:root {
  --bg-dark: #0f0f0f;
  --bg-light: #f8f8f8;
  --text-dark: #eee;
  --text-light: #111;
  --accent: #66ffcc;
  --muted-dark: #888;
  --muted-light: #444;
}

[data-theme="dark"] {
  background-color: var(--bg-dark);
  color: var(--text-dark);
}

[data-theme="light"] {
  background-color: var(--bg-light);
  color: var(--text-light);
}

body {
  margin: 0;
  font-family: 'Segoe UI', sans-serif;
  transition: background 0.3s, color 0.3s;
}

header {
  padding: 2rem;
  text-align: center;
  background: rgba(255, 255, 255, 0.03);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

h1 {
  font-size: 2.5rem;
  margin: 0;
}

header p {
  font-size: 1.2rem;
  color: var(--muted-dark);
}

nav {
  margin-top: 1rem;
}

nav a {
  margin: 0 1rem;
  color: var(--accent);
  text-decoration: none;
  font-weight: bold;
}

nav a:hover,
nav a:focus {
  text-decoration: underline;
}

.theme-toggle {
  float: right;
  margin-top: -2rem;
  margin-right: 1rem;
}

.skip-link {
  position: absolute;
  left: -999px;
  top: auto;
  width: 1px;
  height: 1px;
  overflow: hidden;
}

.skip-link:focus {
  left: 1rem;
  top: 1rem;
  width: auto;
  height: auto;
  padding: 0.5rem 1rem;
  background: var(--accent);
  color: black;
  z-index: 1000;
}

.hero {
  background: url('https://images.unsplash.com/photo-1581090700227-1e8a4f7a99e4?auto=format&fit=crop&w=1600&q=80') no-repeat center center;
  background-size: cover;
  padding: 6rem 2rem;
  text-align: center;
  color: #fff;
}

.hero h2 {
  font-size: 2.5rem;
  margin-bottom: 1rem;
}

.cta-btn {
  background: var(--accent);
  color: black;
  padding: 0.8rem 1.6rem;
  border: none;
  font-size: 1rem;
  border-radius: 6px;
  cursor: pointer;
  margin-top: 1rem;
}

.features {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 2rem;
  padding: 4rem 2rem;
  max-width: 1100px;
  margin: auto;
}

.feature-card {
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid rgba(255, 255, 255, 0.08);
  padding: 1.5rem;
  border-radius: 12px;
}

.feature-card h3 {
  color: var(--accent);
}

pre {
  background: #111;
  padding: 1rem;
  border-radius: 8px;
  overflow-x: auto;
  color: var(--accent);
  font-size: 0.9rem;
  margin: 2rem;
}

main.content {
  padding: 2rem;
  max-width: 1100px;
  margin: auto;
}

main.content h2 {
  color: var(--accent);
}

a:focus {
  outline: 2px dashed var(--accent);
  outline-offset: 2px;
}

footer {
  text-align: center;
  padding: 2rem 1rem;
  font-size: 0.9rem;
  color: var(--muted-dark);
  border-top: 1px solid rgba(255, 255, 255, 0.08);
}

footer a {
  color: var(--muted-dark);
  text-decoration: none;
  margin: 0 1rem;
}

footer a:hover,
footer a:focus {
  color: var(--accent);
}