;
   font-weight: 300 700;
-  src: url(/fonts/space-grotesk-latin-ext-wght-normal.woff2) format("woff2-variations");
+  src: url(/fonts/v1/space-grotesk-latin-ext-wght-normal.woff2) format("woff2-variations");
   unicode-range:
     U+0100-02BA, U+02BD-02C5, U+02C7-02CC, U+02CE-02D7, U+02DD-02FF, U+0304, U+0308, U+0329, U+1D00-1DBF, U+1E00-1E9F, U+1EF2-1EFF, U+2020, U+20A0-20AB, U+20AD-20C0, U+2113, U+2C60-2C7F, U+A720-A7FF;
 }
@@ -107,7 +107,7 @@
   font-style: normal;
   font-display: swap;
   font-weight: 300 700;
-  src: url(/fonts/space-grotesk-latin-wght-normal.woff2) format("woff2-variations");
+  src: url(/fonts/v1/space-grotesk-latin-wght-normal.woff2) format("woff2-variations");
   unicode-range:
     U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
 }
diff --git a/src/styles/global.css b/src/styles/global.css
index 74e6152..7717714 100644
--- a/src/styles/global.css
+++ b/src/styles/global.css
@@ -1,6 +1,7 @@
 /* Scan `src/` only: automatic detection may walk up the file system (docs/design/starter-references.md §6). */
 @import "tailwindcss" source("..");
 @import "./fonts.css";
+@import "./font-fallbacks.css";
 
 /*
  * One file per feature (docs/engineering/code-structure.md §8), in cascade order. Unlayered on