@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&display=swap');

:root {
  --bg-color: #0f172a;
  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  --accent-glow: rgba(99, 102, 241, 0.5);
  --card-bg: rgba(30, 41, 59, 0.7);
  --card-border: rgba(255, 255, 255, 0.08);
  --link-color: #60a5fa;
  --link-hover: #93c5fd;
}

* {
  box-sizing: border-box;
}

body {
  font-family: 'Inter', system-ui, -apple-system, sans-serif;
  line-height: 1.7;
  color: var(--text-primary);
  margin: 0;
  padding: 0;
  background-color: var(--bg-color);
  background-image: 
    radial-gradient(at 0% 0%, rgba(99, 102, 241, 0.15) 0px, transparent 50%),
    radial-gradient(at 100% 100%, rgba(168, 85, 247, 0.15) 0px, transparent 50%);
  background-attachment: fixed;
  min-height: 100vh;
}

/* Container & Glassmorphism */
.container {
  max-width: 900px;
  margin: 4rem auto;
  background: var(--card-bg);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  padding: 3rem;
  border-radius: 16px;
  border: 1px solid var(--card-border);
  box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}

/* Typography */
h1, h2, h3, h4 {
  color: #fff;
  font-weight: 600;
  line-height: 1.3;
  margin-top: 2rem;
  margin-bottom: 1rem;
}

h1 {
  font-size: 2.5rem;
  font-weight: 700;
  letter-spacing: -0.025em;
  background: linear-gradient(to right, #60a5fa, #a855f7);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

h2 {
  font-size: 1.8rem;
  border-bottom: 1px solid var(--card-border);
  padding-bottom: 0.5rem;
}

p {
  margin-bottom: 1.5rem;
  color: var(--text-secondary);
}

a {
  color: var(--link-color);
  text-decoration: none;
  transition: color 0.2s ease, text-shadow 0.2s ease;
}

a:hover {
  color: var(--link-hover);
  text-shadow: 0 0 8px var(--accent-glow);
}

/* Lists */
ul, ol {
  margin-bottom: 1.5rem;
  color: var(--text-secondary);
  padding-left: 1.5rem;
}

li {
  margin-bottom: 0.5rem;
}

/* Inline Code */
code:not([class*="language-"]) {
  background: rgba(0,0,0,0.3);
  color: #e2e8f0;
  padding: 0.2rem 0.4rem;
  border-radius: 6px;
  font-family: 'Fira Code', 'Consolas', monospace;
  font-size: 0.9em;
  border: 1px solid var(--card-border);
}

/* Prism.js overrides */
pre[class*="language-"] {
  border-radius: 8px !important;
  margin: 1.5rem 0 !important;
  border: 1px solid var(--card-border) !important;
  box-shadow: 0 4px 6px rgba(0,0,0,0.3) !important;
}

/* Course Index Specifics */
.course-index {
  list-style: none;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 1rem;
}

.course-index li {
  margin: 0;
}

.course-index a {
  display: block;
  padding: 1.25rem;
  background: rgba(255, 255, 255, 0.03);
  border: 1px solid var(--card-border);
  border-radius: 12px;
  color: var(--text-primary);
  font-weight: 500;
  transition: all 0.2s ease;
}

.course-index a:hover {
  background: rgba(255, 255, 255, 0.08);
  transform: translateY(-2px);
  box-shadow: 0 8px 20px rgba(0,0,0,0.2);
  color: #fff;
}

/* Back button in modules */
.back-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  margin-bottom: 2rem;
  padding: 0.5rem 1rem;
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--card-border);
  border-radius: 8px;
  font-size: 0.9rem;
  color: var(--text-secondary);
}
.back-btn:hover {
  background: rgba(255, 255, 255, 0.1);
  color: #fff;
  text-shadow: none;
}