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

body {
  font-family: 'Poppins', sans-serif;
  background: linear-gradient(to top, #010130, #000);
  color: #f0f0f0;
  min-height: 100vh;
  overflow-x: hidden;
  position: relative;
}

body::before {
  content: "";
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: url('images/stars.png') repeat;
  opacity: 0.1;
  z-index: -1;
  animation: moveStars 60s linear infinite;
}
header {
  background: rgba(0, 0, 0, 0.7);
  backdrop-filter: blur(8px);
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 20px 50px;
  position: sticky;
  top: 0;
  z-index: 999;
}

header h1 {
  font-family: 'Orbitron', sans-serif;
  font-size: 28px;
  color: #00ffff;
  letter-spacing: 2px;
}

nav a {
  margin-left: 25px;
  text-decoration: none;
  color: #aaa;
  font-size: 18px;
  position: relative;
}

nav a.active,
nav a:hover {
  color: #00ffff;
}

nav a:hover::after {
  content: '';
  position: absolute;
  width: 100%;
  height: 2px;
  background: #00ffff;
  left: 0;
  bottom: -5px;
}
main {
  padding: 80px 50px;
}

.page-content {
  animation: fadeIn 1.5s ease;
  max-width: 1000px;
  margin: auto;
}

.page-content h2 {
  font-size: 36px;
  margin-bottom: 20px;
  font-family: 'Orbitron', sans-serif;
  color: #00ffff;
}

.page-content p,
.page-content ul {
  font-size: 18px;
  line-height: 1.8;
  margin-bottom: 20px;
}

.page-content ul {
  list-style-type: disc;
  margin-left: 20px;
}


footer {
  text-align: center;
  padding: 20px;
  background: rgba(0, 0, 0, 0.7);
  backdrop-filter: blur(8px);
  margin-top: 50px;
  font-size: 14px;
  color: #777;
}
#launchBtn {
  animation: rocketShake 2s infinite;
}

.rocket {
  position: fixed;
  bottom: 50px;
  left: 50%;
  width: 40px;
  height: 80px;
  background: url('images/rocket.png') no-repeat center/contain;
  transform: translateX(-50%) scale(1);
  z-index: 9999;
  animation: rocketShake 0.5s infinite;
}

.smoke {
  position: fixed;
  bottom: 0;
  left: 50%;
  width: 100px;
  height: 20px;
  background: radial-gradient(circle, rgba(255,255,255,0.4) 0%, rgba(0,0,0,0) 70%);
  opacity: 0.8;
  transform: translateX(-50%) scale(1);
  z-index: 9998;
  transition: 2s;
}

.launch {
  animation: rocketLaunch 3s forwards;
}

.smokeExpand {
  animation: smokeExpand 3s forwards;
}
.stars {
  position: absolute;
  width: 100%;
  height: 100%;
  background: transparent;
  overflow: hidden;
  top: 0;
  left: 0;
  z-index: 0;
}

.star {
  position: absolute;
  width: 2px;
  height: 2px;
  background: white;
  border-radius: 50%;
  animation: twinkle 2s infinite alternate;
  opacity: 0.8;
}

.shooting-star {
  position: absolute;
  top: -10px;
  width: 150px;
  height: 2px;
  background: linear-gradient(90deg, white, rgba(255,255,255,0));
  animation: shoot 3s linear infinite;
  opacity: 0;
}

.galaxy {
  position: absolute;
  width: 800px;
  height: 800px;
  background: radial-gradient(circle, rgba(255,255,255,0.2) 0%, rgba(255,255,255,0) 80%);
  border-radius: 50%;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  animation: rotateGalaxy 100s linear infinite;
  z-index: 0;
}

.planets-background {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  overflow: hidden;
  z-index: 0;
}

.planet {
  position: absolute;
  width: 80px;
  opacity: 0.7;
  animation: floatPlanet 60s linear infinite;
}

.planet1 {
  top: 10%;
  left: 20%;
}

.planet2 {
  top: 50%;
  left: 70%;
  animation-duration: 90s;
}

.planet3 {
  top: 80%;
  left: 40%;
  animation-duration: 75s;
}

.comet {
  position: fixed;
  top: 0;
  left: -100px;
  width: 50px;
  height: 10px;
  background: linear-gradient(90deg, #fff, #0ff, transparent);
  border-radius: 50%;
  box-shadow: 0 0 20px 5px #0ff;
  opacity: 0.8;
  pointer-events: none;
  z-index: 999;
  transform: rotate(45deg);
}
.spaceship-navbar {
  background: linear-gradient(135deg, #0b0f18, #1b2330);
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 15px 40px;
  box-shadow: 0 0 20px rgba(0, 255, 255, 0.4);
  border-bottom: 2px solid #00ffe1;
  position: sticky;
  top: 0;
  z-index: 1000;
}

.logo {
  font-size: 24px;
  color: #00ffe1;
  font-weight: bold;
  letter-spacing: 2px;
  text-shadow: 0 0 10px #00ffe1;
}

.logo img {
  height: 30px;
  width: auto;
  vertical-align: middle;
  margin-right: 10px;
}

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

.nav-links li {
  margin: 0 15px;
}

.nav-links a {
  text-decoration: none;
  color: #c1f1f9;
  font-size: 18px;
  padding: 8px 15px;
  border: 1px solid transparent;
  border-radius: 20px;
  transition: all 0.4s ease;
}

.nav-links a:hover {
  background-color: rgba(0, 255, 255, 0.2);
  border-color: #00ffe1;
  box-shadow: 0 0 10px #00ffe1;
}

/* ===== CONTENT CARDS & COMPONENTS ===== */
.equation-card {
  background: rgba(15, 30, 60, 0.6);
  border-radius: 12px;
  padding: 1.5rem;
  margin: 1.5rem 0;
  border-left: 4px solid var(--secondary);
}

.equation {
  font-family: 'Courier New', monospace;
  font-size: 1.2rem;
  background: rgba(0, 0, 0, 0.3);
  padding: 1rem;
  border-radius: 6px;
  overflow-x: auto;
}

.code-sample {
  background: #1e1e3f;
  color: #f8f8f2;
  padding: 1rem;
  border-radius: 8px;
  font-family: 'Courier New', monospace;
  overflow-x: auto;
  margin: 1.5rem 0;
  position: relative;
}

.code-sample::before {
  content: 'Python';
  position: absolute;
  top: 0;
  right: 0;
  background: var(--primary);
  color: white;
  padding: 0.2rem 0.5rem;
  border-radius: 0 8px 0 8px;
  font-size: 0.8rem;
}

.simulation-container {
  width: 100%;
  height: 400px;
  background: rgba(0, 0, 0, 0.2);
  border-radius: 8px;
  margin: 2rem 0;
  position: relative;
  overflow: hidden;
}

.concept-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 1.5rem;
  margin: 2rem 0;
}

.concept-card {
  background: rgba(20, 40, 80, 0.5);
  padding: 1.5rem;
  border-radius: 8px;
  border-top: 3px solid var(--secondary);
}

.comment { color: #6a9955; font-style: italic; }
.keyword { color: #569cd6; }
.function { color: #dcdcaa; }
.number { color: #b5cea8; }

.design-principles {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 2rem;
  margin: 3rem 0;
}

.principle-card {
  background: rgba(15, 30, 60, 0.6);
  border-radius: 12px;
  padding: 1.5rem;
  transition: transform 0.3s ease;
  border-top: 3px solid var(--secondary);
}

.principle-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 10px 20px rgba(0, 150, 255, 0.2);
}

.design-visual {
  width: 100%;
  max-width: 800px;
  margin: 2rem auto;
  display: block;
  border-radius: 8px;
  border: 1px solid rgba(0, 204, 255, 0.3);
}

.comparison-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 1.5rem;
  margin: 3rem 0;
}

.rocket-type {
  padding: 1rem;
  background: rgba(20, 40, 80, 0.5);
  border-radius: 8px;
  border-left: 3px solid var(--primary);
}

.aerodynamics-diagram {
  width: 100%;
  height: 300px;
  background: rgba(0, 0, 0, 0.2);
  border-radius: 8px;
  margin: 2rem 0;
  position: relative;
  overflow: hidden;
}

.flow-arrow {
  position: absolute;
  width: 40px;
  height: 40px;
  color: var(--secondary);
  font-size: 24px;
  animation: flowAnimation 8s linear infinite;
}

.rocket-silhouette-container {
  position: fixed;
  bottom: 50px;
  right: 50px;
  width: 150px;
  height: 300px;
  z-index: 10;
}

.rocket-silhouette {
  width: 100%;
  height: auto;
  filter: drop-shadow(0 0 20px rgba(0, 200, 255, 0.7));
  animation: float 6s ease-in-out infinite;
}
.aero-rocket {
  position: absolute;
  left: 50%;
  top: 50%;
  transform: translate(-50%, -50%);
  max-height: 100%;
  max-width: 80px;
  z-index: 2;
}
.mission-timeline {
  display: flex;
  flex-direction: column;
  gap: 2rem;
  margin: 3rem 0;
  position: relative;
}
.timeline-item {
  background: rgba(10, 25, 47, 0.7);
  border-left: 4px solid var(--secondary);
  padding: 1.5rem;
  border-radius: 0 8px 8px 0;
  position: relative;
  z-index: 1;
}
.timeline-item h4 {
  color: var(--secondary);
  margin-bottom: 0.5rem;
}
.rocket-science-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 2rem;
  margin: 3rem 0;
}
.science-card {
  background: rgba(15, 30, 60, 0.6);
  border-radius: 12px;
  padding: 1.5rem;
  transition: transform 0.3s ease;
}
.science-card:hover {
  transform: translateY(-5px);
}
.science-card img {
  width: 100%;
  border-radius: 8px;
  margin-bottom: 1rem;
  height: 200px;
  object-fit: cover;
}
.launch-video-container {
  position: relative;
  padding-bottom: 56.25%;
  height: 0;
  overflow: hidden;
  margin: 2rem 0;
  border-radius: 12px;
}
.launch-video-container iframe {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  border: none;
}
.fuel-diagram {
  width: 100%;
  max-width: 600px;
  margin: 2rem auto;
  display: block;
}
.launch-sequence {
  background: rgba(15, 30, 60, 0.6);
  padding: 1.5rem;
  border-radius: 12px;
  counter-reset: launch-step;
}
.launch-sequence li {
  margin-bottom: 1rem;
  position: relative;
  padding-left: 2.5rem;
}
.launch-sequence li::before {
  counter-increment: launch-step;
  content: counter(launch-step);
  position: absolute;
  left: 0;
  top: 0;
  background: var(--secondary);
  color: white;
  width: 1.8rem;
  height: 1.8rem;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: bold;
}
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes moveStars {
  from { background-position: 0 0; }
  to { background-position: 10000px 5000px; }
}
@keyframes twinkle {
  from { opacity: 0.3; }
  to { opacity: 1; }
}
@keyframes shoot {
  0% { transform: translateX(0) translateY(0) rotate(45deg); opacity: 0; }
  10% { opacity: 1; }
  100% { transform: translateX(600px) translateY(600px) rotate(45deg); opacity: 0; }
}
@keyframes rotateGalaxy {
  from { transform: translate(-50%, -50%) rotate(0deg); }
  to { transform: translate(-50%, -50%) rotate(360deg); }
}
@keyframes floatPlanet {
  0% { transform: translateY(0px) rotate(0deg); }
  50% { transform: translateY(-20px) rotate(180deg); }
  100% { transform: translateY(0px) rotate(360deg); }
}
@keyframes float {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-20px); }
}
@keyframes flowAnimation {
  0% { transform: translateX(-50px) translateY(50px) rotate(0deg); opacity: 0; }
  10% { opacity: 1; }
  90% { opacity: 1; }
  100% { transform: translateX(calc(100vw - 100px)) translateY(150px) rotate(180deg); opacity: 0; }
}