body {
  margin: 0;
  font-family: "Cairo", sans-serif;
  background: radial-gradient(circle at center, #0f172a, #1e1b4b);
  color: #fff;
  scroll-behavior: smooth;
  overflow-x: hidden;
}

.main-header {
  text-align: center;
  background: rgba(0,0,0,0.6);
  padding: 25px;
  box-shadow: 0 8px 25px rgba(0,0,0,0.6);
  backdrop-filter: blur(8px);
}

.main-header h1 {
  font-size: 30px;
  color: #a78bfa;
  text-shadow: 0 0 10px #8b5cf6;
}

.main-header p {
  color: #ddd;
  font-size: 18px;
}

.lesson-container {
  display: flex;
  flex-direction: column;
  gap: 50px;
  max-width: 900px;
  margin: 50px auto;
  padding: 20px;
}

.lesson {
  background: rgba(255,255,255,0.05);
  border-radius: 18px;
  padding: 20px;
  box-shadow: 0 5px 25px rgba(0,0,0,0.5);
  backdrop-filter: blur(10px);
  transform-style: preserve-3d;
  transition: all 0.5s ease;
}

.lesson:hover {
  transform: translateY(-8px) rotateX(3deg);
  box-shadow: 0 10px 35px rgba(139, 92, 246, 0.4);
}

.lesson video {
  width: 100%;
  border-radius: 15px;
  margin-bottom: 15px;
}

.lesson h2 {
  font-size: 22px;
  color: #c4b5fd;
}

.lesson p {
  color: #e5e7eb;
  line-height: 1.8;
  font-size: 17px;
}

.download-btn {
  display: inline-block;
  background: linear-gradient(45deg, #6366f1, #8b5cf6);
  padding: 10px 20px;
  border-radius: 10px;
  color: #fff;
  text-decoration: none;
  font-weight: bold;
  margin-top: 10px;
  transition: 0.3s;
}
.download-btn:hover {
  transform: scale(1.05);
  box-shadow: 0 4px 15px rgba(99, 102, 241, 0.6);
}

.quiz-btn {
  background: linear-gradient(45deg, #22c55e, #16a34a);
  color: #fff;
  padding: 12px 25px;
  border: none;
  border-radius: 12px;
  font-weight: bold;
  font-size: 18px;
  cursor: pointer;
  transition: 0.3s;
}
.quiz-btn:hover {
  transform: scale(1.05);
  box-shadow: 0 4px 20px rgba(34,197,94,0.4);
}

footer {
  text-align: center;
  background: rgba(0,0,0,0.7);
  padding: 25px;
  font-size: 14px;
  margin-top: 50px;
  color: #ccc;
}

/* ظهور تدريجي */
.lesson {
  opacity: 0;
  transform: translateY(50px);
  transition: opacity 0.8s ease, transform 0.8s ease;
}
.lesson.show {
  opacity: 1;
  transform: translateY(0);
}

/* تجاوب */
@media (max-width: 768px) {
  .lesson h2 { font-size: 20px; }
  .lesson p { font-size: 16px; }
}