:root {
  /* Surface & Canvas Palette */
  --bg-canvas: #F7F6F3;
  --bg-surface: #FFFFFF;
  --bg-surface-secondary: #F9F9F8;
  --bg-subtle: #F3F3F4;

  --border-color: #EAEAEA;
  --border-dark: #D4D4D4;

  /* Text Colors */
  --text-primary: #111111;
  --text-secondary: #787774;
  --text-muted: #9A9996;

  /* Semantic Pastels */
  --pale-blue-bg: #E1F3FE;
  --pale-blue-text: #1F6C9F;
  --pale-green-bg: #EDF3EC;
  --pale-green-text: #346538;
  --pale-red-bg: #FDEBEC;
  --pale-red-text: #9F2F2D;
  --pale-yellow-bg: #FBF3DB;
  --pale-yellow-text: #956400;

  /* Typographic Architecture */
  --font-sans: 'Geist Sans', 'Geist', -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Helvetica Neue', Arial, sans-serif;
  --font-serif: 'Newsreader', 'Georgia', serif;
  --font-mono: 'JetBrains Mono', 'ui-monospace', 'SFMono-Regular', monospace;

  /* Radii & Shadows */
  --radius-button: 6px;
  --radius-card: 10px;
  --radius-pill: 9999px;
  --shadow-hover: 0 4px 12px rgba(0, 0, 0, 0.04);

  --transition: all 0.2s cubic-bezier(0.16, 1, 0.3, 1);
}

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

html {
  scroll-behavior: smooth;
  color-scheme: light;
}

body {
  font-family: var(--font-sans);
  background-color: var(--bg-canvas);
  color: var(--text-primary);
  line-height: 1.625;
  font-size: 16px;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

/* Headings - Editorial Serif */
h1,
h2,
h3,
h4,
.hero-title,
.section-title,
.bento-title,
.brand,
.privacy-card h3,
.support-card h3,
.tutorial-card h3 {
  font-family: var(--font-serif);
  color: var(--text-primary);
  font-weight: 400;
  line-height: 1.15;
  letter-spacing: -0.02em;
}

h1,
.hero-title {
  font-size: 3.5rem;
  letter-spacing: -0.03em;
  line-height: 1.1;
}

h2,
.section-title {
  font-size: 2.25rem;
  letter-spacing: -0.02em;
  line-height: 1.15;
}

h3,
.bento-title,
.privacy-card h3,
.support-card h3,
.tutorial-card h3 {
  font-size: 1.35rem;
  letter-spacing: -0.02em;
  line-height: 1.2;
}

a {
  color: var(--text-primary);
  text-decoration: underline;
  text-underline-offset: 3px;
  text-decoration-color: var(--border-dark);
  transition: var(--transition);
}

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

.container {
  max-width: 1080px;
  margin: 0 auto;
  padding: 0 24px;
}

/* Monospace Elements */
.badge-pill,
.section-tag,
.download-meta,
.platform-toggle-btn,
.platform-group-title,
.platform-size,
.window-title,
.step-number,
kbd,
.footer {
  font-family: var(--font-mono);
}

.badge-pill {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 4px 12px;
  border-radius: var(--radius-pill);
  font-size: 0.75rem;
  font-weight: 500;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.badge-blue {
  background-color: var(--pale-blue-bg);
  color: var(--pale-blue-text);
}

.badge-green {
  background-color: var(--pale-green-bg);
  color: var(--pale-green-text);
}

kbd {
  font-size: 0.75rem;
  padding: 2px 6px;
  background: var(--bg-canvas);
  border: 1px solid var(--border-color);
  border-radius: 4px;
  color: var(--text-primary);
}

/* Navigation Bar */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background: rgba(247, 246, 243, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-color);
  padding: 14px 0;
}

.nav-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-serif);
  font-weight: 500;
  font-size: 1.35rem;
  letter-spacing: -0.02em;
  color: var(--text-primary);
  text-decoration: none;
}

.brand img {
  width: 28px;
  height: 28px;
  border-radius: 6px;
}

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

.nav-links a {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-secondary);
  text-decoration: none;
  transition: var(--transition);
}

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

.btn-nav-github {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 14px;
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-button);
  color: var(--text-primary);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  text-decoration: none;
  transition: var(--transition);
}

.btn-nav-github:hover {
  background: var(--bg-subtle);
  border-color: var(--border-dark);
}

/* Hero Section */
.hero {
  padding: 140px 0 70px;
  text-align: center;
}

.hero-badge-wrapper {
  margin-bottom: 24px;
}

.hero-title {
  max-width: 780px;
  margin: 0 auto 20px;
}

.hero-subtitle,
.section-subtitle,
.bento-desc,
.tutorial-desc,
.privacy-card p,
.support-card p,
.support-card ol,
.support-card ul {
  font-family: var(--font-sans);
  color: var(--text-secondary);
  line-height: 1.625;
}

.hero-subtitle {
  font-size: 1.1rem;
  max-width: 640px;
  margin: 0 auto 36px;
  font-weight: 400;
}

strong,
b,
.font-semibold {
  color: var(--text-primary);
  font-weight: 600;
}

/* Download CTA Block */
.download-wrapper {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 14px;
  margin-bottom: 50px;
}

.btn-primary-cta {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 14px 28px;
  background: #111111;
  border: none;
  border-radius: var(--radius-button);
  color: #FFFFFF;
  font-size: 0.95rem;
  font-weight: 500;
  font-family: var(--font-sans);
  cursor: pointer;
  text-decoration: none;
  transition: var(--transition);
}

.btn-primary-cta:hover {
  background: #2a2a2a;
  transform: scale(0.98);
  color: #FFFFFF;
}

.download-meta {
  font-size: 0.8rem;
  color: var(--text-muted);
  display: flex;
  align-items: center;
  gap: 8px;
}

.platform-selector {
  position: relative;
  display: inline-block;
}

.platform-toggle-btn {
  background: transparent;
  border: none;
  color: var(--text-secondary);
  font-size: 0.8rem;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 4px 8px;
  border-radius: 4px;
  transition: var(--transition);
}

.platform-toggle-btn:hover {
  color: var(--text-primary);
  background: rgba(0, 0, 0, 0.04);
}

/* Platform Dropdown Menu Formatting */
.platform-menu {
  display: none;
  position: absolute;
  top: 100%;
  left: 50%;
  transform: translateX(-50%);
  margin-top: 8px;
  width: 340px;
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-card);
  padding: 10px;
  z-index: 20;
  text-align: left;
  box-shadow: var(--shadow-hover);
}

.platform-menu.active {
  display: block;
}

.platform-group-title {
  font-size: 0.7rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-muted);
  padding: 6px 10px 4px;
}

.platform-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 8px 10px;
  color: var(--text-primary);
  font-family: var(--font-sans);
  font-size: 0.85rem;
  white-space: nowrap;
  border-radius: 4px;
  text-decoration: none;
  transition: var(--transition);
}

.platform-item:hover {
  background: var(--bg-canvas);
}

.platform-size {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-muted);
  white-space: nowrap;
}

/* Faux OS Window Chrome Showcase */
.demo-showcase {
  margin-top: 20px;
}

.faux-window {
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-card);
  overflow: hidden;
  transition: var(--transition);
}

.faux-window:hover {
  border-color: var(--border-dark);
  box-shadow: var(--shadow-hover);
}

.faux-window-header {
  height: 36px;
  background: var(--bg-subtle);
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  padding: 0 14px;
  gap: 8px;
}

.window-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: #DADADA;
}

.window-title {
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-left: auto;
  margin-right: auto;
}

.faux-window-body {
  display: block;
  text-decoration: none;
}

.faux-window-body img {
  width: 100%;
  height: auto;
  display: block;
}

.demo-caption {
  font-size: 0.82rem;
  color: var(--text-muted);
  margin-top: 12px;
  text-align: center;
  font-family: var(--font-sans);
}

.demo-caption a {
  color: var(--text-secondary);
  text-decoration: underline;
}

.demo-caption a:hover {
  color: var(--text-primary);
}

/* Bento Box Features Section */
.features-section {
  padding: 90px 0;
  border-top: 1px solid var(--border-color);
}

.section-header {
  margin-bottom: 50px;
}

.section-tag {
  font-size: 0.75rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: 10px;
}

.section-subtitle {
  font-size: 1.05rem;
  max-width: 600px;
}

/* True Asymmetrical 3-Column Bento Grid */
.bento-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}

.bento-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-card);
  padding: 28px;
  transition: var(--transition);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.bento-card:hover {
  box-shadow: var(--shadow-hover);
  border-color: var(--border-dark);
}

.bento-card-large {
  grid-column: span 2;
}

.bento-card-full {
  grid-column: span 3;
}

.bento-card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 16px;
}

.bento-desc {
  font-size: 0.95rem;
}

/* Inline Mark Examples */
.mark-error {
  font-family: var(--font-sans);
  background-color: var(--pale-red-bg);
  color: var(--pale-red-text);
  padding: 2px 6px;
  border-radius: 4px;
}

.mark-suggestion {
  font-family: var(--font-sans);
  background-color: var(--pale-green-bg);
  color: var(--pale-green-text);
  padding: 2px 6px;
  border-radius: 4px;
}

/* Dedicated Privacy & Data Security Section (#privacy) */
.privacy-full-section {
  padding: 90px 0;
  border-top: 1px solid var(--border-color);
  background: var(--bg-canvas);
}

.privacy-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
  margin-bottom: 40px;
}

.privacy-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-card);
  padding: 32px;
  transition: var(--transition);
}

.privacy-card:hover {
  border-color: var(--border-dark);
  box-shadow: var(--shadow-hover);
}

.privacy-card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 14px;
}

.privacy-card p {
  font-size: 0.95rem;
}

.privacy-comparison-table {
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-card);
  padding: 32px;
}

/* Semantic GEO Feature Matrix Table */
.geo-table-wrapper {
  overflow-x: auto;
  margin-top: 20px;
}

.geo-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  font-size: 0.92rem;
}

.geo-table th,
.geo-table td {
  padding: 14px 18px;
  border-bottom: 1px solid var(--border-color);
}

.geo-table th {
  font-family: var(--font-sans);
  font-weight: 600;
  color: var(--text-primary);
  background: var(--bg-subtle);
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.geo-table td:nth-child(1) {
  font-weight: 600;
  color: var(--text-primary);
  width: 25%;
}

.geo-table td:nth-child(2) {
  color: var(--pale-green-text);
  font-weight: 600;
  background: rgba(237, 243, 236, 0.4);
  width: 37.5%;
}

.geo-table td:nth-child(3) {
  color: var(--text-secondary);
  width: 37.5%;
}

.comparison-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
  margin-top: 20px;
}

.comparison-box {
  background: var(--bg-canvas);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-button);
  padding: 20px;
}

.comparison-box h4 {
  font-family: var(--font-sans);
  font-size: 0.95rem;
  font-weight: 600;
  margin-bottom: 12px;
}

.comparison-box ul {
  padding-left: 18px;
  font-size: 0.9rem;
  color: var(--text-secondary);
}

.comparison-box li {
  margin-bottom: 6px;
}

/* Interactive Tutorial & User Guide Section (#tutorial) */
.tutorial-section {
  padding: 90px 0;
  border-top: 1px solid var(--border-color);
  background: var(--bg-surface-secondary);
}

.tutorial-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}

.tutorial-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-card);
  padding: 32px;
  position: relative;
  transition: var(--transition);
}

.tutorial-card:hover {
  border-color: var(--border-dark);
  box-shadow: var(--shadow-hover);
}

.tutorial-card-header {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 16px;
}

.step-number {
  font-size: 0.8rem;
  font-weight: 500;
  color: var(--pale-blue-text);
  background: var(--pale-blue-bg);
  padding: 4px 10px;
  border-radius: var(--radius-pill);
  letter-spacing: 0.05em;
}

.tutorial-desc {
  font-size: 0.95rem;
}

.tutorial-desc ol,
.tutorial-desc ul {
  padding-left: 20px;
  margin-top: 10px;
}

.tutorial-desc li {
  margin-bottom: 8px;
}

/* FAQ Section (#faq) */
.faq-section {
  padding: 90px 0;
  border-top: 1px solid var(--border-color);
  background: var(--bg-canvas);
}

.faq-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}

.faq-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-card);
  padding: 28px;
  transition: var(--transition);
}

.faq-card:hover {
  border-color: var(--border-dark);
  box-shadow: var(--shadow-hover);
}

.faq-card h3 {
  font-family: var(--font-sans);
  font-size: 1.05rem;
  font-weight: 600;
  margin-bottom: 10px;
  line-height: 1.35;
}

.faq-card p {
  font-size: 0.92rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

/* Setup Steps Wrapper */
.setup-steps-wrapper {
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-card);
  padding: 32px;
}

.setup-steps-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  margin-top: 24px;
}

.setup-step-box {
  background: var(--bg-canvas);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-button);
  padding: 24px;
}

.setup-step-box h4 {
  font-family: var(--font-sans);
  font-weight: 600;
  font-size: 1rem;
  margin: 12px 0 8px;
}

.setup-step-box p {
  font-size: 0.9rem;
  color: var(--text-secondary);
}

/* Support & Security Verification Section (#support) */
.support-section {
  padding: 80px 0;
  border-top: 1px solid var(--border-color);
}

.support-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
}

.support-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-card);
  padding: 32px;
}

.support-card ol {
  padding-left: 20px;
}

.support-card li {
  margin-bottom: 8px;
}

.support-actions {
  display: flex;
  gap: 12px;
  margin-top: 20px;
}

.btn-secondary {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 18px;
  background: transparent;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-button);
  color: var(--text-primary);
  font-family: var(--font-sans);
  font-size: 0.88rem;
  font-weight: 500;
  text-decoration: none;
  transition: var(--transition);
}

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

/* Footer */
.footer {
  border-top: 1px solid var(--border-color);
  padding: 36px 0;
  color: var(--text-muted);
  font-size: 0.85rem;
}

.footer-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.footer-links {
  display: flex;
  gap: 20px;
}

.footer-links a {
  color: var(--text-secondary);
  text-decoration: none;
}

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

/* Responsive Breakpoints */
@media (max-width: 860px) {

  h1,
  .hero-title {
    font-size: 2.5rem;
  }

  h2,
  .section-title {
    font-size: 1.85rem;
  }

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

  .bento-card-large,
  .bento-card-full {
    grid-column: span 1;
  }

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

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

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

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

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

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

@media (max-width: 640px) {
  .nav-links {
    display: none;
  }

  .platform-menu {
    width: 300px;
  }

  .footer-container {
    flex-direction: column;
    gap: 14px;
    text-align: center;
  }

  .support-actions {
    flex-direction: column;
  }
}