Bootstrap Forms
<!DOCTYPE html> <html lang="en"> <head> <meta charset="utf-8"> <meta name="viewport" content="width=device-width, initial-scale=1"> <link href="https://cdn.jsdelivr.net/npm/bootstrap@5.3.3/dist/css/bootstrap.min.css" rel="stylesheet"> </head> <body> <div class="mb-3"> <label for="user" class="form-label">Username</label> <input type="text" class="form-control is-invalid" id="user"> <div class="invalid-feedback">Please choose a username.</div> </div> <div class="mb-3"> <label for="code" class="form-label">Referral code</label> <input type="text" class="form-control is-valid" id="code" value="HYR2026"> <div class="valid-feedback">Looks good!</div> </div> <script src="https://cdn.jsdelivr.net/npm/bootstrap@5.3.3/dist/js/bootstrap.bundle.min.js"></script> </body> </html>