*{
    margin: 0;
    padding: 0;
}

html{
    scroll-behavior: smooth;
}

body{
    font-size: 100%;
    font-family: sans-serif;
}

div, section, span, ul, li, a, header{
    box-sizing: border-box;
}

header{
    width: 100%;
    display: flex;
    justify-content: space-between;
    padding: 2px 20px; 
    align-items: center;
    position: fixed;
    background-color: #000;
    z-index: 999;
    top: 0;
    height: 76px;
}

header li{
    list-style: none;
    display: inline-block;
    margin: 0px 15px;
}

header li a{
    color: #fff;
    text-decoration: none;
    font-size: 25px;
    font-weight:bold;
    position: relative;
}

header li a::before {
    content: "";
    position: absolute;
    display: block;
    width: 100%;
    height: 3px;
    bottom: 0;
    background-color: #fff;
    transform: scaleX(0);
    transition: transform 0.3s ease;
}

header li a:hover::before {
    transform: scaleX(1);
}

#hero {
    min-height: 100vh;
    background-color: black;
    justify-content: center;
    align-items: center;
    display: flex;
}

section{
    width: 100%;
    float: left;
    min-height: 100vh;
    position: relative;
    padding: 25px;
    font-size: 25px;
}

#about{
     background-color: #FFF;
}

#safety{
     background-color: #FF7800;
}

#coding{
     background-color: #ddd;;
}

#contact{
     background-color: #111;
}

a.top {
    position: relative;
    top:-101px;
    display: block;
    height: 0;
    width:0;
}

/* Responsive */

@media only screen 
    and (min-device-width: 375px) 
    and (max-device-width: 667px) 
    and (-webkit-min-device-pixel-ratio: 2) { 

    section{
        font-size: 40px;
    }

    #menu li a{
        font-size: 30px;
    }
}