body {
  font-family: 'Poppins', Arial, sans-serif;
  background: linear-gradient(135deg, #f0f4ff, #e8ecf9);
  margin: 0;
  color: #333;
}

/* Navbar */
.navbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  background: linear-gradient(90deg, #667eea, #764ba2);
  padding: 15px 30px;
  box-shadow: 0 4px 12px rgba(0,0,0,0.15);
}
.navbar .logo {
  color: #fff;
  font-weight: 600;
  font-size: 20px;
}
.navbar ul {
  list-style: none;
  display: flex;
  gap: 25px;
  margin: 0;
  padding: 0;
}
.navbar ul li a {
  color: #fff;
  text-decoration: none;
  font-weight: 500;
  padding: 8px 14px;
  border-radius: 6px;
  transition: background 0.3s, transform 0.2s;
}
.navbar ul li a:hover,
.navbar ul li a.active {
  background: rgba(255,255,255,0.25);
  transform: scale(1.05);
}

/* Container */
.container {
  max-width: 1000px;
  margin: 40px auto;
  background: #fff;
  padding: 30px;
  border-radius: 16px;
  box-shadow: 0 8px 20px rgba(0,0,0,0.08);
}
.container h2 {
  text-align: center;
  margin-bottom: 25px;
  color: #444;
  font-weight: 600;
}

/* Filter bar */
.filter-bar {
  display: flex;
  gap: 12px;
  margin: 20px 0;
  flex-wrap: wrap;
  justify-content: center;
}
.filter-bar select,
.filter-bar input {
  padding: 10px 14px;
  border: 1px solid #ccc;
  border-radius: 8px;
  font-size: 14px;
}
.filter-bar button {
  padding: 10px 18px;
  background: linear-gradient(90deg, #667eea, #764ba2);
  color: #fff;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  font-weight: 600;
  transition: transform 0.2s, background 0.3s;
}
.filter-bar button:hover {
  background: #5a67d8;
  transform: translateY(-2px);
}

/* File card */
.file-card {
  background: #f9f9ff;
  padding: 20px;
  margin-bottom: 20px;
  border-radius: 12px;
  box-shadow: 0 4px 12px rgba(0,0,0,0.05);
  transition: transform 0.2s, box-shadow 0.3s;
}
.file-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 6px 16px rgba(0,0,0,0.1);
}
.file-card strong {
  font-size: 16px;
  color: #333;
}
.file-card em {
  font-size: 13px;
  color: #666;
}
.file-card a {
  display: inline-block;
  margin-top: 8px;
  text-decoration: none;
  font-weight: 500;
  color: #667eea;
  transition: color 0.3s;
}
.file-card a:hover {
  color: #764ba2;
}
.download-btn {
  background: #38a169;
  color: #fff;
  padding: 6px 12px;
  border: none;
  border-radius: 6px;
  cursor: pointer;
  margin-left: 10px;
  font-size: 13px;
  transition: background 0.3s;
}
.download-btn:hover {
  background: #2f855a;
}

/* Preview */
.file-preview {
  margin-top: 12px;
}
.file-preview img {
  max-width: 220px;
  border-radius: 10px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.1);
}
.file-preview iframe {
  width: 100%;
  height: 400px;
  border: none;
  border-radius: 10px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.1);
}

/* Pagination */
.pagination {
  margin-top: 25px;
  text-align: center;
}
.pagination a {
  margin: 0 6px;
  padding: 8px 14px;
  background: #fff;
  border: 1px solid #ccc;
  border-radius: 8px;
  text-decoration: none;
  color: #333;
  font-weight: 500;
  transition: background 0.3s, transform 0.2s;
}
.pagination a.active {
  background: linear-gradient(90deg, #667eea, #764ba2);
  color: #fff;
}
.pagination a:hover {
  background: #667eea;
  color: #fff;
  transform: scale(1.05);
}

/* Empty state */
.empty {
  text-align: center;
  color: #777;
  font-style: italic;
  margin-top: 20px;
}

/* Footer */
footer {
  text-align: center;
  padding: 20px;
  background: linear-gradient(90deg, #667eea, #764ba2);
  color: #fff;
  margin-top: 50px;
  border-top-left-radius: 12px;
  border-top-right-radius: 12px;
}