Turn BaseStyles members into a table containing type, default value, and inheritance state, generate BaseStyles.Defaults
Auto-generate layout cascading based on inheritance state
Use BaseStyles.Default instead of hardcoding defaults
Similar to `css-defaults` branch but this does it better - so I'm
deleting that in favour of this.
Rather than hard-coding the default value every time we fetch it:
```cs
var value = Styles.BackgroundColor ?? Color.White;
```
We should be doing something like:
```cs
var value = Styles.BackgroundColor ?? Default.BackgroundColor;
```
Provide default values as fallbacks for style transitions, use LerpProperty inside BaseStyles.FromLerp
In FromLerp, check if the property we're trying to change is actually changing
Prevents us from stomping property changes when a transition is running
with `transition: all` if you have an animation running simulataneously
Move default styles into `DefaultStyles`, make everything readonly
VirtualScrollPanel uses DefaultStyles
Only use fallback inside Lerp functions if from/to are null
Move null checks into Lerp functions, remove logs
Tidy up, use same code path for lerps
Refer to default values in docstrings, inherited/cascading values lerp to their initial `from` values if `to` is unset
Merge fixes, Name -> TypeName
Generate FillDefaults() function, call inside PreLayout.BuildFinal, add Length.Undefined
Fix a bunch of defaults (need better way to check if a property is set tho)
Add `Style.IsDefault( name )`
Bad idea to call FillDefaults here since it will stomp previous keyframes
backdrop-filter-hueRotate is backdrop-filter-hue-rotate (oops)
mask-position defaults to 0,0
Use IsDefault when necessary inside tests (HasValue will always be true for ComputedStyle properties), only check where necessary (i.e. if we're not also checking the value itself)
Scrolling fixes
Remove DefaultStyles, internalize IsDefault, FillDefaults, ApplyCascading
Handle `overflow` prop defaults separately
Use HasScrollY inside panel input
Get rid of remaining null coalescing shit - ComputedStyle properties are no longer null
ComputedStyles has its own class w/ no nullables, helps clean things up
Remove unused, clean up
