:root {
  color-scheme: dark;
  --ink: #f5f7ff;
  --muted: #b5bfd8;
  --paper: #060914;
  --surface: #0d1426;
  --surface-raised: #121c34;
  --line: #263451;
  --brand: #57ddff;
  --brand-strong: #9aecff;
  --accent: #ffb14a;
  --soft: #142b42;
  --focus: #ffdb70;
  --max: 76rem;
  --radius: 1.25rem;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  position: relative;
  isolation: isolate;
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-size: 1rem;
  line-height: 1.7;
}

body::before {
  position: fixed;
  inset: -4vh -4vw;
  z-index: -2;
  content: "";
  background-image: url("/assets/sparkegg-brand.jpg");
  background-position: calc(50% + 14vw) center;
  background-repeat: no-repeat;
  background-size: min(110vw, 110rem) auto;
  filter: saturate(1.16) contrast(1.08);
  opacity: 0.72;
  pointer-events: none;
}

body::after {
  position: fixed;
  inset: 0;
  z-index: -1;
  content: "";
  background:
    linear-gradient(90deg, rgb(6 9 20 / 96%) 0%, rgb(6 9 20 / 82%) 30%, rgb(6 9 20 / 22%) 56%, rgb(6 9 20 / 16%) 74%, rgb(6 9 20 / 32%) 100%),
    linear-gradient(180deg, rgb(8 12 25 / 12%) 0%, rgb(6 9 20 / 28%) 62%, rgb(5 8 18 / 78%) 100%);
  pointer-events: none;
}

a {
  color: var(--brand-strong);
  text-decoration-thickness: 0.1em;
  text-underline-offset: 0.18em;
}

a:hover {
  text-decoration-thickness: 0.18em;
}

:focus-visible {
  outline: 0.2rem solid var(--focus);
  outline-offset: 0.2rem;
}

.skip-link {
  position: fixed;
  top: 0.5rem;
  left: 0.5rem;
  z-index: 20;
  padding: 0.7rem 1rem;
  border-radius: 0.6rem;
  background: var(--ink);
  color: var(--paper);
  transform: translateY(-160%);
}

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

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  border-bottom: 1px solid var(--line);
  background: rgb(6 9 20 / 88%);
  backdrop-filter: blur(1rem);
}

.header-inner,
.site-footer-inner,
main {
  width: min(calc(100% - 2rem), var(--max));
  margin-inline: auto;
}

.header-inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem 1.5rem;
  padding-block: 0.85rem;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.7rem;
  color: var(--ink);
  font-size: 1.05rem;
  font-weight: 850;
  letter-spacing: 0.09em;
  text-decoration: none;
}

.brand-mark {
  display: block;
  width: 2.5rem;
  height: 2.5rem;
  overflow: hidden;
  border: 1px solid rgb(87 221 255 / 72%);
  border-radius: 50%;
  background: #050815;
  box-shadow: 0 0 1.25rem rgb(87 221 255 / 24%);
}

.brand-mark img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.brand-name > span {
  color: var(--brand);
}

.brand-name {
  display: inline-flex;
  align-items: baseline;
  gap: 0.42rem;
}

.brand-name small {
  color: var(--muted);
  font-size: 0.58em;
  font-weight: 750;
  letter-spacing: 0.18em;
}

.site-nav ul,
.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem 1rem;
  margin: 0;
  padding: 0;
  list-style: none;
}

.site-nav a {
  display: inline-block;
  padding: 0.45rem 0.1rem;
  color: #dce5fb;
  font-weight: 650;
}

main {
  min-height: 65vh;
}

.hero {
  display: grid;
  grid-template-columns: minmax(0, 44rem);
  align-items: center;
  min-height: clamp(38rem, 78vh, 56rem);
  padding-block: clamp(3.5rem, 8vw, 7rem);
}

.hero > :first-child {
  position: relative;
  z-index: 1;
  text-shadow: 0 0.15rem 1.4rem rgb(0 0 0 / 62%);
}

.eyebrow {
  margin: 0 0 0.45rem;
  color: var(--brand);
  font-size: 0.92rem;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

h1,
h2,
h3 {
  line-height: 1.25;
}

h1 {
  max-width: 12ch;
  margin: 0;
  font-size: clamp(2.7rem, 7vw, 5.7rem);
  letter-spacing: -0.055em;
}

h2 {
  margin-top: 0;
  font-size: clamp(1.65rem, 4vw, 2.4rem);
}

h3 {
  font-size: 1.25rem;
}

.lead {
  max-width: 44rem;
  margin-block: 1.4rem;
  color: var(--muted);
  font-size: clamp(1.08rem, 2vw, 1.32rem);
}

.hero-visual {
  --egg-mask-rx: min(18vw, 18rem);
  --egg-mask-ry: min(18vw, 18rem);
  position: fixed;
  top: calc(50% + min(4.57vw, 4.57rem));
  left: 64vw;
  z-index: 0;
  display: block;
  width: 1px;
  height: 1px;
  border: 0;
  background: transparent;
  opacity: 0.72;
  pointer-events: none;
  transform: translate(-50%, -50%);
}

.hero-visual img {
  display: none;
}

.orbit {
  position: absolute;
  top: 50%;
  left: 50%;
  border: 1px solid rgb(88 222 255 / 22%);
  border-radius: 50%;
  pointer-events: none;
}

.orbit-one {
  width: 52rem;
  height: 22rem;
  animation: orbit-one-turn 230s linear infinite;
}

.orbit-two {
  width: 44rem;
  height: 28rem;
  border-color: rgb(137 82 255 / 30%);
  box-shadow: 0 0 2.5rem rgb(137 82 255 / 8%);
  animation: orbit-two-turn 310s linear infinite;
}

.orbit-back {
  z-index: 0;
  opacity: 0.48;
  -webkit-mask-image: radial-gradient(ellipse var(--egg-mask-rx) var(--egg-mask-ry) at center, transparent 98%, #000 100%);
  mask-image: radial-gradient(ellipse var(--egg-mask-rx) var(--egg-mask-ry) at center, transparent 98%, #000 100%);
}

.orbit-front {
  z-index: 2;
  border-color: rgb(113 229 255 / 34%);
  filter: drop-shadow(0 0 0.3rem rgb(87 221 255 / 20%));
  -webkit-mask-image: linear-gradient(to bottom, transparent 0 44%, #000 52% 100%);
  mask-image: linear-gradient(to bottom, transparent 0 44%, #000 52% 100%);
}

.orbit-two.orbit-front {
  border-color: rgb(158 112 255 / 38%);
}

.spark-path {
  --spark-radius: 20rem;
  --spark-plane: 0deg;
  --spark-flatten: 0.5;
  --spark-unflatten: 2;
  position: absolute;
  top: 50%;
  left: 50%;
  z-index: 3;
  width: 0;
  height: 0;
  pointer-events: none;
  transform: rotate(var(--spark-plane)) scaleY(var(--spark-flatten));
  transform-origin: center;
}

.spark {
  position: absolute;
  top: 0;
  left: 0;
  border-radius: 50%;
  background: #dffaff;
  pointer-events: none;
  offset-anchor: center;
  offset-path: circle(var(--spark-radius) at 0 0);
  offset-rotate: 0deg;
  transform: translate(-50%, -50%) scaleY(var(--spark-unflatten));
}

.spark-path-large {
  --spark-radius: 19rem;
  --spark-plane: 17deg;
  --spark-flatten: 0.46;
  --spark-unflatten: 2.174;
}

.spark-large {
  width: 0.78rem;
  height: 0.78rem;
  box-shadow: 0 0 0.8rem #dffaff, 0 0 1.8rem #57ddff, 0 0 3rem #8952ff;
  animation: spark-orbit 29s -11.8s linear infinite, spark-depth 29s -11.8s linear infinite;
}

.spark-small {
  width: 0.3rem;
  height: 0.3rem;
  box-shadow: 0 0 0.65rem #57ddff, 0 0 1.2rem #8952ff;
}

.spark-path-small-one {
  --spark-radius: 16.5rem;
  --spark-plane: -41deg;
  --spark-flatten: 0.62;
  --spark-unflatten: 1.613;
}

.spark-small-one {
  animation: spark-orbit 23s -5.4s linear infinite, spark-depth 23s -5.4s linear infinite;
}

.spark-path-small-two {
  --spark-radius: 20.5rem;
  --spark-plane: 63deg;
  --spark-flatten: 0.38;
  --spark-unflatten: 2.632;
}

.spark-small-two {
  width: 0.24rem;
  height: 0.24rem;
  animation: spark-orbit 31s -17.2s linear infinite reverse, spark-depth 31s -17.2s linear infinite reverse;
}

.spark-path-small-three {
  --spark-radius: 17.5rem;
  --spark-plane: -69deg;
  --spark-flatten: 0.72;
  --spark-unflatten: 1.389;
}

.spark-small-three {
  width: 0.38rem;
  height: 0.38rem;
  animation: spark-orbit 37s -28.6s linear infinite, spark-depth 37s -28.6s linear infinite;
}

@keyframes orbit-one-turn {
  from { transform: translate(-50%, -50%) rotate(17deg); }
  to { transform: translate(-50%, -50%) rotate(377deg); }
}

@keyframes orbit-two-turn {
  from { transform: translate(-50%, -50%) rotate(-53deg); }
  to { transform: translate(-50%, -50%) rotate(-413deg); }
}

@keyframes spark-orbit {
  from { offset-distance: 0%; }
  to { offset-distance: 100%; }
}

@keyframes spark-depth {
  0%, 100% { opacity: 0.82; transform: translate(-50%, -50%) scale(0.92) scaleY(var(--spark-unflatten)); }
  12% { opacity: 0.95; transform: translate(-50%, -50%) scale(1.24) scaleY(var(--spark-unflatten)); }
  25% { opacity: 1; transform: translate(-50%, -50%) scale(1.7) scaleY(var(--spark-unflatten)); }
  40% { opacity: 0.9; transform: translate(-50%, -50%) scale(1.18) scaleY(var(--spark-unflatten)); }
  52% { opacity: 0.55; transform: translate(-50%, -50%) scale(0.72) scaleY(var(--spark-unflatten)); }
  61% { opacity: 0.2; transform: translate(-50%, -50%) scale(0.5) scaleY(var(--spark-unflatten)); }
  68%, 82% { opacity: 0; transform: translate(-50%, -50%) scale(0.36) scaleY(var(--spark-unflatten)); }
  91% { opacity: 0.34; transform: translate(-50%, -50%) scale(0.58) scaleY(var(--spark-unflatten)); }
}

.actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.button {
  display: inline-flex;
  min-height: 3rem;
  align-items: center;
  justify-content: center;
  padding: 0.65rem 1.1rem;
  border: 2px solid var(--brand);
  border-radius: 999px;
  background: var(--brand);
  color: #04111a;
  font-weight: 800;
  text-decoration: none;
}

.button-secondary {
  background: var(--surface);
  color: var(--brand-strong);
}

.section {
  position: relative;
  z-index: 1;
  padding-block: clamp(2.5rem, 6vw, 5rem);
}

.section-heading {
  max-width: 46rem;
  margin-bottom: 1.75rem;
}

.grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem;
}

.card {
  padding: clamp(1.2rem, 3vw, 1.8rem);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
  background:
    linear-gradient(145deg, rgb(255 255 255 / 3%), transparent 42%),
    var(--surface);
  box-shadow: 0 1rem 2.5rem rgb(0 0 0 / 18%);
  transition: border-color 180ms ease-out, box-shadow 180ms ease-out, transform 520ms cubic-bezier(0.22, 1, 0.36, 1), opacity 520ms ease-out;
}

.motion-ready .card.reveal-card {
  opacity: 0;
  transform: translateY(1.25rem);
}

.motion-ready .card.reveal-card.is-visible {
  opacity: 1;
  transform: translateY(0);
}

.product-card {
  position: relative;
  overflow: hidden;
}

.product-card:hover,
.product-card:focus-visible,
.product-card:focus-within {
  border-color: rgb(87 221 255 / 70%);
  box-shadow: 0 1.2rem 3rem rgb(0 0 0 / 24%), 0 0 1.8rem rgb(87 221 255 / 12%);
}

@media (hover: hover) and (pointer: fine) {
  .motion-ready .product-card::before {
    position: absolute;
    top: 0;
    bottom: 0;
    width: 42%;
    content: "";
    background: radial-gradient(circle at center, rgb(87 221 255 / 10%), transparent 68%);
    opacity: 0.8;
    pointer-events: none;
    transition: opacity 220ms ease-out, transform 300ms ease-out;
  }

  .motion-ready .product-card[data-insert-from="left"]::before { left: -10%; }
  .motion-ready .product-card[data-insert-from="right"]::before { right: -10%; }

  .motion-ready .product-card::after {
    position: absolute;
    right: 1.8rem;
    bottom: 1.35rem;
    color: rgb(154 236 255 / 68%);
    content: "DETAILS  →";
    font-size: 0.72rem;
    font-weight: 800;
    letter-spacing: 0.14em;
    pointer-events: none;
    transition: opacity 180ms ease-out, transform 180ms ease-out;
  }

  html[lang="ja"].motion-ready .product-card::after {
    content: "カーソルで詳細を表示  →";
    letter-spacing: 0.06em;
  }

  .motion-ready .product-card h3 ~ * {
    opacity: 0;
    transition: opacity 300ms ease-out, transform 300ms ease-out;
  }

  .motion-ready .product-card[data-insert-from="left"] h3 ~ * {
    transform: translateX(-1.25rem);
  }

  .motion-ready .product-card[data-insert-from="right"] h3 ~ * {
    transform: translateX(1.25rem);
  }

  .motion-ready .product-card:is(:hover, :focus-visible, :focus-within, .details-revealed) h3 ~ * {
    opacity: 1;
    transform: translateX(0);
  }

  .motion-ready .product-card:is(:hover, :focus-visible, :focus-within, .details-revealed)::before,
  .motion-ready .product-card:is(:hover, :focus-visible, :focus-within, .details-revealed)::after {
    opacity: 0;
    transform: translateX(0.75rem);
  }

  .motion-ready .product-card.reveal-card.is-visible:is(:hover, :focus-visible, :focus-within) {
    transform: translateY(-0.125rem);
  }
}

.card > :first-child {
  margin-top: 0;
}

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

.tag {
  display: inline-block;
  margin-bottom: 0.35rem;
  padding: 0.12rem 0.6rem;
  border-radius: 999px;
  background: var(--soft);
  color: var(--brand-strong);
  font-size: 0.86rem;
  font-weight: 800;
}

.principles {
  position: relative;
  border-block: 1px solid var(--line);
  color: var(--ink);
}

.principles .eyebrow,
.principles a {
  color: var(--brand-strong);
}

.principles .card {
  border-color: #31415f;
  background: var(--surface-raised);
  color: var(--ink);
}

.prose {
  position: relative;
  z-index: 1;
  max-width: 52rem;
  padding-block: clamp(2.5rem, 6vw, 5rem);
}

.prose h1 {
  max-width: none;
  font-size: clamp(2.1rem, 6vw, 3.7rem);
}

.prose h2 {
  margin-top: 2.4rem;
}

.prose li + li {
  margin-top: 0.45rem;
}

.notice {
  margin-block: 1.5rem;
  padding: 1rem 1.1rem;
  border-left: 0.35rem solid var(--accent);
  background: #191a24;
  color: #f6e8c8;
}

.language-link {
  white-space: nowrap;
}

.site-footer {
  margin-top: 3rem;
  border-top: 1px solid var(--line);
  background: #050812;
}

.site-footer-inner {
  display: grid;
  gap: 1.2rem;
  padding-block: 2rem;
}

.copyright {
  margin: 0;
  color: var(--muted);
}

@media (max-width: 47rem) {
  .site-nav {
    width: 100%;
  }

  .site-nav ul {
    width: 100%;
    gap: 0.25rem 0.9rem;
  }

  body::before {
    inset: -3vh -6vw;
    background-position: center center;
    background-size: auto 100vh;
    opacity: 0.56;
  }

  body::after {
    background:
      linear-gradient(90deg, rgb(6 9 20 / 26%) 0%, rgb(6 9 20 / 10%) 55%, rgb(6 9 20 / 24%) 100%),
      linear-gradient(180deg, rgb(6 9 20 / 34%) 0%, rgb(6 9 20 / 54%) 48%, rgb(5 8 18 / 94%) 100%);
  }

  .hero-visual {
    --egg-mask-rx: 44vw;
    --egg-mask-ry: 44vw;
    top: 57.3%;
    left: 50%;
    opacity: 0.55;
  }

  .orbit-one {
    width: 160vw;
    height: 75vw;
  }

  .orbit-two {
    width: 140vw;
    height: 105vw;
  }

  .spark-path-large {
    --spark-radius: 44vw;
  }

  .spark-path-small-one {
    --spark-radius: 39vw;
  }

  .spark-path-small-two {
    --spark-radius: 47vw;
  }

  .spark-path-small-three {
    --spark-radius: 42vw;
  }

  .motion-ready .product-card.reveal-card[data-insert-from="left"] {
    transform: translateX(-0.75rem);
  }

  .motion-ready .product-card.reveal-card[data-insert-from="right"] {
    transform: translateX(0.75rem);
  }

  .motion-ready .product-card.reveal-card.is-visible {
    transform: translateX(0);
  }

  .motion-ready .product-card::before,
  .motion-ready .product-card::after {
    display: none;
  }

  .motion-ready .product-card[data-insert-from] h3 ~ * {
    opacity: 1;
    transform: none;
  }

  .hero,
  .grid {
    grid-template-columns: 1fr;
  }

  .hero {
    min-height: min(44rem, 82vh);
    padding-top: 3rem;
  }
}

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

  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
  }

  .motion-ready .card.reveal-card,
  .motion-ready .product-card h3 ~ * {
    opacity: 1 !important;
    transform: none !important;
  }

  .orbit-one,
  .orbit-two,
  .spark-path,
  .spark {
    animation: none !important;
  }

  .orbit-one { transform: translate(-50%, -50%) rotate(17deg); }
  .orbit-two { transform: translate(-50%, -50%) rotate(-53deg); }
  .spark { display: none; }
}

@media (prefers-contrast: more) {
  :root {
    --line: #aab7d6;
    --muted: #eef2ff;
    --brand: #8ceaff;
  }

  .card {
    border-width: 2px;
  }
}