oikos/docs/SPEC.md

Oikos - Product Specification

Self-hosted family planner web app for a single household (2–6 people). No app store, no public access. Deployment via Docker on a private Linux server behind an Nginx reverse proxy with SSL.

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Data Model

Every table: id INTEGER PRIMARY KEY, created_at TEXT, updated_at TEXT (ISO 8601).

Users

Column	Type	Constraint
username	TEXT	UNIQUE NOT NULL
display_name	TEXT
password_hash	TEXT	bcrypt
avatar_color	TEXT	HEX color code
role	TEXT	'admin' or 'member'

Tasks

Column	Type	Constraint
title	TEXT	NOT NULL
description	TEXT
category	TEXT	Household, School, Shopping, Repairs, Other
priority	TEXT	none (default), low, medium, high, urgent
status	TEXT	open, in_progress, done
due_date	TEXT	DATE, nullable
due_time	TEXT	TIME, nullable
assigned_to	INTEGER	FK → Users
created_by	INTEGER	FK → Users, NOT NULL
is_recurring	INTEGER	0/1
recurrence_rule	TEXT	iCal RRULE
parent_task_id	INTEGER	FK → Tasks (max 2 levels)

Shopping Lists

Column	Type	Constraint
name	TEXT	NOT NULL (e.g. "Supermarket", "Hardware store")

Shopping Items

Column	Type	Constraint
list_id	INTEGER	FK → Shopping Lists, NOT NULL
name	TEXT	NOT NULL
quantity	TEXT	e.g. "500g", "2 pieces"
category	TEXT	FK → Shopping Categories (by name)
is_checked	INTEGER	0/1
added_from_meal	INTEGER	FK → Meals, nullable

Shopping Categories

Custom, household-wide category list for shopping items. Replaces the old hardcoded category set.

Column	Type	Constraint
id	INTEGER	PRIMARY KEY
name	TEXT	NOT NULL
sort_order	INTEGER	NOT NULL
created_at	TEXT
updated_at	TEXT

Meals

Column	Type	Constraint
date	TEXT	DATE, NOT NULL
meal_type	TEXT	breakfast, lunch, dinner, snack
title	TEXT	NOT NULL
notes	TEXT
recipe_url	TEXT	nullable, URL to recipe
recipe_id	INTEGER	FK → Recipes (ON DELETE SET NULL), nullable
created_by	INTEGER	FK → Users, NOT NULL

Recipes

Reusable recipe cards that can be pre-filled into meal slots.

Column	Type	Constraint
title	TEXT	NOT NULL
notes	TEXT
recipe_url	TEXT	nullable
created_by	INTEGER	FK → Users (CASCADE delete)

Recipe Ingredients

Column	Type	Constraint
recipe_id	INTEGER	FK → Recipes (CASCADE delete), NOT NULL
name	TEXT	NOT NULL
quantity	TEXT
category	TEXT	NOT NULL (default 'Sonstiges')

Meal Ingredients

Column	Type	Constraint
meal_id	INTEGER	FK → Meals, NOT NULL
name	TEXT	NOT NULL
quantity	TEXT
on_shopping_list	INTEGER	0/1

Calendar Events

Column	Type	Constraint
title	TEXT	NOT NULL
description	TEXT
start_datetime	TEXT	DATETIME, NOT NULL
end_datetime	TEXT	DATETIME
all_day	INTEGER	0/1
location	TEXT
color	TEXT	HEX
assigned_to	INTEGER	FK → Users
created_by	INTEGER	FK → Users, NOT NULL
external_calendar_id	TEXT	ID from external calendar
external_source	TEXT	local, google, apple, ics
recurrence_rule	TEXT	iCal RRULE
subscription_id	INTEGER	FK → ICS Subscriptions (CASCADE delete)
user_modified	INTEGER	0/1 — prevents sync overwrite when 1
calendar_ref_id	INTEGER	FK → External Calendars (ON DELETE SET NULL)

External Calendars

Display metadata (name, color) for synced Google/Apple calendars. Populated automatically during sync.

Column	Type	Constraint
source	TEXT	'google' or 'apple', NOT NULL
external_id	TEXT	Calendar ID from the provider, NOT NULL
name	TEXT	Display name from the provider, NOT NULL
color	TEXT	Background color from the provider (HEX)
UNIQUE		(source, external_id)

Notes

Column	Type	Constraint
title	TEXT	nullable
content	TEXT	NOT NULL
color	TEXT	HEX
pinned	INTEGER	0/1
created_by	INTEGER	FK → Users, NOT NULL

Contacts

Column	Type	Constraint
name	TEXT	NOT NULL
category	TEXT	Doctor, School/Nursery, Authority, Insurance, Tradesperson, Emergency, Other
phone	TEXT
email	TEXT
address	TEXT
notes	TEXT

Budget Entries

Column	Type	Constraint
title	TEXT	NOT NULL
amount	REAL	NOT NULL (positive = income, negative = expense)
category	TEXT	Groceries, Rent, Insurance, Transport, Leisure, Clothing, Health, Education, Other
date	TEXT	DATE, NOT NULL
is_recurring	INTEGER	0/1
recurrence_rule	TEXT	iCal RRULE
recurrence_parent_id	INTEGER	FK → Budget Entries (generated instance points to original)
created_by	INTEGER	FK → Users, NOT NULL

Budget Recurrence Skipped

Stores instances of a recurring entry deleted by the user so they are not re-generated.

Column	Type	Constraint
parent_id	INTEGER	FK → Budget Entries, NOT NULL
month	TEXT	YYYY-MM, NOT NULL
PRIMARY KEY		(parent_id, month)

ICS Subscriptions

External calendar feeds subscribed by users (read-only, auto-synced).

Column	Type	Constraint
name	TEXT	NOT NULL
url	TEXT	NOT NULL (https:// or webcal://)
color	TEXT	HEX, default #6366f1
shared	INTEGER	0/1 — visible to all family members when 1
created_by	INTEGER	FK → Users (SET NULL on delete)
etag	TEXT	HTTP ETag for conditional fetch
last_modified	TEXT	HTTP Last-Modified for conditional fetch
last_sync	TEXT	ISO timestamp of last successful sync
created_at	TEXT	ISO timestamp

Sync Config

Key-value table for OAuth tokens and CalDAV credentials.

Column	Type	Constraint
key	TEXT	PRIMARY KEY
value	TEXT	NOT NULL

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Modules

Dashboard (/)

Responsive grid: 1 column on mobile, 2 on tablet, 3 on desktop.

Widgets:

• Greeting: "Good [morning/afternoon/evening], [Name]" + date
• Weather: OpenWeatherMap proxy, 3-day preview, refresh every 30 min, hide widget on API error
• Upcoming events: next 3–5, color-coded by person
• Urgent tasks: priority urgent/high + due_date ≤48h
• Today's meals: meals for the current day
• Pinboard preview: 2–3 pinned notes
• FAB (quick actions): + Task, + Event, + Shopping list item, + Note

Skeleton loading instead of spinners. Clicking any widget navigates to that module.

Tasks (/tasks)

Views:

• List view (default): grouped by category or due date (toggleable), filter: person, priority, status
• Kanban: columns Open → In Progress → Done, drag & drop
• View mode persisted in localStorage; URL parameter ?view=kanban overrides (useful for tablet kiosk setups)

Features:

• CRUD + subtasks (max 2 levels, checkbox list, progress bar)
• Assignment to users (avatar color as indicator)
• Priorities shown visually via color/icon
• Recurring: automatically create next instance on completion
• Mobile swipe: left = done, right = edit
• Badge for overdue tasks

Shopping Lists (/shopping)

• Multiple lists in parallel
• Items: name, category, quantity, checkbox
• Grouping by category (aisle logic)
• Integration with meal plan: "Add ingredients to shopping list" transfers with source reference
• Checked items shown with strikethrough + moved to bottom
• "Clear list" = remove checked items only
• Autocomplete from previous entries (local)
• Mobile swipe: left = check/uncheck, right = delete; × delete button hidden on mobile (swipe takes over)

Meal Plan (/meals)

Weekly view (Mon–Sun), slots: breakfast / lunch / dinner / snack.

• Meal: title + notes + ingredient list
• "→ Shopping list" button: transfer unchecked ingredients of the week to a selected list
• Week navigation forward/back
• Drag & drop between days/slots
• Autocomplete from meal history
• Recipe integration: Select a saved recipe from the meal modal to auto-fill title, notes, URL, and ingredients. Scale ingredient quantities by a numeric factor. Save the current meal as a new recipe with one click.
• Customizable meal visibility: In Settings, users can toggle which meal types (breakfast, lunch, dinner, snack) are shown in the planner. Stored as household-wide preference in sync_config (key: visible_meal_types). At least one type must remain active.

Recipes (/recipes)

Reusable recipe cards linked to meal slots.

• CRUD: title, notes, recipe link, per-ingredient category
• Duplicate existing recipes
• "Add to meal plan" navigates to /meals with the selected recipe pre-filled in the modal
• REST API: GET/POST /api/v1/recipes, PUT/DELETE /api/v1/recipes/:id with ingredient sync

Calendar (/calendar)

Views: Month (default, dot indicators), Week (hour grid), Day (timeline), Agenda (list).

• CRUD: title, description, start/end, all-day, location, color, assignment
• Color-coding per person
• Recurring via iCal RRULE
• Google Calendar: OAuth 2.0, Calendar API v3, two-way sync
• Apple Calendar: CalDAV (tsdav), two-way sync
• ICS Subscriptions: Subscribe to any public ICS/webcal URL (e.g. public holidays, sports schedules). Per-subscription color, private/shared visibility, manual "Sync now" and automatic sync on the shared interval. RRULE events expanded into a rolling ±6/+12 month window. SSRF-protected (DNS pre-resolution), ETag/Last-Modified conditional fetch, 10 MB limit, 15 s timeout. User-edited events are protected from being overwritten (user_modified); a "Reset to original" link restores them.
• External calendar names & colors: Google and Apple sync stores each calendar's display name and background color in the external_calendars table (migration v14). A colored event-cal-label badge appears in event popups, agenda, month, week, and day views when cal_name is present.
• Event location: Event popup and dashboard display the location field with RFC 5545 backslash-escape normalization (\n, \,, \;, \\) via fmtLocation() in public/utils/html.js.
• Configurable sync interval (default 15 min)
• External events visually distinguishable
• Conflicts: external event wins, local additions are preserved

Notes (/notes)

Masonry grid with colored sticky notes.

• CRUD: title (optional), content, color
• Pin → appears at top + on dashboard
• Creator shown (avatar color)
• Markdown-light: bold, italic, lists (regex-based)
• Full-text search: client-side filter bar, filters instantly by title + content

Contacts (/contacts)

• CRUD with category filter
• Phone: tel: link, email: mailto: link
• Address: Maps link (Google/Apple via user agent)
• Real-time search filter
• vCard export: each contact downloadable as .vcf (GET /api/v1/contacts/:id/vcard)
• vCard import: upload file → client-side parser (FN, TEL, EMAIL, ADR, NOTE, CATEGORIES) → create contact

Login (/login)

Unauthenticated users are redirected here. No public registration form - admin creates users via setup wizard (setup.js) or Settings.

• Username + password form
• Error display for wrong credentials
• Rate limiting: 5 attempts/min/IP, 15-min lockout
• After successful login: redirect to dashboard

Settings (/settings)

User management and app configuration. Logged-in users only.

• Profile: change display name, avatar color, password
• User management (admin): create new users, edit/delete existing users, assign roles (admin/member)
• Calendar integration: connect/disconnect Google Calendar OAuth, store Apple Calendar (CalDAV) credentials, configure sync interval; manage ICS URL subscriptions (add, delete, sync now, set color and visibility)
• Weather: configure OpenWeatherMap location
• Language: System (follows navigator.language), German, English, Spanish, French, Italian, Swedish, Greek, Russian, Turkish, Chinese - via oikos-locale-picker web component; switch without page reload
• Tab navigation: Settings is organized in six tabs (General, Meals, Budget, Shopping, Calendar, Account). Sticky tab bar, active tab persists in sessionStorage, Calendar tab auto-activates after OAuth callbacks.
• App info: version, license

Budget (/budget)

Views:

• Monthly overview: income vs. expenses, balance, bar chart by category (Canvas, no library)

• Transaction list: chronological, filterable

• CRUD: title, amount, category, date

• Recurring entries

• Monthly comparison (current vs. previous month)

• CSV export

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Design System

Colors (CSS Custom Properties)

Source of truth: public/styles/tokens.css. Key values (as of v0.20.39):

Palette rationale: Warm-tinted neutral scale (#FAFAF8 → #121211) anchored by an Indigo-600 primary (#4F46E5) that harmonises with the Calendar module violet and the secondary accent. Module colors are semantically separated from severity colors — no hue shared without explicit documentation in tokens.css.

:root {
  /* Neutral canvas — warm linen/unbleached-paper atmosphere */
  --color-bg:              #F5F4F1;   /* neutral-100 */
  --color-surface:         #FFFFFF;
  --color-border:          #E8E7E2;   /* neutral-200 */
  --color-text-primary:    #1C1C1A;   /* neutral-900, 14.7:1 on bg */
  --color-text-secondary:  #6C6B67;   /* neutral-600, 5.0:1 on white */
  --color-text-tertiary:   #6A6964;   /* 4.61:1 on bg */

  /* Primary accent — Indigo (warm bias, harmonises with Calendar/violet) */
  --color-accent:           #4F46E5;  /* Indigo-600, 4.93:1 on white (AA) */
  --color-accent-hover:     #4338CA;  /* Indigo-700, 7.04:1 (AAA) */
  --color-accent-active:    #3730A3;  /* Indigo-800 */
  --color-accent-deep:      #2E2D82;  /* deep Indigo for gradients/weather */
  --color-accent-secondary: #7C5CFC;  /* violet — logo gradient, same Indigo family */
  --color-accent-light:     #EEF2FF;  /* Indigo-50 */
  --color-accent-subtle:    #E0E7FF;  /* Indigo-100 */
  --color-btn-primary:      #4338CA;  /* Indigo-700, 7.04:1 on white (AAA) */
  --color-btn-primary-hover:#3730A3;

  /* Severity — hue-separated from module colors */
  --color-success:       #15803D;     /* 4.54:1 */
  --color-warning:       #A15C0A;     /* 5.23:1 — Amber, distinct from --module-meals */
  --color-danger:        #B91C1C;     /* Red-700, 6.90:1 (AAA) */
  --color-info:          #0969DA;     /* 4.64:1 */

  /* Module accents — domain-specific, not interchangeable with severity */
  --module-dashboard:  #4F46E5;   /* Indigo — follows primary accent */
  --module-tasks:      #15803D;   /* Green — intentional share with --color-success */
  --module-calendar:   #8250DF;   /* Violet */
  --module-meals:      #C2410C;   /* Orange-700 */
  --module-shopping:   #DB2777;   /* Pink-600 — distinct from Meals/Warning */
  --module-notes:      #CA8A04;   /* Gold, 4.08:1 — icons/large-text only */
  --module-contacts:   #0969DA;   /* Blue — distinct from Indigo primary */
  --module-budget:     #0F766E;   /* Teal-700, 5.11:1 */
  --module-settings:   #6E7781;   /* Neutral grey */

  /* Priority */
  --color-priority-medium: #A16207;  /* Amber-700, 6.3:1 — distinct from Warning+Meals */
  --color-priority-high:   #C2410C;  /* = --module-meals (documented share: "hot") */
  --color-priority-urgent: #B91C1C;  /* = --color-danger (documented share: "destructive") */

  /* Glass layer tokens */
  --glass-bg: rgba(255,255,255,0.72);
  --glass-border: rgba(255,255,255,0.55);
  --blur-md: 16px;
  --radius-glass-button: 9999px;       /* capsule */
  --ease-glass: cubic-bezier(0.34, 1.56, 0.64, 1); /* spring */

  /* Glass Vibrancy tokens (Phase 4) */
  --glass-bg-card: rgba(255,255,255,0.52);
  --glass-bg-card-hover: rgba(255,255,255,0.65);
  --glass-bg-input: rgba(255,255,255,0.48);
  --glass-bg-toolbar: rgba(255,255,255,0.58);
  --glass-tint-strength: 6%;

  /* Glass inset specular highlights */
  --glass-inset-soft:     inset 0 1px 0 rgba(255,255,255,0.18);
  --glass-inset-base:     inset 0 1px 0 rgba(255,255,255,0.20);
  --glass-inset-medium:   inset 0 1px 0 rgba(255,255,255,0.22);
  --glass-inset-elevated: inset 0 1px 0 rgba(255,255,255,0.28);
  --glass-inset-strong:   inset 0 1px 0 rgba(255,255,255,0.32);
}

/* Dark mode — Hue preserved (Indigo-400), only Lightness/Saturation adjusted.
   Private --_name tokens prevent duplication between @media and [data-theme]. */
@media (prefers-color-scheme: dark) {
  :root {
    --color-bg: #1A1A18;       /* deep warm */
    --color-surface: #222220;
    --color-border: #2C2C2A;
    --color-text-primary: #F5F4F1;
    --color-text-secondary: #AEADB0;
    --color-accent:            #818CF8;  /* Indigo-400, 6.8:1 on dark surface */
    --color-accent-hover:      #6366F1;  /* Indigo-500 */
    --color-accent-active:     #4F46E5;  /* Indigo-600 — mirrors light primary */
    --color-accent-light:      #2E2D5B;
    --color-accent-subtle:     #252255;
    --color-btn-primary:       #6366F1;  /* 5.5:1 */
    --color-btn-primary-hover: #4F46E5;
    --module-dashboard: #818CF8;
    --module-meals:     #FB923C;  /* Orange-400 */
    --module-shopping:  #F472B6;  /* Pink-400 — mirrors light entanglement */
    --module-budget:    #2DD4BF;  /* Teal-400 */
    --meal-dinner:      #818CF8;
    --glass-bg: rgba(28,28,26,0.75);
    --glass-border: rgba(255,255,255,0.12);
    --glass-bg-card: rgba(38,38,36,0.50);
    --glass-tint-strength: 8%;
  }
}

Typography

• System font stack, headings 600–700
• Body: 16px mobile, 15px desktop, line-height 1.5
• Caption: 13px, var(--color-text-secondary)

Glass Layer (public/styles/glass.css)

Additive CSS file loaded globally after layout.css. Implements a Liquid Glass design language inspired by Apple's iOS 26 Liquid Glass, adapted for CSS/web:

Phase 1-3 (Shell + Components + Polish):

• Translucent surfaces: backdrop-filter: blur() on bottom nav, sidebar, modal overlay, cards on hover. All blur effects are inside @supports (backdrop-filter: blur(1px)) for progressive enhancement.
• Glass tokens: Section 16 of tokens.css defines --glass-bg*, --glass-border*, --blur-xs through --blur-xl, --opacity-glass-*, --glass-highlight*, --glass-shadow-sm/md/lg, --radius-glass-card/inner/chip/button, --ease-glass, --transition-glass. Full dark mode overrides.
• Capsule shapes: Buttons, FAB, and search inputs use --radius-glass-button (pill shape).
• Spring animations: Modal entrance (glass-modal-scale-in / glass-sheet-in), page transitions, and list stagger all use cubic-bezier(0.34, 1.56, 0.64, 1) spring easing.
• FAB attention pulse: fab-ring-pulse keyframe expands a ring around the FAB to signal readiness.
• Nav auto-hide: Bottom bar hides on scroll-down, reappears on scroll-up (mobile only, < 1024px, 4 px hysteresis). CSS: .nav-bottom--hidden { transform: translateY(calc(100% + var(--safe-area-inset-bottom))); }. JS: initNavHideOnScroll() in router.js.

Phase 4 (Vibrancy + Tint):

• Deeper glass penetration: Dashboard widgets, task cards, note items, meal slots, form inputs, toolbars, group toggles, and FAB speed-dial actions all use semi-transparent glass backgrounds (--glass-bg-card, 52% opacity) with backdrop-filter: blur() saturate() so underlying content shines through.
• Module tint: Each glass surface receives a subtle accent color gradient overlay via ::after pseudo-element using color-mix(in srgb, var(--module-accent) var(--glass-tint-strength), transparent). Strength is 6% in light mode, 8% in dark mode.
• App vibrancy background: app-content uses a radial gradient with the active module accent at 3% opacity to provide an ambient color base that glass elements refract.
• Load-order safety: All Phase 4 glass selectors use parent-scoped specificity (.dashboard .widget, .tasks-page .task-card, .meals-page .meal-slot) to prevent override by on-demand page CSS that loads after glass.css.

Accessibility: prefers-reduced-transparency, prefers-reduced-motion, and prefers-contrast: more blocks deactivate blur/animation and restore solid fallbacks across all phases.

Components

• Cards: var(--color-surface) base, glass vibrancy via var(--glass-bg-card) + backdrop-filter: blur(8px) saturate(180%) when supported. var(--radius-md), var(--shadow-sm). Module tint overlay via ::after. Consistent padding var(--space-4) (16px) across all modules.
• Buttons: Primary = accent + white. Secondary = outline. Min-height 44px. Capsule shape via --radius-glass-button. Submit buttons show success (checkmark, 700ms green via .btn--success) and error (shake via .btn--shaking).
• Inputs: var(--radius-sm), 1.5px border, padding 12px 16px. Search inputs use --radius-glass-button and --glass-border-subtle. [required] fields receive validation status on blur (.form-field--error / .form-field--valid). Enter moves focus to the next field; Enter on the last field triggers submit.
• FAB (Floating Action Button): Color follows the module accent token (--module-accent) - each module defines its own accent color. Specular inner highlight + attention ring pulse. Hidden when the virtual keyboard is open (visualViewport.resize, threshold 75% of window height).
• Module accent colors: --module-accent is applied on three visual layers - (1) active nav tab (bottom bar + sidebar stripe), (2) toolbar border-top: 3px, (3) cards/rows border-left: 3px. The active accent is written to --active-module-accent on :root on every navigation change. Falls back to --color-accent for pages without a module context.
• Navigation: Bottom tab bar on mobile (Dashboard, Tasks, Calendar, Meals, More), auto-hides on scroll-down. Sidebar on desktop. Both use glass blur surface.
• Transitions: Directional slide-X animation on page change (forward = from right, back = from left, 200ms) with spring easing. Respects prefers-reduced-motion.
• Empty states: Consistent .empty-state class across all modules (icon + title + description, centered). Compact variant .empty-state--compact for meal slots.
• Modals: Centered panel on desktop with glass overlay. On mobile (< 768px) bottom sheet - spring slide-in from below, sheet handle visible, swipe-to-close (> 80px downward). focusin scrolls inputs into view when the virtual keyboard is open.
• List animation: Staggered spring fade-in on load (stagger() from public/utils/ux.js) - max 5 elements staggered (30ms gap), rest appear immediately.
• Vibration: vibrate() from public/utils/ux.js - short pulses for light actions (10-40ms), pattern [30, 50, 30] for destructive actions (delete). Respects prefers-reduced-motion.
• PWA install prompt: Appears only after 2 user interactions. Dismiss window 7 days; interaction counter resets after dismiss.
• PWA offline fallback: Service worker serves /offline.html when the network is unreachable and index.html is not cached. Includes a reload button.

Breakpoints

• Mobile: < 768px (1 column, bottom nav)
• Tablet: 768–1024px (2 columns, bottom nav)
• Desktop: > 1024px (sidebar + content)

---

Internationalization (i18n)

All UI strings are managed via public/i18n.js. No hardcoded text in JS files outside of locale files.

Architecture

• Module: public/i18n.js - exports: initI18n(), setLocale(), t(key, params?), getLocale(), getSupportedLocales(), formatDate(date), formatTime(date)
• Locale files: public/locales/de.json (reference), public/locales/en.json, public/locales/es.json, public/locales/fr.json, public/locales/it.json, public/locales/sv.json, public/locales/el.json, public/locales/ru.json, public/locales/tr.json, public/locales/zh.json, public/locales/ja.json, public/locales/ar.json, public/locales/hi.json, public/locales/pt.json - structure: { "module.camelCaseKey": "Value" }
• Variables: {{variable}} syntax in translation strings, e.g. t('tasks.assignedTo', { name: 'Anna' })
• Fallback chain: active locale → German (de) → key itself
• Date format: Intl.DateTimeFormat with current locale - use formatDate() and formatTime() from i18n.js

Language Detection

1. localStorage entry oikos-locale (manual selection)
2. navigator.languages[0] (browser language)
3. Fallback: en

Supported Languages

Code	Language	Status
de	German	Reference locale (all keys defined here)
en	English	Full translation
es	Spanish	Full translation
fr	French	Full translation (added v0.16.3)
it	Italian	Full translation (added v0.5.8)
sv	Swedish	Full translation (added v0.11.3)
el	Greek	Full translation (added v0.16.3)
ru	Russian	Full translation (added v0.16.3)
tr	Turkish	Full translation (added v0.16.3)
zh	Chinese (Simplified)	Full translation (added v0.16.3)
ja	Japanese	Full translation (added v0.19.0)
ar	Arabic	Full translation (added v0.19.0)
hi	Hindi	Full translation (added v0.19.0)
pt	Portuguese	Full translation (added v0.19.0)

Adding a New Language

1. Create public/locales/xx.json (copy of de.json, translate)
2. Add 'xx' to SUPPORTED_LOCALES in public/i18n.js
3. Add label in oikos-locale-picker (LOCALE_LABELS['xx'] = 'Name')

Locale Switching

setLocale(locale) saves the selection, loads the new locale file, and fires the locale-changed custom event. All page modules and web components listen to this event and re-render - no page reload required.