.app {

    height: 100vh;

    display: grid;

    grid-template-columns: 240px 1fr 340px;

    overflow: hidden;

}

.main {

    overflow: hidden;

    display: grid;

    grid-template-rows: auto 1fr;

}

.main-header {

    position: sticky;

    top: 0;

    z-index: 5;

    padding: 16px 18px;

    background: var(--bg);

    border-bottom: 1px solid rgba(0,0,0,0.02);

}

.main-body {

    overflow: auto;

    padding: 18px;

}