/*公共样式*/
html {
    font-size: 62.5%;
    font-family: Arial;
}

@media screen and (max-width: 980px) {
    html {
        font-size: 110%;
    }
    header button {
        font-size: 2rem;
    }
}

/*头部样式*/
header {
    width: 100%;
    margin: 0 auto;
    text-align: center;
}

header h1 {
    font-size: 4rem;
    margin-top: 1rem;
    margin-bottom: 1rem;
    font-weight: bold;
}

header button {
    display: block;
    width: 10rem;
    margin: 1.5rem auto;
    padding: 1rem;
    border-radius: 1rem;
    border: none;
    color: white;
    background-color: #8f7a66;
    cursor: pointer;
    outline: none;
}

header button:hover {
    text-decoration: underline;
    background-color: #9f8b77;
}

header p {
    width: 100%;
    margin: 1.5rem auto;
    font-size: 2.5rem;
}

/*头部样式结束*/

/*grid_container开始*/
.grid_container {
    display: flex;
    flex-wrap: wrap;
    justify-content: space-between;
    align-content: space-between;
    width: 46rem;
    height: 46rem;
    padding: 2rem;
    margin: 3rem auto;
    border-radius: 1rem;
    background-color: #bbada0;
    position: relative;
    overflow: hidden;
}

.grid_cell {
    width: 10rem;
    height: 10rem;
    border-radius: .6rem;
    background-color: #ccc0b3;
}

.number_cell {
    line-height: 10rem;
    border-radius: .6rem;
    background-color: #ccc0b3;
    font-size: 5rem;
    font-weight: bold;
    text-align: center;
    position: absolute;
}
/*grid_container结束*/