<h1>50px, 50px, 100px, 200px</h1>
<div class="container">
    <div class="item">1</div>
    <div class="item">2</div>
    <div class="item item-flex-basis1">3</div>
    <div class="item item-flex-basis2">4</div>
</div>
.container {
    width: 400px;
    display: flex;
}

.item {
    width: 50px;
    height: 50px;
}

.item-flex-basis1 {
    flex-basis: 100px;
}

.item-flex-basis2 {
    flex-basis: 50%;
}

.item:nth-child(1) {
    background-color: #fff001;
}

.item:nth-child(2) {
    background-color: #00a5e7;
}

.item:nth-child(3) {
    background-color: #00984b;
}

.item:nth-child(4) {
    background-color: #cd5638;
}

External CSS

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External JavaScript

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