/* Harness engineering learning path. Same look as the /resources hub (resources.css): white canvas, system type,
   quiet colour. This page has its own navbar markup (.site-nav), styled here to match the hub's frosted bar. */

:root {
  color-scheme: light;
  --bg: #ffffff;
  --bg-soft: #f5f5f7;
  --card: #ffffff;
  --ink: #1d1d1f;
  --ink-soft: #6e6e73;
  --ink-faint: #86868b;
  --line: #d2d2d7;
  --hair: rgba(0, 0, 0, 0.08);
  --accent: #0071e3;
  --accent-ink: #0066cc;
  --accent-on-dark: #2997ff;
  --kicker: #bf4800;
  --radius: 24px;
  --ease: cubic-bezier(0.28, 0.11, 0.32, 1);
  --maxw: 1040px;
  --gutter: max(clamp(20px, 5vw, 40px), calc((100% - var(--maxw)) / 2));
  --font: -apple-system, BlinkMacSystemFont, "SF Pro Display", "SF Pro Text", "Inter", "Helvetica Neue", "Segoe UI", Arial, sans-serif;
}

* {
  box-sizing: border-box;
}

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

body {
  min-width: 300px;
  min-height: 100vh;
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font: 17px/1.47 var(--font);
  letter-spacing: -0.011em;
  -webkit-font-smoothing: antialiased;
}

a {
  color: inherit;
  text-decoration: none;
}

a:focus-visible {
  outline: 3px solid var(--accent);
  outline-offset: 3px;
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

h1,
h2,
h3 {
  font-family: var(--font);
  text-wrap: balance;
}

.paper-texture,
.tape {
  display: none;
}

.skip-link {
  position: fixed;
  top: 12px;
  left: 12px;
  z-index: 100;
  padding: 10px 16px;
  border-radius: 980px;
  background: var(--ink);
  color: #fff;
  font-size: 14px;
  transform: translateY(-180%);
  transition: transform 0.2s var(--ease);
}

.skip-link:focus {
  transform: translateY(0);
}

/* Navbar: this page's own markup, made to look like the hub's thin frosted bar */
.site-nav {
  position: sticky;
  top: 0;
  z-index: 80;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  padding: 10px clamp(16px, 4vw, 40px);
  border-bottom: 1px solid var(--hair);
  background: rgba(255, 255, 255, 0.78);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  backdrop-filter: saturate(180%) blur(20px);
  font-size: 13px;
  line-height: 1.47;
  letter-spacing: -0.187px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--ink);
  font-size: 17px;
  font-weight: 600;
  letter-spacing: -0.02em;
  white-space: nowrap;
}

/* The hub marks the brand with a small black dot; the letter inside this one is decoration only. */
.brand-mark {
  flex: none;
  width: 9px;
  height: 9px;
  overflow: hidden;
  border-radius: 50%;
  background: var(--ink);
  font-size: 0;
  line-height: 0;
}

.site-nav nav {
  display: flex;
  align-items: center;
  gap: 26px;
}

.site-nav nav a {
  color: var(--ink);
  font-size: 13px;
  opacity: 0.8;
  white-space: nowrap;
  transition: opacity 0.2s;
}

.site-nav nav a:hover {
  opacity: 1;
}

.site-nav .nav-resource {
  padding: 7px 14px;
  border-radius: 980px;
  background: var(--ink);
  color: #fff;
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0;
  opacity: 1;
  transition: background 0.2s;
}

.site-nav .nav-resource:hover {
  background: #000;
}

/* Kickers, headlines, buttons */
.eyebrow,
.section-kicker {
  margin-bottom: 0;
  color: var(--ink-soft);
  font-size: 17px;
  font-weight: 600;
  letter-spacing: -0.01em;
}

.eyebrow span {
  display: none;
}

.hero h1,
.definition h2,
.section-head h2,
.build-intro h2,
.final-cta h2 {
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.07;
}

.hero h1 em,
.definition h2 em,
.section-head h2 em,
.build-intro h2 em,
.final-cta h2 em {
  color: var(--ink-faint);
  font-style: normal;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 14px 26px;
}

.hero-actions-center {
  justify-content: center;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 22px;
  border-radius: 980px;
  font-size: 17px;
  line-height: 1.2;
  transition: background 0.2s;
}

.button-ink,
.button-light {
  background: var(--accent);
  color: #fff;
}

.button-ink:hover,
.button-light:hover {
  background: #0077ed;
}

.button-paper,
.button-outline {
  padding-inline: 0;
  border-radius: 6px;
  color: var(--accent-ink);
}

.button-paper::after,
.button-outline::after {
  content: "\203A";
}

.button-paper:hover,
.button-outline:hover {
  text-decoration: underline;
}

.button-outline {
  color: var(--accent-on-dark);
}

section[id] {
  scroll-margin-top: 52px;
}

/* Hero */
.hero {
  padding: clamp(64px, 11vw, 132px) var(--gutter) clamp(48px, 7vw, 84px);
  text-align: center;
}

.hero h1 {
  margin: 14px auto 0;
  font-size: clamp(40px, 8vw, 92px);
  line-height: 1.04;
  letter-spacing: -0.035em;
}

.hero-lede {
  max-width: 700px;
  margin: 22px auto 0;
  color: var(--ink-soft);
  font-size: clamp(18px, 2.1vw, 22px);
  line-height: 1.42;
  letter-spacing: -0.012em;
}

.hero .hero-actions {
  justify-content: center;
  margin-top: 30px;
}

/* The route: six stops and the totals */
.hero-board {
  margin-top: clamp(40px, 6vw, 72px);
  padding: clamp(20px, 2.6vw, 30px);
  border-radius: 28px;
  background: var(--bg-soft);
  text-align: left;
}

.board-label {
  margin: 0 0 16px 4px;
  color: var(--ink-soft);
  font-size: 15px;
  font-weight: 600;
}

.hero-board ol {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: clamp(10px, 1.4vw, 16px);
  margin: 0;
  padding: 0;
  list-style: none;
}

.hero-board li {
  display: grid;
  align-content: start;
  gap: 4px;
  padding: 18px 20px 20px;
  border-radius: 18px;
  background: var(--card);
}

.hero-board li > span {
  color: var(--ink-faint);
  font-size: 13px;
  font-weight: 600;
  font-variant-numeric: tabular-nums;
}

.hero-board li strong {
  font-size: 21px;
  font-weight: 600;
  line-height: 1.19;
  letter-spacing: -0.02em;
}

.hero-board li small {
  color: var(--ink-soft);
  font-size: 15px;
  line-height: 1.4;
}

.board-stats {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 10px 48px;
  margin-top: clamp(22px, 3vw, 30px);
  padding-bottom: 4px;
  color: var(--ink-soft);
  font-size: 14px;
  text-align: center;
}

.board-stats strong {
  display: block;
  color: var(--ink);
  font-size: 28px;
  font-weight: 600;
  line-height: 1.2;
  letter-spacing: -0.02em;
}

/* Definition: the black band */
.definition {
  display: grid;
  grid-template-columns: minmax(0, 0.3fr) minmax(0, 1.5fr) minmax(0, 0.75fr);
  align-items: start;
  gap: clamp(28px, 4vw, 56px);
  padding: clamp(64px, 9vw, 112px) var(--gutter);
  background: #000;
  color: #f5f5f7;
}

.definition-index {
  padding-top: 2px;
  color: var(--ink-faint);
  font-size: 15px;
  font-weight: 600;
  line-height: 1.5;
  letter-spacing: 0.04em;
}

.definition .section-kicker {
  color: #a1a1a6;
}

.definition h2 {
  margin: 8px 0 0;
  font-size: clamp(32px, 3.8vw, 44px);
}

.definition-copy > p:last-child {
  max-width: 620px;
  margin: 18px 0 0;
  color: #a1a1a6;
  font-size: clamp(17px, 1.8vw, 19px);
  line-height: 1.47;
}

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

.system-parts li {
  display: grid;
  grid-template-columns: 30px 1fr;
  align-items: baseline;
  gap: 8px;
  padding: 13px 0;
  border-top: 1px solid rgba(255, 255, 255, 0.16);
  font-size: 17px;
  font-weight: 600;
}

.system-parts li:last-child {
  border-bottom: 1px solid rgba(255, 255, 255, 0.16);
}

.system-parts li span {
  color: var(--ink-faint);
  font-size: 13px;
  font-variant-numeric: tabular-nums;
}

/* Watch + read: shared section head */
.watch-section,
.reading-section {
  padding: clamp(56px, 8vw, 104px) var(--gutter);
}

.section-head {
  display: grid;
  grid-template-columns: minmax(0, 1.25fr) minmax(0, 0.75fr);
  align-items: end;
  gap: clamp(20px, 5vw, 72px);
  margin-bottom: clamp(28px, 4vw, 48px);
}

.section-head h2 {
  margin: 8px 0 0;
  font-size: clamp(34px, 5.4vw, 56px);
}

.section-head > p {
  margin-bottom: 6px;
  color: var(--ink-soft);
  font-size: clamp(17px, 1.8vw, 19px);
  line-height: 1.45;
}

/* Video cards */
.video-path {
  display: grid;
  gap: clamp(14px, 1.8vw, 22px);
}

.video-card {
  display: grid;
  gap: 16px;
  padding: clamp(18px, 2.6vw, 30px);
  border-radius: 28px;
  background: var(--bg-soft);
}

.step-rail {
  display: flex;
  align-items: baseline;
  gap: 10px;
}

.step-number {
  color: var(--ink-faint);
  font-size: 13px;
  font-weight: 600;
  font-variant-numeric: tabular-nums;
}

.step-phase {
  color: var(--kicker);
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.02em;
  text-transform: uppercase;
}

.video-content {
  display: grid;
  grid-template-columns: minmax(0, 1.3fr) minmax(0, 0.7fr);
  align-items: start;
  gap: 0 clamp(20px, 3vw, 36px);
}

.video-frame {
  grid-row: span 2;
  overflow: hidden;
  aspect-ratio: 16 / 9;
  border-radius: 18px;
  background: #000;
}

.video-frame iframe {
  display: block;
  width: 100%;
  height: 100%;
  border: 0;
  background: #000;
}

.video-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 8px;
  color: var(--ink-soft);
  font-size: 13px;
  font-variant-numeric: tabular-nums;
}

.video-heading h3 {
  margin-bottom: 10px;
  font-size: clamp(21px, 2.1vw, 25px);
  font-weight: 600;
  line-height: 1.17;
  letter-spacing: -0.022em;
  text-wrap: pretty;
}

.video-heading > p:last-child {
  margin: 0;
  color: var(--ink-soft);
  font-size: 16px;
  line-height: 1.42;
}

.notice {
  margin-top: 18px;
  padding: 16px 18px;
  border-radius: 16px;
  background: var(--card);
}

.notice > p {
  margin-bottom: 6px;
  color: var(--ink);
  font-size: 13px;
  font-weight: 600;
}

.notice ul {
  display: grid;
  gap: 4px;
  margin: 0;
  padding-left: 18px;
  color: var(--ink-soft);
  font-size: 14px;
  line-height: 1.42;
}

/* Build: the grey band */
.build-section {
  display: grid;
  grid-template-columns: minmax(0, 0.85fr) minmax(0, 1.15fr);
  gap: clamp(32px, 6vw, 80px);
  padding: clamp(56px, 8vw, 104px) var(--gutter);
  background: var(--bg-soft);
}

.build-intro {
  position: sticky;
  top: 84px;
  align-self: start;
}

.build-intro h2 {
  margin: 8px 0 0;
  font-size: clamp(34px, 4.8vw, 52px);
}

.build-intro > p {
  max-width: 480px;
  margin: 16px 0 0;
  color: var(--ink-soft);
  font-size: clamp(17px, 1.8vw, 19px);
  line-height: 1.45;
}

.build-brief {
  margin-top: 26px;
  padding: 20px 22px;
  border-radius: 18px;
  background: var(--card);
}

.build-brief span {
  display: block;
  margin-bottom: 6px;
  color: var(--kicker);
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.02em;
  text-transform: uppercase;
}

.build-brief p {
  margin: 0;
  font-weight: 600;
  line-height: 1.4;
}

.build-list {
  margin: 0;
  padding: 6px 26px;
  border-radius: var(--radius);
  background: var(--card);
  list-style: none;
}

.build-list li {
  display: grid;
  grid-template-columns: 34px 1fr;
  gap: 12px;
  padding: 20px 0;
  border-top: 1px solid var(--hair);
}

.build-list li:first-child {
  border-top: 0;
}

.check-number {
  padding-top: 5px;
  color: var(--ink-faint);
  font-size: 13px;
  font-weight: 600;
  font-variant-numeric: tabular-nums;
}

.build-list h3 {
  margin-bottom: 4px;
  font-size: 21px;
  font-weight: 600;
  line-height: 1.19;
  letter-spacing: -0.02em;
}

.build-list p {
  margin: 0;
  color: var(--ink-soft);
  font-size: 16px;
  line-height: 1.42;
}

/* Reading */
.reading-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: clamp(14px, 1.8vw, 22px);
}

.reading-card {
  display: flex;
  min-height: 300px;
  flex-direction: column;
  padding: 26px;
  border-radius: var(--radius);
  background: var(--bg-soft);
  transition: transform 0.35s var(--ease), box-shadow 0.35s var(--ease);
}

.reading-card:hover {
  box-shadow: 0 26px 48px -24px rgba(0, 0, 0, 0.28);
  transform: translateY(-4px);
}

.reading-source {
  margin-bottom: 8px;
  color: var(--kicker);
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.02em;
  text-transform: uppercase;
}

.reading-card strong {
  margin-bottom: 10px;
  font-size: 24px;
  font-weight: 600;
  line-height: 1.14;
  letter-spacing: -0.022em;
}

.reading-card p {
  margin-bottom: 22px;
  color: var(--ink-soft);
  font-size: 16px;
  line-height: 1.42;
}

.reading-action {
  margin-top: auto;
  color: var(--accent-ink);
  font-size: 17px;
}

.reading-card:hover .reading-action {
  text-decoration: underline;
}

/* Closing statement: the black band */
.final-cta {
  padding: clamp(64px, 10vw, 120px) var(--gutter);
  background: #000;
  color: #f5f5f7;
  text-align: center;
}

.final-cta .section-kicker {
  color: #a1a1a6;
  font-size: clamp(18px, 2vw, 21px);
  font-weight: 400;
}

.final-cta h2 {
  margin: 12px auto 0;
  font-size: clamp(32px, 5.6vw, 64px);
}

.final-cta > p:not(.section-kicker) {
  max-width: 620px;
  margin: 20px auto 30px;
  color: #a1a1a6;
  font-size: clamp(17px, 1.8vw, 19px);
}

footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px 24px;
  padding: 22px var(--gutter) 40px;
  color: var(--ink-soft);
  font-size: 13px;
}

footer p {
  margin: 0;
  text-align: center;
}

footer .footer-brand {
  gap: 8px;
  font-size: 13px;
  letter-spacing: 0;
}

footer > a:last-child {
  color: var(--accent-ink);
}

footer > a:last-child:hover {
  text-decoration: underline;
}

@media (max-width: 1060px) {
  .video-content {
    grid-template-columns: 1fr;
    gap: 18px;
  }

  .video-frame {
    grid-row: auto;
  }

  .notice {
    margin-top: 0;
  }
}

@media (max-width: 820px) {
  .definition {
    grid-template-columns: 1fr;
    gap: 22px;
  }

  .section-head {
    grid-template-columns: 1fr;
    gap: 14px;
  }

  .section-head > p {
    max-width: 630px;
  }

  .build-section {
    grid-template-columns: 1fr;
  }

  .build-intro {
    position: static;
  }

  .reading-grid {
    grid-template-columns: 1fr 1fr;
  }

  .reading-evals {
    grid-column: span 2;
    min-height: 0;
  }
}

@media (max-width: 660px) {
  body {
    font-size: 16px;
  }

  .site-nav nav a:not(.nav-resource) {
    display: none;
  }

  .hero-board ol {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .hero-board li {
    padding: 16px;
  }

  .hero-board li strong {
    font-size: 19px;
  }

  .hero-board li small {
    font-size: 14px;
  }

  .board-stats {
    gap: 10px 28px;
  }

  .video-card {
    border-radius: var(--radius);
  }

  .video-frame {
    border-radius: 14px;
  }

  .build-list {
    padding-inline: 22px;
  }

  .reading-grid {
    grid-template-columns: 1fr;
  }

  .reading-card,
  .reading-evals {
    grid-column: auto;
    min-height: 0;
  }

  footer {
    flex-direction: column;
    align-items: flex-start;
  }

  footer p {
    text-align: left;
  }
}

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

  *,
  *::before,
  *::after {
    transition: none !important;
  }

  .reading-card:hover {
    transform: none;
  }
}