/* Space Safari - Simplified Stylesheet */

:root {
  --bg: #0a0e1a;
  --surface: #1a1f35;
  --accent: #4a9eff;
  --text: #e8eaf6;
  --text-muted: #8a92a6;
  --border: #2a3045;
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  min-height: 100vh;
}

.container {
  max-width: 900px;
  margin: 0 auto;
  padding: 2rem 1.5rem;
}

/* Navigation Bar */
.navbar {
  position: sticky;
  top: 0;
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  padding: 1rem 1.5rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  z-index: 99;
}

.navbar .logo {
  font-size: 1.3rem;
  color: var(--accent);
  font-weight: 600;
  text-decoration: none;
}

.navbar .logo:hover {
  text-decoration: none;
}

.menu-toggle {
  display: none;
  background: none;
  border: none;
  color: var(--accent);
  font-size: 1.5rem;
  cursor: pointer;
  padding: 0;
  line-height: 1;
}

/* Side Menu */
.side-menu {
  position: fixed;
  left: 0;
  top: 0;
  width: 300px;
  height: 100vh;
  background: var(--surface);
  border-right: 1px solid var(--border);
  padding: 1.5rem;
  padding-top: 3.5rem;
  overflow-y: auto;
  z-index: 100;
  transform: translateX(-100%);
  transition: transform 0.3s ease;
}

.side-menu.active {
  transform: translateX(0);
}

.side-menu h3 {
  margin-bottom: 1.5rem;
  color: var(--accent);
  font-size: 1.1rem;
}

.menu-close {
  position: absolute;
  top: 1rem;
  right: 1rem;
  background: none;
  border: none;
  color: var(--text);
  font-size: 1.5rem;
  cursor: pointer;
  text-decoration: none;
  display: block;
}

/* Overlay when menu is open */
body.menu-open::before {
  content: "";
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0, 0, 0, 0.5);
  z-index: 97;
}

/* Desktop: Show menu inline in sidebar */
@media (min-width: 1024px) {
  body {
    display: flex;
  }

  .navbar {
    display: none;
  }

  .menu-toggle {
    display: none !important;
  }

  .side-menu {
    position: relative;
    width: 280px;
    height: auto;
    min-height: 100vh;
    border-right: 1px solid var(--border);
    transform: translateX(0);
    padding: 2rem 1.5rem;
    padding-top: 2rem;
    flex-shrink: 0;
  }

  .side-menu.active {
    transform: translateX(0);
  }

  .menu-close {
    display: none;
  }

  .container {
    flex: 1;
  }
}

/* Mobile: Show hamburger menu */
@media (max-width: 1023px) {
  .navbar {
    display: flex;
  }

  .menu-toggle {
    display: block;
  }

  .side-menu {
    width: 280px;
  }
}

/* Typography */
h1 {
  font-size: 2.5rem;
  margin-bottom: 0.5rem;
  color: var(--accent);
}

h2 {
  font-size: 1.8rem;
  margin: 2rem 0 1rem;
  color: var(--text);
}

h3 {
  font-size: 1.3rem;
  margin: 1.5rem 0 0.75rem;
}

p {
  margin-bottom: 1rem;
}

a {
  color: var(--accent);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

/* Header */
header {
  text-align: center;
  padding: 2rem 0;
  border-bottom: 1px solid var(--border);
  margin-bottom: 2rem;
}

.subtitle {
  font-size: 1.1rem;
  color: var(--text-muted);
}

/* Main content */
.intro {
  background: var(--surface);
  padding: 1.5rem;
  border-radius: 8px;
  margin-bottom: 2rem;
  border-left: 3px solid var(--accent);
}

/* Chapter Menu */
.chapter-menu {
  display: grid;
  gap: 0.3rem;
}

.chapter-link {
  display: flex;
  align-items: center;
  gap: 0.8rem;
  padding: 0.65rem 1rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 4px;
  transition: all 0.2s;
  text-decoration: none;
  color: var(--text);
  font-size: 0.95rem;
  min-height: 44px;
}

.chapter-link:hover {
  background: #252a40;
  border-color: var(--accent);
  text-decoration: none;
  transform: translateX(3px);
}

.chapter-number {
  font-size: 0.9rem;
  font-weight: bold;
  color: var(--accent);
  min-width: 2rem;
  flex-shrink: 0;
}

.chapter-title {
  color: var(--text);
  font-weight: 500;
}

/* Footer */
footer {
  margin-top: 3rem;
  padding: 2rem 0;
  border-top: 1px solid var(--border);
  text-align: center;
  font-size: 0.9rem;
  color: var(--text-muted);
}

footer a {
  color: var(--accent);
  margin: 0 0.5rem;
}

/* Chapter Page Styles */
.chapter-page {
  max-width: 800px;
  margin: 0 auto;
  padding: 2rem 1.5rem;
}

.chapter-header {
  margin-bottom: 2rem;
  padding-bottom: 1.5rem;
  border-bottom: 2px solid var(--border);
}

.chapter-page h1 {
  margin-bottom: 1rem;
}

.chapter-meta {
  display: flex;
  gap: 1.5rem;
  flex-wrap: wrap;
  color: var(--text-muted);
  font-size: 0.9rem;
}

.content-section {
  background: var(--surface);
  padding: 1.5rem;
  border-radius: 8px;
  border-left: 3px solid var(--accent);
  margin: 2rem 0;
}

.content-section h3 {
  margin-top: 0;
  color: var(--accent);
}

.key-topics {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-top: 1rem;
}

.key-topics span {
  padding: 0.4rem 0.8rem;
  background: rgba(74, 158, 255, 0.15);
  border: 1px solid var(--accent);
  border-radius: 15px;
  font-size: 0.85rem;
  color: var(--accent);
}

/* Videos Section */
.video-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 1.5rem;
  margin-top: 1rem;
}

.video-card {
  background: var(--surface);
  padding: 1.5rem;
  border-radius: 8px;
  border: 1px solid var(--border);
  text-align: center;
}

.video-card h4 {
  margin: 1rem 0 0.5rem;
  font-size: 1rem;
}

/* Resources */
.resource-list {
  display: grid;
  gap: 1rem;
  margin-top: 1rem;
}

.resource-item {
  padding: 1rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 6px;
}

.resource-item h4 {
  margin-bottom: 0.5rem;
  color: var(--accent);
}

.resource-item p {
  font-size: 0.9rem;
  color: var(--text-muted);
  margin-bottom: 0.5rem;
}

/* Chapter Navigation */
.chapter-nav {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  margin-top: 3rem;
  padding-top: 2rem;
  border-top: 1px solid var(--border);
}

.nav-button {
  flex: 1;
  padding: 1rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 6px;
  text-decoration: none;
  color: var(--text);
  transition: all 0.2s;
}

.nav-button:hover {
  background: #252a40;
  border-color: var(--accent);
  text-decoration: none;
}

.nav-label {
  font-size: 0.85rem;
  color: var(--text-muted);
}

.nav-title {
  font-weight: 600;
  margin-top: 0.5rem;
}

/* Mobile Responsive */
@media (max-width: 768px) {
  h1 {
    font-size: 2rem;
  }

  h2 {
    font-size: 1.5rem;
  }

  .chapter-link {
    flex-direction: column;
    align-items: flex-start;
  }

  .chapter-number {
    min-width: auto;
  }

  .chapter-nav {
    flex-direction: column;
  }

  .video-grid {
    grid-template-columns: 1fr;
  }
}