:root {
  --primary: #0a1f44;
  --primary-light: #132d5c;
  --accent: #007bff;
  --accent-soft: rgba(0, 123, 255, 0.1);
  --surface: #f5f7fa;
  --white: #ffffff;
  --text: #1a2332;
  --text-muted: #5c6b7a;
  --border: #e4e9f0;
  --success: #8bc34a;
  --radius: 16px;
  --shadow: 0 4px 24px rgba(10, 31, 68, 0.08);
  --shadow-sm: 0 2px 12px rgba(10, 31, 68, 0.06);
  --max-width: 820px;
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  background: var(--surface);
  color: var(--text);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

/* Header */
.header {
  background: var(--primary);
  padding: 1.25rem 1.5rem;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: 0 2px 16px rgba(10, 31, 68, 0.15);
}

.header-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.logo-link {
  display: flex;
  align-items: center;
  text-decoration: none;
}

.logo-link img {
  height: 40px;
  width: auto;
  filter: brightness(0) invert(1);
}

.header-nav {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 0.5rem;
}

.header-nav a {
  color: rgba(255, 255, 255, 0.85);
  text-decoration: none;
  font-size: 0.875rem;
  font-weight: 500;
  padding: 0.5rem 1rem;
  border-radius: 999px;
  transition: background 0.2s, color 0.2s;
}

.header-nav a:hover {
  background: rgba(255, 255, 255, 0.12);
  color: var(--white);
}

/* Hero */
.hero {
  background: linear-gradient(160deg, var(--primary) 0%, var(--primary-light) 55%, #1a3a6e 100%);
  color: var(--white);
  padding: 3.5rem 1.5rem 4rem;
  text-align: center;
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(ellipse 80% 60% at 50% 100%, rgba(0, 123, 255, 0.18) 0%, transparent 70%);
  pointer-events: none;
}

.hero-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  position: relative;
}

.hero-logo {
  height: 72px;
  width: auto;
  filter: brightness(0) invert(1);
  margin-bottom: 1.5rem;
}

.hero h1 {
  font-size: clamp(1.75rem, 4vw, 2.25rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 0.75rem;
}

.hero p {
  font-size: 1.05rem;
  color: rgba(255, 255, 255, 0.78);
  max-width: 560px;
  margin: 0 auto 1.75rem;
}

.hero-meta {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  background: rgba(255, 255, 255, 0.1);
  border: 1px solid rgba(255, 255, 255, 0.15);
  border-radius: 999px;
  padding: 0.4rem 1.1rem;
  font-size: 0.85rem;
  color: rgba(255, 255, 255, 0.9);
}

.hero-meta svg {
  opacity: 0.8;
}

/* Layout */
.page {
  max-width: var(--max-width);
  margin: -2rem auto 0;
  padding: 0 1.5rem 4rem;
  position: relative;
  z-index: 1;
}

/* TOC */
.toc {
  background: var(--white);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 1.5rem 1.75rem;
  margin-bottom: 1.5rem;
}

.toc h2 {
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-muted);
  margin-bottom: 0.875rem;
}

.toc ul {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.toc a {
  display: flex;
  align-items: center;
  gap: 0.625rem;
  color: var(--accent);
  text-decoration: none;
  font-weight: 500;
  font-size: 0.95rem;
  padding: 0.35rem 0;
  transition: gap 0.2s;
}

.toc a:hover {
  gap: 0.875rem;
}

.toc a::before {
  content: '';
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--accent);
  flex-shrink: 0;
}

/* Cards */
.card {
  background: var(--white);
  border-radius: var(--radius);
  box-shadow: var(--shadow-sm);
  padding: 2rem 2rem 2.25rem;
  margin-bottom: 1.5rem;
  border: 1px solid var(--border);
}

.card-header {
  display: flex;
  align-items: center;
  gap: 0.875rem;
  margin-bottom: 1.5rem;
  padding-bottom: 1.25rem;
  border-bottom: 1px solid var(--border);
}

.card-icon {
  width: 44px;
  height: 44px;
  border-radius: 12px;
  background: var(--accent-soft);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  color: var(--accent);
}

.card-header h2 {
  font-size: 1.375rem;
  font-weight: 700;
  color: var(--primary);
  letter-spacing: -0.02em;
}

.intro {
  font-size: 1rem;
  color: var(--text-muted);
  margin-bottom: 0;
  padding: 1rem 1.25rem;
  background: var(--surface);
  border-radius: 12px;
  border-left: 3px solid var(--accent);
}

.section-block {
  margin-bottom: 1.75rem;
}

.section-block:last-child {
  margin-bottom: 0;
}

.section-block h3 {
  font-size: 1rem;
  font-weight: 600;
  color: var(--primary);
  margin-bottom: 0.625rem;
}

.section-block p {
  color: var(--text-muted);
  font-size: 0.95rem;
}

.section-block ul {
  list-style: none;
  margin-top: 0.5rem;
}

.section-block ul li {
  position: relative;
  padding-left: 1.375rem;
  color: var(--text-muted);
  font-size: 0.95rem;
  margin-bottom: 0.5rem;
}

.section-block ul li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0.6em;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--accent);
}

/* Icons */
.icon {
  width: 22px;
  height: 22px;
  flex-shrink: 0;
}

.icon-sm {
  width: 14px;
  height: 14px;
}

/* Landing: feature grid */
.feature-grid {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.feature-item {
  display: flex;
  align-items: flex-start;
  gap: 0.875rem;
  padding: 1.25rem;
  background: var(--surface);
  border-radius: 12px;
  border: 1px solid var(--border);
}

.feature-item h3 {
  font-size: 1rem;
  font-weight: 600;
  color: var(--primary);
  margin-bottom: 0.35rem;
}

.feature-item p {
  font-size: 0.9rem;
  color: var(--text-muted);
  line-height: 1.6;
}

/* Landing: steps */
.step-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.step-item {
  display: flex;
  align-items: flex-start;
  gap: 1rem;
}

.step-number {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: var(--accent);
  color: var(--white);
  font-size: 0.875rem;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.step-content {
  flex: 1;
  padding-top: 0.15rem;
}

.step-content h3 {
  font-size: 1rem;
  font-weight: 600;
  color: var(--primary);
  margin-bottom: 0.35rem;
}

.step-content p {
  font-size: 0.9rem;
  color: var(--text-muted);
  line-height: 1.6;
}

.step-icon {
  width: 36px;
  height: 36px;
  border-radius: 10px;
  background: var(--accent-soft);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--accent);
  flex-shrink: 0;
}

/* Landing: stats */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1rem;
}

.stat-card {
  text-align: center;
  padding: 1.5rem 1rem;
  background: var(--surface);
  border-radius: 12px;
  border: 1px solid var(--border);
}

.stat-card .card-icon {
  margin: 0 auto 0.75rem;
}

.stat-value {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--primary);
  letter-spacing: -0.02em;
  margin-bottom: 0.25rem;
}

.stat-label {
  font-size: 0.8rem;
  color: var(--text-muted);
  font-weight: 500;
}

/* Buttons */
.btn-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 1.25rem;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.75rem 1.25rem;
  border-radius: 999px;
  font-size: 0.9rem;
  font-weight: 600;
  text-decoration: none;
  transition: background 0.2s, color 0.2s, border-color 0.2s, opacity 0.2s;
  border: 2px solid transparent;
  cursor: pointer;
}

.btn-primary {
  background: var(--accent);
  color: var(--white);
  border-color: var(--accent);
}

.btn-primary:hover {
  background: #0069d9;
  border-color: #0069d9;
}

.btn-outline {
  background: transparent;
  color: var(--accent);
  border-color: var(--accent);
}

.btn-outline:hover {
  background: var(--accent-soft);
}

.btn-disabled {
  background: var(--surface);
  color: var(--text-muted);
  border-color: var(--border);
  cursor: not-allowed;
  opacity: 0.85;
}

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

.download-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 0.75rem;
  margin-top: 1.25rem;
}

.download-btn {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5rem;
  padding: 1.25rem 1rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  color: var(--text-muted);
  font-size: 0.85rem;
  font-weight: 500;
  cursor: not-allowed;
}

.download-btn span.coming-soon {
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--accent);
  background: var(--accent-soft);
  padding: 0.2rem 0.6rem;
  border-radius: 999px;
}

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

.footer img {
  height: 32px;
  width: auto;
  opacity: 0.7;
  margin-bottom: 0.75rem;
}

.footer p {
  max-width: 480px;
  margin: 0 auto;
  line-height: 1.6;
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.5rem 1.25rem;
  margin-top: 1rem;
}

.footer-links a {
  color: var(--accent);
  text-decoration: none;
  font-weight: 500;
  font-size: 0.85rem;
}

.footer-links a:hover {
  text-decoration: underline;
}

/* Guide pages — numbered steps */
.guide-steps {
  list-style: none;
  counter-reset: guide-step;
  margin-top: 0.5rem;
}

.guide-steps li {
  counter-increment: guide-step;
  position: relative;
  padding-left: 2.75rem;
  margin-bottom: 1.25rem;
  color: var(--text-muted);
  font-size: 0.95rem;
  line-height: 1.65;
}

.guide-steps li::before {
  content: counter(guide-step);
  position: absolute;
  left: 0;
  top: 0.1rem;
  width: 1.75rem;
  height: 1.75rem;
  border-radius: 50%;
  background: var(--accent);
  color: var(--white);
  font-size: 0.8rem;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
}

.guide-steps li strong {
  color: var(--primary);
  font-weight: 600;
}

.notice-box {
  padding: 1rem 1.25rem;
  border-radius: 12px;
  margin-top: 1rem;
  font-size: 0.9rem;
  line-height: 1.6;
}

.notice-box.warning {
  background: #fff8e6;
  border: 1px solid #f5d78e;
  color: #8a6d1d;
}

.notice-box.info {
  background: var(--accent-soft);
  border: 1px solid rgba(0, 123, 255, 0.25);
  color: var(--primary);
}

@media (max-width: 600px) {
  .header-nav {
    display: none;
  }

  .card {
    padding: 1.5rem 1.25rem;
  }

  .hero {
    padding: 2.5rem 1.25rem 3.5rem;
  }

  .hero-logo {
    height: 56px;
  }

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

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

  .btn-row {
    flex-direction: column;
  }

  .btn {
    width: 100%;
  }
}