.red {
    color: red;
}
.yellow {
    color: yellow;
}
.blue {
    color: blue;
}
.green {
    color: green;
}
.background {
    background-color: #d7d0c5;
    background-image: radial-gradient(27% 185%, #F9F6F1 0%, #D7D0C5 100%);
}
button {
    background-color: #6a78f6;
    color: white;
    border: 5px solid #d5d519;
    border-radius: 8px;
    cursor: pointer;
    /* 平滑过渡 */
    transition: background-color 0.5s ease;
}
/* 鼠标悬浮按钮上方特效 */
button:hover {
    background-color: #d5d519;
    border: 5px solid #6a78f6;
}