body {
  font-family: Arial, sans-serif;
  margin: 0;
  background: #f5f5f5;
  color: #333;
}

header {
  display: flex;
  align-items: center;
  background: #12666e;
  color: white;
  padding: 10px 20px;
  position: sticky;
  top: 0;
  z-index: 1000;
}

header .logo {
  display: flex;
  align-items: center;
}

header img {
  height: 40px;
  margin-right: 10px;
}

header h1 {
  margin: 0;
  font-size: 1.5em;
}

.menu-bar {
  background: #12666e;
  display: flex;
  justify-content: center;
  position: sticky;
  top: 60px;
  z-index: 999;
}

.menu {
  display: flex;
  gap: 20px;
  padding: 10px;
}

.menu a {
  color: white;
  text-decoration: none;
  font-weight: bold;
}

.menu a.active {
  text-decoration: underline;
  color: #ffcc00;
}

.hamburger {
  display: none;
  position: absolute;
  right: 15px;
  top: 10px;
  flex-direction: column;
  cursor: pointer;
  color: #ffcc00;
  font-size: 20px;
}

@media (max-width: 768px) {
  .hamburger {
    display: flex;
  }

  .menu {
    display: none;
    flex-direction: column;
    background: #333;
    position: absolute;
    top: 40px;
    right: 0;
    width: 200px;
    padding: 10px;
  }

  .menu.show {
    display: flex;
  }

  .menu-bar {
    justify-content: flex-end;
    height: 50px;
  }
}

sub { font-size: 0.8em; vertical-align: sub; }

sup { font-size: 0.8em; vertical-align: super; }

mark { background-color: yellow; }

abbr {
  border-bottom: 1px dotted #000;
  cursor: help;
  text-decoration: none;
}

img {
  max-width: 100%;
  height: auto;
}

main {
  max-width: 800px;
  margin: 50px auto;
  background: white;
  padding: 20px;
  border-radius: 8px;
  min-height: 60vh;
  box-shadow: 0 0 10px rgba(0,0,0,0.1);
}

footer {
  text-align: center;
  padding: 10px;
  background: #12666e;
  color: white;
  font-size: 0.9em;
}