body {
    font-family: 'Staatliches', cursive;
    padding: 0;
    margin: 0;
    background-color:#131221;
    background-image: url(../img/pawel-czerwinski-ypqyuASFNps-unsplash.jpg);
    background-attachment:fixed;
    background-position: center;    
    background-repeat: no-repeat;
    background-size: cover;
    color: whitesmoke; 
}

p {
    font-family: 'Montserrat', sans-serif;
}

header {
    padding: 0;
    margin: 0;
    background-color: rgba(255, 255, 255, 0.25);  
    text-align: center;
}

h1 {
    display: none;
}

nav {
    padding: 0;
    margin: 0;
    text-align: center;
    display: none;
}

header a {
    text-decoration: none;
    color: seashell; 
    display: block;
    padding: 5px 0; 
}

li:hover {
    background-color: rgba(255, 255, 255, 0.35);
}

header a:hover {
    color: #22265B;
}

nav ul {
    margin: 0;
    padding: 0;
    justify-content: right;
    list-style-type: none;
    font-size: 1.2rem;
}

nav li {
    font-weight: bold;
}

.small-menu {
    font-size: 1.2em;
}

.bigger-menu {
    display: none;
}

button {
    background-color:#131221; 
    color: white; 
    padding: 10px; 
    border: none; 
    font-family: 'Staatliches', cursive;
    font-size: 1.5em;
    position: fixed;
    bottom: 60px; 
    right: 50px; 
    display: none;
}

.top-container {
    height: 500px; 
    display: flex; 
    flex-direction: column;
    justify-content: center;
    text-align: center; 
}

h1 {
    margin-bottom: 0;
    font-size: 4rem;
}

h2 {
    margin-top: 0;
    font-size: 3.5rem;
}

section {
    padding: 20px; 
    margin: 35px; 
    background-color: rgba(255, 255, 255, 0.25);  
}

h3 {
    font-size: 1.8em; 
}

.image-container {
    display: flex;
    flex-flow: row nowrap;
    align-items: center;   
}

.portrait {
    width: 100%; 
    height: auto; 
}

footer {
    background-color: rgba(255, 255, 255, 0.25);  
}

footer > div {
    text-align: center;
    padding-bottom: 30px; 
    padding-top: 70px; 
    font-size: 1.5em; 
}

footer a {
    text-decoration: none;
    color: rgb(234, 210, 248);
}

footer a:hover {
    text-decoration: underline;
}

section ul {
    display: flex; 
    justify-content: center;
    padding-right: 30px;
}

section li {
    text-decoration: none;
    list-style: none;
    text-align: center;
    padding: 25px; 
}

section ul img {
    height: 90px; 
}

#contact img {
    background-color: white;
    border-radius: 20px;
}

p > a {
    text-decoration: none;
    color: whitesmoke; 
}

p > a:hover {
    text-decoration: underline;    
}

* {
    box-sizing: border-box;
}

.jupyter > img{
    background-color: white;
}

.swiper-wrapper img {
    height: 40px; 
}

.active {
    display: block;
}

.img-gallery {
    width: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
}

.btns {
    width: 100%;
    display: flex;
    justify-content: center;   
    align-items: center;       
    margin-top: 20px;
}

.btn {
    background-color: blueviolet;
    color: whitesmoke;
    font-size: 20px;
    padding: 5px 20px;
    border-color: transparent;
    border-radius: 5px;
    cursor: pointer;
}

.prev {
    margin-right: 15px;
}

.btn:disabled {
    background-color: slategrey;
    cursor: not-allowed;
}

.swiper-slide {
    text-align: center;
    margin-top: 20px;
}

.brand {
    margin: 0;
    font-size: 50px; 
    cursor: grab;
    z-index: 10; 
}

.swiper-container {
    height: 200px; 
    margin: 10px; 
    overflow: scroll;
}

.swiper-wrapper img { 
    height: 150px; 
}

@media all and (min-width:541px) {
    header {
        display: flex;
        justify-content: space-between;
        align-items: center;
        height: 75px;  
    }
    h1 {
        display: inline-block;
    }
    nav ul {
        text-align: left; 
        display: flex;
    }
    nav li {
        display: inline-block;
        margin: 5px 10px; 
        border-radius: 3px;
        flex-shrink: 1;
        text-align: center;
    }
    nav a {
        padding: 4px 10px;
         
    }
    .small-menu {
        display: none;
    }
    .bigger-menu {
        display: inline-block;
        font-size: 1.3rem;
        padding: 2px 15px;
        margin-right: 10px;
        border-radius: 3px; 
    }
    nav {
        display: inline-block;
        padding: 15px;
        visibility: hidden;
    }
        
    .personal-info {
        flex: 5 0; 
        display: flex;
        flex-flow: column nowrap;
        justify-content: center;
        margin-right: 20px;
    }
    
    .image-container {
        max-width: 500px; 
        margin: auto; 
    }
    
    .portrait {
        margin: auto;
    }
}

@media all and (min-width:851px) {
    header {
        height: 80px; 
    }
    h1 {
        display: inline-block;
    }
    nav {
        display: block;
        margin: auto;
        visibility: visible;
    }
    nav li {
        display: inline-block;
        margin: 5px 20px; 
        border-radius: 3px;
    }
    nav a {
        font-size: 1.3em;
        padding: 4px 20px; 
    }
    header > a {
        display: none;
    }
    .bigger-menu {
        display: none;
    }
    #about-me {
        display: flex; 
        flex-flow: row nowrap;
    }
    
    .personal-info {
        flex-flow: column nowrap;
        justify-content: center;
    }
    
    .image-container {
        display: block; 
        flex-flow: row nowrap;
        min-height: 450px;
    }

    .swiper-wrapper img {
        height: 170px; 
    }

    .swiper-container {
        height: 200px; 
        margin: 20px; 
    }

}