# Silo Style Guide

> Living reference for the Silo web UI. All modules must follow these conventions to maintain visual consistency across the platform.

---

## Color System

Silo uses the [Catppuccin Mocha](https://github.com/catppuccin/catppuccin) palette exclusively. All colors are referenced via CSS custom properties defined at `:root`.

### Palette

```
--ctp-rosewater:  #f5e0dc
--ctp-flamingo:   #f2cdcd
--ctp-pink:       #f5c2e7
--ctp-mauve:      #cba6f7
--ctp-red:        #f38ba8
--ctp-maroon:     #eba0ac
--ctp-peach:      #fab387
--ctp-yellow:     #f9e2af
--ctp-green:      #a6e3a1
--ctp-teal:       #94e2d5
--ctp-sky:        #89dceb
--ctp-sapphire:   #74c7ec
--ctp-blue:       #89b4fa
--ctp-lavender:   #b4befe
--ctp-text:       #cdd6f4
--ctp-subtext1:   #bac2de
--ctp-subtext0:   #a6adc8
--ctp-overlay2:   #9399b2
--ctp-overlay1:   #7f849c
--ctp-overlay0:   #6c7086
--ctp-surface2:   #585b70
--ctp-surface1:   #45475a
--ctp-surface0:   #313244
--ctp-base:       #1e1e2e
--ctp-mantle:     #181825
--ctp-crust:      #11111b
```

### Semantic Roles

| Role | Token | Usage |
|------|-------|-------|
| Page background | `--ctp-base` | Main content area |
| Panel background | `--ctp-mantle` | Sidebars, detail panes, headers |
| Inset/input background | `--ctp-crust` | Form inputs, code blocks, drop zones |
| Primary accent | `--ctp-mauve` | Primary buttons, active states, links, selection highlights |
| Secondary accent | `--ctp-blue` | Informational highlights, secondary actions |
| Success | `--ctp-green` | Confirmations, positive status |
| Warning | `--ctp-yellow` | Caution states, pending actions |
| Danger | `--ctp-red` | Destructive actions, errors, required indicators |
| Informational | `--ctp-teal` | Auto-generated metadata, system-assigned values |
| Body text | `--ctp-text` | Primary content |
| Secondary text | `--ctp-subtext1` | Descriptions, timestamps |
| Muted text | `--ctp-overlay1` | Placeholders, disabled states |
| Borders | `--ctp-surface0` | Dividers, panel edges |
| Hover borders | `--ctp-surface1` | Interactive element borders, row separators |
| Focus ring | `rgba(203, 166, 247, 0.25)` | `box-shadow` on focused inputs (mauve at 25%) |

### Accent Usage for Data Types

| Data type | Color | Token |
|-----------|-------|-------|
| Assembly | `--ctp-mauve` | Badge, icon tint |
| Part | `--ctp-green` | Badge, icon tint |
| Document | `--ctp-blue` | Badge, icon tint |
| Purchased | `--ctp-peach` | Badge, icon tint |
| Phantom | `--ctp-overlay1` | Badge, icon tint |

These mappings are used anywhere item types appear: list badges, detail pane headers, BOM entries, tree views.

---

## Typography

### Scale

| Role | Size | Weight | Token/Color | Transform |
|------|------|--------|-------------|-----------|
| Page title | 1.1rem | 600 | `--ctp-text` | None |
| Section header | 11px | 600 | `--ctp-overlay0` | Uppercase, `letter-spacing: 0.06em` |
| Form label | 11px | 600 | `--ctp-overlay1` | Uppercase, `letter-spacing: 0.05em` |
| Body text | 13px | 400 | `--ctp-text` | None |
| Table cell | 12px | 400 | `--ctp-text` | None |
| Caption / metadata | 11px | 400 | `--ctp-subtext0` | None |
| Badge text | 10px | 600 | Varies | Uppercase |
| Breadcrumb segment | 13px | 500 | `--ctp-subtext1` | None |
| Breadcrumb active | 13px | 600 | `--ctp-text` | None |

### Font Stack

```css
font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;
```

No external font dependencies. System fonts ensure fast rendering and native feel across platforms.

### Rules

- Never use font sizes below 10px.
- Use `font-weight: 600` for emphasis instead of bold (700). Reserve 700 for page titles only when extra weight is needed.
- `text-transform: uppercase` is reserved for section headers, form labels, and badges. Never uppercase body text or descriptions.

---

## Spacing

Base unit: **4px**. All spacing values are multiples of 4.

| Token | Value | Usage |
|-------|-------|-------|
| `xs` | 4px (0.25rem) | Tight gaps: icon-to-label, tag internal padding |
| `sm` | 8px (0.5rem) | Compact spacing: between related fields, badge padding |
| `md` | 12px (0.75rem) | Standard: form group gaps, sidebar section padding |
| `lg` | 16px (1rem) | Section separation, card padding |
| `xl` | 24px (1.5rem) | Page-level padding, major section breaks |
| `2xl` | 32px (2rem) | Page horizontal padding |

### Application

- **Page padding:** `1.5rem 2rem` (24px vertical, 32px horizontal)
- **Sidebar section padding:** `1rem 1.25rem`
- **Form grid gap:** `1.25rem 1.5rem` (row gap × column gap)
- **Table row height:** 36px minimum (padding included)
- **Table cell padding:** `0.4rem 0.75rem`

---

## Layout

### Page Structure

Every module page follows the same shell:

```
┌─────────────────────────────────────────────────┐
│ Top Nav (52px)                                  │
├──────────┬──────────────────────────────────────┤
│ App Menu │ Page Header (58px)                   │
│ (icons)  ├──────────────────────┬───────────────┤
│          │ Content Area         │ Detail Pane   │
│          │                      │ (360px)       │
│          │                      │               │
│          │                      │               │
└──────────┴──────────────────────┴───────────────┘
```

- **Top nav:** `52px` height, `--ctp-mantle` background, `1px solid --ctp-surface0` bottom border.
- **App menu sidebar:** Icon strip on the left. Module icons, tooltips on hover. Active module highlighted with `--ctp-mauve` indicator.
- **Page header:** `58px` height, `--ctp-mantle` background. Contains page title (with module icon), action buttons right-aligned.
- **Content area:** `--ctp-base` background. Scrollable. Contains list views, kanban boards, or other primary content.
- **Detail pane:** `360px` fixed width, `--ctp-mantle` background, `1px solid --ctp-surface0` left border. Appears on record selection.

### Grid Patterns

**Two-column form:**
```css
display: grid;
grid-template-columns: 1fr 1fr;
gap: 1.25rem 1.5rem;
max-width: 800px;
```

**List + detail:**
```css
display: grid;
grid-template-columns: 1fr 360px;
min-height: calc(100vh - 52px - 58px);
```

### Breakpoints

Not currently required. Silo targets desktop browsers on engineering workstations. If mobile support is added later, breakpoints will be defined at `768px` and `1024px`.

---

## Components

### Buttons

Four tiers. All buttons share a base style:

```css
display: inline-flex;
align-items: center;
gap: 0.35rem;
padding: 0.4rem 0.85rem;
border-radius: 6px;
font-size: 12px;
font-weight: 500;
cursor: pointer;
transition: all 0.15s;
```

| Tier | Name | Background | Border | Text | Hover |
|------|------|-----------|--------|------|-------|
| Primary | `.btn-primary` | `--ctp-mauve` | `--ctp-mauve` | `--ctp-crust` | `--ctp-lavender` bg + border |
| Secondary | `.btn` (default) | `--ctp-surface0` | `--ctp-surface1` | `--ctp-text` | `--ctp-surface1` bg, `--ctp-overlay0` border |
| Ghost | `.btn-ghost` | transparent | transparent | `--ctp-subtext0` | `--ctp-surface0` bg, `--ctp-text` text |
| Danger | `.btn-danger` | transparent | `--ctp-surface1` | `--ctp-red` | `rgba(243, 139, 168, 0.1)` bg, `--ctp-red` border |

Primary is used once per visible context (the main action). All other actions use secondary or ghost. Danger is only for destructive actions and always requires confirmation.

### Badges

Used for type indicators, status labels, and tags.

```css
display: inline-flex;
align-items: center;
padding: 0.15rem 0.5rem;
border-radius: 4px;
font-size: 10px;
font-weight: 600;
text-transform: uppercase;
letter-spacing: 0.03em;
```

Badges use a translucent background derived from their accent color:

```css
/* Example: assembly badge */
background: rgba(203, 166, 247, 0.15);  /* --ctp-mauve at 15% */
color: var(--ctp-mauve);
```

Standard badge colors follow the [accent usage table](#accent-usage-for-data-types). Status badges:

| Status | Color |
|--------|-------|
| Active / Released | `--ctp-green` |
| Draft / In Progress | `--ctp-blue` |
| Review / Pending | `--ctp-yellow` |
| Obsolete / Rejected | `--ctp-red` |
| Locked | `--ctp-overlay1` |

### Form Inputs

All inputs share a base style:

```css
background: var(--ctp-crust);
border: 1px solid var(--ctp-surface1);
border-radius: 6px;
padding: 0.45rem 0.65rem;
font-size: 12px;
color: var(--ctp-text);
transition: border-color 0.15s;
```

| State | Border | Shadow |
|-------|--------|--------|
| Default | `--ctp-surface1` | None |
| Hover | `--ctp-overlay0` | None |
| Focus | `--ctp-mauve` | `0 0 0 0.2rem rgba(203, 166, 247, 0.25)` |
| Error | `--ctp-red` | `0 0 0 0.2rem rgba(243, 139, 168, 0.15)` |
| Disabled | `--ctp-surface0` | None, `opacity: 0.5` |

Placeholder text: `--ctp-overlay0`. Labels sit above inputs (never inline or floating).

### Tag Input

Used for multi-value fields (projects, tags):

```css
display: flex;
flex-wrap: wrap;
gap: 0.3rem;
padding: 0.35rem 0.5rem;
background: var(--ctp-crust);
border: 1px solid var(--ctp-surface1);
border-radius: 6px;
min-height: 36px;
```

Individual tags use the badge pattern: `rgba(accent, 0.15)` background with accent text. Remove button (×) at `opacity: 0.6`, `1.0` on hover.

### Tables

```css
width: 100%;
border-collapse: collapse;
font-size: 12px;
```

| Element | Style |
|---------|-------|
| Header row | `background: --ctp-mantle`, `font-size: 11px`, uppercase, `--ctp-overlay1` text |
| Body row | `border-bottom: 1px solid --ctp-surface0` |
| Row hover | `background: --ctp-surface0` |
| Row selected | `background: rgba(203, 166, 247, 0.08)` |
| Cell padding | `0.4rem 0.75rem` |
| Text columns | Left-aligned |
| Number columns | Right-aligned |
| Date columns | Right-aligned |
| Action columns | Center-aligned |

Row actions use icon buttons (not text links). Icons at 14px, `--ctp-overlay1` default, `--ctp-text` on hover.

### Tabs

Used in detail panes and module sub-views:

```css
display: flex;
gap: 0;
border-bottom: 2px solid var(--ctp-surface0);
```

| State | Style |
|-------|-------|
| Default | `padding: 0.5rem 1rem`, `--ctp-subtext0` text, no border |
| Hover | `--ctp-text` text |
| Active | `--ctp-text` text, `font-weight: 600`, `border-bottom: 2px solid --ctp-mauve` (overlaps container border) |

### Section Dividers

Used to visually group form fields:

```css
display: flex;
align-items: center;
gap: 0.75rem;
grid-column: 1 / -1;   /* span full form grid */
margin-top: 0.75rem;
```

Contains a label (`11px`, uppercase, `--ctp-overlay0`) and a horizontal line (`flex: 1`, `1px solid --ctp-surface0`).

### Sidebar Sections

Stacked vertically within detail panes:

```css
padding: 1rem 1.25rem;
border-bottom: 1px solid var(--ctp-surface0);
```

Last section has no bottom border. Section titles follow the section header typography (11px, uppercase, `--ctp-overlay0`).

### Tooltips

Appear on hover after a 300ms delay. Position: above the target element by default, flip below if insufficient space.

```css
background: var(--ctp-surface0);
border: 1px solid var(--ctp-surface1);
border-radius: 4px;
padding: 0.3rem 0.6rem;
font-size: 11px;
color: var(--ctp-text);
box-shadow: 0 4px 12px rgba(17, 17, 27, 0.4);
```

### Breadcrumbs

Module navigation breadcrumbs:

```
Module Name  >  List View  >  Record Name  >  Sub-view
```

Separator: `>` character in `--ctp-overlay0`. Segments are clickable links in `--ctp-subtext1`. Active (final) segment is `--ctp-text` at `font-weight: 600`.

### Dropdowns / Selects

Follow the input base style. The dropdown menu:

```css
background: var(--ctp-surface0);
border: 1px solid var(--ctp-surface1);
border-radius: 6px;
box-shadow: 0 8px 24px rgba(17, 17, 27, 0.5);
padding: 0.25rem;
max-height: 240px;
overflow-y: auto;
```

Menu items:

```css
padding: 0.4rem 0.65rem;
border-radius: 4px;
font-size: 12px;
color: var(--ctp-text);
cursor: pointer;
```

Hover: `background: --ctp-surface1`. Selected: `background: rgba(203, 166, 247, 0.12)`, `color: --ctp-mauve`, `font-weight: 600`.

---

## Icons

Use [Lucide](https://lucide.dev) icons. Size: 14px for inline/table contexts, 16px for buttons and navigation, 20px for page headers and empty states.

Stroke width: 1.5px (Lucide default). Color inherits from parent text color unless explicitly set.

Do not mix icon libraries. If Lucide does not have a suitable icon, request one be added or create a custom SVG following Lucide's 24×24 grid and stroke conventions.

---

## Transitions & Animation

All interactive state changes use `transition: all 0.15s ease`. This applies to hover, focus, active, and open/close states.

No entrance animations on page load. Content renders immediately. Skeleton loaders are acceptable for async data using a pulsing `--ctp-surface0` → `--ctp-surface1` gradient.

Dropdown menus and tooltips appear instantly (no slide/fade). Collapse/expand panels (if used) transition `max-height` at `0.2s ease`.

---

## Styling Implementation

Silo's React frontend uses **inline `React.CSSProperties` objects** with `var(--ctp-*)` token references. This is the project convention and must not be changed.

### Rules

- No CSS modules, no Tailwind, no external CSS-in-JS libraries.
- Styles are defined as `const` objects at the top of each component file.
- Shared style patterns (button base, input base) can be extracted to a `styles/` directory as exported `CSSProperties` objects.
- Use `as const` or `as React.CSSProperties` for type safety.
- Pseudo-classes (`:hover`, `:focus`) require state-driven inline styles or a thin CSS file for the base pseudo-class rules.

### Example

```typescript
const styles = {
  container: {
    display: 'grid',
    gridTemplateColumns: '1fr 360px',
    height: '100%',
    overflow: 'hidden',
  } as React.CSSProperties,

  sidebar: {
    background: 'var(--ctp-mantle)',
    borderLeft: '1px solid var(--ctp-surface0)',
    display: 'flex',
    flexDirection: 'column' as const,
    overflowY: 'auto' as const,
  } as React.CSSProperties,
};
```

### Pseudo-class CSS

A single `silo-base.css` file provides pseudo-class rules that cannot be expressed inline:

```css
/* Hover, focus, and active states for core interactive elements */
.silo-input:hover { border-color: var(--ctp-overlay0); }
.silo-input:focus { border-color: var(--ctp-mauve); box-shadow: 0 0 0 0.2rem rgba(203, 166, 247, 0.25); }
.silo-btn:hover { /* per-tier overrides */ }
.silo-row:hover { background: var(--ctp-surface0); }
```

Components apply the corresponding class names alongside their inline styles. This is the only place class-based styling is used.

---

## Do / Don't

| Do | Don't |
|----|-------|
| Use `var(--ctp-*)` for every color | Hardcode hex values |
| Use the 4px spacing scale | Use arbitrary padding/margins |
| Use Lucide icons at standard sizes | Mix icon libraries |
| Use inline `CSSProperties` | Use CSS modules or Tailwind |
| One primary button per visible context | Multiple competing primary buttons |
| Use translucent accent backgrounds for badges | Use solid bright backgrounds for badges |
| Use icon buttons for row-level table actions | Use text links in table rows |
| Define styles as `const` at file top | Inline style objects in JSX |
| Show tooltips on icon-only buttons | Leave icon buttons unlabeled |
| Use section dividers to group form fields | Use cards or borders around field groups |
| Follow the breadcrumb pattern for navigation | Use nested tab bars |

---

## Appendix: CSS Custom Properties Block

Paste this at the root of the application stylesheet:

```css
:root {
  --ctp-rosewater: #f5e0dc;
  --ctp-flamingo: #f2cdcd;
  --ctp-pink: #f5c2e7;
  --ctp-mauve: #cba6f7;
  --ctp-red: #f38ba8;
  --ctp-maroon: #eba0ac;
  --ctp-peach: #fab387;
  --ctp-yellow: #f9e2af;
  --ctp-green: #a6e3a1;
  --ctp-teal: #94e2d5;
  --ctp-sky: #89dceb;
  --ctp-sapphire: #74c7ec;
  --ctp-blue: #89b4fa;
  --ctp-lavender: #b4befe;
  --ctp-text: #cdd6f4;
  --ctp-subtext1: #bac2de;
  --ctp-subtext0: #a6adc8;
  --ctp-overlay2: #9399b2;
  --ctp-overlay1: #7f849c;
  --ctp-overlay0: #6c7086;
  --ctp-surface2: #585b70;
  --ctp-surface1: #45475a;
  --ctp-surface0: #313244;
  --ctp-base: #1e1e2e;
  --ctp-mantle: #181825;
  --ctp-crust: #11111b;
}
```