若依前后端分离样式修改

1.修改登录页

找到文件\src\views\login.vue

//修改登录页面背景图
.login {
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100%;
  background-image: url("../assets/images/login-background.jpg");
  background-size: cover;
}
//修改登录按钮颜色
.login_btn {
  width: 360px !important;
  height: 49px;
  font-size: 16px;
  font-weight: 500;
  color: #000000;
  opacity: 1;
  background-color: #FEC900;
  border-color: #FEC900;
}
.login_btn:hover{
  width: 360px !important;
  height: 49px;
  font-size: 16px;
  font-weight: 500;
  color: #000000;
  opacity: 0.82;
  background-color: #FEC900;
  border-color: #FEC900;
}

// 改变input里的字体颜色
.login input::-webkit-input-placeholder {
  color: #EFEFEF;
  font-size: 14px;
}

.login input{
  border: 1px solid #EFEFEF;
  -webkit-text-fill-color: #ededed !important;
  -webkit-box-shadow: 0 0 0px 1000px transparent  inset !important;
  background-color:transparent !important;
  transition: background-color 50000s ease-in-out 0s; //背景色透明  生效时长  过渡效果  启用时延迟的时间
}

2.修改侧边栏样式

1.侧边栏首页样式（首页跟其他侧边栏样式是分开的）

找到文件\src\assets\styles\variables.scss

// 默认菜单主题风格
$base-menu-color:#CECECE; //菜单全部字体颜色
$base-menu-color-active:#F5CB24; //父菜单选中后字体颜色
$base-menu-background:#0C0C0C; // 父菜背景色
$base-logo-title-color: #F5CB24; //系统标题颜色

$base-menu-light-color:rgba(0,0,0,.70);
$base-menu-light-background:#ffffff; // 选中菜单的字体颜色
$base-logo-light-title-color: #001529;

$base-sub-menu-background:#232222; // 子菜单背景颜色
$base-sub-menu-hover:#0C0C0C;  // 子菜单hover背景色
$base-sub-menu-color-active:#F5CB24; // 子菜单、首页选中后的字体颜色

找到文件\src\assets\styles\sidebar.scss
其中首页跟子菜单的样式是新增的
修改侧边栏首页栏选中后的字体颜色

.el-menu-item.is-active {
        color: $base-sub-menu-color-active !important;
    }

修改侧边栏子菜单选中后的字体颜色

 .theme-dark .el-submenu .is-active {
        color: $base-sub-menu-color-active !important;
    }

注意：如果需要新增样式
可以先在variables.scss中新增

然后

最后直接通过$base-sub-menu-color-active就可以调用新增的属性

#app {

  .main-container {
    min-height: 100%;
    transition: margin-left .28s;
    margin-left: $base-sidebar-width;
    position: relative;
  }

  .sidebarHide {
    margin-left: 0!important;
  }

  .sidebar-container {
    -webkit-transition: width .28s;
    transition: width 0.28s;
    width: $base-sidebar-width !important;
    background-color: $base-menu-background;
    height: 100%;
    position: fixed;
    font-size: 0px;
    top: 0;
    bottom: 0;
    left: 0;
    z-index: 1001;
    overflow: hidden;
    -webkit-box-shadow: 2px 0 6px rgba(0,21,41,.35);
    box-shadow: 2px 0 6px rgba(0,21,41,.35);

    /*修改侧边栏首页栏选中后的字体颜色*/
    .el-menu-item.is-active {
        color: $base-sub-menu-color-active !important;
    }

    /*修改侧边栏子菜单选中后的字体颜色*/
    .theme-dark .el-submenu .is-active {
        color: $base-sub-menu-color-active !important;
    }

    // reset element-ui css
    .horizontal-collapse-transition {
      transition: 0s width ease-in-out, 0s padding-left ease-in-out, 0s padding-right ease-in-out;
    }

    .scrollbar-wrapper {
      overflow-x: hidden !important;
    }

    .el-scrollbar__bar.is-vertical {
      right: 0px;
    }

    .el-scrollbar {
      height: 100%;
    }

    &.has-logo {
      .el-scrollbar {
        height: calc(100% - 50px);
      }
    }

    .is-horizontal {
      display: none;
    }

    a {
      display: inline-block;
      width: 100%;
      overflow: hidden;
    }

    .svg-icon {
      margin-right: 16px;
    }

    .el-menu {
      border: none;
      height: 100%;
      width: 100% !important;
    }

    .el-menu-item, .el-submenu__title {
      overflow: hidden !important;
      text-overflow: ellipsis !important;
      white-space: nowrap !important;
    }

    // menu hover
    .submenu-title-noDropdown,
    .el-submenu__title {
      &:hover {
        background-color: rgba(0, 0, 0, 0.06) !important;
      }
    }

    & .theme-dark .is-active > .el-submenu__title {
      color: $base-menu-color-active !important;
    }

    & .nest-menu .el-submenu>.el-submenu__title,
    & .el-submenu .el-menu-item {
      min-width: $base-sidebar-width !important;

      &:hover {
        background-color: rgba(0, 0, 0, 0.06) !important;
      }
    }

    & .theme-dark .nest-menu .el-submenu>.el-submenu__title,
    & .theme-dark .el-submenu .el-menu-item {
      background-color: $base-sub-menu-background !important;
      &:hover {
        background-color: $base-sub-menu-hover !important;
      }
    }
  }

  .hideSidebar {
    .sidebar-container {
      width: 54px !important;
    }

    .main-container {
      margin-left: 54px;
    }

    .submenu-title-noDropdown {
      padding: 0 !important;
      position: relative;

      .el-tooltip {
        padding: 0 !important;

        .svg-icon {
          margin-left: 20px;
        }
      }
    }

    .el-submenu {
      overflow: hidden;

      &>.el-submenu__title {
        padding: 0 !important;

        .svg-icon {
          margin-left: 20px;
        }

      }
    }

    .el-menu--collapse {
      .el-submenu {
        &>.el-submenu__title {
          &>span {
            height: 0;
            width: 0;
            overflow: hidden;
            visibility: hidden;
            display: inline-block;
          }
        }
      }
    }
  }

  .el-menu--collapse .el-menu .el-submenu {
    min-width: $base-sidebar-width !important;
  }

  // mobile responsive
  .mobile {
    .main-container {
      margin-left: 0px;
    }

    .sidebar-container {
      transition: transform .28s;
      width: $base-sidebar-width !important;
    }

    &.hideSidebar {
      .sidebar-container {
        pointer-events: none;
        transition-duration: 0.3s;
        transform: translate3d(-$base-sidebar-width, 0, 0);
      }
    }
  }

  .withoutAnimation {

    .main-container,
    .sidebar-container {
      transition: none;
    }
  }
}

// when menu collapsed
.el-menu--vertical {
  &>.el-menu {
    .svg-icon {
      margin-right: 16px;
    }
  }

  .nest-menu .el-submenu>.el-submenu__title,
  .el-menu-item {
    &:hover {
      // you can use $subMenuHover
      background-color: rgba(0, 0, 0, 0.06) !important;
    }
  }

  // the scroll bar appears when the subMenu is too long
  >.el-menu--popup {
    max-height: 100vh;
    overflow-y: auto;

    &::-webkit-scrollbar-track-piece {
      background: #d3dce6;
    }

    &::-webkit-scrollbar {
      width: 6px;
    }

    &::-webkit-scrollbar-thumb {
      background: #99a9bf;
      border-radius: 20px;
    }
  }
}

3.修改TagsView导航栏样式

找到文件\src\layout\components\TagsView\index.vue
修改选中后的背景色以及背景边框