Niveus: a tactile, adaptive interface language

Bevelled controls with light falling across them, fields as wells, solid
windows, and glass kept for the chrome that floats over everything else.
Warm graphite in dark, soft paper in light, one brand color driving both.
Ships its own fonts (Instrument Sans, JetBrains Mono; OFL).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

niveus/tokens/radius.css

@@ -0,0 +1,24 @@
+/* ==========================================================================
+   Niveus — Radius
+   --------------------------------------------------------------------------
+   Corner softness carries as much of the Niveus character as shadow does.
+   Radii grow with the surface: controls stay modest and machined, containers
+   get noticeably rounder — a window or a popover is a soft object, a button
+   is a key — and only pills, knobs and avatars go fully round.
+   ========================================================================== */
+
+:root {
+  --nv-radius-none: 0;
+  --nv-radius-xs: 0.25rem; /*   4px — tags, swatches, nested chips */
+  --nv-radius-sm: 0.5rem; /*    8px — small controls, menu items */
+  --nv-radius-md: 0.625rem; /* 10px — buttons, inputs, default control radius */
+  --nv-radius-lg: 0.875rem; /* 14px — cards, panels, menus */
+  --nv-radius-xl: 1.25rem; /*  20px — windows, dialogs, sheets, popovers */
+  --nv-radius-2xl: 1.5rem; /*  24px — docks, hero surfaces */
+  --nv-radius-full: 999rem; /*      — pills, avatars, switches */
+
+  /* Nested radius: an inner surface inset by N should be N smaller than its
+     parent, or the corners read as off-center. */
+  --nv-radius-nested-md: calc(var(--nv-radius-lg) - var(--nv-space-2));
+  --nv-radius-nested-lg: calc(var(--nv-radius-xl) - var(--nv-space-3));
+}