Go uses a special reference date/time to define layouts for `time.Format()` and `time.Parse()`.

Reference time:

• `Mon Jan 2 15:04:05 MST 2006`

Common numeric form:

• `2006-01-02 15:04:05`

• `2006` = year
• `01` = month
• `02` = day
• `15` = hour (24h)
• `04` = minute
• `05` = second

layout := "2006-01-02 15:04:05"
t, _ := time.Parse(layout, "2026-01-09 10:30:00")
fmt.Println(t.Format(layout))

• `YYYY-MM-DD` is NOT valid in Go layouts.
• Use `time.RFC3339` for APIs when possible.

• reference /ˈrefərens/: tham chiếu
• layout /ˈleɪaʊt/: mẫu định dạng
• represent /ˌreprɪˈzent/: đại diện
• placeholder /ˈpleɪsˌhoʊldər/: ký hiệu thay thế