body{
    
    background-color: black;
    background: url(./pic/pngtree-background-of-monitor-computer-with-online-game-streaming-desktop-picture-image_15517930.png) center / cover no-repeat fixed;
    opacity: 0.5;
}

.a{
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
}
.b{
    
    text-align: center;
    background-color: rgb(0, 0, 0);
    box-shadow: 0 0 40px yellow;
    opacity: 0.8;
    border-radius: 20px;
    width: 500px;
    height: 200px;
}
.c{
    text-decoration: none;
    color: black;
    font-size: 60%;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-top: 70px;
    margin-left: 90px;
    border-bottom-left-radius: 30px;
    border-top-right-radius: 30px;
    background-color: aqua;
    width: 300px;
    height: 50px;
}
.c:hover{
    text-decoration: none;
    box-shadow: 0 0 15px #00ffff;
    transform: scale(1.05);
}