body {
  background: linear-gradient(135deg,
      #3c3c3c 0%,
      #575252 25%,
      #757070 50%,
      #a1a0a0 75%,
      #b9b9b9 100%);
  background-attachment: fixed;
  font-family: 'Times New Roman', sans-serif;
}


.contentfullscreen {
  color: white;
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  height: 100vh;
}

.contentfullscreen_math {
  color: white;
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  height: 100vh;
  font-size: 2.5em;
}

.contentlearning {
  color: white;
  display: block;
  text-align: left;
  padding: 40px 20px;
  margin: 0 auto;
  max-width: 900px;
}

.listlearning {
  list-style: none;
  padding: 0;
  margin: 20px auto;
  max-width: 800px;
}

.listlearning li:hover {
  background-color: #2a2a2a;
}

.contentiframes {
  color: white;
  display: flex;
  flex-direction: column;
  align-items: center;
  height: 100vh;
}

.contentiframeslearning {
  color: white;
  display: flex;
  flex-direction: column;
  align-items: center;
  width: 560px;
  height: 315px;
}

h1 {
  font-size: 3em;
  margin-bottom: 20px;
}

p {
  font-size: 1.5em;
  max-width: 1200px;
}


.seitentitel {
  text-align: center;
  margin: 40px 0;
  border-bottom: 2px solid #ccc;
  padding-bottom: 10px;
  width: fit-content;
  margin-left: auto;
  margin-right: auto;
  color: white;
}

.link-box_news {
  padding: 8px 12px;
  border: 2px solid #ccc;
  border-radius: 6px;
  text-decoration: none;
  color: white;
  background-color: rgba(255, 255, 255, 0.05);
  transition: all 0.2s ease;
}

.link-box_news:hover {
  border-color: #888;
  text-decoration: underline;
  background-color: rgba(255, 255, 255, 0.15);
}

iframe {
  border: none;
  max-width: 100%;
  width: 100%;
  height: 100%;
}

/* Tab Navigation Programmieren lernen*/
.tab-navigation {
  display: flex;
  justify-content: center;
  padding: 10px;
  gap: 20px;
}

.tab-navigation button {
  background: none;
  border: 2px solid white;
  color: white;
  font-size: 1em;
  padding: 8px 16px;
  cursor: pointer;
  border-radius: 8px;
  transition: background 0.3s;
}

.tab-navigation button:hover,
.tab-navigation button.active {
  background: white;
  color: black;
}

/*Sidebar*/
.sidebar {
  height: 100%;
  width: 0;
  position: fixed;
  z-index: 999;
  top: 0;
  left: 0;
  background-color: #333;
  overflow-x: hidden;
  transition: 0.5s;
  padding-top: 60px;
}

.sidebar a {
  padding: 15px;
  text-decoration: none;
  font-size: 25px;
  color: #ccc;
  display: block;
  transition: 0.3s;
}

.sidebar a:hover {
  color: #fff;
  background-color: transparent;
  transform: scale(1.05);
}

.sidebar .close-btn {
  position: absolute;
  top: 20px;
  right: 25px;
  font-size: 36px;
  color: #fff;
  cursor: pointer;
}

.sidebar.open {
  width: 250px;
}

.submenu {
  display: none;
  padding-left: 15px;
}

.submenu a {
  display: block;
  font-size: 0.95em;
}

/* Hamburger Menu */
.hamburger {
  display: flex;
  flex-direction: column;
  justify-content: space-around;
  width: 30px;
  height: 20px;
  cursor: pointer;
  position: absolute;
  top: 20px;
  left: 20px;
  z-index: 1000;
  transition: transform 0.3s ease;
}

.hamburger div {
  width: 30px;
  height: 5px;
  background-color: #fff;
  transition: 0.4s;
}

.hamburger.open {
  visibility: hidden;
}


.auth-forms-container {
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 10px;
  box-sizing: border-box;
  width: 100%;
}

.auth-forms-container h2 {
  text-align: center;
  width: 100%;
}

.auth-forms-container form {
  display: flex;
  flex-direction: column;
  align-items: stretch;
  width: 90%;
  max-width: 220px;
  margin-bottom: 15px;
}

.auth-forms-container input[type="text"],
.auth-forms-container input[type="password"] {
  margin-bottom: 10px;
  padding: 8px;
  border: 1px solid #ccc;
  border-radius: 4px;
  box-sizing: border-box;
}

.auth-forms-container button[type="submit"] {
  padding: 10px;
  background-color: #5cb85c;
  color: white;
  border: none;
  border-radius: 4px;
  cursor: pointer;
}

.auth-forms-container button[type="submit"]:hover {
  background-color: #4cae4c;
}

.auth-forms-container #message {
  margin-top: 10px;
  color: white;
  text-align: center;
  width: 100%;
}

.logout-btn {
  display: block;
  margin-top: 20px;
  padding: 6px 10px;
  border: 1px solid #f44336;
  background-color: transparent;
  color: #f44336;
  text-align: center;
  font-weight: bold;
  border-radius: 3px;
  font-size: 14px;
  transition: all 0.3s ease;
}

.logout-btn:hover {
  background-color: #f44336;
  color: white;
}


.logout-btn:hover {
  background-color: #d32f2f;
}

.menu-separator {
  margin: 20px 0 10px;
  border: none;
  border-top: 1px solid #ccc;
}




/*Guestbook Styles*/

.guestbook-container {
  padding: 20px;
  color: #333;
  background-color: #f9f9f9;
  border-radius: 8px;
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
  margin-top: 20px;
  margin-bottom: 20px;
  max-width: 800px;
  margin-left: auto;
  margin-right: auto;
  height: auto;
  text-align: left;
}

.guestbook-form-section,
.guestbook-entries-section {
  margin-bottom: 30px;
}

.guestbook-form-section h2,
.guestbook-entries-section h2 {
  color: #555;
  border-bottom: 2px solid #555;
  padding-bottom: 10px;
  margin-bottom: 20px;
}

.guestbook-form-section div {
  margin-bottom: 15px;
}

.guestbook-form-section label {
  display: block;
  margin-bottom: 5px;
  font-weight: bold;
  color: #555;
}

.guestbook-form-section input[type="text"],
.guestbook-form-section textarea,
.reply-form-section input[type="text"],
.reply-form-section textarea {
  width: calc(100% - 22px);
  padding: 10px;
  border: 1px solid #ccc;
  border-radius: 4px;
  font-size: 1em;
}

.guestbook-form-section textarea,
.reply-form-section textarea {
  resize: vertical;
}

.guestbook-form-section button,
.reply-form-section button {
  background-color: #777;
  color: white;
  padding: 10px 15px;
  border: none;
  border-radius: 4px;
  cursor: pointer;
  font-size: 1em;
  transition: background-color 0.3s ease;
}

.guestbook-form-section button:hover,
.reply-form-section button:hover {
  background-color: #555;
}

.guestbook-separator {
  border: 0;
  height: 1px;
  background-color: #ddd;
  margin: 30px 0;
}

.guestbook-entry {
  background-color: #fff;
  border: 1px solid #e0e0e0;
  padding: 15px;
  margin-bottom: 20px;
  border-radius: 6px;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.05);
}

.entry-meta,
.reply-meta {
  font-size: 0.9em;
  color: #777;
  margin-bottom: 5px;
}

.entry-meta strong,
.reply-meta strong {
  color: #333;
}

.entry-text,
.reply-text {
  font-size: 1em;
  line-height: 1.6;
  color: #444;
  word-wrap: break-word;
}

.replies-section {
  margin-top: 15px;
  margin-left: 20px;
  border-left: 3px solid #777;
  padding-left: 15px;
}

.guestbook-reply {
  background-color: #f0f8ff;
  padding: 10px;
  margin-top: 10px;
  border-radius: 4px;
  border: 1px solid #d1e7fd;
}

.reply-form-section {
  margin-top: 15px;
  padding: 10px;
  background-color: #f9f9f9;
  border-radius: 4px;
}

.reply-form-section details summary {
  cursor: pointer;
  color: #555;
  font-weight: bold;
}

.reply-form-section details div {
  margin-top: 10px;
}

.delete-button {
  background-color: #f44336;
  /* Red */
  color: white;
  padding: 5px 10px;
  border: none;
  border-radius: 4px;
  cursor: pointer;
  font-size: 0.9em;
  transition: background-color 0.3s ease;
  margin-left: 5px;
  /* Optional: some space from other elements */
}

.delete-button:hover {
  background-color: #d32f2f;
  /* Darker red */
}

.contentfullscreen_guestbook {
  height: auto;
  min-height: 100vh;
  padding-top: 80px;
  padding-bottom: 40px;
}