.card-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
    margin: 20px 0;
}
.card {
    border: 1px solid #ddd;
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}
.card-header {
    background: #f8f9fa;
    padding: 15px;
    font-weight: bold;
    border-bottom: 1px solid #ddd;
}
.card-body:empty {
    background: repeating-linear-gradient(
        45deg,
        #f8f9fa,
        #f8f9fa 10px,
        #e9ecef 10px,
        #e9ecef 20px
    );
    height: 100px;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
}
.card-body:empty::before {
    content: "No content available";
    color: #6c757d;
    font-style: italic;
    text-align: center;
}
.card-body:not(:empty) {
    padding: 15px;
    background: white;
}