html – This CSS code shows desktop portions on smartphones, I cannot seem to find the issue?

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

/*basic reset*/
* {margin: 0; padding: 0;}

html {
    height: 100%;
    /*Image only BG fallback*/
    
    /*background = gradient + image pattern combo*/
    background: linear-gradient(to right, #0f2027, #203a43, #2c5364);
}

body {
    font-family: montserrat, arial, verdana;
}
/*form styles*/
#msform {
    width: 400px;
    margin: 50px auto;
    text-align: center;
    position: relative;
}
#msform fieldset {
    background: white;
    border: 0 none;
    border-radius: 3px;
    box-shadow: 0 0 15px 1px rgba(0, 0, 0, 0.4);
    padding: 20px 30px;
    box-sizing: border-box;
    width: 80%;
    margin: 0 10%;
    
    /*stacking fieldsets above each other*/
    position: relative;
}
/*Hide all except first fieldset*/
#msform fieldset:not(:first-of-type) {
    display: none;
}
/*inputs*/
#msform input, #msform textarea {
    padding: 15px;
    border: 1px solid #ccc;
    border-radius: 3px;
    margin-bottom: 10px;
    width: 100%;
    box-sizing: border-box;
    font-family: montserrat;
    color: #2C3E50;
    font-size: 13px;
}
/*buttons*/
#msform .action-button {
    width: 100px;
    background: #27AE60;
    font-weight: bold;
    color: white;
    border: 0 none;
    border-radius: 1px;
    cursor: pointer;
    padding: 10px 5px;
    margin: 10px 5px;
}
#msform .action-button:hover, #msform .action-button:focus {
    box-shadow: 0 0 0 2px white, 0 0 0 3px #27AE60;
}
/*headings*/
.fs-title {
    font-size: 15px;
    text-transform: uppercase;
    color: #2C3E50;
    margin-bottom: 10px;
}
.fs-subtitle {
    font-weight: normal;
    font-size: 13px;
    color: #666;
    margin-bottom: 20px;
}
/*progressbar*/
#progressbar {
    margin-bottom: 30px;
    overflow: hidden;
    /*CSS counters to number the steps*/
    counter-reset: step;
}
#progressbar li {
    list-style-type: none;
    color: white;
    text-transform: uppercase;
    font-size: 9px;
    width: 50%;
    float: left;
    position: relative;
}
#progressbar li:before {
    content: counter(step);
    counter-increment: step;
    width: 20px;
    line-height: 20px;
    display: block;
    font-size: 10px;
    color: #333;
    background: white;
    border-radius: 3px;
    margin: 0 auto 5px auto;
}
/*progressbar connectors*/
#progressbar li:after {
    content: '';
    width: 100%;
    height: 2px;
    background: white;
    position: absolute;
    left: -50%;
    top: 9px;
    z-index: -1; /*put it behind the numbers*/
}
#progressbar li:first-child:after {
    /*connector not needed before the first step*/
    content: none; 
}
/*marking active/completed steps green*/
/*The number of the step and the connector before it = green*/
#progressbar li.active:before,  #progressbar li.active:after{
    background: #27AE60;
    color: white;
}
.socials img{
    width: 260px;
    border-radius: 5px;
    margin-bottom: 5px;
}
.socials img:hover{
    opacity: 0.8;
    transition: all 0.25s cubic-bezier(0.31, -0.105, 0.43, 1.4);
}
.socials img:active{
    opacity: 1;
}
h3{
    color: red;
    font-size: 12px;
}
.hidden{
    display: none;
}