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

:root {
  --bg: #0d1117;
  --surface: #161b22;
  --surface2: #21262d;
  --border: #30363d;
  --text: #e6edf3;
  --muted: #8b949e;
  --green: #3fb950;
  --cyan: #79c0ff;
  --yellow: #d29922;
  --orange: #f0883e;
  --red: #f85149;
  --purple: #bc8cff;
  --font-mono: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
}

html { scroll-behavior: smooth; }

body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-sans);
  font-size: 15px;
  line-height: 1.6;
  min-height: 100vh;
}

/* NAV */
nav {
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  padding: 0 2rem;
  display: flex;
  align-items: center;
  gap: 2rem;
  height: 56px;
  position: sticky;
  top: 0;
  z-index: 100;
}

.nav-brand {
  font-family: var(--font-mono);
  font-size: 1rem;
  color: var(--green);
  text-decoration: none;
  letter-spacing: -0.02em;
}

.nav-brand span { color: var(--muted); }

nav a {
  color: var(--muted);
  text-decoration: none;
  font-size: 0.875rem;
  padding: 0.25rem 0.5rem;
  border-radius: 6px;
  transition: color 0.15s, background 0.15s;
}

nav a:hover, nav a.active {
  color: var(--text);
  background: var(--surface2);
}

/* HERO */
.hero {
  padding: 4rem 2rem 2rem;
  max-width: 900px;
  margin: 0 auto;
}

.hero-label {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--green);
  letter-spacing: 0.1em;
  text-transform: uppercase;
  margin-bottom: 0.75rem;
}

.hero h1 {
  font-size: clamp(1.75rem, 4vw, 2.75rem);
  font-weight: 700;
  line-height: 1.2;
  margin-bottom: 1rem;
}

.hero p {
  color: var(--muted);
  font-size: 1.05rem;
  max-width: 580px;
}

/* CARDS GRID */
.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 1rem;
  padding: 2rem;
  max-width: 900px;
  margin: 0 auto;
}

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 1.5rem;
  text-decoration: none;
  color: inherit;
  transition: border-color 0.15s, transform 0.15s;
  display: block;
}

.card:hover {
  border-color: var(--cyan);
  transform: translateY(-2px);
}

.card-icon {
  font-size: 1.75rem;
  margin-bottom: 0.75rem;
}

.card h2 {
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: 0.4rem;
}

.card p {
  color: var(--muted);
  font-size: 0.875rem;
  line-height: 1.5;
}

.card .tag {
  display: inline-block;
  margin-top: 1rem;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--cyan);
  background: rgba(121,192,255,0.1);
  padding: 0.2rem 0.5rem;
  border-radius: 4px;
}

/* QUICK SECTION (homepage) */
.quick-section {
  max-width: 900px;
  margin: 0 auto;
  padding: 0 2rem 4rem;
}

.section-title {
  font-size: 0.7rem;
  font-family: var(--font-mono);
  color: var(--muted);
  letter-spacing: 0.12em;
  text-transform: uppercase;
  border-bottom: 1px solid var(--border);
  padding-bottom: 0.6rem;
  margin-bottom: 1.25rem;
  margin-top: 2.5rem;
}

/* CHEAT SHEET LAYOUT */
.sheet-wrap {
  max-width: 960px;
  margin: 0 auto;
  padding: 0 2rem 5rem;
}

.sheet-hero {
  padding: 3rem 2rem 1.5rem;
  max-width: 960px;
  margin: 0 auto;
}

.sheet-hero h1 {
  font-size: clamp(1.5rem, 3.5vw, 2.25rem);
  font-weight: 700;
  display: flex;
  align-items: center;
  gap: 0.6rem;
}

.sheet-hero p {
  color: var(--muted);
  margin-top: 0.5rem;
  font-size: 0.95rem;
}

.group {
  margin-top: 2.5rem;
}

.group-title {
  font-size: 0.7rem;
  font-family: var(--font-mono);
  color: var(--muted);
  letter-spacing: 0.12em;
  text-transform: uppercase;
  border-bottom: 1px solid var(--border);
  padding-bottom: 0.6rem;
  margin-bottom: 1rem;
}

/* COMMAND TABLE */
.cmds {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

.cmd {
  display: grid;
  grid-template-columns: minmax(260px, 1fr) 1fr;
  gap: 1rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.65rem 1rem;
  align-items: start;
  transition: border-color 0.15s;
}

.cmd:hover { border-color: var(--border); background: var(--surface2); }

.cmd code {
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: var(--cyan);
  word-break: break-all;
}

.cmd code .flag { color: var(--orange); }
.cmd code .arg  { color: var(--purple); }
.cmd code .op   { color: var(--yellow); }

.cmd-desc {
  color: var(--muted);
  font-size: 0.84rem;
  padding-top: 0.05rem;
}

/* TIP BOXES */
.tip {
  background: rgba(63,185,80,0.08);
  border: 1px solid rgba(63,185,80,0.25);
  border-radius: 8px;
  padding: 0.75rem 1rem;
  font-size: 0.84rem;
  color: var(--muted);
  margin-top: 1rem;
}

.tip strong { color: var(--green); }

/* BACK LINK */
.back {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  font-size: 0.82rem;
  color: var(--muted);
  text-decoration: none;
  margin-bottom: 1rem;
  transition: color 0.15s;
}

.back:hover { color: var(--cyan); }

/* FOOTER */
footer {
  border-top: 1px solid var(--border);
  padding: 1.5rem 2rem;
  text-align: center;
  font-size: 0.78rem;
  color: var(--muted);
  font-family: var(--font-mono);
}

/* RESPONSIVE */
@media (max-width: 640px) {
  .cmd {
    grid-template-columns: 1fr;
    gap: 0.25rem;
  }
  nav { gap: 1rem; padding: 0 1rem; }
  .hero, .sheet-hero { padding-left: 1rem; padding-right: 1rem; }
  .cards, .sheet-wrap, .quick-section { padding-left: 1rem; padding-right: 1rem; }
}