Design language comparison
Mercury vs Spline
Both Mercury and Spline commit to a dark-canvas approach, and they pair different display families (arcadia vs Spline Sans). Beyond surface, motion divides them — Mercury is moderate, Spline is expressive.
Palette · side by side
Up to 8 dominant swatches eachSide A · dark
Mercury
Full Page
#ededf3
background
#000000
foreground
#edecfb
background
#ffffff
background
#1e1e2a
background
#70707d
neutral
#5266eb
accent
#cdddff
accent
Side B · dark
Spline
Full Page
#ffffff
background
#000000
foreground
#191a1d
foreground
#888888
foreground
#569cd6
accent
#0062ff
accent
#ce9178
accent
#6a9955
foreground
Typography · side by side
Primary family + weight ladder + sampleSide A · dark
Mercury
Full Page
- Display
- arcadia
- Body
- arcadiaDisplay
- Weights
- 360 · 400 · 420 · 480
Sample
The quick brown fox jumps over the lazy dog.
1234567890 — Body sample renders in the captured family if your browser has it; otherwise system fallback signals the weight ladder.
Side B · dark
Spline
Full Page
- Display
- Spline Sans
- Body
- ui-monospace
- Mono
- ui-monospace
- Weights
- 400 · 500
Sample
The quick brown fox jumps over the lazy dog.
1234567890 — Body sample renders in the captured family if your browser has it; otherwise system fallback signals the weight ladder.
Spacing scale · side by side
Base unit + first 8 scale valuesSide A · dark
Mercury
Full Page
- Base unit
- 4 px
- Container max
- 1376 px
Side B · dark
Spline
Full Page
- Base unit
- 4 px
- Container max
- 652 px
Motion vocabulary · side by side
Level + durations + easingsSide A · dark
Mercury
Full Page
- Level
- moderate
- Libraries
- Framer Motion
Durations
Easings
Side B · dark
Spline
Full Page
- Level
- expressive
- Libraries
- —
Durations
Easings
Palette & spacing overlap
Their palettes share 22% of swatches at the dominant tier — a quiet signal both teams drew from the same neutral library before applying brand accents. Their spacing scales overlap by 50% (4, 8, 12, 16, 20 px shared) — a rhythm any agent can transfer between the two systems with minimal recalibration.
Shared swatches (2)
Curator verdict
Pick a side. Mixing Mercury's dark-first canvas with Spline's expressive motion vocabulary produces visual whiplash. Adopt one system as your primary, study the other for individual technique transfers (e.g. Mercury's spacing, Spline's shadow).