Hi I was just wondering how I can make my CSS button responsive?

/* CSS styles */
* {
    margin:0;
    padding: 0;
    border:0;

}


html,
body{
    background:url("/images/onebug2022heroimage.jpg")no-repeat
 center fixed;


    -webkit-background-size: cover;
    -moz-background-size: cover;
    -o-background-size: cover;
    background-size: cover;
    color:#000;

}

.wrapper{
    max-height: 100%}



header{
    max-width:100%;
    background-color: #0000;
    /*    padding-top: 5%;*/
    padding-bottom: 0.5%;
}


.left-col{
    max-width:35%;
    float:left;
    margin-left: 5%;
    margin-top: 2%;}

.right-col{
    width:70%;
    float:right;
}


.right-col ul{
    width: 100%;
}

.right-col ul li{
    list-style:none;
    float: right;
    display:block;
    padding-top:.4%;
    margin-left:1%;
    padding-right: 1.8%;
      }

.right-col li a{
    text-decoration:none;
    color:white;
}

h1{


    animation: type 3s steps(22);
    overflow: hidden;
    white-space: nowrap;
    font-family:'Noto sans', 'sans serif';
  clear: both;
    width: 50%;
    font-family:'Noto sans', 'sans serif';
    font-weight: 100;
    color: white;
    font-size: 2em;

    margin:0 auto;
    text-align: center;
    padding-bottom: 1%;
   }


h2{
clear: both;
    font-family:'Courgette', 'cursive';
    font-weight: 200;
    color: white;
    font-size: 2em;
    margin:0 auto;
    text-align: center;
    padding-bottom: 1%;
    width: 22ch;

}



h4{
clear: both;
    width: 10%;
    font-family:'Noto sans', 'sans serif';
    font-weight: 100;
    color: white;
    font-size: 2em;

    margin:0 auto;}

sup{ line-height:0;
font-size:65%;
}

@import url(https://fonts.googleapis.com/css?family=Raleway);
#cssmenu,
#cssmenu ul,
#cssmenu ul li,
#cssmenu ul li a,
#cssmenu #menu-button {
    margin: 0;
    padding: 0;
    border: 0;
    list-style: none;
    line-height: 1;
    display: block;
    position: relative;
    -webkit-box-sizing: border-box;
    -moz-box-sizing: border-box;
    box-sizing: border-box;
     left:0%;
}
#cssmenu:after,
#cssmenu > ul:after {
    content: ".";
    display: block;
    clear: both;
    visibility: hidden;
    line-height: 0;
    height: 0;
}
#cssmenu #menu-button {
    display: none;
}
#cssmenu {
    width: auto;
    font-family: Raleway, sans-serif;
    line-height: 1;
}
#cssmenu > ul {
    background: #00000;
}
#cssmenu > ul > li {
    float:left;
    -webkit-perspective: 1000px;
    -moz-perspective: 1000px;
    perspective: 1000px;
    left: 38.18%
}
#cssmenu.align-center > ul {
    font-size: 0;
    text-align: center;
}
#cssmenu.align-center > ul > li {
    display: inline-block;
    float: none;
}
#cssmenu.align-right > ul > li {
    float: right;
}
#cssmenu > ul > li > a {
    padding: 16px 20px;
    font-size: 14px;
    color: #ffffff;
    letter-spacing: 1px;
    text-transform: uppercase;
    text-decoration: none;
    background: #505050;
    -webkit-transition: all .3s;
    -moz-transition: all .3s;
    -o-transition: all .3s;
    transition: all .3s;
    -webkit-transform-origin: 50% 0;
    -moz-transform-origin: 50% 0;
    transform-origin: 50% 0;
    -webkit-transform-style: preserve-3d;
    -moz-transform-style: preserve-3d;
    transform-style: preserve-3d;
}
#cssmenu > ul > li.active > a {
    color: #107CBD;
}
#cssmenu > ul > li:hover > a,
#cssmenu > ul > li > a:hover {
    color: #107cbd;
    -webkit-transform: rotateX(90deg) translateY(-23px);
    -moz-transform: rotateX(90deg) translateY(-23px);
    transform: rotateX(90deg) translateY(-23px);
    -ms-transform: none;
}
#cssmenu > ul > li > a::before {
    position: absolute;
    top: 100%;
    left: 0;
    z-index: -1;
    -webkit-box-sizing: border-box;
    -moz-box-sizing: border-box;
    box-sizing: border-box;
    width: 100%;
    height: 100%;
    padding: 16px 20px;
    color: #107cbd;
    background: #1d1d1d;
    content: attr(data-title);
    -webkit-transition: background 0.3s;
    -moz-transition: background 0.3s;
    transition: background 0.3s;
    -webkit-transform: rotateX(-90deg);
    -moz-transform: rotateX(-90deg);
    transform: rotateX(-90deg);
    -webkit-transform-origin: 50% 0;
    -moz-transform-origin: 50% 0;
    transform-origin: 50% 0;
    -ms-transform: translateY(- -18px);
        }
#cssmenu > ul > li:hover > a::before,
#cssmenu > ul > li > a:hover::before {
    background: #505050;
}
#cssmenu.small-screen {
    width: 100%;
}
#cssmenu.small-screen > ul,
#cssmenu.small-screen.align-center > ul {
    width: 100%;
    text-align: left;
}
#cssmenu.small-screen > ul > li,
#cssmenu.small-screen.align-center {
    float: none;
    display: block;
    border-top: 1px solid rgba(100, 100, 100, 0.1);
}
#cssmenu.small-screen > ul > li:hover > a,
#cssmenu.small-screen > ul > li > a:hover {
    color: #107cbd;
    -webkit-transform: none;
    -moz-transform: none;
    transform: none;
    -ms-transform: none;
}
#cssmenu.small-screen > ul > li > a::before {
    display: none;
}
#cssmenu.small-screen #menu-button {
    display: block;
    padding: 16px 20px;
    cursor: pointer;
    font-size: 14px;
    text-decoration: none;
    color: #ffffff;
    text-transform: uppercase;
    letter-spacing: 1px;
    background: #505050;
}
#cssmenu.small-screen #menu-button:after {
    content: "";
    position: absolute;
    right: 20px;
    top: 17px;
    display: block;
    -webkit-box-sizing: content-box;
    -moz-box-sizing: content-box;
    box-sizing: content-box;
    border-top: 2px solid #ffffff;
    border-bottom: 2px solid #ffffff;
    width: 22px;
    height: 3px;
}
#cssmenu.small-screen #menu-button.menu-opened:after {
    border-top: 2px solid #107cbd;
    border-bottom: 2px solid #107cbd;
}
#cssmenu.small-screen #menu-button:before {
    content: "";
    position: absolute;
    right: 20px;
    top: 27px;
    display: block;
    width: 22px;
    height: 2px;
    background: #ffffff;
}
#cssmenu.small-screen #menu-button.menu-opened:before {
    background: #107cbd;
}


div nav ul li{
    text-align: left;
    display: inline;
    width: %;
    float:left;
    margin-right: .8em;
    font-family: 'Noto Sans';

}

li.changeBackground {
    background-color: #505050;
}

li.changeBackground:hover {
    background-color: ;
}

li.changeBackground:active {

background-color: #107CBD;
}

.homepage-hero-module {
    border-right: none;
    border-left: none;
    position: relative;
}

p{
    position:relative;
    width: 30%;
    padding:1em 1.5em;
    margin:2em auto;
    color: #fff;
    background:#107CBD;
    overflow: hidden;
    font-family:'Noto Sans';
}


p:before{
    content: "";
    position: absolute;
    top: 0;
    right: 0;
    border-width: 0 16px 16px 0;
    border-style: solid;
    border-color: #fff #fff #505050 #505050;
    background: #505050;
    -web-kit-box-shadow: 0 1px 1px rgba(0,0,0,0.3), -1px; rgba(0,0,0.2);
    -moz-box-shadow: 0 1px 1px rgba(0,0,0,0.3), -1px 1px 1px;rgba(0,0,0.2);
    box-shadow:0 1px 1px rgba(0,0,0,0,0.3), -1px 1px 1px  rgba(0,0,0 0.2);
    /* Firefox 3.0 damage limitation*/
    display: block; width: 0;
}

p.rounded{
    -moz-border-radius: 5px 0 5px 5px;
    border-radius: 5px 0 5px 5px;
}

.p.rounded:before{
    border-width: 9px;
    border-color: #fff #fff transparent transparent;
    -moz-border-radius: 0 0 0 5px;
    border-radius: 0 0 0 5px;
}

.link{color:#e68a00;}
.link:hover { color:#d580ff; }



h3{

    font-family:'Noto-Sans', sans-serif;

}
h5{
    font-family:'Noto-Sans', sans-serif;
     float: right;
    margin-top:10px;
}

a{
  color: #fff;

}
a: hover {
  color: #fff;
}

a.btn {
  display: inline-block;
  margin: 9px 0;
  color: #000000;
  background-color: #fff;
  padding: 9px 20px;
  border-radius; 7px;
  text-decoration :none;
  font-weight: 700;
  font-size: .9em;
  }
  a.btn:: after {
    content: '100BB'; padding-left: 8px;
 }
   a.btn: hover{
   color: #fff;
   background-color: #008cda;
 }

footer{

    margin: 1px;
    height:20px;
    width: 100%;
    border-top:3px solid #107CBD;
    clear: both;
    color: #fff;
    line-height:23px;
    background-color:#505050;
    text-align:center;
    position:fixed;
        font-size:12px;
    bottom:0px;
vertical-align:baseline;


}

footer{

    width: 100%;
    padding-top:-1.0%;
    padding-bottom: 2%;
    background-color: #505050;
border-top:0px solid #107CBD;
position:fixed;
text-align:center;