:root {
  --bg: #f7f8fa;
  --surface: #ffffff;
  --border: #e2e5ea;
  --text: #1a1d24;
  --text-muted: #565c68;
  --accent: #1a56db;
  --accent-dark: #163f9e;
  --notice-bg: #eef3ff;
  --notice-border: #c6d7fb;
  --radius: 10px;
  --max-width: 860px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.6;
  font-size: 16px;
}

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

/* Header */

.site-header {
  background: linear-gradient(135deg, #16233f 0%, #1a3a8f 100%);
  color: #fff;
  padding: 64px 0 48px;
}

.site-header .eyebrow {
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-size: 0.8rem;
  font-weight: 600;
  color: #b7c8f5;
  margin: 0 0 12px;
}

.site-header h1 {
  margin: 0 0 12px;
  font-size: 2.1rem;
  line-height: 1.25;
}

.site-header .subtitle {
  margin: 0;
  color: #dbe3f7;
  font-size: 1.05rem;
  max-width: 640px;
}

/* Main */

main {
  padding: 48px 24px 24px;
}

section {
  margin-bottom: 48px;
}

h2 {
  font-size: 1.4rem;
  margin: 0 0 16px;
  padding-bottom: 10px;
  border-bottom: 2px solid var(--border);
}

h3 {
  font-size: 1.05rem;
  margin: 0 0 6px;
}

p {
  color: var(--text-muted);
  margin: 0 0 12px;
}

/* Application summary card */

.app-facts {
  margin-bottom: 24px;
}

.app-facts-card {
  background: var(--surface);
  border: 2px solid var(--accent);
  border-radius: var(--radius);
  padding: 24px;
}

.app-facts-title {
  margin: 0 0 16px;
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--text);
}

.app-facts-list {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 16px 24px;
  margin: 0;
}

.app-facts-list dt {
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  font-weight: 600;
  color: var(--text-muted);
  margin: 0 0 4px;
}

.app-facts-list dd {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text);
  margin: 0;
}

/* Notice callouts */

.notice {
  background: var(--notice-bg);
  border: 1px solid var(--notice-border);
  border-radius: var(--radius);
  padding: 20px 24px;
  margin-bottom: 40px;
}

.notice p {
  color: var(--text);
  margin: 0;
}

/* Lists */

.check-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.check-list li {
  position: relative;
  padding-left: 28px;
  margin-bottom: 10px;
  color: var(--text-muted);
}

.check-list li::before {
  content: "\2713";
  position: absolute;
  left: 0;
  top: 0;
  color: var(--accent);
  font-weight: 700;
}

/* Grid of function cards */

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 16px;
}

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px 20px;
}

.card p {
  margin: 0;
  font-size: 0.92rem;
}

/* Architecture flow */

.flow {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  margin-bottom: 16px;
}

.flow-step {
  background: var(--notice-bg);
  border: 1px solid var(--notice-border);
  color: var(--accent-dark);
  font-weight: 600;
  font-size: 0.9rem;
  padding: 10px 14px;
  border-radius: 8px;
  white-space: nowrap;
}

.flow-arrow {
  color: var(--text-muted);
  font-weight: 700;
}

.flow-caption {
  font-size: 0.92rem;
}

/* Developer card */

.dev-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
}

.dev-name {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 4px;
}

.dev-card a {
  color: var(--accent);
  text-decoration: none;
  font-weight: 600;
}

.dev-card a:hover {
  text-decoration: underline;
}

/* Footer */

.site-footer {
  border-top: 1px solid var(--border);
  padding: 24px 0 48px;
}

.site-footer p {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin: 0;
}

/* Responsive */

@media (max-width: 600px) {
  .site-header {
    padding: 48px 0 36px;
  }

  .site-header h1 {
    font-size: 1.6rem;
  }

  main {
    padding: 36px 20px 16px;
  }

  .flow {
    flex-direction: column;
    align-items: stretch;
  }

  .flow-arrow {
    transform: rotate(90deg);
    text-align: center;
  }
}

/* Content links */

main a {
  color: var(--accent);
  text-decoration: underline;
  text-underline-offset: 2px;
}

main a:hover {
  color: var(--accent-dark);
}

/* Legal pages (privacy / terms) */

.page-meta {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin: 0 0 32px;
}

.back-link {
  margin: 0 0 8px;
  font-weight: 600;
}

.back-link a {
  text-decoration: none;
}

.back-link a:hover {
  text-decoration: underline;
}

/* Footer navigation */

.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 20px;
  margin-bottom: 12px;
}

.footer-links a {
  color: var(--accent);
  text-decoration: none;
  font-size: 0.9rem;
  font-weight: 600;
}

.footer-links a:hover {
  color: var(--accent-dark);
  text-decoration: underline;
}