*{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}
body{
    text-transform: uppercase;
    background-color: #e8e8e8;
}
header{
      position: fixed;
      top: 0;
      width: 100%;
      height: 10vh;
      line-height: 10vh;
      box-shadow: 1px 1px 10px 0 rgba(0,0,0,.2);
      z-index: 3;
      background-color: #e8e8e8;
}
header h1{
    text-align: center;
}
.calendar{
    display: flex;
    margin: 10vh auto;
    width: 95%;
    align-items: center;
    justify-content: space-around;
    flex-wrap: wrap;
    gap :1rem;
}
.sep-calendar{
    box-shadow: 1px 1px 10px 0 rgba(0,0,0,.2),
    -3px -3px 10px 0 #fff;
    border-radius: 10px;
}
.sep-calendar h1{
    text-align: center;
    padding: 1rem;
}
.sep-calendar ul{
    display: grid;
    grid-template-columns: repeat(7,1fr);
    list-style: none;
}
li{
    padding: 5px;
    text-align: center;
}
li:nth-child(7n+1){
 color: #d33e3e;   
}
li:nth-child(7n){
    color:#d33e3e;
}
.prev-month,
.prev-month~li{
    opacity: .5;
}
.first-day,
.first-day~li{
    opacity: 1 !important;
    font-weight: 900;
}
.last-day~li{
    opacity: .5 !important;
    font-weight: 200;
}
.nextpage {
    margin-top: -45px;
    background-color: #e8e8e8;
    color: black;
    font-size: 18px;
    text-align: center;
}
.prevpage{
    margin-top: -60px;
    background-color: #e8e8e8;
    color: black;
    font-size: 18px;
    text-align: center;
}
.nextpage a,.prevpage a{
    color: black;
}