FEATHER SHEETS 1.0

A small, local spreadsheet for Apple Silicon Macs with macOS 13 or later.
No Microsoft account, subscription, browser runtime or network service required.
Standard Excel .xlsx is the normal file format.

START HERE
Command-O: open an Excel workbook.
Command-S: save. Saved files autosave after a short idle period.
Shift-Command-S: Save As to a separate .xlsx file.
Command-R: refresh the latest local file without reopening the window.
Command-F: Find and Replace.
Command-1: Format Cells.
Command-P: Print / PDF Preview.

When installing an update, quit the earlier copy when ready, then open the new app.

EDIT AND STYLE
Double-click a cell. The editor keeps its fonts, colors, alignment, wrapping and
rich-text styling. Return or Tab commits; Escape cancels. Undo inside the editor
changes the draft; after committing, Undo changes the workbook.

Home offers font family/size, bold, italic, underline, text/fill colors, wrapping,
Left/Center/Right and Top/Middle/Bottom alignment. Select a range to format it.
Sheet > Alignment > Center in Cell centers text in both directions. Alignment
applies to the whole cell while keeping mixed text fonts and colors.

Format Cells adds border presets, rotation and numeric/date/currency formats.
It also offers individual borders, indentation and custom/accounting formats.
Select text inside a text cell to change its font or color without restyling the
whole cell. Sheet provides Format Painter, reusable styles and Clear Formatting.
Merge keeps existing data protected; unmerge through the Sheet menu.
Carlito is bundled. Missing fonts are reported; installed fonts can be used.

MOVE AND MAKE ROOM
Swipe horizontally or vertically with two fingers. Drag row/column dividers to
resize. Double-click a divider to fit, or use Fit Row and Fit Column.
Choose freeze controls in Sheet to keep selected rows and columns visible.
View controls zoom, Feather Original, Midnight, Ocean and Sand themes, and five
independently hideable bars. Workbook colors stay unchanged by interface themes.
Shift-Command-F toggles Focus mode; Escape restores the workspace.
Control-Command-F toggles macOS fullscreen.

DATA AND FORMULAS
Edit > Paste Special offers values, formulas, formatting and transpose.
Sheet provides named ranges, tables, multi-column sorting, record filters,
validation/dropdowns and conditional formatting. Option-Escape completes formulas.
Compatible row/column and sheet structure changes update supported references.
A safety message stops operations that cannot preserve linked content reliably.
Edit > Go To accepts cell ranges, names and quoted sheet names. Command-click adds
a selection area; visible-cell selection excludes hidden rows. Window > New View
opens another view of the same workbook. Sheet > Fill provides directions and
number/date series. Row/column hiding, grouping and compatible sheet protection
are available; Excel editing protection is not file encryption.

CSV/TSV opening previews delimiter, encoding, dates and leading-zero handling.
Data provides cleanup, Text to Columns, bounded example fill, duplicate removal,
subtotals and table/filter workflows with preview or Undo where applicable.
Formula tools provide suggestions, reference picking, absolute-reference changes,
formula display, supported dependency tracing/evaluation and watched cells.
Conditional formatting includes common formula, top/bottom and icon-set rules.

The local calculation engine supports an expanded formula set, tables, dynamic
arrays and the 1900/1904 date systems. Edit a spill through its top-left formula
cell. Some unsupported formulas use a smaller fallback. Unavailable results show #RECALC! after
inputs change; original formulas stay in XLSX for recalculation elsewhere.

CHARTS, IMAGES AND PIVOTS
Insert provides bar, line, area, pie and scatter charts. Select an object to move
or resize it; double-click to edit data, titles, series, colors or position.
Objects lists charts and images. Insert Image accepts PNG/JPEG/GIF/TIFF/BMP.
Common chart options include data labels, legends, linear axis bounds/number
formats, six trendline types, fixed/percentage error bars, column/line combinations
and secondary value axes. Unsupported chart features remain guarded or preserved.
Insert > Sparklines creates or edits line, column and win/loss groups, with colors,
markers, blank/hidden-cell handling and supported scaling. These save as real
Excel sparkline structures. Editing one sparkline updates its group.

Insert > Pivot Table selects a source with headers and a destination, then fields,
aggregations and filters. Sheet > Pivot Table Fields rearranges a pivot; Refresh
Selected Pivot pulls new source data. Source edits do not refresh it automatically.
Format generated cells normally; edit values in source cells. Conversion to values
is undoable. Real Excel pivot definitions and full source cache records are saved.
Richer imported pivots remain preserved read-only. Structural edits stay guarded
for pivot workbooks; adding a blank sheet remains available.

Data also provides Goal Seek, numeric scenarios, sensitivity tables, descriptive
statistics and regression reports. Sensitivity results are labeled snapshots;
rerun them after changing assumptions. Scenarios support 1-32 numeric input cells
on one sheet. These tools do not implement all Excel analysis objects.

PRINT
File > Page Setup controls paper, margins in inches, orientation, scale/fit,
centering, gridlines and headings. File also sets/clears a selected print area and
inserts/removes manual page breaks. Fit to Pages overrides manual breaks.
Command-P prepares a searchable PDF preview with Save PDF and native printing.
File > Repeating Print Titles and Headers and Footers configure common repeated
rows/columns and formatted text with page counts, dates and file/sheet fields.
The preview reports unsupported content, including header pictures/effects and
printed comments. Arbitrary title bands inside the print body have limited parity.

REFRESH WITH AN AGENT
Refresh reads the version available locally through macOS/iCloud. A local save
is not proof that iCloud finished uploading remotely. Keep edits in a separate
XLSX copy, cancel, or explicitly discard and refresh. Failed reads keep your work.
Successful Refresh preserves the view where possible and resets old Undo history.
It does not merge simultaneous changes. External changes detected during save
keep both the external file and your unsaved local edits protected.

HISTORY AND RECOVERY
File > Version History restores a prior XLSX as one undoable edit, or opens a copy.
Defaults: 20 versions per file, 30 days, 200 MB total history.
File > Local Storage & Recovery changes retention and shows separate storage totals.

Unsaved work and unfinished cell/formula text checkpoint after about five idle
seconds. Recovery uses XLSX plus small private editor metadata, with a 100 MB
budget and up to 10 inactive copies for 14 days. Active copies stay protected;
a full budget reports a warning. Clean close removes that document's checkpoint.
After an interruption, File > Recover Unsaved Workbooks opens an untitled copy.
Review it and Save As. Saved files remain in Open Recent after restarting.

COMPATIBILITY
Unchanged imported XLSX saves preserve the original bytes. Supported edits retain
styles and unrelated original package content. Rendering, calculation and package
preservation have different limits. Complex custom number formats may be approximated.
Unsupported drawings, rules and metadata can remain preserved without being editable.

Limits: 50 MB compressed / 150 MB expanded XLSX; 200,000 stored cells; 100 sheets;
100,000 rows / 16,384 columns. Pivots: 64 fields, 200,000 source data cells,
100,000 result cells; up to 4 row / 3 column / 4 value fields; 8 MB metadata parts.
Charts: 16 series / 100,000 points. Images: 20 MB / 80 million pixels.
Sparklines: 1,000 groups / 10,000 locations per sheet; bounded 100,000-cell source
ranges and 200,000 preview observations per group. Preview caches are bounded.
Print: 32 areas, one million cells per area, 1,000 pages, 100 MB PDF.

Legacy .xls, macro-enabled .xlsm/VBA, Power Query/Power Pivot, external database
connections, real-time collaboration and bundled AI are outside this release.
Old .feather files can migrate to XLSX. CSV/TSV exchange does not retain styling.
This is a supported Excel-compatible subset, not complete Excel equivalence.

DEFERRED
Histogram/waterfall editing; advanced pivot grouping/drill-down/slicers/timelines/
PivotCharts; linked-workbook calculation/refresh; repeatable query pipelines;
Power Query M/data models; VBA execution/XLSM editing; real-time collaboration;
complex scenarios and native Excel sensitivity data-table objects; threaded
comments; guarded complex structural changes; higher workbook limits.
Research prototypes for these features are not part of the installed application.
