*{
   margin: 0;
   padding: 0;
 }
   
 /* 星星特效*/
 .home {
  height: 100%;
  overflow: hidden;
}

.content {
  perspective: 340px;
  width: 100%;
  position: relative;
}

.stars {
position: absolute;
top: 50%;
left: 50%;
width: 2px;
height: 2px;
z-index: 999;
border-radius: 50%;
box-shadow: -447px 387px #c4c4c4, -401px 118px #fafafa, -109px 217px #d9d9d9, -680px -436px #e3e3e3, 514px 360px #cccccc, -708px 298px #e8e8e8, -696px -270px #ededed, 116px -128px #f7f7f7, 179px 35px white, -404px -90px whitesmoke, -331px -309px #c4c4c4, -363px -24px #d1d1d1, 277px 416px #fafafa, -145px -244px whitesmoke, 123px 62px #d4d4d4, -407px 418px #d9d9d9, 535px 237px #d9d9d9, -466px -78px #f7f7f7, 257px 287px #dedede, 327px -398px #e0e0e0, -602px -38px #c2c2c2, 128px 398px #e6e6e6, 274px -446px #d1d1d1, -602px -298px #c7c7c7, 526px -5px #c4c4c4, -90px -158px #fcfcfc, 5px 294px whitesmoke, -633px 229px #c4c4c4, -475px 427px #dedede, 586px -453px #f2f2f2, 180px -432px #c7c7c7, -637px -88px #cfcfcf, -453px 308px #d6d6d6, -111px 1px #d9d9d9, 573px -450px #ededed, 198px 300px #d6d6d6, -355px 166px #dedede, -715px 13px #e3e3e3, 262px -104px #d1d1d1, 147px 325px #dbdbdb, 1px 399px #dbdbdb, 286px -100px white, 43px -329px #e8e8e8, 617px 55px #d9d9d9, -168px -392px #cccccc, 84px 219px #c9c9c9, 507px -226px #d9d9d9, -327px -70px #e6e6e6, 386px -212px #c4c4c4, -717px 4px #cfcfcf, 502px -231px #e3e3e3, 302px 56px #ededed, 649px 341px #c7c7c7, 569px 350px #c9c9c9, 516px -31px #e6e6e6, 689px 447px #c2c2c2, 591px -206px #fafafa, 422px -137px #e6e6e6, -510px -324px #cccccc, -649px 287px #c2c2c2, -194px -48px #f7f7f7, -279px -329px #d1d1d1, -406px 478px #dbdbdb, -735px -87px #c9c9c9, 30px -197px #dedede, -564px 233px #e6e6e6, -486px -324px #ededed, -54px -7px #ededed, -441px -194px #e3e3e3, -133px -95px #e0e0e0, -722px -73px #d6d6d6, 595px 423px #ededed, 568px -39px #ededed, 370px 377px #d1d1d1, -419px -102px #fcfcfc, -450px 109px #c4c4c4, -57px -119px #d1d1d1, -582px 150px #e6e6e6, 206px -263px #cfcfcf, 582px -461px #c9c9c9, -268px -141px #d9d9d9, -148px 291px #c7c7c7, 254px -179px #c9c9c9, 725px 424px #f0f0f0, 391px -150px #ebebeb, 89px -299px #d4d4d4, 170px 1px #c9c9c9, 243px 209px #c7c7c7, 27px 460px #c9c9c9, -465px -380px #d4d4d4, 530px -360px whitesmoke, -626px 53px #e0e0e0, 706px 218px #d9d9d9, 40px -82px #cccccc, -5px -212px #e6e6e6, -742px 33px #ebebeb, -714px 478px #e0e0e0, -585px -125px #cccccc, -216px 348px #cfcfcf, 601px 332px #ededed, 344px -88px #c4c4c4, 659px -22px #d1d1d1, -411px 188px #d6d6d6, -423px -206px #fcfcfc, -359px -136px #cfcfcf, 612px 406px whitesmoke, 725px 96px whitesmoke, 363px -446px white, -204px 325px #c9c9c9, 740px 176px #fafafa, -489px -352px white, -638px 64px #dbdbdb, 537px -65px #dbdbdb, 151px -32px #ebebeb, 681px 212px #fcfcfc, 604px -149px #e6e6e6, -542px -398px #c4c4c4, -707px 66px whitesmoke, -381px 258px #cfcfcf, -30px 332px #d6d6d6, 512px -381px #c9c9c9, 195px 288px #cccccc, -278px 479px #c7c7c7, 27px -208px #d6d6d6, -288px 15px white, -680px 248px #dedede, 433px 31px #c9c9c9, 150px -206px #d4d4d4, -79px 247px white, -594px 115px #e0e0e0, 99px 292px #e0e0e0, 673px -269px #dedede, -257px -64px #d1d1d1, 449px 81px #f2f2f2, 18px -99px #d1d1d1, -694px 415px #f7f7f7, 240px 264px #e0e0e0, 450px -172px white, 383px 7px #e8e8e8, 338px -73px #c9c9c9, 291px -19px #ebebeb, 659px 137px #d1d1d1, 602px -6px #fcfcfc, 554px 249px #ebebeb, 625px 356px #d9d9d9, 579px -183px #d6d6d6, -20px 250px white, -401px 431px #c4c4c4, -645px -232px #cccccc, -265px -148px white, 553px 258px #d1d1d1, 166px -360px #ebebeb, 719px 51px #ededed, 612px -129px #ebebeb, -465px -104px #f2f2f2, -154px -121px #d9d9d9, -1px 330px #f2f2f2, -666px 248px #f7f7f7, -720px 264px #ededed, 148px -365px #e6e6e6, -388px -349px #c4c4c4, 128px -88px #e3e3e3, -683px -274px #fafafa, -341px 41px #c9c9c9, -59px -471px #f0f0f0, -3px -427px #c2c2c2, 418px 167px #d6d6d6, 343px 247px #c7c7c7, 623px -347px #d1d1d1, 716px -217px white, 243px -409px whitesmoke, -75px -126px #d6d6d6, -730px -91px #c9c9c9, -210px -397px #cfcfcf, -349px 180px #c9c9c9, -567px -281px #e0e0e0, -460px 381px #fcfcfc, -310px -22px #ededed, 450px -1px #dbdbdb, -405px -328px #e3e3e3, 5px 332px #d6d6d6, -294px 302px #fcfcfc, -398px 97px whitesmoke, -696px 325px #cfcfcf, -589px 110px #d6d6d6, 353px -411px #dbdbdb, -697px -318px #ebebeb, -114px -72px #f0f0f0, 259px -193px #fcfcfc, 60px 26px #e6e6e6, -63px -232px white, 205px -372px #f7f7f7, -464px -333px #f2f2f2, -374px 123px white, -377px -386px #c7c7c7, -80px 337px #cccccc, 478px -178px #dbdbdb, 222px 420px #ebebeb, -707px 99px #c4c4c4, 716px -132px #fafafa, -253px -286px #e3e3e3, 646px 178px #f0f0f0, 201px 24px #d1d1d1, 178px -58px #c7c7c7, -557px 368px #ededed, 0px 219px #d9d9d9, -266px -269px #cccccc, 242px -197px #c9c9c9, -419px 193px #c2c2c2, -47px 91px #c7c7c7, -109px 75px #c2c2c2, -146px -453px #d6d6d6, 671px -350px #f2f2f2, 421px -91px #d9d9d9, 738px 19px #ededed, -316px -155px #dedede, 419px 244px #fcfcfc, -278px -418px #d6d6d6, -581px -181px #fcfcfc, 139px 264px #d9d9d9, 691px -11px #ebebeb, -622px 402px #c2c2c2, 219px 396px #f0f0f0, -149px -423px white, -716px -78px #d9d9d9, -590px 341px #e6e6e6, -208px 79px #d6d6d6, -227px -24px #f7f7f7, 239px 262px #d1d1d1, 740px 443px #f7f7f7, 509px 134px #d6d6d6, -555px 232px #e8e8e8, -67px -427px #cfcfcf, -368px 250px #f7f7f7, 715px -415px #fafafa, 411px -301px #f0f0f0, -322px 287px #d9d9d9, -429px -90px #f2f2f2, -327px -387px #f0f0f0, -491px 183px #c2c2c2, -133px 250px #d4d4d4, 538px 139px #e3e3e3, -417px -125px #f0f0f0, 653px -351px #e6e6e6, -549px 38px #d4d4d4, 602px 110px whitesmoke, 415px 105px #e0e0e0, -733px -371px #cfcfcf, 286px 403px #d4d4d4, 11px 320px #c4c4c4, -597px 158px whitesmoke, 716px -350px whitesmoke, 321px 67px #fafafa, -237px -300px #cfcfcf, 74px 152px #c9c9c9, 587px -123px #fcfcfc, 699px -332px whitesmoke, 399px 355px #f7f7f7, -323px 314px #dbdbdb, 89px 416px #c7c7c7, 445px 38px #e3e3e3, 572px 122px #c4c4c4, -258px 372px white, 49px 306px #d9d9d9, 437px -35px #dedede, 566px 174px #f2f2f2, 732px -299px whitesmoke, -410px 394px #ededed, 131px -415px white, 19px -326px #e8e8e8, -700px -188px #d1d1d1, 96px -1px #e0e0e0, -328px -396px #f0f0f0, -117px -214px #fcfcfc, -53px 261px #ebebeb, 80px 134px #d6d6d6, -364px -216px white, -636px -125px #dbdbdb, -639px -265px #e3e3e3, 208px 98px #c7c7c7, 172px 467px #e0e0e0, 435px 309px #e3e3e3, 194px -259px #f0f0f0, 209px -186px #c9c9c9, -312px 418px #fafafa, 229px 407px #c9c9c9, -449px -357px #fafafa, 674px 121px #e8e8e8, 608px -429px #ebebeb, -431px -428px #cfcfcf, 105px 462px #e3e3e3, -179px -372px #e3e3e3, 143px -317px #d6d6d6, -449px -149px #fafafa, -544px 250px #dedede, -220px -323px whitesmoke, 658px 8px whitesmoke, -656px -244px #e8e8e8, 347px 11px whitesmoke, 694px -230px #f7f7f7, -317px 1px #c4c4c4, 28px 23px #fcfcfc, -382px 321px #dbdbdb, 632px -74px #c4c4c4, 154px -245px #c2c2c2, -553px 337px #d6d6d6, -48px -243px #d1d1d1, 92px -391px #cccccc, -71px -256px #cfcfcf, -372px 57px #d9d9d9, 369px -140px #fcfcfc, 675px 81px #c2c2c2, -663px 254px #cccccc, 703px -203px #ededed, 74px -363px #c2c2c2, 643px -458px #d1d1d1, 198px 359px #cccccc, 265px 309px #d4d4d4, -353px -368px #e8e8e8, -465px 439px whitesmoke, 693px 360px #c9c9c9, 634px -397px #d1d1d1, 467px 25px whitesmoke, -558px -272px #e6e6e6, 671px 69px #dbdbdb, 407px 357px #cfcfcf, 379px 80px white, 10px -203px #c9c9c9, 104px -292px #f0f0f0, -667px -29px #d1d1d1, 557px -155px #e6e6e6, -505px 115px #cfcfcf, -605px 164px #f2f2f2, -108px -223px #e0e0e0, 523px -156px #ebebeb, 691px 230px white, -507px -13px #d1d1d1, -349px 332px #dedede, 520px 266px whitesmoke, -66px -250px #e6e6e6, -496px -449px #ebebeb, 414px -170px #dedede, -649px 230px #ebebeb, 598px -92px #c7c7c7, -638px 113px #c2c2c2, 151px 363px #f7f7f7, -445px -241px #f0f0f0, 527px -14px #dedede, 203px -61px #cfcfcf, -716px -284px #ebebeb, -525px 134px #c2c2c2;
animation: fly 15s linear infinite;
transform-style: preserve-3d;
}

.stars:before,
.stars:after {
content: "";
position: absolute;
width: inherit;
height: inherit;
box-shadow: inherit;
}

.stars:before {
transform: translateZ(-300px);
opacity: .6;
}

.stars:after {
transform: translateZ(-600px);
opacity: .4;
}

@keyframes fly
{
from {
    transform: translateZ(0px);
    opacity: .6;
}
to {
    transform: translateZ(200px);
    opacity: .8;
}
}

  /* 头部标题 */
  .header {
    padding: 30px;
    text-align: center;
    background: #99ccff;
  }
   
  .header h1 {
    font-size: 50px;
  }
   
   /* 导航条 */
  .topnav {
    display: flex;
    justify-content: center;
    position: absolute;
    right: 0px;
    top: 20px;
    margin:auto;
  }

  .topnav:after,
  .topnav:before {
    margin-top:0.5em;
    content: "  ";
    display: flex;
    border:dotted #fff;
}

  .topnav:after {
    border-right-color: transparent;
}

  .topnav:before {
    border-left-color: transparent;
}

  .topnav a:link,
  .topnav a:visited {
    color: #000;
    text-decoration: none;
    height: 1.5em;
    overflow: hidden;
}
  
  /* 高三文八链接 */
  .topnavc {
    display: flex;
    justify-content: center;
    position: absolute;
    left:10px;
    top: 20px;
    margin:auto;
  }

  .topnavc:after,
  .topnavc:before {
    margin-top:0.7em;
    content: "";
    display: flex;
    border:dotted rgba(196, 240, 236, 0.829);
}

  .topnavc a:link,
  .topnavc a:visited {
    color: #000;
    text-decoration: none;
    height: 1em;
    overflow: hidden;
}

  .topnavc:after {
    border-right-color: transparent;
}

  .topnavc:before {
    border-left-color: transparent;
}


  .topnavc a {
    display: block;
    text-align: center;
    padding: 14px 16px;
    text-decoration:none;
  }

  .topnavc a:hover {
    background-color:lightblue;
    color: black;
  }



  /* 导航条链接 */
  .topnav a {
    display: block;
    text-align: center;
    padding: 14px 16px;
    text-decoration:none;
  }
   
  /* 字体修改 */
  .title  {
   position:absolute;
   display: flex;
   justify-content: center;
   left: 0;
   right: 0;
   top: 150px;
   margin: auto;
   bottom: 0;
   color: rgb(185, 195, 240);
   font-size: 24px;
   font-weight: 500;
  }

  .titles {
    position: absolute;
    display: flex;
    justify-content: center;
    left: 0;
    right: 0;
    top: 200px;
    margin: auto;
    bottom: 0;
    color: rgb(185, 195, 240);
    font-size: 20px;
    font-weight: 500;
  }
  

  /* 链接颜色修改 */
  .topnav a:hover {
    background-color:lightblue;
    color: black;
  }
   /* 文章卡片效果 */
  .card {
    background-color: white;
    padding: 20px;
    margin-top: 20px;
    text-align: center;
  }
    
   
  /* 小图案 */
  .icons {
    display: flex;
    justify-content: space-between;
    padding: 0 400px;
    box-sizing: border-box;
    overflow: hidden;
}

.icons_items {
    display: flex;
    flex-direction: column;
    /*font-size: 16px;*/
    margin-top: 80px;
    width: 200px;
}

.icons_items_imgs {
    width: 200px;
    margin-bottom: 30px;
}

.icons_items_txts{
    font-size: 16px;
}

 /* 介绍introduce */
 .introduce {
  display: flex;
  flex-direction: column;
}

.introduce_item {
  display: flex;
  justify-content: center;
  margin-top: 60px;
}

.introduce_item_img {
  width: 700px;
  height: 400px;
}

.introduce_item_title {
  width: 350px;
  font-size: 17px;
  line-height: 35px;
  align-self: center;
  padding-left: 100px;
}

.introduce_item_titles {
  width: 300px;
  font-size: 18px;
  line-height: 36px;
  align-self: center;
  padding-right: 100px;
}

  /* 音乐 */
  audio {
    position:fixed;
    bottom: 50px;
    right: 0;
}

.music_img {
    position: fixed;
    bottom: 50px;
    right: 50px;
    width: 40px;
    height: 30px;
    animation: muscis 5s linear infinite;
}

@keyframes muscis {
  from {
      transform: rotate (0deg);
      opacity: .6;
  }
  to {
      transform: rotate(360deg);
      opacity: .8;
  }
}

  /* 底部 */
  .footer {
    padding: 20px;
    text-align: center;
    background:#d6e5f3;
    margin-top: 20px;
  }
   
  /* 响应式布局 - 屏幕尺寸小于 800px 时，两列布局改为上下布局 */
  @media screen and (max-width: 800px) {
    .leftcolumn, .rightcolumn {   
      width: 100%;
      padding: 0;
    }
  }
   
  /* 响应式布局 -屏幕尺寸小于 400px 时，导航等布局改为上下布局 */
  @media screen and (max-width: 400px) {
    .topnav a {
      float: none;
      width: 100%;
    }
  }