html {
  height: 100%;
}

body {
  font-family: "Inter", sans-serif;
  margin: 0;
  padding: 2rem;
  color: #f5f5f5;
  background: linear-gradient(160deg, #1c1c1c, #2a2a40);
  background-size: cover;
  background-position: center;
  background-attachment: fixed;
}

h1 {
  text-align: center;
  font-size: 2rem;
  font-weight: 600;
  margin-bottom: 2.5rem;
  color: #fff;
}

.nav-container {
  max-width: 650px;
  margin: 0 auto;
}

.nav-card:last-child {
  margin-bottom: 0;
}

.nav-card {
  background: rgba(255, 255, 255, 0.08);
  border-radius: 16px;
  padding: 1rem 1.5rem;
  margin-bottom: 1rem;
  box-shadow: 0 3px 10px rgba(0, 0, 0, 0.4);
  backdrop-filter: blur(12px);
  transition: transform 0.15s ease, box-shadow 0.15s ease;
}

.nav-card:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 20px rgba(0, 0, 0, 0.5);
}

.nav-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  cursor: pointer;
}

.nav-title {
  display: flex;
  align-items: center;
  font-size: 1.05rem;
  font-weight: 500;
  color: #fff;
}

.emoji {
  margin-right: 0.5rem;
  opacity: 0.8;
}

.arrow {
  transition: transform 0.3s ease;
  font-size: 1.2rem;
  color: #aaa;
}

.arrow.open {
  transform: rotate(90deg);
  color: #fff;
}

.description {
  margin-top: 0.7rem;
  font-size: 0.95rem;
  line-height: 1.4;
  color: #ddd;
  display: none;
}

.description a {
  display: inline-block;
  margin-top: 0.8rem;
  padding: 0.4rem 0.9rem;
  background: #f5f5f5;
  color: #111;
  border-radius: 8px;
  text-decoration: none;
  font-size: 0.9rem;
  font-weight: 500;
  transition: background 0.2s ease, color 0.2s ease;
}

.description a:hover {
  background: #ddd;
  color: #000;
}

.preview {
  margin-top: 1rem;
  position: relative;
  display: none;
  justify-content: center;
  align-items: center
}

.preview img {
  width: auto;
  height: auto;
  max-width: 100%;
  max-height: 400px;
  border-radius: 14px;
  opacity: 0;
  transition: opacity 0.4s ease;
  object-fit: contain;
  object-position: center;
}

.loader {
  width: 40px;
  height: 40px;
  border: 3px solid #555;
  border-top: 3px solid #f5f5f5;
  border-radius: 50%;
  animation: spin 1s linear infinite;
  margin: 1rem auto;
}

@keyframes spin {
  to {
    transform: rotate(360deg);
  }
}

@media (max-width: 600px) {
  body {
    padding: 1rem;
  }

  h1 {
    font-size: 1.5rem;
    margin-bottom: 1.5rem;
  }

  .nav-container {
    max-width: 95%;
  }

  .nav-card {
    padding: 0.8rem 1rem;
  }

  .nav-title {
    font-size: 1rem;
  }

  .description {
    font-size: 0.9rem;
  }

  .description a {
    font-size: 0.85rem;
    padding: 0.3rem 0.7rem;
  }

  .arrow {
    font-size: 1rem;
  }
}