/* ===== Vercel-style Design System ===== */
:root {
  --bg: #000;
  --bg-secondary: #0a0a0a;
  --bg-card: #111;
  --bg-code: #0a0a0a;
  --bg-hover: #1a1a1a;
  --text: #ededed;
  --text-secondary: #888;
  --text-muted: #666;
  --accent: #0070f3;
  --accent-hover: #0060df;
  --accent-pink: #f81ce5;
  --accent-cyan: #50e3c2;
  --accent-orange: #f5a623;
  --accent-violet: #7928ca;
  --success: #0070f3;
  --border: #222;
  --border-light: #333;
  --radius: 8px;
  --radius-lg: 12px;
  --font: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', 'Consolas', monospace;
  --max-width: 1100px;
  --transition: 150ms ease;
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

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

a:hover {
  color: var(--text);
}

/* ===== Layout ===== */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

section {
  padding: 96px 0;
  border-bottom: 1px solid var(--border);
}

/* ===== Navbar ===== */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background: rgba(0, 0, 0, 0.8);
  backdrop-filter: saturate(180%) blur(20px);
  border-bottom: 1px solid var(--border);
}

.navbar .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 600;
  font-size: 0.95rem;
  color: var(--text);
  letter-spacing: -0.01em;
}

.nav-logo-icon {
  width: 28px;
  height: 28px;
  background: var(--text);
  color: var(--bg);
  border-radius: 6px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 14px;
  font-weight: 800;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 32px;
  list-style: none;
}

.nav-links a {
  color: var(--text-secondary);
  font-size: 0.875rem;
  font-weight: 400;
  transition: color var(--transition);
}

.nav-links a:hover {
  color: var(--text);
}

.nav-right {
  display: flex;
  align-items: center;
  gap: 12px;
}

.lang-toggle {
  display: flex;
  background: transparent;
  border: 1px solid var(--border);
  border-radius: 6px;
  overflow: hidden;
}

.lang-toggle button {
  padding: 5px 12px;
  border: none;
  background: transparent;
  color: var(--text-muted);
  cursor: pointer;
  font-weight: 500;
  font-size: 0.8rem;
  font-family: var(--font);
  transition: all var(--transition);
}

.lang-toggle button.active {
  background: var(--text);
  color: var(--bg);
}

.lang-toggle button:hover:not(.active) {
  color: var(--text);
}

.nav-burger {
  display: none;
  flex-direction: column;
  gap: 4px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
}

.nav-burger span {
  width: 18px;
  height: 1.5px;
  background: var(--text-secondary);
  border-radius: 1px;
  transition: all var(--transition);
}

/* ===== Hero ===== */
.hero {
  padding: 160px 0 100px;
  text-align: center;
  position: relative;
  border-bottom: 1px solid var(--border);
}

.hero::before {
  content: '';
  position: absolute;
  top: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 800px;
  height: 600px;
  background: radial-gradient(ellipse at center, rgba(0, 112, 243, 0.08) 0%, transparent 70%);
  pointer-events: none;
}

.hero-content {
  position: relative;
  z-index: 1;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 5px 14px;
  background: transparent;
  border: 1px solid var(--border-light);
  border-radius: 100px;
  font-size: 0.8rem;
  color: var(--text-secondary);
  margin-bottom: 28px;
  font-weight: 500;
}

.hero h1 {
  font-size: clamp(2.5rem, 6vw, 4rem);
  font-weight: 700;
  line-height: 1.1;
  margin-bottom: 24px;
  letter-spacing: -0.04em;
  color: var(--text);
}

.hero h1 .gradient-text {
  background: linear-gradient(180deg, #fff 0%, rgba(255,255,255,0.7) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-subtitle {
  font-size: 1.125rem;
  color: var(--text-secondary);
  max-width: 560px;
  margin: 0 auto 40px;
  line-height: 1.6;
  font-weight: 400;
}

.hero-endpoint {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  padding: 10px 16px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  font-family: var(--font-mono);
  font-size: 0.875rem;
  color: var(--text);
  margin-bottom: 40px;
}

.hero-endpoint .copy-btn {
  padding: 3px 8px;
  font-size: 0.75rem;
}

.hero-actions {
  display: flex;
  gap: 12px;
  justify-content: center;
  flex-wrap: wrap;
}

/* ===== Buttons ===== */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 10px 20px;
  border-radius: var(--radius);
  font-weight: 500;
  font-size: 0.875rem;
  font-family: var(--font);
  cursor: pointer;
  transition: all var(--transition);
  border: none;
  text-decoration: none;
}

.btn-primary {
  background: var(--text);
  color: var(--bg);
}

.btn-primary:hover {
  background: #ccc;
  color: var(--bg);
}

.btn-secondary {
  background: transparent;
  color: var(--text);
  border: 1px solid var(--border-light);
}

.btn-secondary:hover {
  border-color: var(--text-secondary);
  background: var(--bg-hover);
  color: var(--text);
}

/* ===== Section Headers ===== */
.section-header {
  text-align: center;
  margin-bottom: 64px;
}

.section-tag {
  display: inline-block;
  font-size: 0.8rem;
  font-weight: 500;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  margin-bottom: 16px;
}

.section-header h2 {
  font-size: clamp(1.75rem, 3vw, 2.5rem);
  font-weight: 700;
  margin-bottom: 16px;
  letter-spacing: -0.03em;
}

.section-header p {
  color: var(--text-secondary);
  font-size: 1rem;
  max-width: 560px;
  margin: 0 auto;
}

/* ===== Script Callout ===== */
.script-callout {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 32px;
  align-items: center;
  background:
    radial-gradient(circle at 85% 20%, rgba(0, 112, 243, 0.16), transparent 28%),
    radial-gradient(circle at 10% 10%, rgba(80, 227, 194, 0.08), transparent 24%),
    var(--bg-card);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-lg);
  padding: 32px;
  margin: 0 auto 36px;
  max-width: 900px;
}

.script-badge {
  display: inline-flex;
  align-items: center;
  width: fit-content;
  padding: 4px 10px;
  border: 1px solid rgba(0, 112, 243, 0.35);
  border-radius: 999px;
  color: var(--accent);
  background: rgba(0, 112, 243, 0.08);
  font-size: 0.72rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: 14px;
}

.script-callout h3 {
  font-size: 1.25rem;
  font-weight: 650;
  letter-spacing: -0.02em;
  margin-bottom: 8px;
}

.script-callout p {
  color: var(--text-secondary);
  font-size: 0.9rem;
  max-width: 620px;
}

.script-callout-actions {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  justify-content: flex-end;
}

.manual-separator {
  display: flex;
  align-items: center;
  gap: 16px;
  color: var(--text-muted);
  font-size: 0.85rem;
  margin: 0 auto 20px;
  max-width: 900px;
}

.manual-separator::before,
.manual-separator::after {
  content: '';
  height: 1px;
  background: var(--border);
  flex: 1;
}

/* ===== Steps ===== */
.steps-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1px;
  background: var(--border);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
}

.step-card {
  background: var(--bg);
  padding: 40px 32px;
  text-align: left;
  transition: background var(--transition);
}

.step-card:hover {
  background: var(--bg-card);
}

.step-number {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  border: 1px solid var(--border-light);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 20px;
  font-weight: 600;
  font-size: 0.85rem;
  color: var(--text-secondary);
}

.step-card h3 {
  font-size: 1rem;
  margin-bottom: 8px;
  font-weight: 600;
  letter-spacing: -0.01em;
}

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

/* ===== Service Cards ===== */
.services-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1px;
  background: var(--border);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
}

.service-card {
  background: var(--bg);
  padding: 28px 24px;
  cursor: pointer;
  transition: all var(--transition);
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.service-card:hover {
  background: var(--bg-card);
}

.service-card.active {
  background: var(--bg-card);
}

.service-card.active::after {
  content: '';
  display: block;
  height: 0;
}

.service-icon {
  width: 40px;
  height: 40px;
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  border: 1px solid var(--border);
}

.service-icon img {
  width: 100%;
  height: 100%;
  display: block;
}

.service-icon.codex,
.service-icon.claude,
.service-icon.opencode,
.service-icon.vscode {
  background: var(--bg-card);
}

.service-card h3 {
  font-size: 0.95rem;
  font-weight: 600;
  letter-spacing: -0.01em;
}

.service-card p {
  color: var(--text-secondary);
  font-size: 0.8rem;
  line-height: 1.5;
}

/* ===== Instruction Panels ===== */
.instruction-panel {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 48px;
  margin-top: 24px;
  display: none;
}

.instruction-panel.active {
  display: block;
  animation: fadeIn 0.25s ease;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(4px); }
  to { opacity: 1; transform: translateY(0); }
}

.instruction-panel h3 {
  font-size: 1.25rem;
  font-weight: 600;
  margin-bottom: 32px;
  letter-spacing: -0.02em;
  display: flex;
  align-items: center;
  gap: 10px;
  padding-bottom: 20px;
  border-bottom: 1px solid var(--border);
}

.instruction-step {
  margin-bottom: 32px;
}

.instruction-step h4 {
  font-size: 0.9rem;
  font-weight: 600;
  margin-bottom: 12px;
  color: var(--text);
}

.instruction-step p {
  color: var(--text-secondary);
  font-size: 0.875rem;
  margin-bottom: 12px;
}

.instruction-step ul {
  list-style: none;
  padding: 0;
}

.instruction-step li {
  color: var(--text-secondary);
  font-size: 0.875rem;
  padding: 6px 0;
  padding-left: 16px;
  position: relative;
}

.instruction-step li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 14px;
  width: 4px;
  height: 4px;
  border-radius: 50%;
  background: var(--text-muted);
}

/* ===== Code Blocks ===== */
.code-block {
  position: relative;
  background: var(--bg-code);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin: 12px 0;
  overflow: hidden;
}

.code-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 16px;
  border-bottom: 1px solid var(--border);
  font-size: 0.75rem;
  color: var(--text-muted);
  font-family: var(--font-mono);
}

.code-block pre {
  padding: 16px;
  overflow-x: auto;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  line-height: 1.7;
  color: var(--text);
}

.code-block code {
  font-family: inherit;
}

.copy-btn {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 4px 10px;
  background: transparent;
  border: 1px solid var(--border);
  border-radius: 6px;
  color: var(--text-muted);
  font-size: 0.75rem;
  font-family: var(--font);
  cursor: pointer;
  transition: all var(--transition);
}

.copy-btn:hover {
  color: var(--text);
  border-color: var(--border-light);
}

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

.inline-code {
  display: inline;
  padding: 2px 6px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 4px;
  font-family: var(--font-mono);
  font-size: 0.85em;
  color: var(--text);
}

/* ===== Replace Info ===== */
.replace-info {
  background: rgba(0, 112, 243, 0.04);
  border: 1px solid rgba(0, 112, 243, 0.15);
  border-radius: var(--radius);
  padding: 20px;
  margin: 20px 0;
}

.replace-info h4 {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--accent);
  margin-bottom: 12px;
}

.replace-info ul {
  list-style: none;
  padding: 0;
}

.replace-info li {
  font-size: 0.85rem;
  color: var(--text-secondary);
  padding: 4px 0;
}

.replace-info li code {
  color: var(--text);
  font-family: var(--font-mono);
  font-size: 0.85em;
  background: var(--bg-card);
  border: 1px solid var(--border);
  padding: 1px 5px;
  border-radius: 3px;
}

/* ===== Sessions ===== */
.sessions-content {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 48px;
  align-items: start;
}

.sessions-info {
  display: flex;
  flex-direction: column;
  gap: 28px;
}

.session-point {
  display: flex;
  gap: 16px;
  align-items: flex-start;
}

.session-point-icon {
  width: 40px;
  height: 40px;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--bg-card);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  font-size: 18px;
}

.session-point h4 {
  font-size: 0.9rem;
  font-weight: 600;
  margin-bottom: 4px;
}

.session-point p {
  font-size: 0.85rem;
  color: var(--text-secondary);
  line-height: 1.5;
}

.sessions-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 32px;
}

.sessions-card h3 {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 20px;
  letter-spacing: -0.01em;
}

.sessions-card ol {
  list-style: none;
  counter-reset: step;
  padding: 0;
}

.sessions-card li {
  counter-increment: step;
  padding: 10px 0;
  padding-left: 36px;
  position: relative;
  color: var(--text-secondary);
  font-size: 0.875rem;
  border-bottom: 1px solid var(--border);
}

.sessions-card li:last-child {
  border-bottom: none;
}

.sessions-card li::before {
  content: counter(step);
  position: absolute;
  left: 0;
  top: 10px;
  width: 22px;
  height: 22px;
  border-radius: 50%;
  border: 1px solid var(--border-light);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.7rem;
  font-weight: 600;
  color: var(--text-secondary);
}

/* ===== FAQ ===== */
.faq-list {
  max-width: 720px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 0;
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
}

.faq-item {
  background: var(--bg);
  border-bottom: 1px solid var(--border);
  transition: background var(--transition);
}

.faq-item:last-child {
  border-bottom: none;
}

.faq-item:hover {
  background: var(--bg-card);
}

.faq-question {
  width: 100%;
  padding: 20px 24px;
  background: transparent;
  border: none;
  color: var(--text);
  font-family: var(--font);
  font-size: 0.9rem;
  font-weight: 500;
  text-align: left;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.faq-question::after {
  content: '+';
  font-size: 1.1rem;
  color: var(--text-muted);
  transition: all var(--transition);
  flex-shrink: 0;
  font-weight: 300;
}

.faq-item.open .faq-question::after {
  content: '−';
  color: var(--text);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease;
}

.faq-answer-inner {
  padding: 0 24px 20px;
  color: var(--text-secondary);
  font-size: 0.875rem;
  line-height: 1.7;
}

/* ===== Footer ===== */
.footer {
  border-top: none;
  padding: 48px 0;
}

.footer-content {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 20px;
}

.footer-links {
  display: flex;
  gap: 32px;
  flex-wrap: wrap;
  justify-content: center;
}

.footer-links a {
  color: var(--text-muted);
  font-size: 0.8rem;
  transition: color var(--transition);
}

.footer-links a:hover {
  color: var(--text);
}

.footer-copy {
  color: var(--text-muted);
  font-size: 0.75rem;
}

/* ===== Responsive ===== */
@media (max-width: 900px) {
  .script-callout {
    grid-template-columns: 1fr;
  }

  .script-callout-actions {
    justify-content: flex-start;
  }

  .steps-grid {
    grid-template-columns: 1fr;
  }

  .services-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .sessions-content {
    grid-template-columns: 1fr;
  }

  .instruction-panel {
    padding: 28px;
  }
}

@media (max-width: 640px) {
  section {
    padding: 64px 0;
  }

  .hero {
    padding: 130px 0 64px;
  }

  .nav-links {
    display: none;
    position: fixed;
    top: 64px;
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--bg);
    flex-direction: column;
    padding: 24px;
    gap: 16px;
    border-bottom: 1px solid var(--border);
  }

  .nav-links.open {
    display: flex;
  }

  .nav-burger {
    display: flex;
  }

  .services-grid {
    grid-template-columns: 1fr;
  }

  .hero-endpoint {
    font-size: 0.8rem;
    flex-wrap: wrap;
    justify-content: center;
  }

  .hero-actions {
    flex-direction: column;
    align-items: center;
  }

  .instruction-panel {
    padding: 20px;
  }
}

/* ===== Scrollbar ===== */
::-webkit-scrollbar {
  width: 6px;
  height: 6px;
}

::-webkit-scrollbar-track {
  background: var(--bg);
}

::-webkit-scrollbar-thumb {
  background: var(--border-light);
  border-radius: 3px;
}

::-webkit-scrollbar-thumb:hover {
  background: var(--text-muted);
}

::selection {
  background: rgba(0, 112, 243, 0.3);
  color: white;
}