/* Modern Dark Theme with Blue/Gray Tones (Optimized) */
body {
  margin: 0;
  font-family: "Segoe UI", system-ui, -apple-system, sans-serif;
  background: linear-gradient(135deg, #0c1726 0%, #0a1a2d 100%);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  color: #e3f2fd;
  position: relative;
  overflow-x: hidden;
}

/* Static background element (removed animation) */
body::before {
  content: "";
  position: absolute;
  width: 150%;
  height: 150%;
  background: radial-gradient(
    circle at 50% 50%,
    rgba(42, 129, 204, 0.08) 0%,
    transparent 70%
  );
  z-index: -1;
  opacity: 0.5; /* Static opacity */
}

.container {
  background: rgba(22, 40, 65, 0.85);
  padding: 2.5rem;
  border-radius: 20px;
  box-shadow: 0 12px 40px rgba(5, 18, 32, 0.6),
    inset 0 0 0 1px rgba(64, 156, 255, 0.15);
  text-align: center;
  width: 100%;
  max-width: 420px;
  backdrop-filter: blur(8px);
  border: 1px solid rgba(80, 168, 252, 0.1);
  z-index: 2;
}

h1 {
  margin-bottom: 18px;
  font-size: 2.6rem;
  font-weight: 800;
  color: #a4d5ff;
  text-shadow: 0 0 10px rgba(86, 180, 255, 0.5); /* Static glow */
  letter-spacing: -0.5px;
  position: relative;
  padding-bottom: 0.8rem;
}

h1::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 25%;
  width: 50%;
  height: 3px;
  background: linear-gradient(90deg, transparent, #3a8dff, transparent);
  border-radius: 50%;
}

.puzzle-links {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.1rem;
  margin-top: 1.8rem;
}

.puzzle-link {
  background: linear-gradient(135deg, #1a3d5d 0%, #15314d 100%);
  border-radius: 12px;
  padding: 1.25rem;
  text-decoration: none;
  color: #d6edff;
  font-weight: 600;
  font-size: 1.15rem;
  box-shadow: 0 4px 15px rgba(5, 25, 45, 0.4),
    inset 0 0 0 1px rgba(100, 180, 255, 0.2);
  border: none;
  transition: all 0.3s ease;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
}

.puzzle-link:hover {
  background: linear-gradient(135deg, #215a8a 0%, #1a4770 100%);
  color: #ffffff;
  transform: translateY(-2px); /* Reduced movement */
  box-shadow: 0 6px 12px rgba(10, 70, 150, 0.4); /* Simplified shadow */
}

.puzzle-link:active {
  transform: translateY(1px);
}

.puzzle-link i {
  font-size: 1.3rem;
}

.puzzle-link.completed {
  position: relative;
  background-color: #e8f5e9;
  text-decoration: line-through;
  padding-right: 30px;
}

.puzzle-link.completed::after {
  content: "✓";
  position: absolute;
  right: 10px;
  color: #4CAF50;
  font-weight: bold;
}

.popup {
  z-index: 1000;
}

.home-button {
  display: flex;
  justify-content: center;
  margin: 2px auto 6px;
  width: 100%;
}

.home-button button {
  background: linear-gradient(135deg, #1a3d5d 0%, #15314d 100%);
  border-radius: 12px;
  padding: 8px 18px;
  text-decoration: none;
  color: #d6edff;
  font-weight: 600;
  font-size: 1rem;
  box-shadow: 0 4px 15px rgba(5, 25, 45, 0.4);
  border: 1px solid rgba(80, 168, 252, 0.2);
  transition: all 0.3s ease;
  cursor: pointer;
  font-family: "Segoe UI", system-ui, -apple-system, sans-serif;
}

.home-button button:hover {
  background: linear-gradient(135deg, #215a8a 0%, #1a4770 100%);
  color: #ffffff;
  transform: translateY(-2px);
  box-shadow: 0 6px 12px rgba(10, 70, 150, 0.4);
}

.home-button button:active {
  transform: translateY(1px);
}

/* Mobile optimization */
@media (max-width: 600px) {
  .home-button button {
    padding: 12px 24px;
    font-size: 1rem;
  }

  .container {
    padding: 1.8rem 1.2rem;
    max-width: 95vw;
    border-radius: 16px;
  }

  h1 {
    font-size: 2rem;
    padding-bottom: 0.6rem;
  }

  .puzzle-link {
    padding: 1.1rem;
    font-size: 1rem;
  }
}