RGBA and CSS Opacity Cheat Sheet
Quick opacity values for CSS overlays, shadows, borders and disabled states using modern RGB alpha syntax.
| Use | Value | Note |
|---|---|---|
| 5% | rgb(15 23 42 / 5%) | Very subtle background tint. |
| 10% | rgb(15 23 42 / 10%) | Soft border or shadow. |
| 25% | rgb(15 23 42 / 25%) | Visible overlay or disabled text. |
| 50% | rgb(15 23 42 / 50%) | Modal backdrop on light UI. |
| 80% | rgb(15 23 42 / 80%) | Strong overlay or tooltip background. |
Copy snippet
.modal-backdrop {
background: rgb(15 23 42 / 55%);
}
.subtle-border {
border: 1px solid rgb(15 23 42 / 10%);
}