Car Costs

##Functional characteristics - Write down one note every second: only the amount + mileage is needed for refueling, and the number of liters is optional (the unit price/liter is automatically calculated if filled in); insurance, vehicle tax, NCT, and maintenance are "amounts with dates", which can be freely backfilled with historical dates. You can also add one month's insurance if you start using them in the middle of the year. - Display currencies can be switched: the default is 'CNY (RMB ¥)' or 'EUR / USD / GBP'; only the symbol and number formats are changed, and no exchange rate conversion is performed. You can switch by drop-down `Currency (display only)` on the home page. - One status page for each vehicle: vehicle photo (compressed by the server, uniformly cropped at 4:3, and also used as a thumbnail on the front page), brand/model/year/VIN, and NCT, scheduled NCT re-inspection (with countdown), vehicle tax, insurance expiration badges, will turn yellow within 14 days and red after expiration. - Complete vehicle life cycle: unused vehicles can be retired and history retained, or vehicles, records, photos and attachments can be permanently deleted after clear confirmation. - Archiving of receipts and certificates: PDFs or pictures can be hung on specific expense records or saved as vehicle-level documents; suitable for retaining invoices, insurance certificates, NCT reports and maintenance orders. The default limit for single documents is 10MB. - The real expenses can be clearly seen at a glance: annual expenses, cost per kilometer, and L/100km summarized by category are presented one by one; the home page lists the total and fuel consumption of each vehicle this year. - Milestone verification: Milestone readings are verified according to a timeline and cannot be reversed or impossible values appear. At the same time, backfilling is fully supported (as long as the new reading is between readings on adjacent dates). - Independent mileage recording: Only one mileage reading can be recorded at any time, and the latest reading is displayed on the vehicle page and participated in statistics. - Dual expiration of maintenance and timing belt: starting from the last maintenance/belt change, based on the two lines of time (default 12 months/several years) and mileage (such as 16,000 kilometers/160,000 kilometers), whichever comes first. - The entire NCT process: record expiration, count down to appointment for re-inspection, enter a new validity period after passing, and distinguish between "re-appointment required (fee)/visual re-inspection only (free)" when failing.