calc.css

:root{
    /*These are the root vars*/
    --para-color:#333;
    --title-color: aquamarine;
    --high-color: orange;
}

body{
    overflow-x: hidden;
    margin: 0;
}

h1{
    color: var(--title-color);
    background-color: var(--para-color);
    /*
    calc(-50vw + 50%) is a trick to make it streatch for entire screen
    */
    margin: 0 calc(-50vw + 50%);
    padding: 10px 0.5em;

    /*
    Increase the font size using the calc funtion
    */
    font-size: calc(1vw + 2rem);
}

p{
    color: var(--para-color);
}

.highlight{
    background-color: var(--high-color);
    margin: 0 calc(-50vw + 50%);
    padding: 10px;
}