/* fill whatever container you’re in */
.videoGrid {
    width: 100%;
    /* removed max-width so it stretches to the full parent width */
    margin: 0 auto 2rem auto; /* optional, to center if the parent is wider than its own parent */
}

.videoGrid-list {
    display: grid;
    /* always 3 equal columns of whatever width is available */
    grid-template-columns: repeat(3, 1fr);
    gap: 2rem;
}

/* 2 columns once it can’t comfortably show 3×200px+gaps */
/* 3×200px + 2×1rem ≃ 632px, so I’d break around 640px */
@media (max-width: 640px) {
    .videoGrid-list {
        grid-template-columns: repeat(2, 1fr);
    }
}

/* 1 column once you can’t do 2×200px+gap */
/* 2×200 + 1×1rem ≃ 416px, so break around 420px */
@media (max-width: 420px) {
    .videoGrid-list {
        grid-template-columns: 1fr;
    }
}

/* enforce that your <video> never shrinks below 200px */
.videoGrid-item > video {
    width: 100%;
    min-width: 200px;
    height: auto;
}

.videoGrid-cover {
    position: absolute;
    inset: 0;
    background: transparent;
    cursor: pointer;
    z-index: 100;
    pointer-events: all;
}

/* your expand/close styles remain the same */
.videoGrid-item {
    position: relative;
    cursor: pointer;
    transition: transform .2s ease-in-out;
}
.videoGrid-item:hover {
    transform: scale(1.05);
}
.videoGrid-item.expanded {
    grid-column: 1 / -1;
    transition: unset;
}
.videoGrid-item.expanded:hover {
    transform: unset;
}
.videoGrid-item .expand-close {
    position: absolute;
    top: .5rem;
    right: .5rem;
    background: rgba(0,0,0,0.6);
    border: none;
    color: #fff;
    font-size: 1.5rem;
    line-height: 1;
    width: 1.5rem;
    height: 1.5rem;
    border-radius: 50%;
    cursor: pointer;
}
.videoGrid-item.expanded .videoGrid-cover {
    z-index: 0;
}