trading-ui-patternslisted

# Trading UI Patterns X, TradingView, and Trading212 each solved a different part of the "financial app that doesn't feel like a spreadsheet" problem, and the three solutions are not interchangeable: X's density-and-restraint social feed, TradingView's tabular-figures terminal chrome, and Trading212's input-gated simplicity are distinct disciplines with their own failure modes. Building "in the style of" one of them from memory alone tends to nail the obvious surface (colors, rounded corners) and miss the structural details that actually make a component read as that product's — a watchlist row with no tabular digits, an order ticket whose confirm button is tappable before the input is valid, a like icon that's already filled red before anyone has tapped it. ## The one failure mode a naive rebuild won't catch on its own Direction color (red/green for up/down) is not a fixed constant — it is a function of which market's convention the data represents. US/UK/HK/most of the world uses green=up/red=down; mainland China and Taiwan use the opposite (red is auspicious, associated with rising prices). A watchlist or holdings row built and screenshot-checked against US test data, then pointed at a CN symbol feed without re-deriving the color mapping, renders every single quote backwards — and nothing crashes, nothing looks obviously wrong in a screenshot taken by someone who doesn't already know the correct CN convention. This is the same shape of bug as a sign-convention flip in a