Разработка Блоки со скролингом

@import url('https://fonts.googleapis.com/css?family=Montserrat');

/* Global variables  */

:root {
    --font: 'Montserrat', sans-serif;
    --box-shadow: 0 1px 4px 0 rgba(0, 0, 0, 0.1);
    --text-shadow: 0 1px 1px rgba(0,0,0,.1);
    --light-color: hsla(360, 100%, 100%, .85);
    --seagreen: hsla(149, 29%, 72%, 1); /* #A2CCB6 expressed as hsla  */
    --sandyyellow: hsla(48, 92%, 85%, 1); /* #FCEEB5 Expressed as hsla  */
    --peach: hsla(5, 79%, 68%, 1);/* #EE786E Expressed as hsla  */
}

*, *:before,*:after { box-sizing: border-box}

body {
    width: 100vw;
    height: 100vh;
    margin: 0;
    margin: auto;
    font-family: var(--font);
    line-height: 1.5em;
    color: var(--light-color);
    overflow-x: hidden;
}

p {
    overflow-y: scroll;
    height: 300px;
    max-width: 300px;
    margin: 2vh  auto;
    opacity: 0;
    box-shadow: var(--box-shadow);
    text-shadow: var(--text-shadow);
    animation: fade 2s forwards;
}

/* Box customization  */

p:nth-child(1) { background:var(--seagreen); border:4.2vh solid var(--seagreen); animation-delay: 300ms}
p:nth-child(2) {color: rgba(0,0,0,.6); background:var(--sandyyellow); border:4.2vh  solid var(--sandyyellow); animation-delay: 700ms}
p:nth-child(3) { background:var(--peach); border:4.2vh solid var(--peach); animation-delay: 1200ms}

/* Main scrollbar  */

::-webkit-scrollbar { width: 4vw;max-width: 20px; min-width: 10px}
::-webkit-scrollbar-track { background:  var(--sandyyellow)}
 ::-webkit-scrollbar-thumb { background:  var(--seagreen); box-shadow: 0 0 9px rgba(255,255,255,.9), 0 0 25px rgba(255,255,255,.6)}
 ::-webkit-scrollbar-thumb:hover { background: var(--peach); box-shadow: 0 0 15px var(--light-color), 0 0 35px var(--peach)}

/* Box scrollbar  */

 p::-webkit-scrollbar { width: 2vw; max-width: 20px; min-width: 10px}
 p::-webkit-scrollbar-track { background: rgba(0,0,0,.1)}
 p::-webkit-scrollbar-thumb { background: rgba(0,0,0,.3); box-shadow: 0 0 9px rgba(255,255,255,.9), 0 0 25px var(--light-color)}

 p::-webkit-scrollbar-thumb:hover {    background: rgba(0,0,0,.5)}
 p:nth-child(1)::-webkit-scrollbar-thumb:hover { box-shadow: 0 0 15px var(--sandyyellow), 0 0 35px var(--peach)}
 p:nth-child(2)::-webkit-scrollbar-thumb:hover { box-shadow: 0 0 15px var(--seagreen), 0 0 35px var(--peach)}
 p:nth-child(3)::-webkit-scrollbar-thumb:hover { box-shadow: 0 0 15px var(--seagreen), 0 0 35px var(--peach)}

/* Fade in animation  */

@keyframes fade {
    0% { opacity: 0; filter: blur(20px); transform:scale(4)}
    40% { opacity: 0; filter: blur(20px); transform:scale(4)}
    63% { opacity: 1; filter: blur(5px); transform:scale(1.1)}
    70% { opacity: 1; filter: blur(10px); transform:scale(1)}
    86% { opacity: 1; filter: blur(0); transform:scale(1)}
    100% { opacity: 1; filter: blur(0); transform:scale(1)}
}

/* Grid/ Media Query  */

 @media only screen and (min-width: 60em) {

body {
    height:100vh;
    display: grid;
    grid-template-columns: 1fr 1fr 1fr;
    grid-template-rows: 1fr;
    grid-gap: 80px;
    max-width: 80%;
    margin-top: 10vh;
}
}