* {
  --website-width: min(800px, 90vw);

  --bg-color:        #4e4e4e;
  --footer-bg-color: #141114d8;
  --text-color-1:    #f5f5f5;
  --text-color-2:    #ececec;
  --text-color-3:    #e6e6e6;
  --link-color:      #ffffff;

  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

@font-face {
  font-family: neon-font;
  src: url('../fonts/neon-font.ttf');
}

html {
  scroll-behavior: smooth;
}

body {
  background-color: var(--bg-color);
  background-image: url('../images/dark-concrete-texture-background.jpg');
  background-position: center;
  background-repeat: no-repeat;
  background-size: cover;
  background-attachment: fixed;
  background-blend-mode: multiply;

  color: var(--text-color-1);
  font-family: sans-serif;
  
  padding-bottom: 75px;

  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 20px;
}

h1 {
  margin-top: 10px;
}

h1, h2 {
  font-size: 2.5em;
  text-align: center;
  text-shadow:  #ffffff 0 0 10px,
                #ff0000 3px 0,
                #0084ff -3px 0;
  font-family: neon-font;
}

section#self-introduction,
section#github-repositories,
section#kontakt {
  width: var(--website-width);
  display: flex;
  flex-direction: column;
  gap: 10px;
}
section#github-repositories .card {
  gap: 15px;
}
section#self-introduction > div.container,
section#github-repositories > div.container {
  display: inline-flex;
  flex-wrap: wrap;
  gap: 15px;
}
section#self-introduction > div.container > div {
  display: flex;
  flex-wrap: wrap;
  flex: 1 1 250px;
  gap: 15px;
}

section#kontakt {
  text-align: center;
}

.card {
  display: flex;
  flex-direction: column;
  gap: 10px;
  flex: 1 1 250px;
  padding: 15px;
  border-radius: 20px;
  background-color: #00ffea1f;
  backdrop-filter: blur(2px);
  box-shadow: var(--footer-bg-color) 10px 10px 10px;
}
.card h3 {
  font-size: 1.5em;
}
.card p {
  font-size: 1em;
  text-align: justify;
}



footer {
  font-size: 1em;
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  width: 100%;
  padding: 10px;
  background-color: var(--footer-bg-color);
  backdrop-filter: blur(2px);
}

footer p {
  text-align: center;
}

p, ul {
  color: var(--text-color-2);
  line-height: 23px;
}
ul {
  padding-left: 30px;
}
a {
  color: var(--link-color);
}


div.retractable-element {
  height: 60px;
  width: 140px;

  background-color: #0084ffcc;
  backdrop-filter: blur(2px);

  padding: 10px;
  border-radius: 0 30px 30px 0;

  position: fixed;
  left: -85px;
  top: 25%;

  z-index: 1;

  transition: 0.3s;

  display: flex;
  justify-content: space-between;
  align-items: center;
}

div.retractable-element > a {
  text-decoration: none;
  font-size: 1.25em;
}

div.retractable-element:hover {
  left: 0px;
}

div.retractable-element > img.svg {
  width: 40px;
}

div.retractable-element#github-reference {
  top: calc(25% + 70px);
}