First up, read the FAQ. This is literally one of the answers there. The FAQ is in the pinned topics. You would have had to ignore it to find the post-discussion button.

Since I'm here, I'll answer anyway
>"Idling Complete"
Long story short: You've run out of cards to gain from the idlemaster program. Steam/Valve give you only half (50%) of 1 single badge level for free. The rest you're expected to buy or trade for.
In short your idlemaster "Car" is out of fuel. You want it to get you more cards? Buy or obtain (via giveaways) more card-giving games.

To pre-empt a few followups I often get:
"Can I use <Free to play game, usually TF2> for cards?": Yes but you'll need to pay them about $20 USD to get 1 free card. Not cost effective but a nice freebie if you would spend that cash anyway.
"How do I get more games?": Check the storefront for cheap deals, you can easily get games 50c or less. Or if you're unable/unwilling to pay, join one of the dozens of giveaway groups, who will host giveaways or link to giveaways (depending on the group)
"Will turning the cards into gems/trading the cards mean it will work after they're gone?" Nope. Once your counter hits 0 that's the end.