low-key
/ˈləʊˈkiː/adjective
1- not elaborate, showy, or intensive; modest or restrained低调的; 不事张扬的; 有节制的, 克制的：
their marriage was a very quiet, low-key affair.
他们的婚礼是非常宁静和低调的。
1.1
- Art & Photography having a predominance of dark or muted tones【艺术, 摄】低调的, 暗调的。