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

:root {
  --color-bg: #ffffff;
  --color-text: #111111;
  --color-text-secondary: #555555;
  --color-border: #e0e0e0;
  --color-kbd-bg: #f2f2f2;
  --color-kbd-border: #d5d5d5;
  --max-width: 980px;
  --font-stack: -apple-system, BlinkMacSystemFont, "SF Pro Text", "Helvetica Neue", Helvetica, Arial, sans-serif;
  --font-serif: "New York", "Iowan Old Style", Baskerville, Georgia, serif;
  --font-mono: "SF Mono", SFMono-Regular, ui-monospace, Menlo, monospace;
  --transition-fast: 0.15s ease;
  --transition-base: 0.25s ease;
}

@media (prefers-color-scheme: dark) {
  :root {
    --color-bg: #111111;
    --color-text: #eeeeee;
    --color-text-secondary: #999999;
    --color-border: #2a2a2a;
    --color-kbd-bg: #222222;
    --color-kbd-border: #333333;
  }
}

html {
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  scroll-behavior: smooth;
  scroll-padding-top: 5rem;
}

body {
  font-family: var(--font-stack);
  color: var(--color-text);
  background: var(--color-bg);
  font-size: 1.0625rem;
  line-height: 1.75;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

::selection {
  background: var(--color-text);
  color: var(--color-bg);
}

a {
  color: var(--color-text);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 0.15em;
  transition: opacity var(--transition-fast);
}

a:hover {
  opacity: 0.6;
  text-decoration: underline;
}

img {
  max-width: 100%;
  height: auto;
}

/* Header / Nav */
.site-header {
  padding: 0 2rem;
}

.site-header nav {
  max-width: var(--max-width);
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 56px;
}

.site-header .logo {
  font-family: var(--font-serif);
  font-size: 1.375rem;
  font-weight: 700;
  color: var(--color-text);
  text-decoration: none;
}

.site-header .logo:hover {
  text-decoration: none;
  opacity: 1;
}

.nav-links {
  list-style: none;
  display: flex;
  gap: 2rem;
}

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

.nav-links a:hover,
.nav-links a.active {
  color: var(--color-text);
  opacity: 1;
  text-decoration: none;
}

/* Main content */
main {
  flex: 1;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 4rem 2rem;
  width: 100%;
}

/* Hero section */
.hero {
  text-align: center;
  padding: 6rem 0;
  border-bottom: 1px solid var(--color-border);
  margin-bottom: 3.5rem;
}

.hero h1 {
  font-family: var(--font-serif);
  font-size: 4.5rem;
  font-weight: 700;
  letter-spacing: -0.025em;
  line-height: 1.05;
  margin-bottom: 1.25rem;
}

.hero p {
  font-size: 1.25rem;
  color: var(--color-text-secondary);
  max-width: 600px;
  margin: 0 auto 2.5rem;
  line-height: 1.6;
}

.btn {
  display: inline-block;
  background: var(--color-text);
  color: var(--color-bg);
  padding: 0.8rem 2rem;
  border-radius: 100px;
  font-size: 0.9375rem;
  font-weight: 600;
  border: none;
  cursor: pointer;
  text-decoration: none;
  transition: opacity var(--transition-base);
}

.btn:hover {
  opacity: 0.75;
  text-decoration: none;
}

/* Page content */
.page-header {
  margin-bottom: 2.5rem;
  padding-bottom: 2rem;
  border-bottom: 1px solid var(--color-border);
}

.page-header h1 {
  font-family: var(--font-serif);
  font-size: 3rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.1;
  margin-bottom: 0.5rem;
}

.page-header p {
  color: var(--color-text-secondary);
}

.content-section {
  margin-bottom: 3.5rem;
  padding-top: 3.5rem;
  border-top: 1px solid var(--color-border);
}

.content-section:first-of-type {
  border-top: none;
  padding-top: 0;
}

.content-section h2 {
  font-family: var(--font-serif);
  font-size: 1.75rem;
  font-weight: 700;
  letter-spacing: -0.01em;
  margin-bottom: 1rem;
}

.content-section h3 {
  font-family: var(--font-stack);
  font-size: 0.8125rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-bottom: 0.625rem;
  margin-top: 2rem;
}

.content-section p,
.content-section ul,
.content-section ol {
  color: var(--color-text-secondary);
  line-height: 1.75;
  margin-bottom: 1rem;
}

.content-section ul,
.content-section ol {
  padding-left: 1.5rem;
}

.content-section li {
  margin-bottom: 0.5rem;
}

/* Tables */
table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: 1.5rem;
  font-size: 0.9375rem;
}

th, td {
  text-align: left;
  padding: 0.75rem 1rem;
  border-bottom: 1px solid var(--color-border);
}

th {
  font-family: var(--font-stack);
  font-size: 0.6875rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--color-text-secondary);
  border-bottom: 2px solid var(--color-text);
}

td {
  color: var(--color-text-secondary);
}

/* Keyboard shortcut tags */
kbd {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  line-height: 1;
  padding: 0.2em 0.45em;
  background: var(--color-kbd-bg);
  border: 1px solid var(--color-kbd-border);
  border-radius: 4px;
  white-space: nowrap;
}

/* FAQ items */
.faq-item {
  margin-bottom: 0;
  padding: 1.5rem 0;
  border-bottom: 1px solid var(--color-border);
}

.faq-item:first-child {
  border-top: 1px solid var(--color-border);
}

.faq-item dt {
  font-family: var(--font-serif);
  font-size: 1.125rem;
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: 0.5rem;
  font-style: normal;
}

.faq-item dd {
  color: var(--color-text-secondary);
  line-height: 1.75;
}

/* Table of contents */
.toc {
  background: transparent;
  border-radius: 0;
  padding: 0 0 2rem;
  margin-bottom: 2.5rem;
}

.toc h2 {
  font-family: var(--font-stack);
  font-size: 0.6875rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-text-secondary);
  margin-bottom: 0.75rem;
}

.toc ol {
  padding-left: 1.25rem;
  margin: 0;
}

.toc li {
  margin-bottom: 0.375rem;
  font-size: 0.9375rem;
}

.toc a {
  color: var(--color-text-secondary);
  text-decoration-color: var(--color-border);
}

.toc a:hover {
  color: var(--color-text);
  opacity: 1;
}

/* Use case cards */
.use-case {
  margin-bottom: 1rem;
}

.use-case strong {
  color: var(--color-text);
}

/* Status indicator colors (for help page controller table) */
.status-grey { color: #8e8e93; }
.status-orange { color: #ff9500; }
.status-green { color: #30d158; }

/* Footer */
.site-footer {
  padding: 2.5rem 2rem;
  text-align: center;
  font-size: 0.75rem;
  color: var(--color-text-secondary);
}

.footer-links {
  list-style: none;
  display: flex;
  justify-content: center;
  gap: 1.5rem;
  margin-bottom: 0.75rem;
}

.footer-links a {
  color: var(--color-text-secondary);
  font-size: 0.6875rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  text-decoration: none;
  transition: color var(--transition-fast);
}

.footer-links a:hover {
  color: var(--color-text);
  opacity: 1;
}

/* Responsive — Tablet */
@media (max-width: 768px) {
  .hero {
    padding: 4rem 0;
  }

  .hero h1 {
    font-size: 3.25rem;
  }

  .hero p {
    font-size: 1.125rem;
  }

  main {
    padding: 3rem 1.5rem;
  }

  .page-header h1 {
    font-size: 2.5rem;
  }

  .content-section {
    margin-bottom: 2.5rem;
    padding-top: 2.5rem;
  }

  .content-section h2 {
    font-size: 1.5rem;
  }
}

/* Responsive — Mobile */
@media (max-width: 600px) {
  .hero {
    padding: 3rem 0;
  }

  .hero h1 {
    font-size: 2.25rem;
  }

  .hero p {
    font-size: 1rem;
  }

  .nav-links {
    gap: 1rem;
  }

  .nav-links a {
    font-size: 0.6875rem;
  }

  main {
    padding: 2rem 1rem;
  }

  .page-header h1 {
    font-size: 2rem;
  }

  .content-section {
    margin-bottom: 2rem;
    padding-top: 2rem;
  }

  .content-section h2 {
    font-size: 1.375rem;
  }

  table {
    font-size: 0.875rem;
  }

  th, td {
    padding: 0.5rem 0.625rem;
  }
}