s.css

:root {
    --backgroundColor: rgba(246, 241, 209);
    --colorShadeA: rgb(106, 163, 137);
    --colorShadeB: rgb(121, 186, 156);
    --colorShadeC: rgb(150, 232, 195);
    --colorShadeD: rgb(187, 232, 211);
    --colorShadeE: rgb(205, 255, 232);
  }
  
  @import url("https://fonts.googleapis.com/css?family=Open+Sans:400,400i,700");
  * {
    box-sizing: border-box;
  }
  *::before,
  *::after {
    box-sizing: border-box;
  }
  body {
    font-family: "OpenSans", sans-serif;
    font-size: 1rem;
    line-height: 2;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0;
    min-height: 100vh;
    background: var(--backgroundColor);
  }
  button {
    position: relative;
    display: inline-block;
    cursor: pointer;
    outline: none;
    border: 0;
    vertical-align: middle;
    text-decoration: none;
    font-size: 1.5rem;
    color: var(--colorShadeA);
    font-weight: 700;
    text-transform: uppercase;
    font-family: inherit;
  }
  
  button.big-button {
    padding: 1em 2em;
    border: 2px solid var(--colorShadeA);
    border-radius: 1em;
    background: var(--colorShadeE);
    transform-style: preserve-3d;
    transition: all 175ms cubic-bezier(0, 0, 1, 1);
  }
  button.big-button::before {
    position: absolute;
    content: "";
    width: 100%;
    height: 100%;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--colorShadeC);
    border-radius: inherit;
    box-shadow: 0 0 0 2px var(--colorShadeB), 0 0.75em 0 0 var(--colorShadeA);
    transform: translate3d(0, 0.75em, -1em);
    transition: all 175ms cubic-bezier(0, 0, 1, 1);
  }
  
  button.big-button:hover {
    background: var(--colorShadeD);
    transform: translate(0, 0.375em);
  }
  
  button.big-button:hover::before {
    transform: translate3d(0, 0.75em, -1em);
  }
  
  button.big-button:active {
    transform: translate(0em, 0.75em);
  }
  
  button.big-button:active::before {
    transform: translate3d(0, 0, -1em);
  
    box-shadow: 0 0 0 2px var(--colorShadeB), 0 0.25em 0 0 var(--colorShadeB);
  }