#gtr-overlay{
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    background: rgba(0,0,0,0.6);
    display: none;
    z-index: 9999999;
}

#gtr-overlay.active{
    display: flex;
    justify-content: center;
    align-items: center;
}

#gtr-modal-box{
    background:#fff;
    width:400px;
    max-width:90%;
    padding:30px;
    border-radius:10px;
    box-shadow:0 25px 60px rgba(0,0,0,0.4);
    position:relative;
}

#gtr-modal-box input{
    width:100%;
    padding:12px;
    margin-bottom:12px;
    border:1px solid #ccc;
    border-radius:6px;
}

#gtr-modal-box button{
    width:100%;
    padding:12px;
    background:#007cba;
    color:#fff;
    border:none;
    border-radius:6px;
    cursor:pointer;
}

#gtr-close{
    position:absolute;
    top:12px;
    right:15px;
    font-size:22px;
    cursor:pointer;
}

#gtr-course-title{
    font-weight:600;
    margin-bottom:15px;
    color:#007cba;
}

.btn-loader{
    border:3px solid #fff;
    border-top:3px solid rgba(255,255,255,0.3);
    border-radius:50%;
    width:18px;
    height:18px;
    display:inline-block;
    animation:spin 0.8s linear infinite;
}

@keyframes spin{
    0%{transform:rotate(0deg);}
    100%{transform:rotate(360deg);}
}

#gtr-msg.error{
    color:red;
    margin-top:10px;
}

.shake{
    animation:shakeAnim 0.4s;
}

@keyframes shakeAnim{
    0%{transform:translateX(0);}
    25%{transform:translateX(-5px);}
    50%{transform:translateX(5px);}
    75%{transform:translateX(-5px);}
    100%{transform:translateX(0);}
}