* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
} 
body {
    font-family: 'Roboto', sans-serif;
    background-color: #f5f5f5;
    /* 更明亮的背景色 */
    color: #333;
    /* 更暗的字体颜色 */
    line-height: 1.6;
    padding: 0;
    margin: 0;
    overflow-x: hidden;
    transition: background-color 0.3s, color 0.3s;
}

header {
    background-color: #ffffff;
    /* 头部背景白色 */
    /* padding: 20px 0; */
    text-align: center; 
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.1);
    /* 微弱的阴影 */
}
.logoimg{
    height: 160px;
    max-width: 1200px;
    margin: 0 auto;
}
.logoimg>img{
    width: 100%;
    height: 100%;
}
header .logo {
    color: #f7a923;
    /* 蓝色文字 */
    font-size: 40px;
    font-weight: bold;
    text-transform: uppercase;
    letter-spacing: 5px;
    text-shadow: 0 0 10px rgba(0, 123, 255, 0.4);
    /* 蓝色光晕 */
}

.content {
    padding: 50px 20px;
    transform: translateY(-15px);
    text-align: center;
    max-width: 1200px;
    margin: 0 15px; 
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
    /* 更轻微的阴影 */
    background-color: #ffffff;
    /* 背景白色 */
    border-radius: 20px;
}
#content_box{
    margin: 0 auto;
    max-width: 1200px;
}
h1 {
    font-size: 42px;
    margin-bottom: 20px;
    color: #007bff;
    /* 蓝色标题 */
    text-shadow: 0 0 10px rgba(0, 123, 255, 0.4);
    /* 蓝色光晕 */
}

p {
    font-size: 18px;
    margin: 35px;
    color: #666;
    /* 更柔和的文字颜色 */
}

.tabs {
    display: flex;
    justify-content: start;
    margin-bottom: 25px;
    font-size: 25px;
    overflow-x: auto;
    /* 允许横向滚动 */
    white-space: nowrap;
    /* 防止选项卡换行 */
    padding-bottom: 10px;
    /* 给选项卡底部增加一点空隙 */
}

.tab-btn {
    background-color: #f0f0f0;
    /* 选项卡按钮背景颜色 */
    color: #b3b3b3;
    /* 按钮文字颜色 */
    padding: 15px 30px;
    margin: 25px 20px 15px;
    font-size: 18px;
    font-weight: 800;
    border: none;
    cursor: pointer;
    border-radius: 30px;
    transition: background-color 0.3s, transform 0.3s, box-shadow 0.3s;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
    /* 微弱的阴影 */
}

.tab-btn.active {
    font-style: oblique;
    background-image: linear-gradient(90deg, #49d391, #34d0aa);
    /* 选中时背景色变为蓝色 */
    color: #ffffff;
    /* 字体颜色改为白色 */
    transform: scale(1.1) translateY(-5px);
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.4);
    /* 蓝色阴影 */

}

.tab-btn:hover {
    box-shadow: 0 8px 15px rgba(0, 0, 0, 0.2);
    /* 暗一些的阴影 */
}

.ipa-container {
    display: flex;
    flex-wrap: wrap;
    /* 音标按钮在小屏上换行 */
    justify-content: center;
    gap: 15px;
    /* 给按钮之间增加一点间隔 */
}

.ipa-btn {

    background-color: #ffffff;
    padding: 18px;
    border-radius: 12px;
    font-size: 1.2em;
    cursor: pointer;
    transition: background-color 0.3s, transform 0.3s, box-shadow 0.3s;
    font-weight: 600;
    position: relative;
    color: #666;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
}

.ipa-btn:hover {
    /* 悬停时按钮颜色加深 */
    transform: scale(1.1);
}

footer {
    text-align: center;
    padding: 20px;
    background-color: #ffffff;
    /* 底部白色背景 */
    color: #333;
    /* 深色文字 */
    font-size: 14px;
    border-top: 2px solid #ddd;
    /* 淡灰色边框 */
    box-shadow: 0 -4px 10px rgba(0, 0, 0, 0.1);
    /* 微弱的阴影 */
}

.tab-content {
    display: none;
}

.tab-content.active {
    display: block;
}

/* 夜间模式 */
body.dark-mode {
    background-color: #333;
    color: #f5f5f5;
}

body.dark-mode header,
body.dark-mode .content,
body.dark-mode footer {
    background-color: #444;
    /* 深色背景 */
}

body.dark-mode .diagram-container img{
    filter: brightness(0.73) invert(1);
}
body.dark-mode .coming-soon{
    filter: brightness(0.73) invert(1);
}

body.dark-mode .tab-btn {
    background-color: #555;
    color: #999999;
}

body.dark-mode .tab-btn.active {
    background-color: #f7a923;
    color: #333;
    font-style: oblique;
}

body.dark-mode .ipa-btn {
    background-color: #555;
    color: #f5f5f5;
}

.theme-switch {
    position: absolute; 
    cursor: pointer;
    background-color: #f7a923;
    padding: 5px 7px;
    border-radius: 188%;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
    transition: transform 0.3s, box-shadow 0.3s;
    transform: translate(45px, 10px);
    z-index: 99;
}
.theme-switch::before {
    content: '';
    position: absolute;
    bottom: -9px;
    left: 50%;
    transform: translateX(-50%);
    width: 17px;
    height: 5px;
    background: #38cf9b;
    opacity: 0.7;
    border-radius: 50px
}
.theme-switch:hover {
    transform: translate(45px, 10px) scale(1.1);
    box-shadow: 0 8px 15px rgba(0, 0, 0, 0.3);
}

@media (max-width: 768px) {
    .ipa-btn {
        padding: 15px 25px;
        font-size: 18px;
    }

    h1 {
        font-size: 36px;
    }

    .tab-btn {
        padding: 12px 25px;
        font-size: 18px;
    }

    .tabs {
        flex-direction: row;
        /* 保持选项卡水平排列 */
    }

    .ipa-container {
        flex-direction: row;
        /* 音标按钮水平排列 */
    }
}

@media (max-width: 480px) {
    .ipa-btn {
        padding: 12px 20px;
        font-size: 30px;
    }

    h1 {
        font-size: 30px;
    }

    .tab-btn {
        padding: 10px 20px;
        font-size: 16px;
    }

    .tabs {
        flex-direction: row;
        /* 保持选项卡水平排列 */
    }

    .ipa-container {
        flex-direction: row;
        /* 音标按钮水平排列 */
    }
}

.coming-soon {
    font-family: "Arial", sans-serif;
    font-size: 24px;
    color: #d1cccc;
    text-align: center;
    margin: 20%;
    font-style: italic;
    letter-spacing: 2px;
}


.diagram-container {
    text-align: center; 
    border-radius: 20px;
    overflow: hidden;
    margin: 0 15px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.1); 
}

.diagram-container img { 
    width: 100%;
    height: 100%; 
    display: block;
}