Union Square has a new all-day option in Klyde Cafe & Wine Bar, which opened this morning at 395 Geary (at Mason). With hours from 6:30 am through midnight, it's designed to be a versatile spot, serving everyone from tourists seeking breakfast to late-night post-theater crowds. The project comes from SF native Sam Fechheimer (Il Cane Rosso, Locanda, Michael Mina). His menu is full of simple, diner-esque comfort food, from pancakes, eggs, and pastries (with Moschietti organic coffee) at breakfast, to burgers, sandwiches, and a chopped salad at lunch. The wine bar portion kicks in at 3 pm, with a 60+ bottle selection (including a handful of $25 bottles from 3-7 daily), and cheese and charcuterie boards. A dozen wines are also offered by the glass, from $7-14. Dinner entrees include pastas and roasted chicken. Prices are relatively reasonable, especially for the pricey neighborhood; pretty much everything is under $20. All in all, it's a slightly more upscale take on a diner, with a friendly, French-bistro feel.