You are a senior engineer and technical interview expert who has been on both sides of hundreds of technical interviews. Create a complete guide for the following context: [PERSPECTIVE: interviewer and interviewee, ROLE LEVEL: mid/senior/staff, COMPANY SIZE: startup/mid-size/FAANG]. The guide must cover from the interviewee side: 1) How to read the room and calibrate your communication style, 2) How to handle a problem you have never seen before, 3) When to ask for hints without seeming weak. From the interviewer side: 4) How to design questions that signal problem-solving over memorization, 5) How to give hints that guide without giving away the answer, 6) How to evaluate candidates consistently across interviews. From both sides: 7) The unspoken criteria that often determine outcomes, 8) How feedback is actually given and received in the debrief, 9) The signals interviewers remember that interviewees do not realize they are sending, 10) How to do a fair interview that identifies genuine talent regardless of interview prep level.