/* Remember Me — site styles
   Plain CSS, no build step. System font stack, one accent colour taken from the app. */

:root {
  --accent: #5b4ee8;
  --accent-soft: #eceafc;
  --ink: #1d1d1f;
  --ink-2: #4a4a4f;
  --ink-3: #86868b;
  --ground: #fbfbfd;
  --tint: #f2f2f6;
  --line: #d9d9de;
  --dark: #151517;
  --dark-2: #1f1f22;
  --dark-line: #333338;
  --dark-ink: #f5f5f7;
  --dark-ink-2: #b8b8c0;
  --radius: 22px;
  --wrap: 760px;
  --wrap-wide: 1120px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 56px; }
body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Text", "Helvetica Neue", Helvetica, Arial, sans-serif;
  font-size: 17px;
  line-height: 1.5;
  color: var(--ink);
  background: var(--ground);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
img, video { max-width: 100%; height: auto; display: block; }
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }
h1, h2, h3, h4 { margin: 0; letter-spacing: -0.015em; }
p { margin: 0 0 1em; }
code { font-family: "SF Mono", Menlo, Consolas, monospace; font-size: 0.92em; }

.wrap { width: 100%; max-width: var(--wrap); margin: 0 auto; padding-inline: 20px; }
.wrap-wide { max-width: var(--wrap-wide); }

/* ── Top bar ─────────────────────────────────────────── */
.topbar {
  position: sticky; top: 0; z-index: 20;
  background: rgba(251,251,253,0.82);
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  border-bottom: 1px solid rgba(0,0,0,0.08);
}
.topbar-inner {
  max-width: var(--wrap-wide);
  display: flex; align-items: center; justify-content: space-between; gap: 24px;
  height: 52px;
}
.brand { font-weight: 600; color: var(--ink); font-size: 17px; white-space: nowrap; }
.brand:hover { text-decoration: none; }
.topnav { display: flex; gap: 26px; overflow-x: auto; scrollbar-width: none; }
.topnav::-webkit-scrollbar { display: none; }
.topnav a { color: var(--ink-2); font-size: 13px; white-space: nowrap; padding: 6px 0; }
.topnav a:hover { color: var(--ink); text-decoration: none; }
.topnav a.active { color: var(--ink); font-weight: 600; }

/* ── Hero ────────────────────────────────────────────── */
.hero { padding-block: 84px 40px; text-align: center; }
.eyebrow { color: var(--ink-3); font-size: 15px; font-weight: 500; margin-bottom: 14px; }
.hero h1 { font-size: clamp(44px, 8vw, 84px); line-height: 1.02; font-weight: 700; letter-spacing: -0.03em; }
.lede { max-width: 620px; margin: 24px auto 0; font-size: clamp(18px, 2.3vw, 22px); line-height: 1.45; color: var(--ink-2); }
.hero-actions { display: flex; gap: 12px; justify-content: center; flex-wrap: wrap; margin-top: 30px; }

.btn {
  display: inline-block; padding: 11px 22px; border-radius: 999px;
  font-size: 16px; font-weight: 500; line-height: 1.2;
  border: 1px solid transparent; cursor: pointer;
}
.btn:hover { text-decoration: none; }
.btn-primary { background: var(--accent); color: #fff; }
.btn-primary:hover { background: #4a3fd6; }
.btn-ghost { border-color: var(--line); color: var(--ink); background: transparent; }
.btn-ghost:hover { border-color: var(--ink-3); }
.btn-disabled { border-color: var(--line); color: var(--ink-3); cursor: default; }

.video-frame { margin: 56px 0 0; }
.video-frame video {
  width: 100%; aspect-ratio: 1662 / 1246;
  border-radius: var(--radius); background: #000;
  box-shadow: 0 30px 80px rgba(0,0,0,0.18);
}
.video-frame figcaption { margin-top: 14px; color: var(--ink-3); font-size: 14px; }

/* ── Sections ────────────────────────────────────────── */
.section { padding-block: 96px; }
.section-tint { background: var(--tint); }
.section-dark { background: var(--dark); color: var(--dark-ink); }
.section-dark .prose, .section-dark p { color: var(--dark-ink-2); }
.section-dark h2, .section-dark h3, .section-dark h4, .section-dark strong { color: var(--dark-ink); }
.section-dark a { color: #a89ffb; }

.section-num {
  font-family: "SF Mono", Menlo, Consolas, monospace;
  font-size: 13px; color: var(--accent); margin-bottom: 14px; letter-spacing: 0.06em;
}
.section-dark .section-num { color: #a89ffb; }
.section h2 { font-size: clamp(30px, 4.6vw, 48px); line-height: 1.08; font-weight: 700; letter-spacing: -0.025em; margin-bottom: 22px; }
.prose { font-size: 19px; line-height: 1.55; color: var(--ink-2); }
.prose.small { font-size: 16px; color: var(--ink-3); margin-top: 28px; }
.section-dark .prose.small { color: var(--dark-ink-2); }
h3.sub { font-size: 22px; font-weight: 600; margin: 56px 0 14px; }

/* Three tiles */
.three-up { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; margin-top: 44px; }
.tile { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 26px 24px; }
.tile h3 { font-size: 20px; margin-bottom: 8px; }
.tile p { color: var(--ink-2); font-size: 16px; margin: 0; }

/* Who */
.who { display: grid; grid-template-columns: repeat(3, 1fr); gap: 32px; margin: 44px 0 0; }
.who dt { font-weight: 600; font-size: 18px; margin-bottom: 8px; }
.who dd { margin: 0; color: var(--ink-2); font-size: 16px; }

/* Steps */
.step {
  display: grid; grid-template-columns: 1fr 1fr; gap: 48px; align-items: center;
  margin-top: 80px;
}
.step-flip .step-text { order: 2; }
.step-text h3 { font-size: clamp(26px, 3.2vw, 36px); line-height: 1.12; margin-bottom: 18px; font-weight: 700; }
.step-text p { color: var(--ink-2); font-size: 17px; }
.step-label {
  font-family: "SF Mono", Menlo, Consolas, monospace;
  font-size: 12px; color: var(--accent); letter-spacing: 0.06em; text-transform: uppercase; margin-bottom: 14px;
}
.phone { margin: 0; justify-self: center; width: min(100%, 320px); }
.phone img {
  border-radius: 34px; border: 1px solid rgba(0,0,0,0.12);
  box-shadow: 0 24px 60px rgba(0,0,0,0.16);
}
.phone-pair { display: flex; gap: 20px; justify-content: center; }
.phone-pair .phone { width: min(48%, 260px); }

/* Rail of screens */
.rail-outer { margin-top: 48px; }
.rail {
  display: flex; gap: 28px; overflow-x: auto; scroll-snap-type: x mandatory;
  --rail-inset: max(20px, calc((100vw - var(--wrap-wide)) / 2 + 20px));
  padding-block: 12px 28px;
  padding-inline: var(--rail-inset);
  scroll-padding-inline: var(--rail-inset);
  scrollbar-width: thin; scrollbar-color: var(--dark-line) transparent;
}
.rail-item { flex: 0 0 auto; width: 250px; margin: 0; scroll-snap-align: start; }
.rail-item img {
  border-radius: 28px; border: 1px solid var(--dark-line);
  box-shadow: 0 20px 50px rgba(0,0,0,0.5);
}
.rail-item figcaption { margin-top: 16px; font-size: 14px; line-height: 1.45; color: var(--dark-ink-2); }
.rail-item figcaption strong { display: block; color: var(--dark-ink); font-size: 15px; margin-bottom: 3px; }
.rail-hint { color: var(--ink-3); font-size: 13px; margin-top: 4px; max-width: var(--wrap-wide); }

/* Definition table (reminders) */
.defs { width: 100%; border-collapse: collapse; margin-top: 40px; font-size: 16px; }
.defs th { text-align: left; font-size: 13px; color: var(--ink-3); font-weight: 500; padding: 0 12px 12px 0; border-bottom: 1px solid var(--line); }
.defs td { vertical-align: top; padding: 18px 12px 18px 0; border-bottom: 1px solid var(--line); }
.defs td:first-child { font-style: italic; color: var(--ink-2); width: 32%; }
.defs td:nth-child(2) { font-weight: 600; white-space: nowrap; }

.notes-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 32px; margin-top: 48px; }
.notes-grid h3, .notes-grid h4 { font-size: 17px; font-weight: 600; margin-bottom: 8px; }
.notes-grid p { font-size: 15px; color: var(--ink-2); margin: 0; }

/* Facts list */
.facts { list-style: none; padding: 0; margin: 40px 0 0; display: grid; gap: 18px; }
.facts li { padding-left: 22px; position: relative; font-size: 16px; color: var(--ink-2); }
.facts li::before { content: ""; position: absolute; left: 0; top: 10px; width: 8px; height: 8px; border-radius: 50%; background: var(--accent); }
.facts li strong { color: var(--ink); }
.facts-dark li { color: var(--dark-ink-2); }
.facts-dark li::before { background: #a89ffb; }

/* Tables */
.table-scroll { overflow-x: auto; margin-top: 36px; -webkit-overflow-scrolling: touch; }
table.compare, table.stack { width: 100%; border-collapse: collapse; font-size: 15px; min-width: 640px; }
table.compare th, table.stack th {
  text-align: left; font-weight: 500; font-size: 13px; color: var(--ink-3);
  padding: 0 14px 12px 0; border-bottom: 1px solid var(--line); vertical-align: bottom;
}
table.compare td, table.stack td { padding: 13px 14px 13px 0; border-bottom: 1px solid var(--line); vertical-align: top; }
table.compare td:first-child { font-weight: 500; }
table.compare .us { color: var(--accent); font-weight: 600; }
table.compare th.us { color: var(--accent); }
.section-dark table.stack th { color: var(--dark-ink-2); border-color: var(--dark-line); }
.section-dark table.stack td { border-color: var(--dark-line); color: var(--dark-ink-2); }
.section-dark table.stack td:first-child, .section-dark table.stack td:nth-child(2) { color: var(--dark-ink); }
.section-dark table.jobs td:nth-child(2) { color: var(--dark-ink); }
.section-dark table.jobs td:first-child { color: var(--dark-ink-2); }
table.stack td:nth-child(2) { font-weight: 500; white-space: nowrap; }
table.jobs td:nth-child(2) { white-space: normal; }

/* Architecture list */
.arch { padding-left: 22px; margin: 28px 0 24px; display: grid; gap: 16px; font-size: 16px; }
.arch li { color: var(--dark-ink-2); }
.arch li::marker { color: #a89ffb; font-family: "SF Mono", Menlo, monospace; font-size: 13px; }

/* Docs cards */
.docs-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; margin-top: 44px; }
.doc-card {
  background: #fff; border: 1px solid var(--line); border-radius: var(--radius);
  padding: 28px 26px; display: flex; flex-direction: column; gap: 8px;
}
.doc-card-soon { background: var(--tint); }
.doc-kind { font-family: "SF Mono", Menlo, Consolas, monospace; font-size: 12px; color: var(--ink-3); letter-spacing: 0.04em; margin: 0; }
.doc-card h3 { font-size: 21px; }
.doc-card p { color: var(--ink-2); font-size: 15px; margin: 0; flex: 1; }
.doc-card .btn { align-self: flex-start; margin-top: 14px; font-size: 14px; padding: 9px 16px; max-width: 100%; overflow-wrap: anywhere; }

/* Footer */
.footer { border-top: 1px solid var(--line); padding-block: 40px; color: var(--ink-3); font-size: 13px; }
.footer p { margin: 0 0 4px; }

/* ── Responsive ──────────────────────────────────────── */
@media (max-width: 860px) {
  .three-up, .who, .notes-grid { grid-template-columns: 1fr; }
  .step { grid-template-columns: 1fr; gap: 32px; margin-top: 64px; }
  .step-flip .step-text { order: 0; }
  .docs-grid { grid-template-columns: 1fr; }
  .section { padding-block: 72px; }
  .hero { padding-block: 56px 32px; }
  .defs td:first-child { width: auto; }
  .defs td:nth-child(2) { white-space: normal; }
}
@media (max-width: 520px) {
  .topbar-inner { height: auto; flex-direction: column; align-items: flex-start; gap: 4px; padding-block: 10px; }
  .topnav { width: 100%; gap: 18px; }
  .phone-pair { flex-direction: column; align-items: center; }
  .phone-pair .phone { width: min(100%, 280px); }
  .defs, .defs thead, .defs tbody, .defs tr, .defs td { display: block; }
  .defs thead { display: none; }
  .defs tr { border-bottom: 1px solid var(--line); padding-block: 14px; }
  .defs td { border: 0; padding: 4px 0; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
}

/* Dark-section overrides for the notes grid (it appears in both light and dark sections) */
.section-dark .notes-grid p { color: var(--dark-ink-2); }
.section-dark .notes-grid code { color: var(--dark-ink); }

/* Technical page: the dark section is the whole page, so it starts right under the top bar */
.tech-page { min-height: calc(100vh - 52px); padding-top: 72px; }
.tech-page .section-num { text-transform: uppercase; }

/* "Thinks ahead" section */
.section-accent { background: var(--accent-soft); }
.ahead-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; margin-top: 44px; }
.ahead-card { background: #fff; border-radius: var(--radius); padding: 26px 24px; border: 1px solid rgba(91,78,232,0.18); }
.ahead-say { font-size: 19px; font-weight: 600; line-height: 1.3; color: var(--ink); margin: 0 0 10px; letter-spacing: -0.01em; }
.ahead-arrow { color: var(--accent); font-size: 20px; margin: 0 0 10px; line-height: 1; }
.ahead-does { font-size: 15.5px; color: var(--ink-2); margin: 0; }
.prose.centered { text-align: center; max-width: 720px; margin-inline: auto; margin-top: 36px; color: var(--ink-2); }
@media (max-width: 860px) { .ahead-grid { grid-template-columns: 1fr; } }