# Real-Time Bitcoin Card Update

## ✅ Feature Implemented

The main Bitcoin card on the dashboard now updates in **real-time** using WebSocket data, exactly like the market list.

### Changes Made

#### 1. HTML IDs Added
Added specific IDs to the Bitcoin card elements so JavaScript can target them:
- **Price**: Added `id="btc-card-price"`
- **24h Change**: Added `id="btc-card-change"`

#### 2. WebSocket Subscription
Added `btc_usdt` to the WebSocket pairs list:
```javascript
'btc_usdt': { 
    priceEl: 'btc-card-price', 
    changeEl: 'btc-card-change', 
    lastPrice: null 
}
```

#### 3. Intelligent Styling Logic
Refactored the `updateMarketData` function.
- **Before**: It blindly overwrote all CSS classes with `text-[10px]`, which would have made the main Bitcoin card text too small.
- **After**: It now intelligently **toggles** only the color classes (`text-green-500` / `text-red-500`) while preserving existing sizing and styling classes.
  - Bitcoin Card: Keeps `text-sm font-bold` (Normal size)
  - Market List: Keeps `text-[10px] font-bold` (Small size)

### How It Works

1.  **Connects**: Establishes one secure WebSocket connection to LBank.
2.  **Subscribes**: Listens for `btc_usdt`, `bnb_usdt`, `pol_usdt`, `sol_usdt`.
3.  **Updates**: When a Bitcoin price tick arrives:
    *   Updates the price number instantly.
    *   Updates the percentage change.
    *   Changes color to **Green** if positive, **Red** if negative.

### Verification

*   **Price**: Check the "Price" at the bottom of the Bitcoin card. It should change roughly every second.
*   **Color**: If Bitcoin goes up/down, the percentage text color will change accordingly.
*   **Performance**: Uses the existing connection, so 0 additional latency.

The Bitcoin card is now live! 🚀