body {
    font-family: Arial, sans-serif;
    line-height: 1.6;
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

header {
    background: #333;
    color: #fff;
    padding: 20px 0;
    text-align: center;
}

header h1 {
    margin: 0;
}
header h2 {
    margin: 0;
    color: #fff;
}
header h3 {
    margin: 0;
    color: #fff;
}


.navbar-nav {
    justify-content: center;
}

.navbar-nav .nav-item .nav-link {
    color: #fff;
    padding: 10px 15px;
}

.container {
    max-width: 1140px;
    margin: 20px auto;
    padding: 0 15px;
}

/* h2 {
    color: #333;
    margin-bottom: 20px;
} */

.subsection-heading {
    margin-top: 30px;
    margin-bottom: 15px;
    font-size: 1.4rem;
}

.Challenge {
    margin: 35px 0;
}

.challenge-card {
    padding: 22px 24px;
    border: 1px solid #ddd;
    border-radius: 4px;
    background: #fafafa;
}

.challenge-copy {
    max-width: 850px;
}

.challenge-question {
    margin: 0 0 15px;
    color: #333;
    font-size: 1.5rem;
    line-height: 1.3;
}

.challenge-copy p {
    margin-bottom: 0;
}

.challenge-tracks {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 24px;
    margin: 22px 0 0;
}

.challenge-track {
    padding: 16px 18px;
    border: 1px solid #cfe0f5;
    border-radius: 4px;
    background: #f5f9ff;
}

.challenge-track-tag {
    display: inline-block;
    margin-bottom: 8px;
    color: #007bff;
    font-size: 0.72rem;
    font-weight: 700;
    letter-spacing: 0.08em;
    text-transform: uppercase;
}

.challenge-track h4 {
    margin: 0 0 5px;
    color: #333;
    font-size: 1.05rem;
    font-weight: 700;
}

.challenge-track p {
    margin: 0;
    color: #555;
    font-size: 0.9rem;
    line-height: 1.45;
}

.challenge-group-label {
    margin: 20px 0 0;
    color: #777;
    font-size: 0.85rem;
    font-weight: 700;
    letter-spacing: 0.04em;
    text-transform: uppercase;
}

.challenge-group-label + .challenge-metrics {
    margin-top: 12px;
}

.challenge-metrics {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
    margin: 22px 0;
}

.challenge-metric {
    padding-left: 14px;
    border-left: 3px solid #ccc;
}

.challenge-metric h4 {
    margin: 0 0 5px;
    color: #333;
    font-size: 1rem;
    font-weight: 700;
}

.challenge-metric p {
    margin: 0;
    color: #555;
    font-size: 0.9rem;
    line-height: 1.45;
}

.challenge-group-label + .challenge-timeline {
    margin-top: 12px;
}

.challenge-timeline {
    margin: 22px 0 0;
    border: 1px solid #cfe0f5;
    border-radius: 4px;
    background: #fff;
    overflow-x: auto;
}

.challenge-timeline-table {
    width: 100%;
    min-width: 560px;
    margin: 0;
    border-collapse: collapse;
    font-size: 0.9rem;
}

.challenge-timeline-table th {
    padding: 10px 16px;
    border-bottom: 1px solid #cfe0f5;
    background: #f5f9ff;
    color: #26517f;
    font-size: 0.72rem;
    font-weight: 700;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    text-align: left;
    white-space: nowrap;
}

.challenge-timeline-table td {
    padding: 12px 16px;
    border-top: 1px solid #eef2f7;
    color: #555;
    line-height: 1.45;
    vertical-align: top;
}

.challenge-timeline-table tbody tr:first-child td {
    border-top: 0;
}

.challenge-timeline-table .timeline-phase {
    color: #333;
    font-weight: 700;
    white-space: nowrap;
}

.challenge-timeline-table .timeline-when {
    color: #26517f;
    font-weight: 600;
    white-space: nowrap;
}

.challenge-timeline-note {
    margin: 10px 0 0;
    color: #777;
    font-size: 0.83rem;
    line-height: 1.45;
}

.challenge-footer {
    display: flex;
    align-items: center;
    gap: 28px;
    padding-top: 22px;
    border-top: 1px solid #ddd;
}

.challenge-footer p {
    flex: 1;
    margin: 0;
    color: #555;
    font-size: 0.93rem;
}

.challenge-button {
    display: inline-flex;
    flex-shrink: 0;
    align-items: center;
    gap: 9px;
    color: #007bff;
    font-weight: 700;
    text-decoration: none;
}

.challenge-button:hover,
.challenge-button:focus {
    color: #0056b3;
    text-decoration: underline;
}

.challenge-contribute {
    margin-top: 22px;
    padding: 16px 18px;
    border: 1px solid #cfe0f5;
    border-radius: 4px;
    background: #f5f9ff;
}

.challenge-contribute-title {
    margin: 0 0 7px;
    color: #333;
    font-size: 1.05rem;
    font-weight: 700;
}

.challenge-contribute p {
    margin: 0;
    color: #555;
    font-size: 0.9rem;
    line-height: 1.45;
}

.challenge-contribute p + p {
    margin-top: 10px;
}

.challenge-contribute-cta .challenge-button {
    margin-left: 4px;
    font-size: 0.9rem;
}

.Sponsors {
    margin: 35px 0;
}

.prospectus-embed {
    margin-top: 22px;
    border: 1px solid #ddd;
    border-radius: 4px;
    overflow: hidden;
    background: #fff;
}

.prospectus-embed object {
    display: block;
    width: 100%;
    height: 85vh;
    min-height: 520px;
    border: 0;
}

.prospectus-actions {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 22px;
    padding: 12px 16px;
    border-top: 1px solid #ddd;
    background: #fafafa;
}

.prospectus-actions span {
    flex: 1;
    color: #777;
    font-size: 0.82rem;
    letter-spacing: 0.02em;
}

.prospectus-actions .challenge-button {
    font-size: 0.9rem;
}

.prospectus-fallback {
    margin: 0;
    padding: 40px 20px;
    color: #555;
    font-size: 0.93rem;
    text-align: center;
}

.prospectus-mobile-cta {
    display: none;
    margin-top: 22px;
    padding: 16px 18px;
    border: 1px solid #cfe0f5;
    border-radius: 4px;
    background: #f5f9ff;
}

.prospectus-mobile-cta p {
    margin: 0;
    color: #555;
    font-size: 0.9rem;
    line-height: 1.45;
}

.prospectus-mobile-cta .challenge-contribute-cta {
    margin-top: 10px;
}

code {
    padding: 1px 5px;
    border-radius: 3px;
    background: #f0f3f7;
    color: #26517f;
    font-size: 0.85em;
}

/* template / formatting callouts (Call for Papers + Challenge) */
.format-note {
    margin: 20px 0;
    padding: 16px 18px;
    border: 1px solid #cfe0f5;
    border-radius: 4px;
    background: #f5f9ff;
}

.format-note-title {
    margin: 0 0 7px;
    color: #333;
    font-size: 1.05rem;
    font-weight: 700;
}

.format-note p {
    margin: 0;
    color: #555;
    font-size: 0.9rem;
    line-height: 1.45;
}

.format-note p + p {
    margin-top: 10px;
}

.format-note code {
    padding: 1px 5px;
    border-radius: 3px;
    background: #e7effa;
    color: #26517f;
    font-size: 0.85em;
}

.format-note p.format-note-warn {
    padding: 9px 12px;
    border-left: 3px solid #c0261b;
    border-radius: 3px;
    background: #fdf2f1;
    color: #8f2119;
}

.format-note-warn b {
    color: #c0261b;
}

.format-note-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 10px 26px;
    margin-top: 13px;
}

.format-note-actions .challenge-button {
    font-size: 0.9rem;
}

.people-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
    gap: 25px 20px;
    margin-bottom: 20px;
}

.speaker, .organizer {
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
}

.speaker img, .organizer img {
    border-radius: 50%;
    margin-bottom: 10px;
    width: 130px;
    height: 130px;
    object-fit: cover;
    flex-shrink: 0;
}

.sponsor {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 20px;
}

.sponsor img {
    max-width: 100%;
    height: 100px;
    object-fit: contain;
    object-position: left center;
}

.speaker-info, .organizer-info {
    max-width: 100%;
}

.speaker-info h3, .organizer-info h3 {
    margin-top: 0;
    margin-bottom: 5px;
    font-size: 1.05rem;
}

.speaker-info p, .organizer-info p {
    margin: 5px 0;
    font-size: 0.85rem;
    line-height: 1.35;
}

footer {
    background: #333;
    color: #fff;
    text-align: center;
    padding: 10px 0;
    margin-top: 20px;
}

@media (max-width: 767px) {
    .challenge-card {
        padding: 20px;
    }

    .challenge-question {
        font-size: 1.4rem;
    }

    .challenge-metrics,
    .challenge-tracks {
        grid-template-columns: 1fr;
    }

    .challenge-timeline-table th,
    .challenge-timeline-table td {
        padding: 10px 12px;
    }

    .challenge-footer {
        align-items: stretch;
        flex-direction: column;
        gap: 18px;
    }

    .challenge-button {
        justify-content: center;
    }

    .prospectus-embed {
        display: none;
    }

    .prospectus-mobile-cta {
        display: block;
    }

    .people-grid {
        grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
        gap: 20px 15px;
    }

    .speaker img, .organizer img {
        width: 110px;
        height: 110px;
    }
}

#goToTopBtn {
    display: none; /* Hidden by default */
    position: fixed; /* Fixed/sticky position */
    bottom: 20px; /* Place the button at the bottom of the page */
    right: 30px; /* Place the button 30px from the right */
    z-index: 99; /* Make sure it does not overlap */
    font-size: 18px; /* Increase font size */
    border: none; /* Remove borders */
    outline: none; /* Remove outline */
    background-color: #555; /* Set a background color */
    color: white; /* Text color */
    cursor: pointer; /* Add a mouse pointer on hover */
    padding: 15px; /* Some padding */
    border-radius: 4px; /* Rounded corners */
}

#goToTopBtn:hover {
    background-color: #333; /* Add a dark-grey background on hover */
}