@import url('https://fonts.googleapis.com/css2?family=Raleway:wght@400;700&display=swap'); 

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    background: #050801;
    font-family: 'Raleway', sans-serif;
    font-weight: bold;
}

a {
    position: relative;
    display: inline-block;
    padding: 25px 30px;
    margin:40px 0;
    color: #03f46f;
    text-decoration: none;
    text-transform: uppercase;
    transition: 0.5s;
    letter-spacing: 4px;
    overflow:hidden;
    margin-right: 50px;
}

a:hover {
    background: #03e9f4;
    color: #050801;
    box-shadow:0 0 5px #03f46f, 0 0 25px #03f46f, 0 0 50px #03f46f, 0 0 100px #03e9f4;
    -webkit-box-reflect: below 1px linear-gradient(transparent, #0005);
}

a:nth-child(1){
    filter: hue-rotate(240deg);
}
a:nth-child(2){
    filter: hue-rotate(120deg);
}
a:nth-child(3){
    filter: hue-rotate(60deg);
}
a span {
    position:absolute;
    display:block;
}

a span:nth-child(1) {
    top: 0;
    left: 0;
    width: 100%;
    height: 2px;
    background: linear-gradient(0deg, transparent, #03f46f);
    animation: animate1 1s infinite;
}

@keyframes animate1 {
    0% {
        left: -100%;
    }
    50%,
    100% {
        left: 100%;
    }
}

a span:nth-child(2) {
    top: -100%;
    right: 0;
    width: 2px;
    height: 100%;
    background: linear-gradient(100deg, transparent, #03f46f);
    animation: animate2 1s linear infinite;
    animation-delay: 0.25s ;
}

@keyframes animate2 {
    0% {
        top: -100%;
    }
    50%,
    100% {
        top: 100%;
    }
}
a span:nth-child(3) {
    bottom: 0;
    right: 0;
    width:100%;
    height: 2px;
    background: linear-gradient(270deg, transparent, #03f46f);
    animation: animate3 1s linear infinite;
    animation-delay: 0.5s;
}

@keyframes animate3 {
    0% {
        right: -100%;
    }
    50%,
    100% {
        right: 100%;
    }
}

a span:nth-child(4) {
    bottom: -100%;
    left: 0;
    width: 2px;
    height: 100%;
    background: linear-gradient(360deg, transparent, #03f46f);
    animation: animate4 1s linear infinite;
    animation-delay: 0.75s ;
}

@keyframes animate4 {
    0% {
        bottom: -100%;
    }
    50%,
    100% {
        bottom: 100%;
    }
}

@media screen and (max-width: 700px) {
    body {
        display:flex;
        flex-direction: column;
        justify-content: start;
        align-items: flex-start;
        margin-right: 10%;
        margin-left: 10%;
        font-size: 10px;
    }
    a {
        height: 100px;
        width: 50%;
    }

    .b {
        margin-left: 17%;
    }
    .c {
        margin-left: 34%;
    }
    .d {
        margin-left: 51%;
    }
}