Use standard locale codes:
- ISO 639-1 language codes: `en`, `ja`, `de`, `fr`, `sv`, etc.
- With region when needed: `pt_BR`, `zh_CN`, `zh_TW`, `en_IE`

### Cache Behavior

- Language items are cached for 1 hour by `SystemHelper`
- Restart the application after adding new languages

### Auto-Generated Files

Never edit these files manually (marked with `@author FreeGen`):
- `FessLabels.java`
- `FessMessages.java`

    /** Default cron expression for daily tasks (daily at midnight). */
    public static final String DEFAULT_DAILY_CRON_EXPRESSION = "0 0 * * *";

    /** Default cron expression for hourly tasks (every hour). */
    public static final String DEFAULT_HOURLY_CRON_EXPRESSION = "0 * * * *";

    /** Default interval time in milliseconds for file system crawling. */
    public static final int DEFAULT_INTERVAL_TIME_FOR_FS = 1000;

inherit;\n}\n@media (min-width: 1200px) {\n  legend {\n    font-size: 1.5rem;\n  }\n}\nlegend + * {\n  clear: left;\n}\n\n::-webkit-datetime-edit-fields-wrapper,\n::-webkit-datetime-edit-text,\n::-webkit-datetime-edit-minute,\n::-webkit-datetime-edit-hour-field,\n::-webkit-datetime-edit-day-field,\n::-webkit-datetime-edit-month-field,\n::-webkit-datetime-edit-year-field {\n  padding: 0;\n}\n\n::-webkit-inner-spin-button {\n  height: auto;\n}\n\n[type=search] {\n  outline-offset: -2px;\n  -webkit-appearance:...

dding:0;margin-bottom:.5rem;font-size:calc(1.275rem + .3vw);line-height:inherit}@media (min-width:1200px){legend{font-size:1.5rem}}legend+*{clear:left}::-webkit-datetime-edit-day-field,::-webkit-datetime-edit-fields-wrapper,::-webkit-datetime-edit-hour-field,::-webkit-datetime-edit-minute,::-webkit-datetime-edit-month-field,::-webkit-datetime-edit-text,::-webkit-datetime-edit-year-field{padding:0}::-webkit-inner-spin-button{height:auto}[type=search]{outline-offset:-2px;-webkit-appearance:textfie...