:root {
  --bg: #0d1117;
  --bg-alt: #161b22;
  --text: #c9d1d9;
  --accent: #58a6ff;
  --muted: #8b949e;
  --border: #30363d;
}

body.light {
  --bg: #f5f5f5;
  --bg-alt: #ffffff;
  --text: #24292e;
  --accent: #0070f3;
  --muted: #57606a;
  --border: #d0d7de;
}

/* Global */
body {
  font-family: 'Atkinson Hyperlegible', 'Fira Code', monospace;
  background: radial-gradient(circle at bottom, var(--bg) 0%, #000 100%);
  color: var(--text);
  margin: 0;
  padding: 0;
  line-height: 1.7;
  overflow-x: hidden;
  scroll-behavior: smooth;
  transition: background 0.4s ease, color 0.4s ease;
}

/* Stars background */
.stars {
  position: fixed;
  width: 200%;
  height: 200%;
  top: -50%;
  left: -50%;
  background: url('https://www.transparenttextures.com/patterns/stardust.png') repeat;
  animation: drift 120s linear infinite;
  z-index: -1;
  opacity: 0.15;
}
@keyframes drift {
  from { transform: translate(0,0); }
  to { transform: translate(100px,100px); }
}

/* Header */
header {
  text-align: center;
  padding: 4rem 1rem;
  background: linear-gradient(90deg, #0b1a2a, var(--bg-alt), #0b1a2a);
  background-size: 200% 200%;
  animation: gradientShift 10s ease infinite;
  box-shadow: 0 0 20px rgba(88,166,255,0.2);
  position: relative;
  transition: background 0.4s ease;
}
@keyframes gradientShift {
  0% { background-position: 0% 50%; }
  50% { background-position: 100% 50%; }
  100% { background-position: 0% 50%; }
}
h1 {
  font-family: 'Fira Code', monospace;
  color: var(--accent);
  margin-bottom: 0.5rem;
  letter-spacing: 2px;
  font-size: 2.5rem;
}
header p {
  color: var(--muted);
  font-size: 1.1rem;
}

/* Theme toggle button */
#theme-toggle {
  position: absolute;
  top: 1rem;
  right: 1rem;
  background: var(--bg-alt);
  color: var(--accent);
  border: 1px solid var(--border);
  border-radius: 50%;
  width: 2.5rem;
  height: 2.5rem;
  cursor: pointer;
  font-size: 1.2rem;
  transition: all 0.3s ease;
}
#theme-toggle:hover {
  transform: scale(1.1);
  box-shadow: 0 0 10px var(--accent);
}

/* Cards */
.card {
  background: rgba(22, 27, 34, 0.75);
  border: 1px solid var(--border);
  border-radius: 10px;
  max-width: 800px;
  margin: 2rem auto;
  padding: 2rem;
  box-shadow: 0 0 15px rgba(88, 166, 255, 0.1);
  transition: transform 0.3s ease, box-shadow 0.3s ease, background 0.4s ease;
}
body.light .card {
  background: rgba(255,255,255,0.8);
}
.card:hover {
  transform: translateY(-4px);
  box-shadow: 0 0 25px rgba(88, 166, 255, 0.25);
}

/* Headings */
h2 {
  color: var(--accent);
  border-bottom: 1px solid var(--border);
  padding-bottom: 0.3rem;
  font-family: 'Fira Code', monospace;
}

/* Links */
a {
  color: var(--accent);
  text-decoration: none;
  transition: color 0.2s ease, text-shadow 0.2s ease;
  font-family: 'Fira Code', monospace;
}
a:hover {
  color: #9cc9ff;
  text-shadow: 0 0 8px var(--accent);
}
ul { list-style: none; padding: 0; }
li { margin: 0.6rem 0; }

/* Footer */
footer {
  text-align: center;
  padding: 2rem 0;
  border-top: 1px solid var(--border);
  font-size: 0.9rem;
  color: var(--muted);
}
.disabled {
  color: #666;
  cursor: default;
  text-decoration: none;
}