/* Filter button (all, upcoming and past) */
.conference-filter-btn {
    border: 2px solid var(--primary-blue);
    padding: 8px 20px;
    border-radius: 999px;
    text-decoration: none;
    font-weight: 500;
    color: var(--primary-blue);
    transition: all 0.2s ease;
    background-color: white;
}

.conference-filter-btn:hover {
    background-color: var(--primary-blue);
    color: white;
}

.conference-filter-btn.active {
    background-color: var(--primary-blue);
    color: white;
    pointer-events: none;
}


.filter-box {
    background: #f8f9fa;
    padding: 1rem;
    border-radius: 6px;
    box-shadow: 0 0 5px rgba(0,0,0,0.05);
}

.filter-header {
    font-weight: 500;
    border-left: 3px solid red;
    padding-left: 0.5rem;
    color: #333;
}

.card-img-top {
    height: 200px;
    object-fit: cover;
}

.card.conference-card {
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.card.conference-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.15);
}