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/typography.css

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+/* ==========================================================================
+   Niveus — Typography
+   --------------------------------------------------------------------------
+   One type scale, used everywhere. Sizes are in rem so they respect the user's
+   browser font size; line heights are unitless so they inherit correctly.
+   ========================================================================== */
+
+:root {
+  /* --- Families ----------------------------------------------------------- */
+  /* Both ship with Niveus (fonts.css); the rest of each stack only covers the
+     moment before they load, or a context that cannot load them. */
+  --nv-font-family-sans:
+    "Instrument Sans", "Inter var", "Inter", -apple-system, BlinkMacSystemFont,
+    "Segoe UI", "Helvetica Neue", Arial, sans-serif;
+  --nv-font-family-mono:
+    "JetBrains Mono", "SF Mono", "IBM Plex Mono", ui-monospace, "Menlo",
+    "Consolas", monospace;
+
+  /* --- Size scale ---------------------------------------------------------- */
+  --nv-font-size-2xs: 0.6875rem; /* 11px — dense metadata, never body text */
+  --nv-font-size-xs: 0.75rem; /*  12px */
+  --nv-font-size-sm: 0.8125rem; /* 13px */
+  --nv-font-size-md: 0.9375rem; /* 15px — default body size */
+  --nv-font-size-lg: 1.0625rem; /* 17px */
+  --nv-font-size-xl: 1.25rem; /*  20px */
+  --nv-font-size-2xl: 1.5rem; /*   24px */
+  --nv-font-size-3xl: 1.875rem; /* 30px */
+  --nv-font-size-4xl: 2.375rem; /* 38px */
+  --nv-font-size-5xl: 3rem; /*     48px */
+
+  /* --- Weight -------------------------------------------------------------- */
+  --nv-font-weight-regular: 400;
+  --nv-font-weight-medium: 500;
+  --nv-font-weight-semibold: 600;
+  --nv-font-weight-bold: 700;
+
+  /* --- Line height --------------------------------------------------------- */
+  --nv-line-height-tight: 1.18; /* display and large headings */
+  --nv-line-height-snug: 1.32; /*  headings, single-line controls */
+  --nv-line-height-normal: 1.5; /* body copy */
+  --nv-line-height-relaxed: 1.68; /* long-form reading */
+
+  /* --- Letter spacing -------------------------------------------------------
+     Large text needs negative tracking to stay optically even; small caps-ish
+     labels need positive tracking to stay readable. */
+  --nv-letter-spacing-tighter: -0.022em;
+  --nv-letter-spacing-tight: -0.012em;
+  --nv-letter-spacing-normal: 0em;
+  --nv-letter-spacing-wide: 0.02em;
+  --nv-letter-spacing-wider: 0.06em;
+  /* Engraved labels: small mono capitals, spaced like markings on a panel. */
+  --nv-letter-spacing-engraved: 0.1em;
+
+  /* --- Composite roles ------------------------------------------------------
+     Applied as classes in base.css (.nv-display, .nv-heading, …). Kept as
+     tokens so applications can compose their own elements from the same
+     values instead of guessing. */
+  --nv-font-display: var(--nv-font-weight-semibold) var(--nv-font-size-4xl) /
+    var(--nv-line-height-tight) var(--nv-font-family-sans);
+  --nv-font-heading: var(--nv-font-weight-semibold) var(--nv-font-size-2xl) /
+    var(--nv-line-height-snug) var(--nv-font-family-sans);
+  --nv-font-title: var(--nv-font-weight-semibold) var(--nv-font-size-lg) /
+    var(--nv-line-height-snug) var(--nv-font-family-sans);
+  --nv-font-body: var(--nv-font-weight-regular) var(--nv-font-size-md) /
+    var(--nv-line-height-normal) var(--nv-font-family-sans);
+  --nv-font-label: var(--nv-font-weight-medium) var(--nv-font-size-sm) /
+    var(--nv-line-height-snug) var(--nv-font-family-sans);
+  --nv-font-caption: var(--nv-font-weight-regular) var(--nv-font-size-xs) /
+    var(--nv-line-height-normal) var(--nv-font-family-sans);
+  --nv-font-code: var(--nv-font-weight-regular) var(--nv-font-size-sm) /
+    var(--nv-line-height-normal) var(--nv-font-family-mono);
+  /* The engraved label: section markers, the clock, anything that names a
+     region rather than being read. Paired with uppercase and the engraved
+     tracking (see .nv-overline in base.css). */
+  --nv-font-engraved: var(--nv-font-weight-medium) var(--nv-font-size-2xs) /
+    var(--nv-line-height-snug) var(--nv-font-family-mono);
+
+  /* --- Measure --------------------------------------------------------------- */
+  --nv-measure-narrow: 44ch;
+  --nv-measure: 68ch;
+  --nv-measure-wide: 82ch;
+}