:root {
  --bg-color: #0d1117;
  --bg-card: #161b22;
  --text-primary: #e6edf3;
  --text-secondary: #8b949e;
  --accent-blue: #2f81f7;
  --accent-orange: #fd8c73;
  --border-color: #30363d;
}

* {
  box-sizing: border-box;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji";
  line-height: 1.6;
  color: var(--text-primary);
  background-color: var(--bg-color);
  margin: 0;
  padding: 0;
  font-size: 18px; /* readable with large text */
}

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

a:hover, a:focus {
  text-decoration: underline;
  color: var(--accent-orange);
  outline: 2px solid var(--accent-orange);
  outline-offset: 2px;
}

header {
  background-color: var(--bg-card);
  padding: 2rem 1rem;
  text-align: center;
  border-bottom: 1px solid var(--border-color);
}

.site-title {
  margin: 0;
  font-size: 2.5rem;
  font-weight: bold;
  background: linear-gradient(to right, var(--accent-blue), var(--accent-orange));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  display: inline-block;
}

nav {
  margin-top: 1rem;
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 1.5rem;
}

nav a {
  font-weight: 600;
  font-size: 1.1rem;
  padding: 0.5rem;
}

main {
  max-width: 800px;
  margin: 2rem auto;
  padding: 0 1rem;
}

.card {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 2rem;
  margin-bottom: 2rem;
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

h1, h2, h3, h4 {
  margin-top: 0;
  color: var(--text-primary);
}

h1 {
  font-size: 2.2rem;
  margin-bottom: 1rem;
  border-bottom: 2px solid var(--border-color);
  padding-bottom: 0.5rem;
}

h2 {
  font-size: 1.6rem;
  margin-top: 2rem;
  color: var(--accent-orange);
}

p, ul, ol {
  margin-bottom: 1.5rem;
}

ul {
  padding-left: 1.5rem;
}

li {
  margin-bottom: 0.5rem;
}

.placeholder {
  display: inline-block;
  background-color: #3b2c15;
  color: #ffa657;
  padding: 0.2rem 0.5rem;
  border-radius: 4px;
  border: 1px dashed var(--accent-orange);
  font-family: monospace;
  font-weight: bold;
}

footer {
  text-align: center;
  padding: 2rem 1rem;
  color: var(--text-secondary);
  border-top: 1px solid var(--border-color);
  margin-top: 4rem;
}

@media (max-width: 600px) {
  body {
    font-size: 16px;
  }

  .card {
    padding: 1.5rem;
  }

  h1 {
    font-size: 1.8rem;
  }

  h2 {
    font-size: 1.4rem;
  }

  nav {
    flex-direction: column;
    align-items: center;
    gap: 0.8rem;
  }
}