:root {
  --bg: #fbfcfd;
  --paper: #ffffff;
  --ink: #111827;
  --muted: #5c6672;
  --line: #dce4ec;
  --blue: #1769ff;
  --teal: #00a7b5;
  --green: #24a45a;
  --yellow: #f4aa16;
  --orange: #ef6a31;
  --shadow: 0 18px 50px rgba(31, 45, 61, 0.12);
  --radius: 8px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  overflow-x: hidden;
  background:
    linear-gradient(180deg, rgba(255, 255, 255, 0.88), rgba(251, 252, 253, 0.95)),
    radial-gradient(circle at 20% 10%, rgba(0, 167, 181, 0.08), transparent 28%),
    var(--bg);
  color: var(--ink);
  font-family:
    Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

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

img {
  display: block;
  max-width: 100%;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  min-height: 68px;
  padding: 0 5vw;
  border-bottom: 1px solid rgba(220, 228, 236, 0.72);
  background: rgba(255, 255, 255, 0.82);
  backdrop-filter: blur(16px);
}

.brand,
.nav-links,
.hero-actions,
.site-footer {
  display: flex;
  align-items: center;
}

.brand {
  gap: 10px;
  font-weight: 800;
  font-size: 18px;
}

.brand-mark {
  display: grid;
  place-items: center;
  width: 30px;
  height: 30px;
  border: 2px solid var(--ink);
  border-radius: 50%;
  font-family: ui-monospace, SFMono-Regular, Consolas, monospace;
  line-height: 1;
}

.nav-links {
  gap: 28px;
  color: var(--muted);
  font-size: 14px;
  font-weight: 650;
}

.nav-links a:hover,
.header-action:hover,
.note-row:hover strong {
  color: var(--blue);
}

.header-action {
  color: var(--blue);
  font-size: 14px;
  font-weight: 750;
}

.hero {
  position: relative;
  display: grid;
  grid-template-columns: minmax(320px, 0.86fr) minmax(420px, 1.14fr);
  align-items: center;
  min-height: calc(100vh - 68px);
  overflow: hidden;
  background: var(--paper);
}

.hero > *,
.water-band > * {
  min-width: 0;
}

.hero::after,
.section-flow::after {
  position: absolute;
  right: 0;
  bottom: -1px;
  left: 0;
  height: 88px;
  background:
    linear-gradient(175deg, transparent 48%, var(--bg) 49%),
    radial-gradient(80% 110% at 20% 100%, rgba(0, 167, 181, 0.16), transparent 55%);
  content: "";
  pointer-events: none;
}

.hero-copy {
  position: relative;
  z-index: 2;
  padding: 72px 0 128px 5vw;
}

.site-line {
  margin: 0 0 16px;
  color: var(--teal);
  font-family: ui-monospace, SFMono-Regular, Consolas, monospace;
  font-size: 13px;
  font-weight: 800;
  letter-spacing: 0;
  text-transform: uppercase;
}

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

h1 {
  max-width: 720px;
  margin-bottom: 22px;
  font-size: clamp(48px, 7vw, 92px);
  line-height: 0.95;
  letter-spacing: 0;
}

h2 {
  margin-bottom: 14px;
  font-size: clamp(32px, 4vw, 56px);
  line-height: 1.02;
  letter-spacing: 0;
}

h3 {
  margin-bottom: 12px;
  font-size: 22px;
  line-height: 1.1;
}

.hero-text,
.section-heading p,
.dashboard-copy p,
.teaching-grid p,
.site-footer p {
  color: var(--muted);
  font-size: 18px;
  line-height: 1.65;
}

.hero-text {
  max-width: 660px;
}

.hero-actions {
  flex-wrap: wrap;
  gap: 12px;
  margin: 34px 0;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 48px;
  padding: 0 20px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  font-size: 15px;
  font-weight: 800;
}

.button.primary {
  border-color: var(--blue);
  background: var(--blue);
  color: #fff;
  box-shadow: 0 12px 24px rgba(23, 105, 255, 0.22);
}

.button.secondary {
  background: #fff;
}

.code-card {
  width: min(100%, 430px);
  max-width: 430px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: rgba(255, 255, 255, 0.88);
  box-shadow: var(--shadow);
  font-family: ui-monospace, SFMono-Regular, Consolas, monospace;
}

.code-card ol {
  margin: 0;
  padding: 18px 20px 18px 48px;
  color: #7b8795;
}

.code-card li {
  padding: 5px 0;
}

.code-card span {
  color: #15803d;
}

.code-card em {
  color: var(--orange);
  font-style: normal;
}

.hero-media {
  position: relative;
  min-width: 0;
  min-height: calc(100vh - 68px);
}

.hero-media::before {
  position: absolute;
  inset: 0 auto 0 0;
  z-index: 1;
  width: 32%;
  background: linear-gradient(90deg, #fff 0%, rgba(255, 255, 255, 0.86) 48%, transparent 100%);
  content: "";
}

.hero-media img {
  width: 100%;
  height: calc(100vh - 68px);
  object-fit: cover;
  object-position: center;
}

.intro-river {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 0;
  margin: -40px auto 0;
  padding: 0 5vw;
  position: relative;
  z-index: 3;
}

.intro-river div {
  min-height: 132px;
  padding: 28px;
  border: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.9);
  box-shadow: 0 12px 34px rgba(31, 45, 61, 0.08);
}

.intro-river div:first-child {
  border-radius: var(--radius) 0 0 var(--radius);
}

.intro-river div:last-child {
  border-radius: 0 var(--radius) var(--radius) 0;
}

.intro-river strong,
.intro-river span {
  display: block;
}

.intro-river strong {
  margin-bottom: 8px;
  font-size: 18px;
}

.intro-river span {
  color: var(--muted);
  line-height: 1.5;
}

.section {
  padding: 112px 5vw;
}

.section-heading {
  max-width: 760px;
  margin-bottom: 42px;
}

.lane-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.lane-card {
  min-height: 330px;
  padding: 34px 30px;
  border-right: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.55);
}

.lane-card:last-child {
  border-right: 0;
}

.lane-card p {
  min-height: 88px;
  color: var(--muted);
  line-height: 1.6;
}

.lane-card a,
.note-row {
  font-weight: 800;
}

.lane-icon,
.note-icon {
  display: grid;
  place-items: center;
  width: 52px;
  height: 52px;
  margin-bottom: 28px;
  border: 2px solid currentColor;
  border-radius: 50%;
  font-size: 25px;
  font-weight: 900;
}

.ai {
  color: var(--blue);
}

.robotics {
  color: var(--green);
}

.weather {
  color: var(--teal);
}

.diy {
  color: var(--yellow);
}

.lane-card h3,
.lane-card p,
.lane-card a {
  color: var(--ink);
}

.lane-card.ai h3,
.ai-dot {
  color: var(--blue);
}

.lane-card.robotics h3,
.robot-dot {
  color: var(--green);
}

.lane-card.weather h3,
.weather-dot {
  color: var(--teal);
}

.lane-card.diy h3,
.diy-dot {
  color: var(--yellow);
}

.interest-section {
  background:
    linear-gradient(180deg, #fff 0%, #f7fbfd 100%),
    linear-gradient(90deg, rgba(0, 167, 181, 0.06), transparent);
}

.interest-grid {
  display: grid;
  grid-template-columns: minmax(320px, 1.2fr) repeat(3, minmax(220px, 1fr));
  gap: 16px;
}

.interest-card {
  display: flex;
  flex-direction: column;
  min-height: 300px;
  padding: 28px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: rgba(255, 255, 255, 0.78);
  box-shadow: 0 12px 34px rgba(31, 45, 61, 0.08);
}

.interest-card.featured {
  background:
    linear-gradient(135deg, rgba(23, 105, 255, 0.1), rgba(0, 167, 181, 0.1)),
    #fff;
}

.interest-kicker {
  width: max-content;
  margin-bottom: 16px;
  padding: 7px 10px;
  border: 1px solid rgba(23, 105, 255, 0.16);
  border-radius: 999px;
  background: #eef5ff;
  color: var(--blue);
  font-size: 12px;
  font-weight: 850;
  text-transform: uppercase;
}

.interest-card p {
  color: var(--muted);
  line-height: 1.6;
}

.interest-card a:not(.button) {
  margin-top: auto;
  color: var(--blue);
  font-weight: 850;
}

.interest-card .button {
  width: max-content;
  margin-top: auto;
}

.notes-section {
  background:
    linear-gradient(180deg, #fff 0%, var(--bg) 100%),
    linear-gradient(90deg, rgba(23, 105, 255, 0.04), transparent);
}

.notes-list {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
  background: var(--paper);
}

.note-row {
  display: grid;
  grid-template-columns: 60px 1fr auto;
  align-items: center;
  gap: 20px;
  padding: 20px 24px;
  border-bottom: 1px solid var(--line);
}

.note-row:last-child {
  border-bottom: 0;
}

.note-row small {
  display: block;
  margin-top: 4px;
  color: var(--muted);
  font-size: 14px;
  font-weight: 500;
  line-height: 1.45;
}

.note-icon {
  width: 42px;
  height: 42px;
  margin: 0;
  font-size: 20px;
}

.note-tag {
  min-width: 92px;
  padding: 8px 10px;
  border-radius: 999px;
  background: #eef5ff;
  color: var(--blue);
  text-align: center;
  font-size: 12px;
}

.water-band {
  position: relative;
  display: grid;
  grid-template-columns: minmax(320px, 0.82fr) minmax(420px, 1.18fr);
  gap: 56px;
  align-items: center;
  overflow: hidden;
  background:
    linear-gradient(135deg, rgba(0, 167, 181, 0.12), rgba(23, 105, 255, 0.07) 46%, rgba(244, 170, 22, 0.1)),
    #f7fbfd;
}

.water-band::before {
  position: absolute;
  top: -70px;
  right: -5vw;
  left: -5vw;
  height: 140px;
  background: radial-gradient(90% 110% at 50% 100%, #fff 0 58%, transparent 59%);
  content: "";
}

.dashboard-copy,
.dashboard-panel {
  position: relative;
  z-index: 1;
}

.dashboard-panel {
  border: 1px solid rgba(17, 24, 39, 0.08);
  border-radius: var(--radius);
  background: rgba(255, 255, 255, 0.86);
  box-shadow: var(--shadow);
}

.status-row {
  display: grid;
  grid-template-columns: 18px 1fr auto;
  gap: 14px;
  align-items: center;
  padding: 22px 24px;
  border-bottom: 1px solid var(--line);
}

.status-row strong {
  color: var(--muted);
  font-size: 14px;
}

.status-light {
  width: 10px;
  height: 10px;
  border-radius: 50%;
}

.running {
  background: var(--green);
}

.learning {
  background: var(--blue);
}

.planning {
  background: var(--yellow);
}

.meter {
  height: 12px;
  margin: 24px;
  border-radius: 999px;
  background: #e8eef5;
  overflow: hidden;
}

.meter span {
  display: block;
  width: 68%;
  height: 100%;
  border-radius: inherit;
  background: linear-gradient(90deg, var(--teal), var(--blue), var(--yellow));
}

.dashboard-stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  border-top: 1px solid var(--line);
}

.dashboard-stats div {
  padding: 22px 24px;
  border-right: 1px solid var(--line);
}

.dashboard-stats div:last-child {
  border-right: 0;
}

.dashboard-stats strong,
.dashboard-stats span {
  display: block;
}

.dashboard-stats strong {
  font-size: 34px;
}

.dashboard-stats span {
  color: var(--muted);
  font-size: 13px;
}

.teaching-section {
  background: #fff;
}

.teaching-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}

.teaching-grid div {
  min-height: 220px;
  padding: 30px;
  background: #fff;
}

.site-footer {
  justify-content: space-between;
  gap: 24px;
  padding: 42px 5vw;
  border-top: 1px solid var(--line);
  background: #f6f8fb;
}

.site-footer div {
  max-width: 640px;
}

.site-footer p {
  margin: 8px 0 0;
  font-size: 15px;
}

.site-footer a {
  color: var(--blue);
  font-weight: 800;
}

@media (max-width: 980px) {
  .site-header {
    align-items: flex-start;
    flex-direction: column;
    padding-top: 16px;
    padding-bottom: 16px;
  }

  .nav-links {
    flex-wrap: wrap;
    gap: 14px 22px;
  }

  .header-action {
    display: none;
  }

  .hero,
  .water-band {
    grid-template-columns: minmax(0, 1fr);
  }

  .hero {
    min-height: auto;
  }

  .hero-copy {
    width: 100%;
    padding: 56px 5vw 40px;
  }

  .hero-media,
  .hero-media img {
    min-height: 380px;
    height: 52vh;
  }

  .hero-media::before {
    display: none;
  }

  .intro-river,
  .lane-grid,
  .interest-grid,
  .teaching-grid,
  .dashboard-stats {
    grid-template-columns: 1fr;
  }

  .intro-river {
    margin-top: 24px;
  }

  .intro-river div,
  .intro-river div:first-child,
  .intro-river div:last-child {
    border-radius: 0;
  }

  .lane-card {
    min-height: 260px;
    border-right: 0;
    border-bottom: 1px solid var(--line);
  }

  .interest-card {
    min-height: 240px;
  }

  .dashboard-stats div {
    border-right: 0;
    border-bottom: 1px solid var(--line);
  }
}

@media (max-width: 640px) {
  .site-header {
    position: static;
  }

  .nav-links {
    display: none;
  }

  h1 {
    max-width: 100%;
    font-size: 38px;
    line-height: 1.03;
  }

  .hero-copy {
    width: min(100vw, 390px);
    max-width: 100vw;
    padding-right: 24px;
    padding-left: 24px;
    justify-self: start;
    overflow: hidden;
  }

  .hero-text,
  .hero-actions,
  .code-card {
    max-width: 100%;
  }

  .hero-actions,
  .site-footer {
    align-items: stretch;
    flex-direction: column;
  }

  .button {
    width: 100%;
  }

  .interest-card .button {
    width: 100%;
  }

  .section {
    padding: 72px 5vw;
  }

  .note-row,
  .status-row {
    grid-template-columns: 1fr;
  }

  .note-icon {
    display: none;
  }

  .note-tag {
    width: max-content;
  }
}