# [Clever property usage to create a light-dark probe](https://x.com/thomas_sweet/status/2082201527234531388?s=46)

Published: Wed, Jul 29, 2026
Source: [x.com/thomas_sweet](https://x.com/thomas_sweet/status/2082201527234531388?s=46)

```css
@property --scheme-probe {
  syntax: "<color>";
  inherits: true;
  initial-value: white;
}

.card {
  --scheme-probe: light-dark(white, black);
}

@container style(--scheme-probe: black) {
  .swatch {
    border-style: dashed; /* any property */
  }
}
```