/* overall styling */
* {
  font-family: "Montserrat", sans-serif;
  text-align: center;
}

html, body {
  margin: 0;
  padding: 0;
  height: 100%;
  background: hsl(200, 80%, 10%);
  background-repeat: round;
}

header {
  width: 100%;
  display: flex;
  box-sizing: border-box;
  align-items: center;
  justify-content: center;
  background-image: url('https://brueserwebdesign.de/wp-content/uploads/2023/09/code-og.webp');
  background-size: fixed;
  background-position: center;
  padding: 50px;
}

h1 {
  color: #FFF;
  width: 100%;
  margin: 0;
  font-size: 50px;
  text-shadow: 5px 5px #000;
}

p {
  width: 60%;
  position: relative;
  text-align: center;
  margin: 0 auto;
  margin-bottom: 20px;
  font-size: 20px;
}

hr {
  color: #ddd;
  width: 100%;
  margin-top: 40px;
}

codeblock {
  display: flex;
  background-color: #ddd;
  border: #ddd 1px solid;
  border-radius: 6px;
  font-family: "Google Sans Code", sans-serif;
  font-size: 16px;
  line-height: 1.2;
  padding: 30px 20px;
  overflow-x: auto;
  white-space: pre-line;
  text-wrap-mode: nowrap;
  justify-content: space-around;
  text-align: left;
}

a:link {
  color: hsl(240, 88%, 7%);
}
a:hover {
  color: hsl(240, 100%, 70%);
}
a:visited {
  color: hsl(240, 100%, 30%);
}

/* navigation */
.nav-bar {
  display: flex;
  justify-content: center;
  background-color: hsl(200, 80%, 20%);
  flex-wrap: wrap;
  position: sticky;
  top: 0;
  z-index: 1000;
  column-gap: 2px;
}
.nav a {
  display: inline-flex;
  color: white;
  text-decoration: none;
  font-weight: bold;
  padding: 15px 14px;
  border-radius: 2px;
  transition: background-color 0.2s ease;
}
.nav a:hover,
.nav a.active {
  background-color: #00c389;
  color: black;
}

/* for collapsable topics */
.collapsible-container {
  width: 80%;
  max-height: fit-content;
  margin: 20px auto;
  background-color: #f5f5f5;
  padding: 10px;
  border-radius: 6px;
  box-shadow: 0 0 10px rgba(0,0,0,0.1);
}
.collapsible-header {
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  font-weight: bold;
  margin: 20px auto;
}
.arrow {
  display: inline-block;
  transition: transform 0.3s ease;
  margin-right: 8px;
}
.collapse {
  max-height: fit-content;
  overflow: hidden;
  transition: max-height 0.3s ease;
}
.collapse.closed {
  max-height: 0;
}
.arrow.rotated {
  transform: rotate(-90deg);
}

/* table section */
table {
  margin: auto;
}
table, th, td {
  border: 1px solid #000;
  border-collapse: collapse;
  padding: 7px;
  width: 60%;
}
.list {
  width: 60%;
  position: relative;
  text-align: center;
  margin: 0 auto;
  margin-bottom: 20px;
}
.list ul {
  list-style-type: none;
  padding-left: 0;
  margin: 0;
}

/* color section */
#blue {
  color: blue;
}
#green {
  color: green;
}
#red {
  color: red;
}
#sat {
  color: hsl(200, 80%, 20%)
}
#lit {
  color: hsl(200, 20%, 80%)
}
#blue-color {
  color: blue;
}
#blue-hex {
  color: #00F;
}
#blue-rgb {
  color: rgb(0, 0, 255);
}
#blue-hsl {
  color: hsl(240, 100%, 50%);
}
#blue-oprgba{
  color: rgba(0, 0, 255, 0.5);
}
#blue-ophsla{
  color: hsla(240, 100%, 50%, 0.5);
}

/* breadcrumb section */
.breadcrumb {
  display: flex;
  justify-content: center;
  padding: 0;
  margin: 20px auto;
}
.breadcrumb li {
  list-style-type: none;
}
.breadcrumb li a {
  display: inline-block;
  color: #fff;
  background: darkcyan;
  position: relative;
  height: 30px;
  line-height: 30px;
  text-align: center;
  margin-right: 15px;
  padding: 0 5px;
  text-decoration: none;
}
.breadcrumb li a::before,
.breadcrumb li a::after {
  content: "";
  position: absolute;
  border-color: darkcyan;
  border-style: solid;
  border-width: 15px 5px;
}
.breadcrumb li a::before {
  left: -10px;
  border-left-color: transparent;
}
.breadcrumb li a::after {
  left: 100%;
  border-color: transparent;
  border-left-color: darkcyan;
}
.breadcrumb li a:hover {
  background-color: blue;
}
.breadcrumb li a:hover::before {
  border-color: blue;
  border-left-color: transparent;
}
.breadcrumb li a:hover::after {
  border-left-color: blue;
}

/* footer */
.page-wrapper {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}
.placeholder {
  flex: 1;
}
footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  background-color: hsl(200, 80%, 15%);
  padding: 20px 40px;
}
.footer-left,
.footer-center,
.footer-right {
  flex: 1;
  display: flex;
  align-items: center;
}
.footer-left {
  justify-content: flex-start;
}
.footer-center {
  justify-content: center;
}
.footer-right {
  justify-content: flex-end;
}
.fish-wrapper {
  position: relative;
  width: 140px;
  height: 140px;
  margin: 0 auto;
}
.footer-img {
  position: absolute;
  top: 0;
  left: 0;
  width: inherit;
  height: inherit;
  object-fit: contain;
}
.fish:hover {
  animation: swim 1.5s infinite alternate ease-in-out;
}
@keyframes swim {
  0% { transform: translateY(0px) translateX(0px); }
  100% { transform: translateY(5px) translateX(2px);}
}
#author {
  color: #818181;
  text-decoration: none;
  font-weight: 500;
  margin: 0;
}
#author:hover {
  color: #555555;
}
#author:active {
  color: #757575;
}

/*media queries*/
@media only screen and (max-width: 480px), (orientation: portrait) {
  p {
    width: 90%;
    font-size: 14px;
  }
  codeblock {
    font-size: 13px;
  }
  h1 {
    font-size: 30px;
  }
  .breadcrumb {
    font-size: 8px;
  }
}