* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            font-family: Helvetica, 'Helvetica Neue', Arial, sans-serif;
        }

        body {
            background: #ffffff;
            min-height: 100vh;
            display: flex;
            align-items: center;
            justify-content: center;
            padding: 30px 16px;
        }

        .register-card {
            background: white;
            border-radius: 20px;
            box-shadow: 0 8px 26px rgba(15, 23, 42, 0.12);
            padding: 45px 40px;
            width: 100%;
            max-width: 450px;
            border: 1px solid #eef2f7;
        }

        .register-card h5 {
            color: #1e3c72;
            font-weight: 700;
            text-align: center;
            margin-bottom: 6px;
            font-size: 1.4rem;
        }

        .register-card p.subtitle {
            color: #999;
            text-align: center;
            font-size: 0.9rem;
            margin-bottom: 28px;
        }

        .btn-microsoft {
            width: 100%;
            padding: 12px 16px;
            border: none;
            border-radius: 999px;
            background: #2d2d30;
            color: #fff;
            font-size: 1rem;
            font-weight: 700;
            display: flex;
            align-items: center;
            justify-content: center;
            gap: 12px;
            text-decoration: none;
            margin-top: 14px;
            box-shadow: 0 4px 15px rgba(31, 41, 55, 0.18);
            transition: transform 0.3s ease, box-shadow 0.3s ease;
        }

        .btn-microsoft:hover {
            transform: translateY(-2px);
            box-shadow: 0 6px 20px rgba(31, 41, 55, 0.28);
            color: #fff;
        }

        .ms-logo {
            width: 20px;
            height: 20px;
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 2px;
            flex: 0 0 20px;
        }

        .ms-logo span:nth-child(1) { background: #f25022; }
        .ms-logo span:nth-child(2) { background: #7fba00; }
        .ms-logo span:nth-child(3) { background: #00a4ef; }
        .ms-logo span:nth-child(4) { background: #ffb900; }

        .alert {
            border-radius: 10px;
            font-size: 0.88rem;
            margin-bottom: 18px;
        }

        .login-link {
            text-align: center;
            margin-top: 22px;
            font-size: 0.88rem;
            color: #777;
        }

        .login-link a {
            color: #334155;
            font-weight: 600;
            text-decoration: none;
        }

        .login-link a:hover {
            text-decoration: underline;
        }