.h5c3-tool__main {
    align-items: stretch;
    display: flex;
    gap: 16px;
    width: 100%;
}

.h5c3-tool__panel {
    display: flex;
    flex: 0 0 calc(50% - 8px);
    flex-direction: column;
    max-width: calc(50% - 8px);
    min-width: 0;
}