/* RESET & BASE */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}
body {
  font-family: 'Poppins', sans-serif;
  background: #f5f7fa;
  color: #333;
  scroll-behavior: smooth;
}

/* NAVIGATION */
nav {
  background: #1e1e2f;
  padding: 20px 40px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  position: sticky;
  top: 0;
  z-index: 999;
  box-shadow: 0 4px 12px rgba(0,0,0,0.3);
}
nav h1 {
  color: #00d8ff;
  font-size: 1.8em;
  font-weight: 700;
}
nav ul {
  list-style: none;
  display: flex;
  gap: 30px;
}
nav ul li a {
  color: #fff;
  text-decoration: none;
  font-weight: 500;
  padding: 8px 12px;
  border-radius: 5px;
  transition: all 0.3s ease;
}
nav ul li a:hover {
  background: #00d8ff;
  color: #1e1e2f;
}

/* HERO */
.hero {
  background: linear-gradient(rgba(0,0,0,0.5), rgba(0,0,0,0.6)),
              url('https://images.unsplash.com/photo-1581090700227-1e8e8ca5ac92?auto=format&fit=crop&w=1600&q=80') center/cover no-repeat;
  padding: 120px 40px;
  text-align: center;
  color: white;
}
.hero h2 {
  font-size: 3em;
  margin-bottom: 20px;
  animation: fadeInDown 1s ease-in-out;
}
.hero p {
  font-size: 1.3em;
  max-width: 600px;
  margin: 0 auto;
  animation: fadeInUp 1s ease-in-out;
}

/* MAIN CONTENT */
main {
  padding: 50px 30px;
  display: flex;
  flex-direction: column;
  gap: 50px;
}
section {
  position: relative;
  padding: 80px 40px;
  border-radius: 12px;
  min-height: 400px;
  background: #fff;
  box-shadow: 0 8px 24px rgba(0,0,0,0.08);
  background-size: cover;
  background-position: center;
  color: white;
  display: flex;
  flex-direction: column;
  justify-content: center;
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}

section:hover {
  transform: translateY(-5px);
  box-shadow: 0 12px 28px rgba(0,0,0,0.15);
}

section::before {
  content: "";
  position: absolute;
  inset: 0;
  background: rgba(0,0,0,0.5); /* dark overlay */
  border-radius: 12px;
  z-index: 0;
}

section h3,
section p {
  position: relative;
  z-index: 1;
  color: #fff;
}

/* TOPIC LIST */
.topic-list {
  padding: 0 40px;
}
.topic-list li {
  margin: 15px 0;
  list-style: none;
}
.topic-list li a {
  display: inline-block;
  text-decoration: none;
  color: #0077cc;
  font-weight: bold;
  transition: all 0.3s;
}
.topic-list li a:hover {
  color: #00b894;
  transform: scale(1.02);
}

/* QUIZ LEVELS */
.quiz-levels {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 30px;
  padding: 30px 0;
}
.quiz-btn {
  padding: 15px 30px;
  background: #0077cc;
  color: white;
  text-decoration: none;
  font-size: 1.1em;
  border-radius: 50px;
  transition: all 0.3s ease;
  box-shadow: 0 4px 12px rgba(0,0,0,0.2);
}
.quiz-btn:hover {
  background: #005fa3;
  transform: scale(1.05);
}

/* FOOTER */
footer {
  background: #1e1e2f;
  color: white;
  text-align: center;
  padding: 20px;
  font-size: 0.95em;
  margin-top: 60px;
}

/* ANIMATIONS */
@keyframes fadeInDown {
  from {
    opacity: 0;
    transform: translateY(-30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}