/* styles.css */

.sidebar {
  position: fixed;
  top: 0;
  left: 0;
  width: 200px;
  height: 100%;
  background-color: #111;
  padding: 2rem 1rem;
  overflow-y: auto;
}

.sidebar ul {
  list-style: none;
}

.sidebar li {
  margin-bottom: 1rem;
}

.sidebar a {
  color: #ccc;
  text-decoration: none;
  font-weight: bold;
  transition: color 0.2s ease;
}

.sidebar a:hover {
  color: #fff;
}

.sidebar strong {
  display: block;
  color: #fff;
  font-size: 0.95rem;
  margin-top: 1.5rem;
  margin-bottom: 0.5rem;
  padding-bottom: 0.2rem;
  border-bottom: 1px solid #333;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.sidebar ul ul {
  padding-left: 1rem;
}

.sidebar ul ul li {
  margin-bottom: 0.5rem;
}

.sidebar ul ul a {
  font-weight: normal;
  color: #aaa;
  font-size: 0.9rem;
}

.sidebar ul ul a:hover {
  color: #fff;
}

main {
  margin-left: 110px;
}


* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: sans-serif;
  background: #0a0a0a;
  color: #eee;
  line-height: 1.6;
  padding: 2rem;
  max-width: 800px;
  margin: auto;
}

header {
  text-align: center;
  margin-bottom: 2rem;
}

h1 {
  font-size: 2.5rem;
  margin-bottom: 0.5rem;
}

.tagline {
  font-size: 1.2rem;
  color: #eee;
}

section {
  margin-bottom: 3rem;
}

.section p {
  color: #eee;
  font-size: 1rem;
  line-height: 1.6;
  margin-bottom: 1.5rem;
  padding: 0 1rem;
  max-width: 700px;
  margin-left: auto;
  margin-right: auto;
}

.section a {
  color: #fb2;
}
.section h2 {
  font-size: 1.6rem;
  margin-bottom: 1rem;
}

.levels {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1rem;
}

.level {
  background: black;
  border-left: 5px solid #ccc;
  padding: 1rem;
  border-radius: 6px;
}

.level h3 {
  margin-bottom: 0.5rem;
}

.level.easy {
  border-color: #2ecc71;
}
.level.medium {
  border-color: #f1c40f;
}
.level.hard {
  border-color: #e74c3c;
}

footer {
  text-align: center;
  font-size: 0.9rem;
  color: #eee;
  padding-top: 2rem;
  border-top: 1px solid #ddd;
}
.explain {
  display: block;
  font-size: 0.85rem;
  color: #aaa;
  margin-top: 0.25rem;
}
/* Hide sidebar on mobile */
@media (max-width: 768px) {
  .sidebar {
    display: none;
  }

  body {
    padding-left: 1rem;
    padding-right: 1rem;
  }

  main {
    margin-left: 0;
  }
}