HTML+Sass实现HambergurMenu(汉堡包式菜单)

/*设置颜色及max-width*/$primary-color: rgba(13,110,139,.75);$overlay-color: rgba(24,39,51,.85);$max-width: 980px;/*设置文本颜色，如果背景色浅，则设置为黑色，否则设置为白色*/@function set-text-color($color){  @if(lightness($color)>70){    @return #333;  }@else{    @return #fff;  }}/*混合器，设置背景色及文本颜色*/@mixin set-background($color){  background-color: $color;  color: set-text-color($color);}

@import '_config';*{  margin: 0;  padding: 0;}.container{  max-width: $max-width;  margin: 0 auto;}/*给showcase设置背景颜色，利用伪类再添加一个背景图，同时将背景图的z-index设置为-1（这样图片会显示在里面）；然后为了让文字显示在中间，所以使用flex布局*/.showcase{  position: relative;  height: 100vh;  background-color: $primary-color;  &:before{    content: '';    position: absolute;    left: 0;    top: 0;    width: 100%;    height: 100%;    background: url('../img/pexels-photo-533923.jpeg') no-repeat center center / cover;    z-index: -1;  }  &-inner{    display: flex;    height: 100%;    flex-direction: column;    justify-content: center;    align-items: center;    text-align: center;    color: #fff;    font-weight: 100;    h1{      font-size: 4rem;      padding: 1.2rem 0;    }    p{      white-space: pre-wrap;      font-size: 1.6rem;      padding: 0.85rem 0;    }    .btn{      padding: .65rem 1rem;        /*使用混合器设置背景色及文本颜色*/      @include set-background(lighten($primary-color,30%));      border: none;      border: 1px solid $primary-color;      border-radius: 5px;      text-decoration: none;      outline: none;      transition: all .2s ease .1s;        /*按钮hover的时候利用css3的scale设置一个缩放效果*/      &:hover{        @include set-background(lighten($overlay-color,30%));        border-color: lighten($overlay-color, 25%);        transform: scale(.98);      }    }  }}/*原理：通过checkbox的点中与否来进行样式的变化（将checkbox透明度设置为0，z-index设置更高），单击时，会出现菜单，再次点击，菜单消失*//*给menu-wrap设置fixed，这样showcase就会占满整个屏幕;同时将checkbox的opacity设置为0；另外注意，需要将checkbox的z-index设置为2，因为hamburger的z-index设置为1，不然会点击不起作用*/.menu-wrap{  position: fixed;  left: 0;  top: 0;  z-index: 1;  .toggle{    position: absolute;    left: 0;    top: 0;    width: 50px;    height: 50px;    opacity: 0;    z-index: 2;    cursor: pointer;      /*当checkbox为checked时，设置hamburger里面的div及伪类的旋转效果*/    &:checked ~ .hamburger>div{      transform: rotate(135deg);        /*伪类实际上旋转了225度，需要将top设置为0，不然形成的❌长短不一致*/      &:before,&:after{        transform: rotate(90deg);        top: 0;      }    }      /*当checkbox选中时再hover，也会设置一个旋转效果*/    &:checked:hover ~ .hamburger>div{      transform: rotate(235deg);    }    &:checked ~ .menu{      visibility: visible;      >div{        transform: scale(1);        >div{          opacity: 1;        }      }    }  }      .hamburger{    position: absolute;    left: 0;    top: 0;    width: 60px;    height: 60px;    padding: 1rem;    background-color: $primary-color;    box-sizing: border-box;    display: flex;    flex-direction: column;    justify-content: center;    align-items: center;    text-align: center;    z-index: 1;      /*div自身生成中间的横线，然后设置定位为relative，后面再将其伪类设置为absolute，      相对于div进行偏移*/    >div{      position: relative;      left: 0;      top: 0;      width: 100%;      height: 2px;      background-color: #fff;      transition: all .7s ease;        /*利用伪类生成第一条和第三条横线*/      &:before,      &:after{        content: '';        position: absolute;        left: 0;        top: -10px;        width: 100%;        height: 2px;        background-color: inherit;      }      &:after{        top: 10px;      }    }  }    /*设置选中后的菜单的样式*/    /*将menu设置为fixed，同时宽高为100%，然后设置display为flex，否则菜单不会出现在中间*/  .menu{    position: fixed;    left: 0;    top: 0;    width: 100%;    height: 100%;    overflow: hidden;    display: flex;    justify-content: center;    align-items: center;    visibility: hidden;    /*将菜单设置为不可见，然后在checkbox选中时设置为可见*/    transition: all .75s ease;    >div{      @include set-background($overlay-color);      width: 200vw;      height: 200vh;      overflow: hidden;      border-radius: 50%;      display: flex;      justify-content: center;      align-items: center;      text-align: center;      transform: scale(0);      transition: all .4s ease;      >div{        max-width: 90vw;        max-height: 90vh;        opacity: 0;        transition: all .4s ease;        >ul>li{          list-style: none;          font-size: 2rem;          padding: .85rem 0;          text-transform: uppercase;          transform: skew(-5deg,-5deg) rotate(5deg);/*设置文字倾斜*/          a{            color: inherit;            text-decoration: none;            transition: color .4s ease;          }        }      }    }  }}