In the candlelight, her figure faded in and out of sight.
Tips
history
Attested in Pu Songling's Qing-dynasty 聊斋志异·珠儿: 则见其若隐若现,恍惚如烟雾 - 'he saw her now visible now hidden, vague as mist.' Classic Liaozhai atmospheric writing.
usage
Used both for literal sights (mist, shadows, distant objects) and figurative meaning (hints, implications, elusive feelings). The 若...若... pattern means 'as if ... as if ...' - structurally 'as-if-hidden, as-if-visible'.