html {
    display: flex;
    box-sizing: border-box;
    padding: 0;
    margin: 0;
}
html,body,.viewport{
    width:100%;
}

*,
*:before,
*:after {
    box-sizing: inherit;
}

img {
    border: 1px solid rgb(0, 255, 255);
    border-radius: 4px;
    padding: 1px;
    max-height: 300px;
}

body {
    font-size: 1.25em;
    line-height: 1.5;
    font-family: serif;
    background-color: rgba(47, 63, 93, 0.6);
    margin: 0;
    padding: 0;
}
p{
    text-indent: 50px;
}

.pv-container {
    display: flex;
    flex-direction: column;
    justify-content: flex-start;
    width: 100%;
}
.pv-footer{
    display: -webkit-box;
    display: -moz-box;
    display: - ms-flexbox;
    display: -webkit-flex;
    display: flex;
    flex-wrap: wrap;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    width:100%;

}

.pv-footer,
.pv-header {
    background-color: #f0fffe;
}

.pv-main {
    display: flex;
    width: 100%;
}
table, th, td {
    border: 1px solid black;
    border-collapse: collapse;
}
th, td {
    padding: 5px;
    text-align: left;
}

.pv-content {
    margin-top: 20px;
}

.pv-article {
    background-color: white;
}

.pv-article-body {
    padding: 1rem;
}

.pv-article img {
    max-width: 100%;
}

.pv-article {
    background-color: rgb(255, 255, 255);
}

.pv-article,
.pv-header {
    margin-bottom: 0rem;
}

.pv-article-page {
    background-color: rgb(255, 255, 255);
    margin-bottom: 1rem;
}

.pv-header {
    padding-top: 0;
    background-image: url("bolt.png");
    background-repeat: no-repeat;
    background-position: center;
    background-size: contain;
    /* margin: auto; */
    text-align: center;
    width: 100%;
}

.button1 {
    border-radius: 5px;
    border: 2px solid #6495ED;
    background-color: #BCD2EE;
    height: 40px;
    width: 100px;
    text-align: center;
    font-size: 17px;
    display: flex;
    align-items: center;
    justify-content: center;
}
.button2 {
    border-radius: 5px;
    border: 2px solid #6495ED;
    background-color: #BCD2EE;
    height: 40px;
    width: 100px;
    text-align: center;
    font-size: 20px;

}
a:hover {
    color: #2ff7ff;
}

.pv-sidebar {
    display: flex;
    flex: wrap;
    background-color: rgba(244, 247, 221, 0.99);
    justify-content: center;
}

.side-bar-nav {
    padding-left: 2%;
    padding-right: 2%;
    text-align: center;
}

#nav-a ul li{
    display:inline-block;
    float:left
}

ul {
    list-style-type: none;
    text-align: center;
    padding: 0;
}

li {
    text-align: left;
    font-size: 20px;
}

li a:hover {
    background-color: aqua;
    color: white;
}

#firstNumber,#secondNumber,#thirdNumber {
    height: 1.50em;
    width: 3em;
    font-size: 1.25em;
    
}
#problemButton {
    
    height: 1.50em;
    font-size: 1.25em;
    
}
#aBtn {
    font-size: 2em;
    color: green;
}



@media only screen and (max-width:800px) {
    .pv-main {
        flex-direction: column;
    }
    .pv-header {
        margin-bottom: 1rem;
    }
    
    .pv-content {
        padding: 1rem;
        flex: 1;
    }
    .pv-article{
        margin-bottom: 1rem;
    }
    img {
        max-width: 100%;
    }
    .pv-footer {
         display: -webkit-box;
    display: -moz-box;
    display: - ms-flexbox;
    display: -webkit-flex;
    display: flex;
    flex-wrap: wrap;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    width:100%;
    }
    
}

@media only screen and (min-width: 801px) {
    .pv-header
     {
        width: 100%
    }
    .pv-footer {
         display: -webkit-box;
    display: -moz-box;
    display: - ms-flexbox;
    display: -webkit-flex;
    display: flex;
    flex-wrap: wrap;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    width:100%;
    }
    .pv-article-page {
        padding: 10px;
        box-sizing: border-box;
        margin-bottom: 20px;
        flex-basis: 100%;
    }
    .pv-article-body {
        max-width: 800px;
    }
    .pv-article-page-control {
        display: flex;
        flex-wrap: wrap;
    }
    .dock-control {
        text-align: center;
        margin-right: 20px;
        margin-left: 20px;
    }
    .dock-controls-other {
        text-align: center;
        margin-right: 50px;
    }
    .pv-content {
        flex: 8;
        margin-left: 1rem;
        margin-right: 1rem;
        display: flex;
        flex-wrap: wrap;
        justify-content: space-around;
        min-height: 100vh;
    }
    .pv-sidebar {
        flex: 2;
    }
    .pv-article-second {
        padding: 10px;
        box-sizing: border-box;
        margin-bottom: 30px;
        margin-right: 1rem;
        flex-basis: 27%;
        max-height: 700px;
    }
}