* {
    margin: 0;
    padding: 0; 
    box-sizing: border-box;
}

.container {
    width: 100%;
    height: 100vh;
    background-color: #dedede;
    display: flex;
    align-items: center;
    justify-content: center;
}

.quadrado {
    width: 200px;
    height: 200px;
    background-color: blue;
    margin: 10px;
}