What are the dimensions of the case, and will it fit comfortably in a standard gaming desk setup?

Case dimensions are (L)439X(W)285X(H)400mm.

Does this Micro ATX case support full-sized graphics cards, and if so, what is the maximum GPU length it can accommodate?

Yes, this Micro ATX case supports full-sized graphics cards with a maximum length of 400mm.

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Micro ATX Case, Mini-ITX Gaming PC Case 2 Tempered Glass Panels & Front Panel Micro ATX PC Case USB 3.0 Type-C 3.2/360mm Water Cooling Ready - Black

Double-sided glass design appearance is super horizontal, bright effect can be seen at a glance.(Please put down the chassis to remove, prevent side panel from falling and touching the ceramic tile and breaking the front glass panel can also be removed)
Good compatibility: Support ATX, Micro-ATX, Mini-ITX motherboard large space, motherboard compatibility is better, easy to install!
Maximum length of graphics card 400mm: Supports 40 series graphics cards.
Strong heat dissipation system nine fan positions: create a comprehensive heat dissipation structure.
Classic I/0, faster data transfer configuration USB3.2Gen2 Type-C interface, as fast as you think!
Case dimensions :(L)439X(W)285X(H)400mm
Color: White/black