/* 背景 */
.sec4 {
    background: linear-gradient(to right top, #b4dff2, #7df0d0);
    min-height: 100vh;
    background-size: 100%;
}
/* 小圆点 */
.sec4_circle1 {
    background: white;
    background: linear-gradient(
        to right bottom,
        rgba(255, 113, 191, 0.8),
        rgba(230, 255, 253, 0.3)
    );
    height: 20rem;
    width: 20rem;
    position: absolute;
    border-radius: 25%;
    bottom: 30%;
    left: 10%;
    transform: rotate(66deg);
}
.sec4_circle2 {
    background: white;
    background: linear-gradient(
        to right bottom,
        rgba(208, 252, 228, 0.8),
        rgba(255, 225, 225, 0.3)
    );
    height: 20rem;
    width: 20rem;
    position: absolute;
    border-radius: 25%;
    top: 20%;
    right: 10%;
    transform: rotate(33deg);
}
.sec4_circle3 {
    background: white;
    background: linear-gradient(
        to right bottom,
        rgba(255, 225, 225, 0.8),
        rgba(255, 255, 255, 0.3)
    );
    height: 20rem;
    width: 20rem;
    position: absolute;
    border-radius: 25%;
    bottom: 5%;
    right: 40%;
    transform: rotate(99deg);
}
/* 主体部分 */
#section4 {
    display: flex;
    justify-content: center;
    align-items: center;
}
.sec4_main_box {
    width: 1200px;
    height: 600px;
    background-color: rgba(255, 255, 255, 0.3);
    border-radius: 25px;
    backdrop-filter: blur(0.2rem);
}
/* ------------------------------------- */
#sec4_app {
    display: flex;
    flex-direction: column;
    align-items: center;
}
.sec4_title {
    text-align: center;
    font-size: 30px;
    color: rgb(255, 60, 141);
    margin-top: 50px;
}
.sec4_search {
    width: 500px;
    height: 40px;
    margin: 50px auto 0;
    border: 1px solid rgba(204, 204, 204, 0.5);
    display: flex;
    border-radius: 10px;
    overflow: hidden;
}
.sec4_input {
    flex: 8;
    padding-left: 10px;
}
.sec4_button {
    flex: 2;
    background-color: rgb(255, 60, 141);
    color: #fff;
    font-size: 20px;
}
.sec4_select {
    display: flex;
    width: 500px;
    margin: 20px auto 0;
    text-align: center;
}
.sec4_select a {
    flex: 1;
    font-size: 18px;
}
.sec4_select a:hover {
    color: rgb(255, 60, 141);
}
.sec4_ul {
    width: 100%;
    margin-top: 50px;
    display: flex;
    text-align: center;
}
.sec4_li {
    flex: 1;
    background-color: rgba(204, 204, 204, 0.2);
    border-radius: 20px;
    margin: 0 5px;
}
.sec4_weather .tianqi {
    font-size: 30px;
    font-weight: 700;
    color: rgb(255, 143, 38);
    margin-top: 30px;
}
.sec4_weather .qiwen {
    font-size: 20px;
    color: skyblue;
    margin-top: 20px;
}
.sec4_weather .date {
    font-size: 16px;
    color: tomato;
    margin: 10px 0;
}