/* Visually hidden utility class for accessibility */
.visually-hidden {
  position: absolute !important;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.skip-link {
  position: absolute;
  left: -999px;
  top: auto;
  width: 1px;
  height: 1px;
  overflow: hidden;
  z-index: 100;
  background: #0056b3;
  color: #fff;
  padding: 8px 16px;
  border-radius: 4px;
}
.skip-link:focus {
  left: 10px;
  top: 10px;
  width: auto;
  height: auto;
  outline: 2px solid #fff;
}
@media (max-width: 600px) {
  .container {
    padding: 10px;
    margin-top: 10px;
  }
  button {
    width: 100%;
    font-size: 1em;
  }
  h1, h2 {
    font-size: 1.3em;
  }
}
body {
  font-family: 'Segoe UI', sans-serif;
  background: #002147;
  color: #fff;
  margin: 0;
  padding: 0;
}

.container {
  max-width: 600px;
  margin: auto;
  padding: 20px;
  background: #fff;
  color: #222;
  margin-top: 50px;
  border-radius: 8px;
  box-shadow: 0 0 15px rgba(0,0,0,0.1);
}

.hidden {
  display: none;
}

h1, h2 {
  text-align: center;
  color: #002147;
}

ul {
  list-style: none;
  padding: 0;
}

li {
  background: #ececec;
  margin: 8px 0;
  padding: 10px;
  border-radius: 5px;
  cursor: pointer;
}

li:hover {
  background: #dcdcdc;
}

button {
  display: block;
  margin: 20px auto;
  padding: 10px 20px;
  background: #0056b3;
  border: none;
  color: #fff;
  border-radius: 5px;
  cursor: pointer;
  font-size: 1.1em;
}

button:hover {
  background: #003366;
}

#explanation {
  margin-top: 10px;
  font-style: italic;
}