/* Primer — primerfuture.com
   Palette is the app's, both columns of it. Dark is the default because the app
   is dark; light applies only when the visitor's OS asks for light. */

:root {
  --void: #0a0b0d;
  --surface: #14161a;
  --raised: #1c1f25;
  --hairline: #262a31;
  --text: #e8e8ea;
  --muted: #8a8d93;
  --faint: #5e6269;
  --signal: #4fd8e8;
  --coherence: #7ce8b0;
  --caution: #e8c87f;
  --on-signal: #05171b;
  --on-coherence: #061a12;
}

@media (prefers-color-scheme: light) {
  :root {
    --void: #f6f7f9;
    --surface: #edf0f5;
    --raised: #e3e7ee;
    --hairline: #d5dae2;
    --text: #181b21;
    --muted: #585f6b;
    --faint: #808894;
    --signal: #007286;
    --coherence: #097453;
    --caution: #926410;
    --on-signal: #fafbfc;
    --on-coherence: #fafbfc;
  }
}

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

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
}

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

.wrap {
  max-width: 720px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ---- header ---- */

header.site {
  border-bottom: 1px solid var(--hairline);
  padding: 20px 0;
}

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

.brand {
  font-size: 17px;
  font-weight: 650;
  letter-spacing: 0.01em;
  color: var(--text);
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 9px;
}

/* The mark: a small filled dot, the signal colour. The app's idea in one
   shape, and it costs no request. */
.brand::before {
  content: "";
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--signal);
  box-shadow: 0 0 12px var(--signal);
}

.brand-nav {
  display: flex;
  gap: 20px;
  font-size: 14px;
}

.brand-nav a {
  color: var(--muted);
  text-decoration: none;
}

.brand-nav a:hover {
  color: var(--signal);
}

/* ---- hero ---- */

.hero {
  padding: 86px 0 64px;
  border-bottom: 1px solid var(--hairline);
}

.eyebrow {
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--signal);
  margin-bottom: 18px;
}

.hero h1 {
  font-size: clamp(34px, 7vw, 52px);
  line-height: 1.08;
  letter-spacing: -0.03em;
  font-weight: 700;
  margin-bottom: 20px;
  max-width: 15em;
}

.hero .lede {
  font-size: clamp(17px, 2.4vw, 20px);
  color: var(--muted);
  max-width: 34em;
  margin-bottom: 34px;
}

.cta-row {
  display: flex;
  align-items: center;
  gap: 18px;
  flex-wrap: wrap;
}

.btn {
  display: inline-block;
  background: var(--signal);
  color: var(--on-signal);
  font-weight: 650;
  font-size: 15px;
  text-decoration: none;
  padding: 13px 24px;
  border-radius: 10px;
  transition: opacity 0.15s, transform 0.15s;
}

.btn:hover {
  opacity: 0.9;
  transform: translateY(-1px);
}

.cta-note {
  font-size: 14px;
  color: var(--faint);
}

/* ---- sections ---- */

section.band {
  padding: 62px 0;
  border-bottom: 1px solid var(--hairline);
}

h2.section {
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--faint);
  margin-bottom: 26px;
}

.prose p {
  color: var(--muted);
  margin-bottom: 16px;
  max-width: 36em;
}

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

.prose strong {
  color: var(--text);
  font-weight: 600;
}

/* ---- three-up ---- */

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 18px;
}

.card {
  background: var(--surface);
  border: 1px solid var(--hairline);
  border-radius: 14px;
  padding: 22px 22px 24px;
}

.card .num {
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.12em;
  color: var(--signal);
  margin-bottom: 10px;
}

.card h3 {
  font-size: 16px;
  font-weight: 650;
  letter-spacing: -0.01em;
  margin-bottom: 7px;
}

.card p {
  font-size: 14.5px;
  color: var(--muted);
}

/* ---- sample lesson ---- */

.lesson {
  background: var(--surface);
  border: 1px solid var(--hairline);
  border-radius: 16px;
  overflow: hidden;
}

.lesson-head {
  padding: 20px 24px 18px;
  border-bottom: 1px solid var(--hairline);
  background: var(--raised);
}

.lesson-meta {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--faint);
  margin-bottom: 9px;
}

.chip {
  color: var(--coherence);
  border: 1px solid var(--coherence);
  border-radius: 999px;
  padding: 2px 9px;
  font-size: 10px;
  letter-spacing: 0.1em;
}

.lesson-head h3 {
  font-size: 20px;
  font-weight: 650;
  letter-spacing: -0.015em;
  margin-bottom: 6px;
}

.lesson-head p {
  color: var(--muted);
  font-size: 15px;
}

.lesson-body {
  padding: 22px 24px 24px;
}

.lesson-body .label {
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--faint);
  margin-bottom: 8px;
}

.lesson-body ol {
  padding-left: 20px;
  color: var(--muted);
  font-size: 15px;
}

.lesson-body li {
  margin-bottom: 7px;
}

.affirm {
  margin-top: 22px;
  padding-top: 18px;
  border-top: 1px solid var(--hairline);
  color: var(--coherence);
  font-size: 15.5px;
}

/* ---- footer ---- */

footer.site {
  padding: 30px 0 48px;
  font-size: 14px;
  color: var(--faint);
}

footer.site .wrap {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

footer.site a {
  color: var(--faint);
  text-decoration: none;
}

footer.site a:hover {
  color: var(--signal);
}

footer.site nav {
  display: flex;
  gap: 20px;
  flex-wrap: wrap;
}

/* ---- legal pages (privacy, terms) ---- */

.legal {
  padding: 54px 0 20px;
}

.legal h1 {
  font-size: clamp(28px, 5.5vw, 40px);
  line-height: 1.12;
  letter-spacing: -0.025em;
  font-weight: 700;
  margin-bottom: 10px;
}

.legal .meta {
  font-size: 14px;
  color: var(--faint);
  margin-bottom: 30px;
}

.legal h2 {
  font-size: 19px;
  font-weight: 650;
  letter-spacing: -0.015em;
  margin: 38px 0 12px;
}

.legal h3 {
  font-size: 15.5px;
  font-weight: 650;
  margin: 22px 0 8px;
  color: var(--text);
}

.legal p,
.legal li {
  color: var(--muted);
  margin-bottom: 13px;
}

.legal ul {
  padding-left: 22px;
  margin-bottom: 14px;
}

.legal li {
  margin-bottom: 7px;
}

.legal strong {
  color: var(--text);
  font-weight: 600;
}

.legal a {
  color: var(--signal);
}

/* Summary and the not-advice notice. The second is the one that matters for an
   app about your own mind, so it gets the caution colour rather than blending
   into the prose. */
.legal .card {
  background: var(--surface);
  border: 1px solid var(--hairline);
  border-radius: 14px;
  padding: 18px 20px;
  margin-bottom: 16px;
}

.legal .card p:last-child {
  margin-bottom: 0;
}

.legal .card.note {
  border-left: 3px solid var(--caution);
}

.legal .card.note strong {
  color: var(--caution);
}