Duration and easing tokens
Five durations and four curves, mirrored from the stylesheet into lib/design/tokens.ts and kept in step by a test. New motion names a token instead of writing a number.
| --dur-instant | 100ms |
| --dur-quick | 160ms |
| --dur-base | 240ms |
| --dur-move | 380ms |
| --dur-stage | 560ms |
| --ease-out | cubic-bezier(0.16, 1, 0.3, 1) |
| --ease-in | cubic-bezier(0.55, 0, 1, 0.45) |
| --ease-in-out | cubic-bezier(0.65, 0, 0.35, 1) |
| --spring | cubic-bezier(0.34, 1.56, 0.64, 1) |