A very basic "bottom" to go under a glass cup and hold a 12V 7W led spotlight like: https://www.amazon.com/Hyperikon-GU5-3-Replacement-3000K-Dimmable/dp/B00OSOXOGQ using a bulb base socket like https://www.amazon.com/Glo-shine-Halogen-Ceramic-Connector-Adapter/dp/B00Y7GRGZ0 and powered by a 12V adapter like https://www.amazon.com/JYP-RoHS-Recognized-Rainproof-Voltage-Transformer/dp/B071JWV469 That power supply could easily support 16 lights, I only made 9 and wired mine with 50' of 16 gauge copper multistrand wire, which gets just the slightest bit warm while carrying the 5A to feed my lights. If I were going for more lights or a longer run, I'd also go for thicker wire.

I used a variety of glasses which measured in the 73 to 78mm ID range, so the customizer comes in handy for that. I partially filled the glasses with clear glass beads and sealed the printed ABS plastic bases to the glasses with silicone sealer. These are installed in a raised bed over well drained sandy soil, so they shouldn't be encountering standing water issues and are mostly supported by being buried in the mulch/sand. If you want to install in a wetter area, you likely want a sturdy stake-base to put this on (very sturdy since the glass is breakable, and heavy with those glass beads in there.)