body{
    background-color:hsl(0, 0%, 8%);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    height: 100vh;
    color: white;
    font-size: 14px;
}
.card{
    background-color: hsl(0, 0%, 12%);
    width: 350px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    border-radius: 20px;
    padding: 20px;

}
.card img{
    width: 30%;
    border-radius: 50%;
}
span{
    color: hsl(75, 94%, 57%);
}
p{
    font-size: 12px;
}
button{
    display:block;
    padding: 5px;
    margin: 10px;
    width: 90%;
    height: 50px;
    font-size: 16px;
    font-weight: bold;
    color: white;
    background-color: hsl(0, 0%, 20%);
    border-radius: 5px;
    border: none;
    cursor: pointer;
    
}
button:hover{
    background-color: hsl(75, 94%, 57%);
}
footer {
    position: absolute;
    bottom: 0; /* 4. 设置页脚position为absolute之后，再将其bottom值设为0，即可使其处于页面的底部 */
    /* background-color: hsl(0, 0%, 12%); */
    width: 100%;
}
.attribution { font-size: 11px; text-align: center; }
.attribution a { color: hsl(228, 45%, 44%); }
@media (max-width:600px) {
    body{
        font-size: 12px;
    }
    .card{
        border: 15px;
        width: 90%;
        min-width: 280px;
        padding: 10px;
    }
    footer{
        display: none;
    }
    p{
        font-size: 10px;
    }
    button{
        font-size: 14px;
    }
}