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#grid {
display: grid;
width: 100%;
grid-template-columns: 20px 1fr;
}
#areaA {
background-color: lime;
}
#areaB {
background-color: yellow;
}
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.container {
display: grid;
/* Repeat 2 times, each column takes up 1 fraction (fr) of the available space */
grid-template-columns: repeat(2, 1fr);
}