body {
  margin: 0;
  font-family: sans-serif;
  display: flex;
  flex-direction: row;
  min-height: 100vh;
}

/* Tělo jako Flex kontejner */
.layout {
  display: flex;
  flex-direction: row;
  min-height: 100vh;
}

/* Menu – fixní šířka vlevo */
#menu-placeholder {
  width: 250px;
  background-color: #f9f9f9;
  padding: 1rem;
  border-right: 1px solid #ccc;
}

.main-nav {
  background-color: #f4f4f4;
  padding: 1rem;
  font-family: sans-serif;
  border-right: 1px solid #ccc;
  max-width: 250px;
}

.main-nav ul {
  list-style: none;
  padding-left: 0;
  margin: 0;
}

.main-nav li {
  margin: 0.5rem 0;
}

.main-nav > ul > li {
  font-weight: bold;
  margin-top: 1rem;
}

.main-nav a {
  text-decoration: none;
  color: #333;
}

.main-nav a:hover {
  text-decoration: underline;
  color: #0077cc;
}

.main-nav li ul {
  padding-left: 1rem;
  margin-top: 0.5rem;
  font-weight: normal;
}

.main-nav li ul li {
  margin: 0.3rem 0;
}


main.content {
  flex: 1;
  padding: 2rem;
  background-color: #fff;
  max-width: 960px;
  margin: 0 auto;
  border-radius: 6px;
  box-shadow: 0 0 8px rgba(0,0,0,0.05);
}

main.content p {
  text-align: justify;
}

h1, h2, h3 {
  color: #2c3e50;
}

pre {
  background-color: #272822;
  color: #f8f8f2;
  padding: 1rem;
  border-radius: 4px;
  overflow-x: auto;
}

.note, .task, .challenge {
  padding: 1rem;
  border-left: 4px solid;
  margin: 1rem 0;
  border-radius: 4px;
}

.note {
  border-color: #3498db;
  background: #eaf4fd;
}

.task {
  border-color: #f39c12;
  background: #fff3cd;
}

.challenge {
  border-color: #e74c3c;
  background: #fdecea;
}

/* Řeší problém se zalomením v seznamu */
ul, ol {
  margin: 1em 0;
  padding-left: 2em;
}

li {
  display: list-item;
  white-space: normal;
  margin-bottom: 0.5em;
}