body, html {
    margin: 0;
    padding: 0;
}

#t-right {
    position: fixed;
    top: 0;
    right: 0;
    bottom: 0;
    height: 300px;
    width: 300px;
    
    background: silver;
    vertical-align: middle;
}

#t-left {
    background: pink;
    padding-right: 300px;
}

#centrado {
    vertical-align: middle;
    border: solid red 1px;
    display: inline-block;
    height: 20px;
    
    margin-top: 50%;
    }