First, we are initializing Painterro js paint:

Painterro({
toolbarHeightPx: 54,
buttonSizePx:42,
backgroundFillColor: '#222',
}).show()

Now some CSS (we recommend CSS preprocessor, but for best compatibility, here I will show just a simple CSS):

.ptro-holder {
bottom: 32px;
}
.ptro-icon-btn[class] {
border-radius: 27px;
background-color: #272a2f;
box-shadow: inset -1px -1px 8px 1px rgba(0, 0, 0, 0.7);
position: relative;
color: #c4c8cb;
}
.ptro-icon-btn[disabled] {
color: #575757;
}
.ptro-icon-btn:not([disabled]):hover[class] {
background-color: #233 !important;
color: #c4c8cb !important;
}
.ptro-color-active-control[class] {
background-color: #656565;
box-shadow: inset 1px 1px 8px 1px rgba(0, 0, 0, 0.7);
}
.ptro-color-active-control[class]::after {
box-shadow: inset -1px -1px 8px 1px rgba(255, 255, 255, 0.1);
}
.ptro-icon-btn::after {
content:'';
width: 100%; height: 100%;
border-radius: 27px;
position: absolute;
box-shadow: inset 1px 1px 8px 1px rgba(255, 255, 255, 0.1);
}
.ptro-color-main[class] {
background-color: #34393d;
}
.ptro-wrapper[class] {
background-color: #34393d;
}

And result:

Image for a hint