What fire tends to mean
Drive, transformation, courage and passion. Often placed in the south in northern-hemisphere practice, and represented by a candle.
Finding it today
Sunlight through a window. A lamp. The warmth of a mug in your hands. A candle if you have one, or an LED tealight if open flame isn't safe where you live.
Safety, plainly
Never leave a flame unattended, and never use one in a space where it isn't allowed. Substituting a lamp does not weaken a practice.