:focus-visible vs outline: none — an interactive frontend engineering case study with broken/fixed demo, junior-to-staff tone switcher, and Casey AI guide.

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prefers-reduced-motion Contracts — an interactive frontend engineering case study with broken/fixed demo, junior-to-staff tone switcher, and Casey AI guide.

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When Micro-Frontends Stop Sharing a Design System — an interactive frontend engineering case study with broken/fixed demo, junior-to-staff tone switcher, and Casey AI guide.

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MCP: Host, Client, and Server Roles — an interactive frontend engineering case study with broken/fixed demo, junior-to-staff tone switcher, and Casey AI guide.

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Context Window Budget for FE Tasks — an interactive frontend engineering case study with broken/fixed demo, junior-to-staff tone switcher, and Casey AI guide.

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Paste Error, Zero Learning (Anti-pattern) — an interactive frontend engineering case study with broken/fixed demo, junior-to-staff tone switcher, and Casey AI guide.

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Streaming Tokens Without Layout Thrash — an interactive frontend engineering case study with broken/fixed demo, junior-to-staff tone switcher, and Casey AI guide.

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@media (prefers-reduced-motion) — an interactive frontend engineering case study with broken/fixed demo, junior-to-staff tone switcher, and Casey AI guide.

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One Listener, Thousand Rows — an interactive frontend engineering case study with broken/fixed demo, junior-to-staff tone switcher, and Casey AI guide.

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Static Site, Zero Backend (L0) — an interactive frontend engineering case study with broken/fixed demo, junior-to-staff tone switcher, and Casey AI guide.

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The One Pixel That Broke the Layout — an interactive frontend engineering case study with broken/fixed demo, junior-to-staff tone switcher, and Casey AI guide.

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Z-Index Is Not Magic — an interactive frontend engineering case study with broken/fixed demo, junior-to-staff tone switcher, and Casey AI guide.

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Ghost Updates and Race Conditions — an interactive frontend engineering case study with broken/fixed demo, junior-to-staff tone switcher, and Casey AI guide.

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Closures and Stale State in Handlers — an interactive frontend engineering case study with broken/fixed demo, junior-to-staff tone switcher, and Casey AI guide.

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The Event Loop: One Thread, Many Queues — an interactive frontend engineering case study with broken/fixed demo, junior-to-staff tone switcher, and Casey AI guide.

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fetch + AbortController: Cancel Ghost Requests — an interactive frontend engineering case study with broken/fixed demo, junior-to-staff tone switcher, and Casey AI guide.

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When Skeletons Beat Spinners (Product) — an interactive frontend engineering case study with broken/fixed demo, junior-to-staff tone switcher, and Casey AI guide.

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The Layout Shift You Forgot (Fonts) — an interactive frontend engineering case study with broken/fixed demo, junior-to-staff tone switcher, and Casey AI guide.

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LCP Is Often Text, Not Your Hero Image — an interactive frontend engineering case study with broken/fixed demo, junior-to-staff tone switcher, and Casey AI guide.

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Fake Progress Bars and Trust — an interactive frontend engineering case study with broken/fixed demo, junior-to-staff tone switcher, and Casey AI guide.

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Why Skeleton Screens Beat Spinners — an interactive frontend engineering case study with broken/fixed demo, junior-to-staff tone switcher, and Casey AI guide.

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Two Trees: Hydration Explained — an interactive frontend engineering case study with broken/fixed demo, junior-to-staff tone switcher, and Casey AI guide.

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Keys Are Identity, Not Index — an interactive frontend engineering case study with broken/fixed demo, junior-to-staff tone switcher, and Casey AI guide.

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Secrets in the Client Bundle (Never) — an interactive frontend engineering case study with broken/fixed demo, junior-to-staff tone switcher, and Casey AI guide.

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URL as Source of Truth for Filters — an interactive frontend engineering case study with broken/fixed demo, junior-to-staff tone switcher, and Casey AI guide.

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Fitts's Law and Tap Target Sizing — an interactive frontend engineering case study with broken/fixed demo, junior-to-staff tone switcher, and Casey AI guide.

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Hick's Law: Why More Nav Items Slow Users Down — an interactive frontend engineering case study with broken/fixed demo, junior-to-staff tone switcher, and Casey AI guide.

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Miller's Rule: Chunking Long Forms — an interactive frontend engineering case study with broken/fixed demo, junior-to-staff tone switcher, and Casey AI guide.

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The 400ms Rule: Doherty Threshold — an interactive frontend engineering case study with broken/fixed demo, junior-to-staff tone switcher, and Casey AI guide.

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Gestalt: Spacing Is Syntax — an interactive frontend engineering case study with broken/fixed demo, junior-to-staff tone switcher, and Casey AI guide.

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Cognitive Load and Error Recovery UX — an interactive frontend engineering case study with broken/fixed demo, junior-to-staff tone switcher, and Casey AI guide.

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