Dark Mode On/Off
div {
float: left;
}
.second {
background: #ccc;
}
<div>Tree</div>
<div class="second">View</div>
<style>
#box {
display: flex;
}
#b {
flex-grow: 100;
border: 1px solid green;
}
</style>
<div id='box'>
<div id='a'>Tree</div>
<div id='b'>View</div>
</div>
html, body {
height: 100%;
}
body {
display: flex;
}
.second {
flex-grow: 1;
}
<div style="background: #bef;">Tree</div>
<div class="second" style="background: #ff9;">View</div>
.leftSide {
float: left;
width: 50px;
background-color: green;
}
.rightSide {
float: left;
width: calc(100% - 50px);
background-color: red;
}<div style="width:200px">
<div class="leftSide">a</div>
<div class="rightSide">b</div>
</div>