/* BACKGROUND */
body {
  background: linear-gradient(135deg, #0b1120, #0f172a);
  color: #e2e8f0;
  font-family: Arial, sans-serif;
}

/* PAGE WRAPPER */
.grade-page {
  max-width: 1200px;
  margin: auto;
  padding: 30px 15px 60px;
}

/* BACK BUTTON */
.back-btn {
  display: inline-block;
  margin-bottom: 20px;
  padding: 12px 20px;
  background: #38bdf8;
  color: #020617;
  border-radius: 10px;
  text-decoration: none;
  font-weight: bold;
  font-size: 1.1rem;
  transition: transform 0.2s ease;
}

.back-btn:hover {
  transform: translateX(-5px);
}

/* MAIN TITLE */
.grade-page h1 {
  text-align: center;
  font-size: 3rem;
  color: #38bdf8;
  margin-bottom: 5px;
}

/* TAGLINE */
.grade-subtitle {
  text-align: center;
  font-size: 1.5rem;
  color: #94a3b8;
  margin-bottom: 25px;
}

/* MODULE CARDS */
.module {
  background: #0f172a;
  padding: 25px;
  border-radius: 16px;
  margin-bottom: 20px;
  box-shadow: 0 10px 30px rgba(0,0,0,0.5);
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.module:hover {
  transform: translateY(-6px);
  box-shadow:
    0 20px 50px rgba(56,189,248,0.25),
    0 0 0 1px rgba(56,189,248,0.2);
}

/* MODULE TITLE (Tynker Animation) */
.module h2 {
  color: #22c55e;
  font-size: 2rem;
  margin-bottom: 15px;
  transition: all 0.3s ease;
}

.module:hover h2 {
  color: #38bdf8;
  text-shadow: 0 0 10px rgba(56,189,248,0.7);
}

/* CHAPTER GRID */
.chapter-list {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 12px;
  list-style: none;
  padding: 0;
}

/* CHAPTER BUTTONS */
.chapter-list a {
  display: block;
  padding: 14px;
  background: #1e293b;
  color: #e2e8f0;
  border-radius: 12px;
  text-decoration: none;
  font-size: 1.1rem;
  font-weight: bold;
  text-align: center;
  transition: all 0.25s ease;
}

.chapter-list a:hover {
  background: #38bdf8;
  color: #020617;
  transform: scale(1.05);
}

/* MOBILE */
@media (max-width: 768px) {
  .grade-page h1 { font-size: 2.2rem; }
  .grade-subtitle { font-size: 1.2rem; }
  .module h2 { font-size: 1.6rem; }
  .chapter-list {
    grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  }
}