/* ============================================
   TOKENS: Inter Tight + system mono for code comments
============================================ */
@import url('https://fonts.googleapis.com/css2?family=Inter+Tight:wght@400;500;600;700&display=swap');

:root {
  --ink: #0A0A0A;
  --ink-2: #3A3A3A;
  --ink-3: #6A6A6A;
  --ink-4: #9A9A9A;
  --bg: #F2F2F2;
  --bg-2: #E8E8E8;
  --bg-rule: #D4D4D4;
  --annotation-bg: #EAEAEA;
  --annotation-border: #0A0A0A;
}

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

html { scroll-behavior: smooth; }

body {
  font-family: 'Inter Tight', -apple-system, BlinkMacSystemFont, sans-serif;
  background: var(--bg);
  color: var(--ink);
  font-size: 17px;
  line-height: 1.55;
  font-variant-numeric: lining-nums;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

/* Refined focus rings: keyboard navigation only */
:focus { outline: none; }
:focus-visible {
  outline: 2px solid var(--ink);
  outline-offset: 3px;
  border-radius: 2px;
}

a {
  color: var(--ink);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
  transition: opacity 0.2s ease;
}
a:hover { opacity: 0.6; }

.wrap {
  max-width: 760px;
  margin: 0 auto;
  padding: 0 24px;
}

.wrap--wide {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ============================================
   NAV
============================================ */
.nav {
  padding: 28px 0;
  border-bottom: 1px solid var(--bg-rule);
  background: var(--bg);
  position: sticky;
  top: 0;
  z-index: 10;
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  background: rgba(242, 242, 242, 0.85);
}

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

.nav__brand {
  font-weight: 600;
  font-size: 15px;
  letter-spacing: -0.01em;
  text-decoration: none;
}

.nav__brand:hover { opacity: 1; }

.nav__back {
  font-size: 14px;
  color: var(--ink-2);
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

/* ============================================
   ARTICLE HEADER
============================================ */
.article-header {
  padding: 80px 0 56px;
  border-bottom: 1px solid var(--bg-rule);
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--ink-3);
  margin-bottom: 32px;
}

.eyebrow__dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--ink);
}

.article-title {
  font-size: clamp(32px, 5vw, 56px);
  font-weight: 600;
  line-height: 1.08;
  letter-spacing: -0.025em;
  margin-bottom: 24px;
}

.article-subtitle {
  font-size: clamp(18px, 2.4vw, 22px);
  font-weight: 400;
  line-height: 1.45;
  color: var(--ink-2);
  letter-spacing: -0.01em;
  margin-bottom: 40px;
  max-width: 640px;
}

.article-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 24px;
  font-size: 13px;
  color: var(--ink-3);
}

.article-meta__item {
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

.article-meta__item strong {
  font-weight: 500;
  color: var(--ink-2);
}

/* ============================================
   LEAD ANSWER (AEO-optimized, typographic emphasis only)
============================================ */
.lead-answer {
  margin: 48px 0 56px;
}

.lead-answer__label {
  font-family: ui-monospace, 'SF Mono', Monaco, Consolas, monospace;
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-3);
  margin-bottom: 18px;
  display: block;
}

.lead-answer__text {
  font-size: clamp(19px, 2.2vw, 21px);
  line-height: 1.5;
  font-weight: 500;
  letter-spacing: -0.005em;
  color: var(--ink);
  max-width: 660px;
}

.lead-answer__text strong {
  font-weight: 600;
}

/* ============================================
   ARTICLE BODY
============================================ */
.article-body {
  padding: 56px 0 80px;
}

.article-body h2 {
  font-size: clamp(24px, 3.4vw, 32px);
  font-weight: 600;
  line-height: 1.2;
  letter-spacing: -0.02em;
  margin: 64px 0 20px;
  scroll-margin-top: 100px;
}

.article-body h2:first-child { margin-top: 0; }

.article-body h3 {
  font-size: 20px;
  font-weight: 600;
  line-height: 1.3;
  letter-spacing: -0.01em;
  margin: 36px 0 14px;
}

.article-body p {
  margin-bottom: 20px;
  color: var(--ink);
}

.article-body p + p { margin-top: 0; }

.article-body strong {
  font-weight: 600;
}

.article-body ul,
.article-body ol {
  margin: 20px 0 24px 24px;
  padding: 0;
}

.article-body li {
  margin-bottom: 10px;
  padding-left: 6px;
}

.article-body li::marker {
  color: var(--ink-3);
}

/* ============================================
   TABLE OF CONTENTS
============================================ */
.toc {
  margin: 40px 0 56px;
  padding: 28px 32px;
  border: 1px solid var(--bg-rule);
  border-radius: 4px;
  background: rgba(255, 255, 255, 0.4);
}

.toc__label {
  font-family: ui-monospace, 'SF Mono', Monaco, Consolas, monospace;
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-3);
  margin-bottom: 16px;
}

.toc__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 8px;
}

@media (min-width: 640px) {
  .toc__list {
    grid-template-columns: 1fr 1fr;
    gap: 8px 32px;
  }
}

.toc__list li {
  margin: 0;
  padding: 0;
  font-size: 14px;
  display: flex;
  align-items: baseline;
  gap: 10px;
}

.toc__num {
  font-family: ui-monospace, 'SF Mono', Monaco, Consolas, monospace;
  font-size: 11px;
  color: var(--ink-4);
  font-weight: 500;
  min-width: 18px;
}

.toc__list a {
  text-decoration: none;
  color: var(--ink-2);
  font-weight: 500;
}

.toc__list a:hover { color: var(--ink); opacity: 1; }

/* ============================================
   ANNOTATION (the signature element)
   Quiet vertical-ruled notes on the page itself
============================================ */
.annotation {
  margin: 24px 0 32px;
  padding: 6px 0 6px 22px;
  border-left: 2px solid var(--ink-3);
  font-family: ui-monospace, 'SF Mono', Monaco, 'Cascadia Code', 'Roboto Mono', Consolas, monospace;
  font-size: 12.5px;
  line-height: 1.7;
  color: var(--ink-3);
}

.annotation__tag {
  font-weight: 600;
  color: var(--ink);
  letter-spacing: 0.02em;
}

.annotation__slash {
  color: var(--ink-4);
  margin-right: 4px;
}

/* ============================================
   COMPARISON TABLE
============================================ */
.compare-wrap {
  margin: 36px 0 40px;
  overflow-x: auto;
  border: 1px solid var(--bg-rule);
  border-radius: 4px;
}

.compare {
  width: 100%;
  border-collapse: collapse;
  font-size: 14px;
  min-width: 600px;
}

.compare th,
.compare td {
  padding: 14px 18px;
  text-align: left;
  border-bottom: 1px solid var(--bg-rule);
  vertical-align: top;
}

.compare th {
  background: var(--bg-2);
  font-weight: 600;
  font-size: 13px;
  letter-spacing: -0.005em;
  color: var(--ink);
}

.compare tbody th {
  background: transparent;
  font-weight: 500;
  font-size: 13px;
  color: var(--ink-3);
  white-space: nowrap;
}

.compare td {
  color: var(--ink-2);
}

.compare tr:last-child td,
.compare tr:last-child th {
  border-bottom: none;
}

/* ============================================
   FAQ
============================================ */
.faq {
  margin-top: 24px;
}

.faq__item {
  border-bottom: 1px solid var(--bg-rule);
  padding: 20px 0;
}

.faq__item:first-child {
  border-top: 1px solid var(--bg-rule);
}

.faq__q {
  font-size: 17px;
  font-weight: 600;
  letter-spacing: -0.01em;
  margin-bottom: 10px;
  color: var(--ink);
}

.faq__a {
  font-size: 15px;
  color: var(--ink-2);
  line-height: 1.55;
}

/* ============================================
   META REVEAL BLOCK
============================================ */
.meta-reveal {
  margin: 56px 0;
  padding: 36px;
  background: var(--ink);
  color: var(--bg);
  border-radius: 4px;
}

.meta-reveal__label {
  font-family: ui-monospace, 'SF Mono', Monaco, Consolas, monospace;
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-4);
  margin-bottom: 18px;
}

.meta-reveal h2 {
  color: var(--bg);
  margin: 0 0 16px;
  font-size: 28px;
  font-weight: 600;
  letter-spacing: -0.02em;
}

.meta-reveal p {
  color: rgba(242, 242, 242, 0.85);
  margin-bottom: 14px;
  font-size: 16px;
}

.meta-reveal p:last-child { margin-bottom: 0; }

.meta-reveal ul {
  margin: 16px 0 0 20px;
  padding: 0;
}

.meta-reveal li {
  color: rgba(242, 242, 242, 0.85);
  margin-bottom: 8px;
  font-size: 15px;
}

.meta-reveal li::marker {
  color: var(--ink-4);
}

/* ============================================
   CTA BLOCK
============================================ */
.cta {
  margin: 80px 0 0;
  padding: 56px 0;
  border-top: 1px solid var(--bg-rule);
  text-align: left;
}

.cta__title {
  font-size: clamp(24px, 3.4vw, 32px);
  font-weight: 600;
  letter-spacing: -0.02em;
  line-height: 1.2;
  margin-bottom: 16px;
}

.cta__text {
  font-size: 16px;
  color: var(--ink-2);
  margin-bottom: 24px;
  max-width: 540px;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  background: var(--ink);
  color: var(--bg);
  padding: 14px 22px;
  border-radius: 4px;
  text-decoration: none;
  font-weight: 500;
  font-size: 15px;
  letter-spacing: -0.005em;
  transition: opacity 0.2s ease;
}

.btn:hover { opacity: 0.85; }

.btn__arrow {
  display: inline-block;
  transition: transform 0.2s ease;
}

.btn:hover .btn__arrow { transform: translateX(3px); }

/* ============================================
   FOOTER
============================================ */
.footer {
  padding: 32px 0 48px;
  border-top: 1px solid var(--bg-rule);
  font-size: 13px;
  color: var(--ink-3);
}

.footer__inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 16px;
}

.footer__links {
  display: flex;
  gap: 24px;
}

.footer__links a {
  color: var(--ink-3);
  text-decoration: none;
}

.footer__links a:hover { color: var(--ink); opacity: 1; }

/* ============================================
   RESPONSIVE
============================================ */
@media (max-width: 640px) {
  .article-header { padding: 48px 0 40px; }
  .answer-block { padding: 24px; }
  .answer-block__text { font-size: 16px; }
  .toc { padding: 22px 24px; }
  .meta-reveal { padding: 28px; }
  .annotation { padding: 4px 0 4px 18px; font-size: 12px; }
  .article-body h2 { margin: 48px 0 16px; }
}