/* =============================
   CSS Variables — Dark (default)
   ============================= */
:root {
  --bg: #0d1117;
  --surface: #161b22;
  --surface-hover: #1c2128;
  --border: #30363d;
  --text: #c9d1d9;
  --text-muted: #8b949e;
  --accent: #39d353;
  --accent-dim: #2ea043;
  --accent-glow: rgba(57, 211, 83, 0.15);
  --code-bg: #010409;
  --shadow: rgba(0, 0, 0, 0.4);
  --tab-active-bg: #21262d;
  --transition: 0.25s ease;
}

[data-theme="light"] {
  --bg: #ffffff;
  --surface: #f6f8fa;
  --surface-hover: #eaeef2;
  --border: #d0d7de;
  --text: #1f2328;
  --text-muted: #656d76;
  --accent: #1a7f37;
  --accent-dim: #116329;
  --accent-glow: rgba(26, 127, 55, 0.12);
  --code-bg: #f6f8fa;
  --shadow: rgba(0, 0, 0, 0.08);
  --tab-active-bg: #ffffff;
}

/* =============================
   Reset & Base
   ============================= */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; }

body {
  background: var(--bg);
  color: var(--text);
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  font-size: 16px;
  line-height: 1.6;
  transition: background var(--transition), color var(--transition);
  min-height: 100vh;
}

a { color: var(--accent); text-decoration: none; transition: opacity 0.2s; }
a:hover { opacity: 0.8; }

/* =============================
   Header / Nav
   ============================= */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--bg);
  border-bottom: 1px solid var(--border);
  padding: 0 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 60px;
  backdrop-filter: blur(8px);
  transition: background var(--transition), border-color var(--transition);
}

.site-header .logo {
  font-family: "Courier New", Courier, monospace;
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--accent);
  letter-spacing: 0.05em;
}

.logo .prompt { color: var(--text-muted); margin-right: 4px; }

.header-controls {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.btn-icon {
  background: var(--surface);
  border: 1px solid var(--border);
  color: var(--text);
  border-radius: 6px;
  padding: 0.3rem 0.7rem;
  font-size: 0.85rem;
  cursor: pointer;
  transition: background var(--transition), border-color var(--transition);
  font-family: inherit;
}

.btn-icon:hover { background: var(--surface-hover); }

/* =============================
   Hero
   ============================= */
.hero {
  padding: 6rem 1.5rem 5rem;
  text-align: center;
  max-width: 860px;
  margin: 0 auto;
}

.hero-badge {
  display: inline-block;
  font-family: "Courier New", Courier, monospace;
  font-size: 0.78rem;
  color: var(--accent);
  background: var(--accent-glow);
  border: 1px solid var(--accent-dim);
  border-radius: 20px;
  padding: 0.25rem 0.9rem;
  margin-bottom: 1.5rem;
  letter-spacing: 0.04em;
}

.hero h1 {
  font-size: clamp(2rem, 5vw, 3.4rem);
  font-weight: 800;
  line-height: 1.15;
  letter-spacing: -0.02em;
  margin-bottom: 1.2rem;
}

.hero h1 .accent { color: var(--accent); }

.hero-subtitle {
  font-size: 1.1rem;
  color: var(--text-muted);
  max-width: 600px;
  margin: 0 auto 2.5rem;
}

.hero-ctas {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
}

.btn-primary {
  background: var(--accent);
  color: #0d1117;
  font-weight: 700;
  border: none;
  border-radius: 8px;
  padding: 0.7rem 1.4rem;
  font-size: 0.95rem;
  cursor: pointer;
  transition: opacity 0.2s, transform 0.15s;
  font-family: inherit;
}

.btn-primary:hover { opacity: 0.9; transform: translateY(-1px); }

.btn-secondary {
  background: transparent;
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.7rem 1.4rem;
  font-size: 0.95rem;
  cursor: pointer;
  transition: background var(--transition), border-color var(--transition), transform 0.15s;
  font-family: inherit;
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.btn-secondary:hover { background: var(--surface); transform: translateY(-1px); }

.hero-install {
  margin-top: 2.5rem;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
}

.install-snippet {
  background: var(--code-bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.6rem 1.2rem;
  font-family: "Courier New", Courier, monospace;
  font-size: 0.9rem;
  color: var(--accent);
  display: flex;
  align-items: center;
  gap: 0.8rem;
}

.install-snippet .prompt-char { color: var(--text-muted); }

.copy-btn {
  background: none;
  border: none;
  cursor: pointer;
  color: var(--text-muted);
  font-size: 1rem;
  padding: 0;
  transition: color 0.2s;
  display: flex;
  align-items: center;
}

.copy-btn:hover { color: var(--accent); }
.copy-btn.copied { color: var(--accent); }

/* cursor blink */
.cursor {
  display: inline-block;
  width: 10px;
  height: 1em;
  background: var(--accent);
  margin-left: 2px;
  vertical-align: text-bottom;
  animation: blink 1s step-end infinite;
}

@keyframes blink {
  0%, 100% { opacity: 1; }
  50% { opacity: 0; }
}

/* =============================
   Sections
   ============================= */
section { padding: 5rem 1.5rem; }
section:nth-child(even) { background: var(--surface); transition: background var(--transition); }

.section-inner {
  max-width: 1100px;
  margin: 0 auto;
}

.section-title {
  font-size: clamp(1.6rem, 3vw, 2.2rem);
  font-weight: 700;
  margin-bottom: 0.6rem;
  letter-spacing: -0.01em;
}

.section-subtitle {
  color: var(--text-muted);
  font-size: 1rem;
  margin-bottom: 3rem;
}

/* =============================
   Features Grid
   ============================= */
.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 1.2rem;
}

.feature-card {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1.5rem;
  transition: background var(--transition), border-color var(--transition), transform 0.2s, box-shadow 0.2s;
}

.feature-card:hover {
  border-color: var(--accent-dim);
  box-shadow: 0 0 0 1px var(--accent-dim), 0 4px 20px var(--shadow);
  transform: translateY(-2px);
}

[data-theme="light"] .feature-card { background: var(--surface); }

.feature-icon {
  font-size: 1.8rem;
  margin-bottom: 0.8rem;
  display: block;
}

.feature-title {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 0.4rem;
  color: var(--text);
}

.feature-desc {
  font-size: 0.9rem;
  color: var(--text-muted);
  line-height: 1.5;
}

/* =============================
   How it works
   ============================= */
.steps {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 2rem;
  position: relative;
}

.step {
  text-align: center;
  padding: 1.5rem;
}

.step-number {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  border: 2px solid var(--accent);
  border-radius: 50%;
  color: var(--accent);
  font-weight: 700;
  font-size: 1.1rem;
  margin-bottom: 1rem;
}

.step-title {
  font-weight: 700;
  margin-bottom: 0.5rem;
  font-size: 1rem;
}

.step-desc { font-size: 0.9rem; color: var(--text-muted); }

.step-code {
  display: inline-block;
  font-family: "Courier New", Courier, monospace;
  font-size: 0.85rem;
  background: var(--code-bg);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 0.3rem 0.7rem;
  color: var(--accent);
  margin-top: 0.6rem;
}

/* =============================
   Installation Tabs
   ============================= */
.tabs {
  display: flex;
  gap: 0;
  border-bottom: 1px solid var(--border);
  margin-bottom: 1.5rem;
  flex-wrap: wrap;
}

.tab-btn {
  background: none;
  border: none;
  border-bottom: 2px solid transparent;
  padding: 0.6rem 1.2rem;
  font-size: 0.9rem;
  color: var(--text-muted);
  cursor: pointer;
  transition: color 0.2s, border-color 0.2s;
  font-family: inherit;
  margin-bottom: -1px;
}

.tab-btn:hover { color: var(--text); }
.tab-btn.active { color: var(--accent); border-bottom-color: var(--accent); }

.tab-panel { display: none; }
.tab-panel.active { display: block; }

.code-block {
  background: var(--code-bg);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 1.2rem 1.5rem;
  position: relative;
  transition: background var(--transition), border-color var(--transition);
}

.code-block pre {
  font-family: "Courier New", Courier, monospace;
  font-size: 0.88rem;
  color: var(--text);
  white-space: pre-wrap;
  line-height: 1.7;
}

.code-block .comment { color: var(--text-muted); }
.code-block .cmd { color: var(--accent); }

.code-copy-btn {
  position: absolute;
  top: 0.8rem;
  right: 0.8rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 0.3rem 0.6rem;
  font-size: 0.75rem;
  color: var(--text-muted);
  cursor: pointer;
  transition: background var(--transition), color 0.2s;
  font-family: inherit;
}

.code-copy-btn:hover { color: var(--accent); background: var(--surface-hover); }
.code-copy-btn.copied { color: var(--accent); }

/* =============================
   About Author
   ============================= */
.about-card {
  display: flex;
  gap: 2.5rem;
  align-items: flex-start;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 2.5rem;
  transition: background var(--transition), border-color var(--transition);
}

[data-theme="light"] .about-card { background: var(--bg); }

.about-avatar {
  width: 120px;
  height: 120px;
  border-radius: 50%;
  border: 3px solid var(--accent);
  flex-shrink: 0;
  object-fit: cover;
}

.about-info h3 {
  font-size: 1.4rem;
  font-weight: 700;
  margin-bottom: 0.3rem;
}

.about-role {
  color: var(--accent);
  font-size: 0.9rem;
  margin-bottom: 0.8rem;
  font-family: "Courier New", Courier, monospace;
}

.about-bio {
  color: var(--text-muted);
  font-size: 0.95rem;
  margin-bottom: 1.2rem;
  line-height: 1.6;
}

.social-links {
  display: flex;
  gap: 0.7rem;
  flex-wrap: wrap;
}

.social-link {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.4rem 0.9rem;
  font-size: 0.85rem;
  color: var(--text);
  transition: background var(--transition), border-color var(--transition), color 0.2s;
}

.social-link:hover { border-color: var(--accent); color: var(--accent); opacity: 1; }

[data-theme="light"] .social-link { background: var(--surface); }

/* =============================
   Footer
   ============================= */
footer {
  border-top: 1px solid var(--border);
  padding: 2rem 1.5rem;
  text-align: center;
  color: var(--text-muted);
  font-size: 0.85rem;
  transition: border-color var(--transition);
}

footer a { color: var(--text-muted); }
footer a:hover { color: var(--accent); opacity: 1; }

.footer-inner {
  max-width: 1100px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5rem;
}

.footer-links {
  display: flex;
  gap: 1.2rem;
  flex-wrap: wrap;
  justify-content: center;
}

/* =============================
   Responsive
   ============================= */
@media (max-width: 640px) {
  .about-card { flex-direction: column; align-items: center; text-align: center; }
  .social-links { justify-content: center; }
  .hero { padding: 4rem 1rem 3rem; }
  section { padding: 3.5rem 1rem; }
  .hero-ctas { flex-direction: column; align-items: center; }
}

/* =============================
   Demo Terminal
   ============================= */
.demo-terminal {
  border: 1px solid var(--border);
  border-radius: 10px;
  overflow: hidden;
  max-width: 700px;
  margin: 0 auto;
  box-shadow: 0 8px 32px var(--shadow);
}

.terminal-bar {
  background: #21262d;
  padding: 0.6rem 1rem;
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.terminal-dot {
  width: 12px;
  height: 12px;
  border-radius: 50%;
}
.terminal-dot.red    { background: #ff5f57; }
.terminal-dot.yellow { background: #febc2e; }
.terminal-dot.green  { background: #28c840; }

.terminal-title {
  font-size: 0.75rem;
  color: #8b949e;
  margin-left: auto;
  font-family: "Courier New", Courier, monospace;
}

.terminal-body {
  background: #010409;
  padding: 1.4rem 1.6rem;
}

.terminal-body pre {
  font-family: "Courier New", Courier, monospace;
  font-size: 0.88rem;
  line-height: 1.8;
  color: #c9d1d9;
  white-space: pre-wrap;
}

.terminal-body .t-prompt  { color: #39d353; }
.terminal-body .t-question { color: #79c0ff; }
.terminal-body .t-answer  { color: #c9d1d9; }
.terminal-body .t-success { color: #39d353; }
.terminal-body .t-muted   { color: #8b949e; }

/* =============================
   Scrollbar
   ============================= */
::-webkit-scrollbar { width: 8px; }
::-webkit-scrollbar-track { background: var(--bg); }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 4px; }
::-webkit-scrollbar-thumb:hover { background: var(--text-muted); }