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diff --git a/src/app/assets/fonts/inter-latin-opsz-normal.woff2 b/src/app/assets/fonts/inter-latin-opsz-normal.woff2
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diff --git a/src/app/assets/fonts/space-grotesk-latin-wght-normal.woff2 b/src/app/assets/fonts/space-grotesk-latin-wght-normal.woff2
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diff --git a/src/app/assets/fonts/space-mono-latin-400-italic.woff2 b/src/app/assets/fonts/space-mono-latin-400-italic.woff2
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diff --git a/src/app/assets/fonts/space-mono-latin-700-italic.woff2 b/src/app/assets/fonts/space-mono-latin-700-italic.woff2
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diff --git a/src/app/assets/fonts/syne-latin-800-normal.woff2 b/src/app/assets/fonts/syne-latin-800-normal.woff2
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diff --git a/src/app/styles/app.css b/src/app/styles/app.css
index 909b793..89b27ff 100644
--- a/src/app/styles/app.css
+++ b/src/app/styles/app.css
@@ -1,5 +1,6 @@
 @import "tailwindcss";
 @import "tw-animate-css";
+@import "./fonts.css";
 
 @variant dark (&:where(.dark, .dark *));
 
diff --git a/src/app/styles/fonts.css b/src/app/styles/fonts.css
new file mode 100644
index 0000000..2d953fd
--- /dev/null
+++ b/src/app/styles/fonts.css
@@ -0,0 +1,78 @@
+/*
+    Self-hosted interface fonts (latin subset only).
+    Vendored from @fontsource — see docs/interface-font-selfhost-benchmark.md.
+    Variable faces (Inter, Space Grotesk) keep their wght axis; Inter also keeps opsz.
+    url()s are resolved + content-hashed by Vite at build → immutable long-cache.
+*/
+
+/* Inter — variable wght + opsz, the body/secondary UI font (--font-secondary) */
+@font-face {
+    font-family: 'Inter';
+    font-style: normal;
+    font-display: swap;
+    font-weight: 100 900;
+    src: url('../assets/fonts/inter-latin-opsz-normal.woff2') format('woff2');
+    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;
+}
+@font-face {
+    font-family: 'Inter';
+    font-style: italic;
+    font-display: swap;
+    font-weight: 100 900;
+    src: url('../assets/fonts/inter-latin-opsz-italic.woff2') format('woff2');
+    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;
+}
+
+/* Space Grotesk — variable wght, the primary/display UI font (--font-primary) */
+@font-face {
+    font-family: 'Space Grotesk';
+    font-style: normal;
+    font-display: swap;
+    font-weight: 300 700;
+    src: url('../assets/fonts/space-grotesk-latin-wght-normal.woff2') format('woff2');
+    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;
+}
+
+/* Space Mono — static 400/700 × roman/italic (--font-mono) */
+@font-face {
+    font-family: 'Space Mono';
+    font-style: normal;
+    font-display: swap;
+    font-weight: 400;
+    src: url('../assets/fonts/space-mono-latin-400-normal.woff2') format('woff2');
+    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;
+}
+@font-face {
+    font-family: 'Space Mono';
+    font-style: italic;
+    font-display: swap;
+    font-weight: 400;
+    src: url('../assets/fonts/space-mono-latin-400-italic.woff2') format('woff2');
+    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;
+}
+@font-face {
+    font-family: 'Space Mono';
+    font-style: normal;
+    font-display: swap;
+    font-weight: 700;
+    src: url('../assets/fonts/space-mono-latin-700-normal.woff2') format('woff2');
+    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;
+}
+@font-face {
+    font-family: 'Space Mono';
+    font-style: italic;
+    font-display: swap;
+    font-weight: 700;
+    src: url('../assets/fonts/space-mono-latin-700-italic.woff2') format('woff2');
+    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;
+}
+
+/* Syne — static 800, the logo font (--font-logo) */
+@font-face {
+    font-family: 'Syne';
+    font-style: normal;
+    font-display: swap;
+    font-weight: 800;
+    src: url('../assets/fonts/syne-latin-800-normal.woff2') format('woff2');
+    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;
+}