*{
    margin:0;
    padding:0;
    box-sizing:border-box;
}

body{
    font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
    background:#f4f4f4;
    color:#222;
}

/* =========================
   MAIN CONTAINER
========================== */

.invitation-section{
    min-height:100vh;
    display:flex;
    align-items:center;
    justify-content:center;
    padding:40px 20px;
    background:
    linear-gradient(rgba(255,255,255,0.94), rgba(255,255,255,0.94)),
    url('https://images.unsplash.com/photo-1511818966892-d7d671e672a2?q=80&w=1974&auto=format&fit=crop');
    background-size:cover;
    background-position:center;
}

.invitation-card{
    width:100%;
    max-width:650px;
    background:#ffffff;
    border-radius:14px;
    overflow:hidden;
    box-shadow:0 12px 40px rgba(0,0,0,0.12);
    border:1px solid #e5e7eb;
}

/* =========================
   HEADER
========================== */

.top-strip{
    height:8px;
    background:linear-gradient(to right,#d97706,#f97316);
}

.card-header{
    padding:35px 30px 25px;
    text-align:center;
    background:#fff;
}

.conference-logo{
    width:300px;
    /*height:120px;*/
    object-fit:contain;
    margin-bottom:20px;
}

.conference-title{
    font-size:52px;
    font-weight:800;
    color:#d97706;
    letter-spacing:1px;
    margin-bottom:10px;
    text-shadow:2px 2px 5px rgba(0,0,0,0.12);
}

.conference-subtitle{
    font-size:22px;
    color:#222;
    font-weight:600;
    line-height:1.4;
    margin-bottom:15px;
}

.conference-meta{
    font-size:16px;
    color:#555;
    line-height:1.8;
}

/* =========================
   BODY
========================== */

.card-body{
    padding:35px 30px;
    background:#fafafa;
    border-top:1px solid #eee;
    border-bottom:1px solid #eee;
}

.welcome-text{
    font-size:18px;
    color:#333;
    line-height:1.8;
    margin-bottom:25px;
}

.highlight{
    color:#a94438;
    font-weight:700;
}

/* =========================
   FORM
========================== */

.input-group{
    margin-bottom:22px;
}

.input-label{
    display:block;
    margin-bottom:10px;
    font-size:15px;
    font-weight:600;
    color:#333;
}

.input-field{
    width:100%;
    height:52px;
    border:1px solid #d1d5db;
    border-radius:8px;
    padding:0 16px;
    font-size:15px;
    outline:none;
    transition:0.3s;
}

.input-field:focus{
    border-color:#d97706;
    box-shadow:0 0 0 4px rgba(217,119,6,0.12);
}

/* =========================
   BUTTONS
========================== */

.button-group{
    display:flex;
    gap:15px;
    margin-top:28px;
}

.btn{
    flex:1;
    height:52px;
    border:none;
    border-radius:8px;
    font-size:15px;
    font-weight:600;
    cursor:pointer;
    transition:0.3s;
    display: flex;
    align-items: center;
    justify-content: center;
    text-decoration: none;
}

.btn-primary{
    background:#a94438;
    color:#fff;
}

.btn-primary:hover{
    background:#92392e;
}

.btn-secondary{
    background:#ffffff;
    color:#444;
    border:1px solid #d1d5db;
}

.btn-secondary:hover{
    background:#f5f5f5;
}

.btn:disabled {
    opacity: 0.7;
    cursor: not-allowed;
}

/* =========================
   FOOTER
========================== */

.card-footer{
    padding:25px 30px;
    text-align:center;
    background:#fff;
}

.footer-name{
    font-size:24px;
    font-weight:700;
    color:#222;
    margin-bottom:8px;
}

.footer-role{
    color:#555;
    margin-bottom:15px;
}

.footer-contact{
    font-size:14px;
    color:#666;
    line-height:1.8;
}

/* =========================
   MODAL PDF VIEWER
========================== */

.modal-overlay{
    position:fixed;
    inset:0;
    background:rgba(0,0,0,0.65);
    display:none;
    align-items:center;
    justify-content:center;
    z-index:999;
    padding:20px;
}

.modal{
    width:100%;
    max-width:1100px;
    height:90vh;
    background:#fff;
    border-radius:10px;
    overflow:hidden;
    display:flex;
    flex-direction:column;
}

.modal-header{
    padding:18px 22px;
    background:#f3e8ff;
    display:flex;
    justify-content:space-between;
    align-items:center;
}

.modal-title{
    font-size:22px;
    font-weight:700;
    color:#3b0764;
}

.close-btn{
    background:none;
    border:none;
    font-size:28px;
    cursor:pointer;
    color:#555;
}

.pdf-preview-container {
    width: 100%;
    height: 100%;
    overflow-y: auto;
    background: #525659;
    display: flex;
    justify-content: center;
    padding: 20px;
}

#pdfPreview {
    background: white;
    box-shadow: 0 0 20px rgba(0,0,0,0.3);
    transform-origin: top center;
}

.modal-footer{
    padding:18px 22px;
    display:flex;
    justify-content:flex-end;
    gap:15px;
    border-top:1px solid #eee;
    background: #fff;
}

/* Loader */
.loader {
    width: 20px;
    height: 20px;
    border: 3px solid #f3f3f3;
    border-top: 3px solid #d97706;
    border-radius: 50%;
    animation: spin 1s linear infinite;
    display: none;
    margin-left: 10px;
}

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

/* =========================
   RESPONSIVE
========================== */

@media(max-width:768px){

    .conference-title{
        font-size:38px;
    }

    .conference-subtitle{
        font-size:18px;
    }

    .button-group{
        flex-direction:column;
    }

    .card-body,
    .card-header,
    .card-footer{
        padding:25px 20px;
    }

}