body {
  margin: 0;
  font-family: 'Inter', sans-serif;
  background: #121212;
  color: #e0e0e0;
  scroll-behavior: smooth;
}

.back-button {
  position: fixed;
  top: 16px;
  left: 16px;
  background-color: rgba(0, 0, 0, 0.6);
  color: #fff;
  padding: 8px 11px;
  border-radius: 25%;
  font-size: 18px;
  z-index: 1000;
  text-decoration: none;
  transition: background-color 0.3s ease;
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.4);
}

.back-button:hover {
  background-color: rgba(0, 0, 0, 0.8);
}

header {
  background: #181818;
  padding: 30px 20px;
  text-align: center;
  border-bottom: 1px solid #2a2a2a;
}

header h1 {
  margin: 0 0 15px;
  font-size: 2.2rem;
  color: #00ccff;
}

.tabs {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 12px;
}

.tab-button {
  padding: 10px 25px;
  background: linear-gradient(135deg, #00ccff, #0088ff);
  color: #fff;
  border: none;
  border-radius: 30px;
  font-weight: bold;
  font-size: 0.95rem;
  :cursor: pointer;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.tab-button:hover {
  transform: scale(1.05);
  box-shadow: 0 4px 12px rgba(0, 204, 255, 0.3);
}

.tab-button.active {
  background: linear-gradient(135deg, #00ffcc, #00ccff);
  color: #121212;
}

main {
  max-width: 950px;
  margin: 40px auto;
  padding: 0 20px;
}

.tab-content {
  display: none;
  padding: 30px 10px;
  margin-bottom: 60px;
  animation: fadeIn 0.5s ease;
}

.tab-content.active {
  display: block;
}

h2 {
  color: #00ccff;
  margin-bottom: 10px;
}

h3 {
  color: #cccccc;
  margin-top: 30px;
  font-size: 1.1rem;
}

ul {
  padding-left: 20px;
  margin-top: 10px;
}

a {
  color: #00ccff;
  text-decoration: underline;
}

footer {
  background: #1a1a1a;
  text-align: center;
  padding: 20px;
  font-size: 0.9rem;
  color: #888;
  border-top: 1px solid #333;
}

#scrollTopBtn {
  position: fixed;
  bottom: 20px;
  right: 20px;
  background: #00ccff;
  color: #121212;
  border: none;
  padding: 10px 12px;
  border-radius: 25%;
  font-size: 23px;
  :cursor: pointer;
  box-shadow: 0 0 12px rgba(0,0,0,0.4);
  display: none;
  z-index: 999;
}

#scrollTopBtn:hover {
  background: #00aacc;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: translateY(0); }
}