perf: improve header performance by hiding when not in view (Intersection Observer API)

Description

Contributor guide

Tech stack

typescriptjavascripthtmlcss

Domain

frontendperformance

Issue type

performance

DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.

3

Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.

1-3 hours

Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.

stale

ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.

clear

Prerequisites

Intersection Observer APITypeScriptCSS

Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.

70

Research direction

This task involves implementing the Intersection Observer API to hide the header when it is not in the viewport. Start by locating the header component (likely in src/components/Header.tsx or similar). Add an effect that creates an IntersectionObserver to observe the header element. When the intersection ratio is 0, add a CSS class to hide the header (e.g., display: none). Ensure the header reappears when it becomes visible again. Test the behavior on scroll. Consider performance implications and ensure no layout shift.