Microsoft has steadily added back features it once removed, tweaking the operating system to satisfy the users not yet living in the Post-PC era we all figured would be here by now. To one thing Microsoft has held firm, though: Windows 8 is an operating system for every device, every need, every person. Take the new Lenovo ThinkPad 8, a $399 slate that competes simultaneously with tablets (high-res screen, lots of media-friendly features) and laptops (a full version of Windows 8.1, lots of productivity-centric software). This time it’s swung the other way, building an agile brain into a fairly standard tablet body.