:root {
  --bg-color: #080c14;
  --card-bg: rgba(18, 26, 43, 0.75);
  --primary-color: #6366f1;
  --secondary-color: #a855f7;
  --accent-color: #06b6d4;
  --text-main: #f8fafc;
  --text-muted: #94a3b8;
  --border-color: rgba(255, 255, 255, 0.1);
  --glow-shadow: 0 0 20px rgba(99, 102, 241, 0.35);
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: 'Tajawal', sans-serif;
  scroll-behavior: smooth;
}

body {
  background-color: var(--bg-color);
  color: var(--text-main);
  background-image: 
    radial-gradient(circle at 15% 15%, rgba(99, 102, 241, 0.08) 0%, transparent 40%),
    radial-gradient(circle at 85% 85%, rgba(168, 85, 247, 0.08) 0%, transparent 40%),
    radial-gradient(circle at 25px 25px, rgba(255, 255, 255, 0.03) 2px, transparent 0);
  background-size: 100% 100%, 100% 100%, 40px 40px;
  overflow-x: hidden;
}

/* Navbar */
.navbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1.2rem 8%;
  background: rgba(8, 12, 20, 0.85);
  backdrop-filter: blur(15px);
  position: fixed;
  top: 0;
  width: 100%;
  z-index: 1000;
  border-bottom: 1px solid var(--border-color);
}

.logo {
  font-size: 1.6rem;
  font-weight: 900;
  letter-spacing: 1px;
}

.logo span {
  color: var(--primary-color);
}

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

.nav-links a {
  color: var(--text-main);
  text-decoration: none;
  font-weight: 500;
  transition: color 0.3s ease;
}

.nav-links a:hover {
  color: var(--accent-color);
}

.burger {
  display: none;
  cursor: pointer;
}

.burger div {
  width: 25px;
  height: 3px;
  background-color: var(--text-main);
  margin: 5px;
  transition: all 0.3s ease;
}

.burger.toggle .line1 {
  transform: rotate(-45deg) translate(-5px, 6px);
}

.burger.toggle .line2 {
  opacity: 0;
}

.burger.toggle .line3 {
  transform: rotate(45deg) translate(-5px, -6px);
}

/* Hero Section */
.hero-section {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 8rem 8% 4rem;
  text-align: center;
}

.hero-content {
  max-width: 800px;
}

.badge-hero {
  display: inline-block;
  background: rgba(99, 102, 241, 0.15);
  color: var(--accent-color);
  border: 1px solid rgba(6, 182, 212, 0.3);
  padding: 0.4rem 1.2rem;
  border-radius: 30px;
  font-size: 0.9rem;
  font-weight: 700;
  margin-bottom: 1.5rem;
}

.hero-content h1 {
  font-size: 3.5rem;
  font-weight: 900;
  margin-bottom: 1rem;
  line-height: 1.2;
}

.highlight {
  background: linear-gradient(135deg, var(--primary-color), var(--secondary-color), var(--accent-color));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.subtitle {
  font-size: 1.6rem;
  color: var(--accent-color);
  margin-bottom: 1rem;
  font-weight: 700;
}

.description {
  font-size: 1.15rem;
  color: var(--text-muted);
  margin-bottom: 2.5rem;
  line-height: 1.8;
}

.hero-btns {
  display: flex;
  gap: 1.2rem;
  justify-content: center;
}

.btn {
  padding: 0.9rem 2.2rem;
  border-radius: 50px;
  text-decoration: none;
  font-weight: 700;
  transition: all 0.3s ease;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.btn-primary {
  background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
  color: #fff;
  box-shadow: 0 10px 25px rgba(99, 102, 241, 0.4);
}

.btn-primary:hover {
  transform: translateY(-3px);
  box-shadow: 0 15px 30px rgba(99, 102, 241, 0.6);
}

.btn-secondary {
  border: 1px solid var(--border-color);
  background: rgba(255, 255, 255, 0.03);
  color: var(--text-main);
}

.btn-secondary:hover {
  background: rgba(255, 255, 255, 0.1);
  border-color: var(--accent-color);
  transform: translateY(-3px);
}

/* Courses Section */
.courses-section {
  padding: 6rem 8%;
}

.section-title {
  text-align: center;
  font-size: 2.5rem;
  margin-bottom: 1rem;
  position: relative;
}

.section-title::after {
  content: '';
  display: block;
  width: 80px;
  height: 4px;
  background: linear-gradient(90deg, var(--primary-color), var(--accent-color));
  margin: 10px auto 0;
  border-radius: 2px;
}

.section-subtitle {
  text-align: center;
  color: var(--text-muted);
  margin-bottom: 3rem;
  font-size: 1.1rem;
}

.courses-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(340px, 1fr));
  gap: 2.5rem;
}

.course-card {
  background: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: 24px;
  padding: 2.5rem;
  position: relative;
  backdrop-filter: blur(10px);
  transition: transform 0.1s ease, box-shadow 0.3s ease, border-color 0.3s ease;
  transform-style: preserve-3d;
  display: flex;
  flex-direction: column;
}

.course-card:hover {
  border-color: var(--primary-color);
  box-shadow: var(--glow-shadow);
}

.card-tag {
  position: absolute;
  top: 20px;
  left: 20px;
  background: rgba(99, 102, 241, 0.2);
  color: var(--accent-color);
  padding: 0.3rem 0.8rem;
  border-radius: 20px;
  font-size: 0.8rem;
  font-weight: 700;
  border: 1px solid rgba(6, 182, 212, 0.3);
}

.card-icon {
  font-size: 3rem;
  margin-bottom: 1rem;
}

.course-card h3 {
  font-size: 1.8rem;
  margin-bottom: 1rem;
}

.card-desc {
  color: var(--text-muted);
  margin-bottom: 1.5rem;
  line-height: 1.6;
}

.course-card h4 {
  font-size: 1.1rem;
  color: var(--accent-color);
  margin-bottom: 1rem;
}

.skills-list {
  list-style: none;
}

.skills-list li {
  margin-bottom: 0.8rem;
  color: var(--text-main);
  display: flex;
  align-items: flex-start;
  gap: 0.6rem;
  font-size: 0.95rem;
  line-height: 1.5;
}

.skills-list span {
  color: var(--accent-color);
  font-weight: bold;
}

/* Tabs for Robotics Projects */
.projects-tabs-container {
  margin-top: 1rem;
  background: rgba(8, 12, 20, 0.6);
  border: 1px solid var(--border-color);
  border-radius: 16px;
  padding: 1.2rem;
}

.tabs-header {
  display: flex;
  gap: 0.5rem;
  overflow-x: auto;
  padding-bottom: 0.6rem;
  margin-bottom: 1rem;
}

.tab-btn {
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--border-color);
  color: var(--text-muted);
  padding: 0.5rem 1rem;
  border-radius: 12px;
  cursor: pointer;
  white-space: nowrap;
  font-size: 0.85rem;
  font-weight: 700;
  transition: all 0.3s ease;
}

.tab-btn.active {
  background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
  color: #fff;
  border-color: transparent;
}

.tab-pane {
  display: none;
  animation: fadeIn 0.4s ease-in-out;
}

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

.tab-pane h5 {
  color: var(--accent-color);
  font-size: 1.1rem;
  margin-bottom: 0.3rem;
}

.tab-pane p {
  color: var(--text-main);
  font-size: 0.95rem;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(6px); }
  to { opacity: 1; transform: translateY(0); }
}

/* Gallery Section */
.gallery-section {
  padding: 6rem 8%;
  background: rgba(0, 0, 0, 0.2);
}

.video-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 2rem;
}

.video-card {
  background: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: 18px;
  overflow: hidden;
  transition: all 0.3s ease;
  cursor: pointer;
}

.video-card:hover {
  transform: translateY(-8px);
  border-color: var(--accent-color);
  box-shadow: var(--glow-shadow);
}

.thumb-container {
  position: relative;
  width: 100%;
  aspect-ratio: 16 / 9;
  background: #000;
  display: flex;
  align-items: center;
  justify-content: center;
}

.thumb-container video {
  width: 100%;
  height: 100%;
  object-fit: cover;
  pointer-events: none;
}

.play-overlay {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 50px;
  height: 50px;
  background: rgba(99, 102, 241, 0.85);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-size: 1.2rem;
  transition: transform 0.3s ease;
}

.video-card:hover .play-overlay {
  transform: translate(-50%, -50%) scale(1.15);
}

.video-info {
  padding: 1.2rem;
}

.video-title {
  font-size: 1.05rem;
  color: var(--text-main);
  text-align: center;
}

/* Modal Window */
.video-modal {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.88);
  backdrop-filter: blur(8px);
  z-index: 2000;
  align-items: center;
  justify-content: center;
  padding: 2rem;
}

.video-modal.show {
  display: flex;
}

.modal-content {
  position: relative;
  width: 100%;
  max-width: 850px;
  background: #0f172a;
  border-radius: 20px;
  border: 1px solid var(--border-color);
  overflow: hidden;
}

.close-modal {
  position: absolute;
  top: 15px;
  left: 20px;
  font-size: 2rem;
  color: #fff;
  cursor: pointer;
  z-index: 10;
}

.modal-body {
  width: 100%;
  aspect-ratio: 16 / 9;
  display: flex;
  align-items: center;
  justify-content: center;
  background: #000;
}

.modal-body video {
  width: 100%;
  height: 100%;
  border-radius: 12px;
}

/* Footer */
footer {
  text-align: center;
  padding: 4rem 8% 2rem;
  border-top: 1px solid var(--border-color);
  background: rgba(8, 12, 20, 0.95);
}

.footer-content h3 {
  font-size: 1.8rem;
  margin-bottom: 0.5rem;
}

.footer-content p {
  color: var(--text-muted);
}

.copyright {
  margin-top: 2rem;
  font-size: 0.9rem;
}

/* Responsive Styles */
@media (max-width: 768px) {
  .nav-links {
    position: absolute;
    right: 0;
    height: 100vh;
    top: 0;
    background-color: var(--bg-color);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    width: 75%;
    transform: translateX(100%);
    transition: transform 0.4s ease-in-out;
  }

  .nav-active {
    transform: translateX(0%);
  }

  .burger {
    display: block;
  }

  .hero-content h1 {
    font-size: 2.2rem;
  }
}