:root {
  --cyan: #1db7d9;
  --cyan-deep: #1299b8;
  --navy: #073d76;
  --ink: #031428;
  --deep: #02101f;
  --foam: #e8f7fb;
  --mist: #9ecfe0;
  --muted: #8aaec2;
  --line: rgba(29, 183, 217, 0.22);
  --card: rgba(7, 61, 118, 0.35);
}

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

html {
  scroll-behavior: smooth;
}

section,
#problem,
#concept,
#sounds {
  scroll-margin-top: 88px;
}

body {
  font-family: "Avenir Next", "Segoe UI", Helvetica, Arial, sans-serif;
  color: var(--foam);
  background: var(--ink);
  line-height: 1.55;
}

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

a {
  color: inherit;
}

.wrap {
  width: min(1080px, calc(100% - 40px));
  margin: 0 auto;
}

.nav {
  position: sticky;
  top: 0;
  z-index: 20;
  backdrop-filter: blur(18px);
  background: rgba(3, 20, 40, 0.82);
  border-bottom: 1px solid var(--line);
}

.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 76px;
  gap: 16px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  color: white;
  font-weight: 800;
  letter-spacing: 0.16em;
  font-size: 0.92rem;
}

.brand img {
  width: 42px;
  height: 42px;
  border-radius: 12px;
}

.nav-links {
  display: flex;
  gap: 22px;
  list-style: none;
  flex-wrap: wrap;
  justify-content: flex-end;
}

.nav-links a {
  color: var(--mist);
  text-decoration: none;
  font-size: 0.92rem;
}

.nav-links a:hover,
.nav-links a[aria-current="page"] {
  color: var(--cyan);
}

.hero {
  padding: 88px 0 48px;
  background:
    radial-gradient(circle at 85% 0%, rgba(29, 183, 217, 0.22), transparent 36%),
    linear-gradient(180deg, #052a54 0%, var(--ink) 70%);
}

.hero-mark {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-bottom: 28px;
}

.hero-mark img {
  width: 72px;
  height: 72px;
  border-radius: 18px;
}

.eyebrow {
  color: var(--cyan);
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  font-size: 0.74rem;
}

.hero h1,
.problem h2,
.section-title {
  font-family: Georgia, "Iowan Old Style", "Palatino Linotype", serif;
  font-weight: 500;
  letter-spacing: -0.02em;
  line-height: 1.12;
  text-transform: lowercase;
}

.hero h1 {
  font-size: clamp(2.2rem, 5.4vw, 4.1rem);
  max-width: 16ch;
  margin: 10px 0 22px;
}

.lede {
  max-width: 42ch;
  color: #d7eef5;
  font-size: 1.18rem;
}

.actions {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  margin-top: 28px;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  text-decoration: none;
  border: 0;
  border-radius: 999px;
  padding: 13px 24px;
  font-weight: 700;
  font-size: 0.95rem;
  cursor: pointer;
  font-family: inherit;
}

.btn-primary {
  background: var(--cyan);
  color: white;
}

.btn-primary:hover {
  background: var(--cyan-deep);
}

.btn-ghost {
  border: 1px solid rgba(255, 255, 255, 0.35);
  color: white;
  background: transparent;
}

.plate {
  margin: 8px 0 0;
  border-radius: 28px;
  overflow: hidden;
  border: 1px solid var(--line);
}

.plate img {
  width: 100%;
  height: min(560px, 62vw);
  object-fit: cover;
}

.caption {
  padding: 12px 4px 0;
  color: var(--muted);
  font-size: 0.86rem;
}

.problem {
  padding: 88px 0 40px;
}

.problem h2 {
  font-size: clamp(1.9rem, 4.2vw, 3.2rem);
  max-width: 18ch;
  margin: 12px 0 20px;
}

section {
  padding: 72px 0;
}

.section-kicker {
  color: var(--cyan);
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: lowercase;
  font-size: 0.78rem;
  margin-bottom: 10px;
}

.section-title {
  font-size: clamp(1.7rem, 3vw, 2.4rem);
  margin-bottom: 16px;
}

.copy {
  color: var(--mist);
  max-width: 62ch;
  font-size: 1.05rem;
}

.copy + .copy {
  margin-top: 14px;
}

.stats {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 18px;
  margin-top: 36px;
}

.stat-card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 22px;
  padding: 26px 22px;
}

.stat-card b {
  display: block;
  color: var(--cyan);
  font-size: clamp(1.8rem, 3vw, 2.6rem);
  font-family: Georgia, "Iowan Old Style", serif;
  font-weight: 500;
  line-height: 1;
  margin-bottom: 12px;
}

.stat-card p {
  color: var(--mist);
  font-size: 0.98rem;
}

.note {
  margin-top: 22px;
  color: var(--muted);
  font-size: 0.9rem;
  max-width: 70ch;
}

.concept-list {
  display: grid;
  gap: 0;
  margin-top: 28px;
  border-top: 1px solid var(--line);
}

.concept-list li {
  list-style: none;
  display: grid;
  grid-template-columns: 56px 1fr;
  gap: 16px;
  padding: 22px 0;
  border-bottom: 1px solid var(--line);
  align-items: baseline;
}

.concept-list span {
  color: var(--cyan);
  font-weight: 800;
  letter-spacing: 0.08em;
  font-size: 0.82rem;
}

.sounds {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 18px;
  margin-top: 28px;
}

.wave-card {
  background: var(--deep);
  border: 1px solid var(--line);
  border-radius: 22px;
  padding: 22px;
}

.wave-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 16px;
}

.wave-card h3 {
  font-size: 1rem;
  font-weight: 600;
  text-transform: lowercase;
}

.play-btn {
  width: 44px;
  height: 44px;
  border: 0;
  border-radius: 50%;
  background: var(--cyan);
  color: white;
  cursor: pointer;
  display: grid;
  place-items: center;
  flex-shrink: 0;
}

.play-btn:hover {
  background: var(--cyan-deep);
}

.play-btn:focus-visible {
  outline: 2px solid var(--foam);
  outline-offset: 3px;
}

.play-icon {
  width: 0;
  height: 0;
  border-style: solid;
  border-width: 7px 0 7px 12px;
  border-color: transparent transparent transparent white;
  margin-left: 2px;
}

.play-btn.is-playing .play-icon {
  width: 12px;
  height: 12px;
  border: 0;
  margin-left: 0;
  background: linear-gradient(
    to right,
    white 0,
    white 4px,
    transparent 4px,
    transparent 8px,
    white 8px,
    white 12px
  );
}

.wave-stage {
  position: relative;
  overflow: hidden;
}

.wave-card svg {
  width: 100%;
  height: 92px;
}

.wave-progress {
  position: absolute;
  inset: 0 auto 0 0;
  width: 0%;
  background: rgba(29, 183, 217, 0.16);
  pointer-events: none;
}

.wave-card audio {
  display: block;
  width: 100%;
  margin-top: 14px;
  height: 36px;
}

.wave-error {
  margin-top: 10px;
  color: #ffb4b4;
  font-size: 0.82rem;
}

.wave-credit {
  margin-top: 12px;
  color: var(--muted);
  font-size: 0.82rem;
}

.why {
  display: grid;
  grid-template-columns: 0.9fr 1.1fr;
  gap: 36px;
  align-items: center;
}

.why-points {
  display: grid;
  gap: 22px;
}

.why-points h3 {
  font-size: 1.15rem;
  margin-bottom: 8px;
  text-transform: lowercase;
}

.sketch {
  border-radius: 22px;
  overflow: hidden;
  border: 1px solid var(--line);
}

.sketch img {
  width: 100%;
  height: auto;
}

.footer {
  background: var(--deep);
  color: var(--muted);
  padding: 28px 0;
}

.footer-inner {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
  font-size: 0.92rem;
}

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

.page {
  padding: 56px 0 88px;
}

.page h1 {
  font-size: 2.4rem;
  margin: 8px 0 20px;
}

.prose p,
.prose li {
  color: var(--mist);
  margin-bottom: 14px;
}

.prose h2 {
  font-size: 1.3rem;
  margin: 28px 0 10px;
}

.prose ul {
  padding-left: 20px;
}

.prose a {
  color: var(--cyan);
}

@media (max-width: 860px) {
  .stats,
  .sounds,
  .why {
    grid-template-columns: 1fr;
  }

  .hero {
    padding: 56px 0 32px;
  }

  .nav-links {
    gap: 12px;
  }

  .plate img {
    height: 240px;
  }
}