:root {
            --primary-color: #0b84b3;
            --secondary-color: #8ad1ed;
        }

        body {
            background-color: #f8f9fa;
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
        }

        .register-container {
            background-color: white;
            border-radius: 15px;
            box-shadow: 0 0 20px rgba(0, 0, 0, 0.1);
            overflow: hidden;
            margin-top: 30px;
        }

        .register-header {
            background: linear-gradient(to left, var(--secondary-color), var(--primary-color));
            color: white;
            padding: 20px;
            text-align: center;
        }

        .register-form {
            padding: 30px;
        }

        .form-icon {
            position: absolute;
            right: 15px;
            top: 50%;
            transform: translateY(-50%);
            color: var(--primary-color);
        }

        .form-control {
            padding-right: 40px;
            border-radius: 8px;
            border: 1px solid #ced4da;
        }

        .form-control:focus {
            border-color: var(--primary-color);
            box-shadow: 0 0 0 0.25rem rgba(11, 132, 179, 0.25);
        }

        .btn-register {
            background: linear-gradient(to left, var(--secondary-color), var(--primary-color));
            border: none;
            border-radius: 8px;
            padding: 12px;
            font-weight: bold;
            transition: all 0.3s;
        }

        .btn-register:hover {
            transform: translateY(-2px);
            box-shadow: 0 5px 15px rgba(11, 132, 179, 0.3);
        }

        .invalid-feedback {
            display: block;
            color: #dc3545;
            font-size: 0.875em;
            margin-top: 0.25rem;
        }

        .is-invalid {
            border-color: #dc3545;
        }

        .is-invalid:focus {
            box-shadow: 0 0 0 0.25rem rgba(220, 53, 69, 0.25);
        }

        @media (max-width: 768px) {
            .register-container {
                margin-top: 15px;
            }

            .register-form {
                padding: 20px;
            }
        }