* {
    box-sizing: border-box;
}
.block {
    height: 1000px;
    background: #1a1717;
}
.block__text {
    font-size: 30px;
    color: white;
}
.block__rectangle {
    position: fixed;
    left: 50%;
    right: 50px;
    bottom: 100px;
    background-color: white;
    min-height: 100px;
}
.block__circle {
    position: relative;
    left: 100px;
    bottom: 50px;
    width: 100px;
    height: 100px;
    border-radius: 50px;
    background: red;
}