.header {
    margin: 0;
    height:57px;
    display: flex;
    flex-direction: row;
    justify-content: space-between; /* justify - 对齐 */
    position: fixed;
    top:0px;
    left:0px;
    right:0px;
    background-color: white;
    border-bottom-width : 1px;
    border-bottom-style: solid;
    border-bottom-color: rgba(0,0,0,0.15);
    z-index: 100;
}

.left-section {
    align-items: center;
    display: flex;
}

.middle-section {
    flex: 1;
    margin-left: 70px;
    margin-right: 35px;
    max-width: 500px;   /* 最大宽度设置 */
    display: flex;
    flex-direction: row;
    align-items: center;
    
}

.search-button {
    height: 40px;
    width: 66px;
    background-color: rgb(240, 240, 240);
    border : 1px solid rgb(192, 192, 192);
    margin-left: -1px;
    margin-right: 10px;
    position: relative;
    cursor: pointer;
}

.voice-search-button {
    height:40px;
    width: 40px;
    border-radius: 20px;
    border:none;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    cursor: pointer;
}

.voice-search-icon {
    height:24px;
}

.upload-icon-container, .youtube-apps-ico-container, .notification-icon-container  {
    position: relative;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    cursor: pointer;
}

.search-button .tooltip, 
.voice-search-button .tooltip,
.upload-icon-container .tooltip,
.youtube-apps-ico-container .tooltip,
.notification-icon-container .tooltip
       { /* search-button 容器下边的 .tooltip*/
    position: absolute;
    background-color: gray;
    color: white;
    padding: 4px 8px;
    border-radius: 3px;
    font-size: 12px;
    bottom: -35px;
    opacity: 0;
    transition: opacity 0.218s;
    pointer-events: none;
    white-space: nowrap;
}

.left-section .tooltip
       { /* search-button 容器下边的 .tooltip*/
    position: absolute;
    background-color: gray;
    color: white;
    padding: 4px 8px;
    border-radius: 3px;
    font-size: 12px;
    bottom: -20px;
    left : 80px;
    opacity: 0;
    transition: opacity 0.218s;
    pointer-events: none;
    white-space: nowrap
}

.search-button:hover .tooltip,
.voice-search-button:hover .tooltip,
.upload-icon-container:hover .tooltip,
.youtube-apps-ico-container:hover .tooltip,
.notification-icon-container:hover .tooltip,
.left-section:hover .tooltip
{
    opacity: 1;
}



.search-bar {
    flex:1;
    height:38.94px;
    padding-left: 10px;
    padding-top: 0;
    padding-bottom: 0;
    font-size: 16px;
    border: 1px solid rgb(192, 192, 192);
    border-top-left-radius: 2px;
    border-bottom-left-radius: 2px ;
    box-shadow: inset 1px 2px 3px drgb(192, 192, 192);
    width: 0; /* remove default width */
}

.search-bar::placeholder{   /*修改placehoder字体*/
    font-size: 16px;
}

.search-icon {
    height: 25px;
}



.right-section {
    width:180px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-shrink: 0; /* 保持子元素的间距 */
    margin-left: 29px;
    margin-right: 24px;
}

.notification-icon-container {
    position: relative;
}

.notification-count {
    position: absolute;
    top : -3px;
    right: -5px;
    background-color: rgb(200, 0, 0);
    color: white;
    font-size: 11px;
    padding: 1.5px 5px;
    border-radius: 10px;
}

.upload-icon {
    height:24px;
}

.youtube-apps-icon {
    height:24px;
}

.notification-icon {
    height:24px;
    cursor: pointer;
}

.current-user-picture {
    height:32px;
    border-radius: 16px;
}

.hamburger-menu {
    height: 24px;
    margin-left: 24px;
    margin-right: 24px;
    cursor: pointer;
}

.youtube-logo {
    height:20px;
    cursor: pointer;
}