:root {
  --ink: #20252b;
  --muted: #68717a;
  --line: #d8dde1;
  --soft: #f4f7f8;
  --accent: #135f7a;
  --accent-deep: #0d455a;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: 82px;
}

body {
  margin: 0;
  background: #fff;
  color: var(--ink);
  font-family:
    "BIZ UDPGothic", "Yu Gothic", "YuGothic", "Hiragino Kaku Gothic ProN",
    Meiryo, sans-serif;
  -webkit-font-smoothing: antialiased;
}

img {
  max-width: 100%;
}

a {
  color: inherit;
}

.site-nav {
  position: sticky;
  z-index: 20;
  top: 0;
  border-bottom: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.96);
  box-shadow: 0 2px 12px rgba(25, 37, 45, 0.05);
  backdrop-filter: blur(10px);
}

.nav-inner,
.hero-inner,
.section,
.footer-inner {
  width: min(1120px, calc(100% - 48px));
  margin: 0 auto;
}

.nav-inner {
  display: flex;
  min-height: 58px;
  align-items: center;
  justify-content: space-between;
  gap: 28px;
}

.brand {
  font-size: 13px;
  font-weight: 800;
  letter-spacing: 0.04em;
  text-decoration: none;
}

.brand span {
  color: var(--muted);
  font-weight: 400;
}

.nav-links {
  display: flex;
  gap: 26px;
}

.nav-links a {
  color: var(--muted);
  font-size: 12px;
  font-weight: 700;
  text-decoration: none;
}

.nav-links a:hover,
.nav-links a:focus-visible {
  color: var(--accent);
}

.brand:focus-visible,
.nav-links a:focus-visible,
.button:focus-visible,
.product-links a:focus-visible,
.text-link:focus-visible,
.book-covers a:focus-visible {
  outline: 3px solid rgba(19, 95, 122, 0.28);
  outline-offset: 4px;
}

.hero {
  overflow: hidden;
  border-bottom: 1px solid var(--line);
}

.hero-inner {
  display: grid;
  min-height: 650px;
  padding: clamp(72px, 9vw, 112px) 0;
  grid-template-columns: minmax(0, 1.03fr) minmax(390px, 0.97fr);
  align-items: center;
  gap: clamp(48px, 7vw, 88px);
}

.eyebrow {
  margin: 0 0 16px;
  color: var(--accent);
  font-size: 11px;
  font-weight: 800;
  letter-spacing: 0.2em;
}

h1,
h2,
h3,
p {
  overflow-wrap: anywhere;
}

h1 {
  margin: 0;
  font-size: clamp(39px, 5.5vw, 66px);
  line-height: 1.4;
  letter-spacing: 0.035em;
}

h1 span {
  color: var(--accent-deep);
}

.lead {
  max-width: 650px;
  margin: 28px 0 0;
  color: var(--muted);
  font-size: 16px;
  line-height: 2;
}

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

.button {
  display: inline-flex;
  min-height: 48px;
  padding: 12px 19px;
  align-items: center;
  justify-content: center;
  gap: 16px;
  border: 1px solid var(--accent);
  font-size: 12px;
  font-weight: 800;
  text-decoration: none;
  transition:
    background 0.18s ease,
    color 0.18s ease,
    transform 0.18s ease;
}

.button:hover {
  transform: translateY(-2px);
}

.button.primary {
  background: var(--accent);
  color: #fff;
}

.button.primary:hover {
  background: var(--accent-deep);
}

.button.secondary {
  background: #fff;
  color: var(--accent);
}

.button.secondary:hover {
  background: var(--soft);
}

.keywords {
  display: flex;
  margin: 34px 0 0;
  padding: 0;
  gap: 28px;
  color: var(--muted);
  font-size: 9px;
  font-weight: 800;
  letter-spacing: 0.18em;
  list-style: none;
}

.keywords li + li::before {
  margin-right: 28px;
  color: var(--line);
  content: "/";
}

.receiver-stage {
  position: relative;
  width: 600px;
  height: 530px;
  margin-left: -38px;
  perspective: 1100px;
}

.signal-card,
.receiver-console {
  position: absolute;
  overflow: hidden;
  border: 1px solid rgba(19, 95, 122, 0.13);
  border-radius: 11px;
  background:
    linear-gradient(150deg, rgba(19, 95, 122, 0.028), transparent 48%),
    rgba(255, 255, 255, 0.96);
  box-shadow:
    0 24px 54px rgba(25, 37, 45, 0.1),
    0 3px 10px rgba(25, 37, 45, 0.05);
}

.receiver-console {
  z-index: 3;
  top: 66px;
  left: 24px;
  width: 350px;
  transform: rotate(-3deg) rotateY(-3deg);
}

.signal-card svg {
  display: block;
  width: 100%;
  height: auto;
  color: var(--accent);
}

.card-label {
  min-height: 34px;
  margin: 0;
  padding: 0 13px;
  border-bottom: 1px solid rgba(19, 95, 122, 0.08);
  color: var(--accent);
  font-size: 8px;
  font-weight: 800;
  letter-spacing: 0.12em;
  line-height: 34px;
  white-space: nowrap;
}

.waterfall-card {
  z-index: 1;
  top: 2px;
  right: -5px;
  width: 390px;
  transform: rotate(5deg) rotateY(-4deg);
}

.qpsk-card {
  z-index: 8;
  top: 178px;
  right: -2px;
  width: 190px;
  transform: rotate(7deg) rotateY(-3deg);
}

.qam-card {
  z-index: 7;
  bottom: 15px;
  left: -3px;
  width: 202px;
  transform: rotate(-6deg) rotateY(4deg);
}

.eye-card {
  z-index: 6;
  right: 38px;
  bottom: -2px;
  width: 365px;
  transform: rotate(2deg) rotateY(-2deg);
}

.console-bar {
  display: flex;
  min-height: 38px;
  padding: 0 13px;
  align-items: center;
  gap: 9px;
  border-bottom: 1px solid rgba(19, 95, 122, 0.1);
  color: var(--accent);
  font-size: 9px;
  font-weight: 800;
  letter-spacing: 0.13em;
}

.console-bar small {
  margin-left: auto;
  font-size: 8px;
  opacity: 0.6;
}

.console-lamp {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 0 4px rgba(19, 95, 122, 0.08);
}

.console-spectrum {
  display: block;
  width: 100%;
  height: auto;
  color: var(--accent);
}

.console-grid {
  fill: none;
  stroke: var(--accent);
  stroke-width: 1;
  opacity: 0.075;
}

.console-spectrum-fill {
  fill: var(--accent);
  opacity: 0.045;
}

.console-spectrum-line {
  fill: none;
  stroke: var(--accent);
  stroke-linejoin: round;
  stroke-width: 2;
  opacity: 0.42;
  vector-effect: non-scaling-stroke;
}

.console-axis-labels,
.eye-axis-labels {
  fill: var(--accent);
  font-size: 8px;
  font-weight: 800;
  letter-spacing: 0.11em;
  opacity: 0.28;
}

.chart-grid,
.eye-grid,
.constellation-grid {
  fill: none;
  stroke: var(--accent);
  stroke-width: 1;
  opacity: 0.07;
}

.waterfall-noise {
  fill: none;
  stroke: var(--accent);
  stroke-linecap: round;
  stroke-width: 1.1;
  opacity: 0.075;
}

.waterfall-carriers {
  fill: none;
  stroke: var(--accent);
  stroke-linecap: round;
  stroke-width: 4;
  opacity: 0.09;
}

.waterfall-carriers .carrier-strong {
  stroke-width: 7;
  opacity: 0.78;
}

.eye-traces {
  fill: none;
  stroke: var(--accent);
  stroke-linecap: round;
  stroke-width: 1.35;
  opacity: 0.27;
}

.eye-traces .eye-jitter {
  stroke-width: 0.8;
  opacity: 0.42;
}

.eye-traces .eye-secondary {
  stroke-width: 0.75;
  opacity: 0.26;
}

.eye-grid .ui-boundary {
  stroke-dasharray: 3 4;
  opacity: 0.65;
}

.eye-grid .sample-line {
  stroke-width: 1.2;
  opacity: 0.85;
}

.eye-grid .transition-line {
  stroke-dasharray: 2 5;
  opacity: 0.4;
}

.eye-samples {
  fill: var(--accent);
  opacity: 0.42;
}

.eye-decision-label {
  fill: var(--accent);
  font-size: 7px;
  font-weight: 800;
  letter-spacing: 0.1em;
  opacity: 0.23;
}

.constellation-points {
  fill: var(--accent);
  opacity: 0.34;
}

.console-metrics {
  display: grid;
  margin: 0;
  padding: 11px 13px 13px;
  border-top: 1px solid rgba(19, 95, 122, 0.09);
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 9px;
}

.console-metrics div {
  min-width: 0;
}

.console-metrics dt {
  color: var(--muted);
  font-size: 7px;
  font-weight: 700;
  letter-spacing: 0.08em;
}

.console-metrics dd {
  margin: 4px 0 0;
  color: var(--accent);
  font-size: 9px;
  font-weight: 800;
  font-variant-numeric: tabular-nums;
  white-space: nowrap;
}

.section {
  padding: clamp(72px, 9vw, 108px) 0;
  scroll-margin-top: 58px;
}

.section + .section {
  border-top: 1px solid var(--line);
}

.section-heading {
  display: grid;
  margin-bottom: 38px;
  grid-template-columns: 1fr minmax(280px, 0.72fr);
  align-items: end;
  gap: 48px;
}

h2 {
  margin: 0;
  font-size: clamp(28px, 3.6vw, 42px);
  line-height: 1.5;
  letter-spacing: 0.035em;
}

.section-heading > p,
.books-copy > p:not(.eyebrow) {
  margin: 0;
  color: var(--muted);
  font-size: 14px;
  line-height: 1.9;
}

.product-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 22px;
}

.product-card {
  display: flex;
  min-height: 330px;
  padding: 30px;
  border: 1px solid var(--line);
  background:
    linear-gradient(145deg, rgba(19, 95, 122, 0.035), transparent 42%),
    #fff;
  flex-direction: column;
  transition:
    border-color 0.18s ease,
    box-shadow 0.18s ease,
    transform 0.18s ease;
}

.product-card:hover {
  border-color: rgba(19, 95, 122, 0.45);
  box-shadow: 0 16px 38px rgba(25, 37, 45, 0.09);
  transform: translateY(-3px);
}

.product-standard {
  margin: 0;
  color: var(--accent);
  font-size: 10px;
  font-weight: 800;
  letter-spacing: 0.13em;
}

.product-card h3 {
  margin: 16px 0 0;
  font-size: 23px;
  letter-spacing: 0.025em;
}

.product-card > p:not(.product-standard) {
  margin: 22px 0 0;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.85;
}

.product-links {
  display: grid;
  margin-top: auto;
  padding-top: 28px;
  gap: 10px;
}

.product-links a,
.text-link {
  display: flex;
  padding-bottom: 7px;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  border-bottom: 1px solid currentColor;
  color: var(--accent);
  font-size: 12px;
  font-weight: 800;
  text-decoration: none;
}

.books {
  display: grid;
  grid-template-columns: minmax(260px, 0.72fr) minmax(0, 1.28fr);
  align-items: center;
  gap: clamp(54px, 8vw, 100px);
}

.books-copy > p:not(.eyebrow) {
  margin-top: 24px;
}

.text-link {
  width: fit-content;
  margin-top: 30px;
  gap: 52px;
}

.book-covers {
  display: grid;
  padding: 36px;
  background: var(--soft);
  grid-template-columns: repeat(3, minmax(0, 1fr));
  align-items: center;
  gap: 20px;
}

.book-covers a {
  display: block;
  transition: transform 0.18s ease;
}

.book-covers a:nth-child(1) {
  transform: rotate(-3deg);
}

.book-covers a:nth-child(2) {
  transform: translateY(-12px);
}

.book-covers a:nth-child(3) {
  transform: rotate(3deg);
}

.book-covers a:hover {
  transform: translateY(-8px);
}

.book-covers img {
  display: block;
  width: 100%;
  height: auto;
  box-shadow: 0 14px 28px rgba(25, 37, 45, 0.18);
}

.event {
  display: grid;
  grid-template-columns: 0.55fr 1fr auto;
  align-items: center;
  gap: 46px;
}

.event-label span {
  color: var(--accent);
  font-size: clamp(26px, 3vw, 38px);
  font-weight: 300;
  letter-spacing: 0.05em;
}

.event-details h2 {
  font-size: 25px;
}

.event-details p {
  margin: 12px 0 0;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.8;
}

.event-action {
  display: grid;
  justify-items: start;
  gap: 9px;
}

.event-action small {
  color: var(--muted);
  font-size: 9px;
  line-height: 1.6;
}

footer {
  border-top: 1px solid var(--line);
}

.footer-inner {
  display: grid;
  padding: 34px 0;
  grid-template-columns: auto 1fr auto;
  align-items: center;
  gap: 30px;
  color: var(--muted);
  font-size: 10px;
}

.footer-inner strong {
  color: var(--ink);
  font-size: 12px;
}

.footer-inner p {
  margin: 0;
}

@media (max-width: 900px) {
  .hero-inner {
    min-height: auto;
    grid-template-columns: 1fr;
  }

  .receiver-stage {
    width: min(600px, 100%);
    margin: 0 auto;
  }

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

  .product-card:last-child {
    grid-column: 1 / -1;
  }

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

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

  .event .button {
    width: fit-content;
  }
}

@media (max-width: 620px) {
  .nav-inner,
  .hero-inner,
  .section,
  .footer-inner {
    width: min(100% - 32px, 1120px);
  }

  .nav-inner {
    min-height: 54px;
  }

  .nav-links {
    gap: 14px;
  }

  .nav-links a {
    font-size: 10px;
  }

  .hero-inner {
    padding: 64px 0 72px;
    gap: 48px;
  }

  h1 {
    font-size: clamp(34px, 11vw, 48px);
  }

  .lead {
    font-size: 14px;
    line-height: 1.9;
  }

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

  .button {
    width: 100%;
  }

  .keywords {
    gap: 12px;
  }

  .keywords li + li::before {
    margin-right: 12px;
  }

  .receiver-stage {
    height: 500px;
  }

  .receiver-console {
    top: 64px;
    left: 0;
    width: 66%;
  }

  .waterfall-card {
    top: 8px;
    right: -2%;
    width: 72%;
  }

  .qpsk-card {
    top: 178px;
    right: 1%;
    width: 42%;
    transform: rotate(4deg);
  }

  .qam-card {
    bottom: 4px;
    left: 2%;
    width: 46%;
    transform: rotate(-4deg);
  }

  .eye-card {
    right: 2%;
    bottom: 12px;
    width: 72%;
    transform: rotate(1deg);
  }

  .constellation-card .card-label {
    padding: 0 9px;
    font-size: 6px;
    letter-spacing: 0.06em;
  }

  .console-metrics {
    grid-template-columns: 1fr 1fr;
  }

  .section {
    padding: 64px 0;
  }

  .section-heading {
    grid-template-columns: 1fr;
    gap: 18px;
  }

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

  .product-card,
  .product-card:last-child {
    min-height: 310px;
    grid-column: auto;
  }

  .book-covers {
    padding: 28px 22px;
    gap: 12px;
  }

  .event {
    grid-template-columns: 1fr;
    gap: 24px;
  }

  .footer-inner {
    grid-template-columns: 1fr;
    gap: 8px;
  }
}

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

  .button,
  .product-card,
  .book-covers a {
    transition: none;
  }
}