/*設(shè)置顏色及max-width*/
$primary-color: rgba(13,110,139,.75);
$overlay-color: rgba(24,39,51,.85);
$max-width: 980px;

/*設(shè)置文本顏色，如果背景色淺，則設(shè)置為黑色，否則設(shè)置為白色*/
@function set-text-color($color){
  @if(lightness($color)>70){
    @return #333;
  }@else{
    @return #fff;
  }
}

/*混合器，設(shè)置背景色及文本顏色*/
@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;
}

/*給showcase設(shè)置背景顏色，利用偽類再添加一個(gè)背景圖，同時(shí)將背景圖的z-index設(shè)置為-1（這樣圖片會(huì)顯示在里面）；
然后為了讓文字顯示在中間，所以使用flex布局*/
.showcase{
  position: relative;
  height: 100vh;
  background-color: $primary-color;
  &:before{
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background: url('../img/pexels-photo-533923.jpeg') no-repeat center center / cover;
    z-index: -1;
  }
  &-inner{
    display: flex;
    height: 100%;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
    color: #fff;
    font-weight: 100;
    h1{
      font-size: 4rem;
      padding: 1.2rem 0;
    }
    p{
      white-space: pre-wrap;
      font-size: 1.6rem;
      padding: 0.85rem 0;
    }
    .btn{
      padding: .65rem 1rem;
        /*使用混合器設(shè)置背景色及文本顏色*/
      @include set-background(lighten($primary-color,30%));
      border: none;
      border: 1px solid $primary-color;
      border-radius: 5px;
      text-decoration: none;
      outline: none;
      transition: all .2s ease .1s;
        /*按鈕hover的時(shí)候利用css3的scale設(shè)置一個(gè)縮放效果*/
      &:hover{
        @include set-background(lighten($overlay-color,30%));
        border-color: lighten($overlay-color, 25%);
        transform: scale(.98);
      }
    }
  }
}

/*原理：通過(guò)checkbox的點(diǎn)中與否來(lái)進(jìn)行樣式的變化（將checkbox透明度設(shè)置為0，z-index設(shè)置更高），單擊時(shí)，會(huì)出現(xiàn)菜單，再次點(diǎn)擊，菜單消失*/
/*給menu-wrap設(shè)置fixed，這樣showcase就會(huì)占滿整個(gè)屏幕;同時(shí)將checkbox的opacity設(shè)置為0；
另外注意，需要將checkbox的z-index設(shè)置為2，因?yàn)閔amburger的z-index設(shè)置為1，不然會(huì)點(diǎn)擊不起作用
*/
.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;
      /*當(dāng)checkbox為checked時(shí)，設(shè)置hamburger里面的div及偽類的旋轉(zhuǎn)效果*/
    &:checked ~ .hamburger>div{
      transform: rotate(135deg);
        /*偽類實(shí)際上旋轉(zhuǎn)了225度，需要將top設(shè)置為0，不然形成的❌長(zhǎng)短不一致*/
      &:before,&:after{
        transform: rotate(90deg);
        top: 0;
      }
    }

      /*當(dāng)checkbox選中時(shí)再hover，也會(huì)設(shè)置一個(gè)旋轉(zhuǎn)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自身生成中間的橫線，然后設(shè)置定位為relative，后面再將其偽類設(shè)置為absolute，
      相對(duì)于div進(jìn)行偏移*/
    >div{
      position: relative;
      left: 0;
      top: 0;
      width: 100%;
      height: 2px;
      background-color: #fff;
      transition: all .7s ease;
        /*利用偽類生成第一條和第三條橫線*/
      &:before,
      &:after{
        content: '';
        position: absolute;
        left: 0;
        top: -10px;
        width: 100%;
        height: 2px;
        background-color: inherit;
      }
      &:after{
        top: 10px;
      }
    }
  }

    /*設(shè)置選中后的菜單的樣式*/
    /*將menu設(shè)置為fixed，同時(shí)寬高為100%，然后設(shè)置display為flex，否則菜單不會(huì)出現(xiàn)在中間*/
  .menu{
    position: fixed;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    overflow: hidden;
    display: flex;
    justify-content: center;
    align-items: center;
    visibility: hidden;    /*將菜單設(shè)置為不可見，然后在checkbox選中時(shí)設(shè)置為可見*/
    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);/*設(shè)置文字傾斜*/
          a{
            color: inherit;
            text-decoration: none;
            transition: color .4s ease;
          }
        }
      }
    }
  }
}