* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  background: linear-gradient(135deg, #0f1419, #1a2332, #0d1117);
  color: #e6edf3;
  min-height: 100vh;
  overflow-x: hidden;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

header {
  position: fixed;
  top: 0;
  width: 100%;
  background: rgba(22, 27, 34, 0.95);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid #30363d;
  z-index: 1000;
  transition: background 0.3s ease;
}

nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 0;
}

.logo {
  font-size: 1.5rem;
  font-weight: bold;
  color: #58a6ff;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.logo::before {
  content: "⚡";
  font-size: 1.8rem;
  animation: pulse 2s infinite;
}

@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.7; }
}

.nav-links {
  display: flex;
  list-style: none;
  gap: 2rem;
}

.nav-links a {
  color: #e6edf3;
  text-decoration: none;
  position: relative;
  transition: color 0.3s;
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -5px;
  left: 0;
  width: 0;
  height: 2px;
  background: #58a6ff;
  transition: width 0.3s;
}

.nav-links a:hover {
  color: #58a6ff;
}

.nav-links a:hover::after {
  width: 100%;
}

main {
  margin-top: 80px;
  padding: 2rem 0;
}

.hero {
  text-align: center;
  padding: 4rem 0;
  position: relative;
  background: radial-gradient(circle, rgba(88,166,255,0.1) 0%, transparent 70%);
}

.hero h1 {
  font-size: 3rem;
  margin-bottom: 1rem;
  background: linear-gradient(135deg, #58a6ff, #39d353);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  animation: fadeInUp 1s ease;
}

.hero p {
  color: #8b949e;
  font-size: 1.2rem;
  animation: fadeInUp 1s ease 0.2s both;
}

@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(30px); }
  to { opacity: 1; transform: translateY(0); }
}

.files-section {
  padding: 4rem 0;
}

.section-title {
  text-align: center;
  font-size: 2.5rem;
  margin-bottom: 3rem;
  color: #58a6ff;
}

.turma-container {
  margin-bottom: 2rem;
  border-radius: 12px;
  overflow: hidden;
  background: rgba(22,27,34,0.5);
  border: 1px solid #30363d;
}

.turma-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1.5rem;
  cursor: pointer;
  background: rgba(88,166,255,0.1);
  border-bottom: 1px solid #58a6ff;
  transition: background 0.3s;
}

.turma-header:hover { background: rgba(88,166,255,0.15); }

.turma-title { font-size: 1.8rem; color: #58a6ff; font-weight: bold; }
.turma-subtitle { font-size: 1rem; color: #8b949e; }
.collapse-icon { font-size: 1.5rem; color: #58a6ff; transition: transform 0.3s; }
.turma-container.active .collapse-icon { transform: rotate(180deg); }

.turma-content {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.4s ease;
}
.turma-container.active .turma-content { max-height: 2000px; }

.files-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.5rem;
  padding: 2rem 0;
}

.file-card {
  background: rgba(22,27,34,0.8);
  border-radius: 12px;
  border: 1px solid #30363d;
  padding: 1.5rem;
  transition: all 0.3s;
  position: relative;
}

.file-card:hover {
  transform: translateY(-5px);
  border-color: #58a6ff;
  box-shadow: 0 10px 30px rgba(88,166,255,0.2);
}

.file-icon { font-size: 2.5rem; margin-bottom: 1rem; display: block; }
.file-card h3 { font-size: 1.2rem; margin-bottom: 0.8rem; }
.file-card p { color: #8b949e; margin-bottom: 1.2rem; font-size: 0.9rem; line-height: 1.5; }

.download-btn {
  background: linear-gradient(135deg, #238636, #39d353);
  color: white;
  border-radius: 8px;
  padding: 0.7rem 1.2rem;
  text-decoration: none;
  font-weight: 500;
  font-size: 0.9rem;
  display: inline-block;
  transition: all 0.3s;
}

.download-btn:hover { transform: scale(1.05); box-shadow: 0 5px 15px rgba(57,211,83,0.3); }

footer {
  background: rgba(22,27,34,0.95);
  border-top: 1px solid #30363d;
  padding: 2rem 0;
  text-align: center;
  color: #8b949e;
}

.floating-shapes { display: none; } /* desativadas para simplificar */

@media (max-width: 768px) {
  .hero h1 { font-size: 2rem; }
  .nav-links { display: none; }
  .files-grid { grid-template-columns: 1fr; }
  .turma-title { font-size: 1.5rem; }
}