#sideBar {
    float: left !important;
    width: 300px !important;
    margin-right: 0px;  /* 左右留间距，不贴死 */
}

/* 精准计算：左侧300 + 间距20 */
#mainContent {
    float: right !important;
    width: calc(100% - 80px) !important;
}

#sideBarMain {
    background: #eef7f3;
    padding: 10px;
    border-radius: 6px;
}

.day {
    background: #f8f5f0;
    border-radius: 8px;
    padding: 15px;
    margin-bottom: 15px;
}

/* 关键：补上页面最外层，彻底消灭白色空白 */
#home,
body,
#mainContent,
#postDetail,
.postBody,
#postBody,
.post {
    background: #f8f5f0 !important;
}