:root {
  --paper: #eef5f1;
  --paper-2: #e3efe9;
  --ink: #0b1f2a;
  --ink-soft: #29434c;
  --muted: #5c7478;
  --teal: #19c3a6;
  --violet: #7b6cf6;
  --coral: #ff6b5a;
  --line: rgba(11, 31, 42, 0.16);
  --line-strong: rgba(11, 31, 42, 0.32);
  --display: "Songti SC", "Noto Serif SC", "Source Han Serif SC", "STSong", "SimSun", serif;
  --body: "PingFang SC", "Noto Sans SC", "Microsoft YaHei", system-ui, -apple-system, sans-serif;
  --mono: "IBM Plex Mono", "SFMono-Regular", Consolas, "Liberation Mono", monospace;
  --gutter: clamp(1.25rem, 5vw, 4.5rem);
  --max: 1280px;
}

* { box-sizing: border-box; }

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

body {
  margin: 0;
  background:
    radial-gradient(1200px 700px at 8% -10%, rgba(25, 195, 166, 0.13), transparent 60%),
    radial-gradient(900px 600px at 100% 10%, rgba(123, 108, 246, 0.10), transparent 55%),
    var(--paper);
  color: var(--ink);
  font-family: var(--body);
  font-size: 16px;
  line-height: 1.7;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: 3;
  pointer-events: none;
  opacity: 0.045;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='180' height='180'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.82' numOctaves='3' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
  mix-blend-mode: multiply;
}

::selection {
  background: var(--teal);
  color: var(--ink);
}

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

a:focus-visible,
button:focus-visible {
  outline: 2px solid var(--violet);
  outline-offset: 4px;
}

:where(section, article)[id] {
  scroll-margin-top: 96px;
}

.skip-link {
  position: absolute;
  left: 1rem;
  top: -3rem;
  z-index: 20;
  padding: 0.6rem 0.9rem;
  background: var(--ink);
  color: var(--paper);
  font-family: var(--mono);
  font-size: 0.75rem;
  letter-spacing: 0.08em;
  transition: top 0.2s ease;
}

.skip-link:focus {
  top: 1rem;
}

.mono {
  font-family: var(--mono);
  font-size: 0.7rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
}

/* ---------- Header ---------- */

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  gap: 2rem;
  max-width: var(--max);
  margin: 0 auto;
  padding: 1.1rem var(--gutter);
  background: color-mix(in srgb, var(--paper) 82%, transparent);
  backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--line);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.65rem;
  flex-shrink: 0;
}

.brand-mark {
  display: grid;
  place-items: center;
  width: 30px;
  height: 30px;
  color: var(--ink);
}

.brand-mark svg {
  width: 100%;
  height: 100%;
}

.brand-word {
  font-family: var(--body);
  font-size: 0.82rem;
  font-weight: 700;
  letter-spacing: 0.22em;
}

.brand-lab {
  margin-left: 0.35rem;
  font-family: var(--mono);
  font-size: 0.6rem;
  font-weight: 400;
  letter-spacing: 0.18em;
  color: var(--muted);
}

.site-nav {
  display: flex;
  gap: 1.6rem;
  margin-left: auto;
  font-size: 0.82rem;
  color: var(--ink-soft);
}

.site-nav a {
  position: relative;
  padding-bottom: 2px;
}

.site-nav a::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: 100%;
  height: 1px;
  background: var(--ink);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.25s ease;
}

.site-nav a:hover::after {
  transform: scaleX(1);
}

.status-pill {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  padding: 0.35rem 0.7rem;
  border: 1px solid var(--line-strong);
  font-family: var(--mono);
  font-size: 0.62rem;
  letter-spacing: 0.1em;
  white-space: nowrap;
}

.status-dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--teal);
  box-shadow: 0 0 0 3px rgba(25, 195, 166, 0.16);
  animation: pulse 2.4s ease-in-out infinite;
}

/* ---------- Hero ---------- */

.hero {
  display: grid;
  grid-template-columns: minmax(0, 1.12fr) minmax(320px, 0.88fr);
  gap: clamp(2rem, 6vw, 6rem);
  align-items: center;
  max-width: var(--max);
  margin: 0 auto;
  padding: clamp(3rem, 7vw, 6.5rem) var(--gutter) clamp(3.5rem, 8vw, 7rem);
}

.eyebrow {
  margin: 0 0 1.4rem;
  font-family: var(--mono);
  font-size: 0.68rem;
  letter-spacing: 0.18em;
  color: var(--muted);
}

.hero h1 {
  margin: 0;
  font-family: var(--display);
  font-size: clamp(3.2rem, 7.4vw, 7.4rem);
  font-weight: 600;
  line-height: 0.96;
  letter-spacing: -0.045em;
}

.nowrap {
  white-space: nowrap;
}

.aurora-word {
  position: relative;
  display: inline-block;
  background: linear-gradient(100deg, #0f8f7e 0%, var(--teal) 22%, var(--violet) 58%, var(--coral) 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.aurora-word::after {
  content: "";
  position: absolute;
  left: 0.02em;
  right: 0.04em;
  bottom: -0.08em;
  height: 0.12em;
  background: linear-gradient(90deg, var(--teal), var(--violet) 60%, transparent);
  clip-path: polygon(0 42%, 12% 20%, 27% 52%, 44% 26%, 61% 58%, 78% 32%, 100% 46%, 100% 100%, 0 100%);
  opacity: 0.75;
}

.lede {
  max-width: 34rem;
  margin: 1.8rem 0 0;
  color: var(--ink-soft);
  font-size: clamp(1rem, 1.15vw, 1.12rem);
  line-height: 1.85;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 1.2rem;
  margin-top: 2.4rem;
}

.button {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.85rem 1.25rem;
  font-size: 0.85rem;
  letter-spacing: 0.02em;
  border: 1px solid transparent;
  transition: background 0.2s ease, color 0.2s ease, border-color 0.2s ease, transform 0.2s ease;
}

.button:hover {
  transform: translateY(-1px);
}

.button.primary {
  background: var(--ink);
  color: var(--paper);
  border-color: var(--ink);
}

.button.primary:hover {
  background: var(--teal);
  border-color: var(--teal);
  color: var(--ink);
}

.button.quiet {
  padding-inline: 0.2rem;
  color: var(--ink-soft);
  border-bottom: 1px solid var(--line-strong);
}

.button.quiet:hover {
  color: var(--ink);
  border-color: var(--ink);
}

.hero-footnote {
  margin: 2rem 0 0;
  color: var(--muted);
  font-size: 0.78rem;
  letter-spacing: 0.02em;
}

/* ---------- Observation window ---------- */

.hero-visual {
  position: relative;
}

.observation-window {
  position: relative;
  aspect-ratio: 4 / 5;
  overflow: hidden;
  background:
    radial-gradient(80% 60% at 70% 20%, rgba(25, 195, 166, 0.18), transparent 60%),
    radial-gradient(70% 60% at 20% 80%, rgba(123, 108, 246, 0.22), transparent 60%),
    #081a22;
  border: 1px solid rgba(11, 31, 42, 0.5);
  box-shadow: 0 24px 60px -30px rgba(8, 26, 34, 0.55);
}

.aurora {
  position: absolute;
  inset: -12%;
  width: 124%;
  height: 124%;
  opacity: 0.95;
}

.ribbon {
  transform-origin: center;
  animation: drift 18s ease-in-out infinite alternate;
}

.ribbon-b {
  animation-duration: 24s;
  animation-direction: alternate-reverse;
}

.ribbon-c {
  animation-duration: 30s;
}

.window-grid {
  position: absolute;
  inset: 0;
  background-image:
    repeating-linear-gradient(to right, rgba(238, 245, 241, 0.07) 0 1px, transparent 1px 72px),
    repeating-linear-gradient(to bottom, rgba(238, 245, 241, 0.07) 0 1px, transparent 1px 72px);
  mask-image: linear-gradient(to bottom, black, transparent 92%);
}

.window-caption {
  position: absolute;
  left: 1.1rem;
  right: 1.1rem;
  top: 1rem;
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  color: rgba(238, 245, 241, 0.62);
  font-size: 0.58rem;
}

.window-caption span {
  white-space: nowrap;
}

.station-card {
  position: absolute;
  left: -1.6rem;
  bottom: -1.6rem;
  width: min(78%, 300px);
  padding: 1.15rem 1.25rem 1.1rem;
  background: var(--paper);
  border: 1px solid var(--line-strong);
  box-shadow: 0 18px 40px -28px rgba(8, 26, 34, 0.6);
}

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

.station-value {
  margin: 0.25rem 0 0.9rem;
  font-family: var(--display);
  font-size: 1.35rem;
  letter-spacing: -0.02em;
}

.station-meta {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 0.7rem;
  margin: 0;
  padding-top: 0.85rem;
  border-top: 1px solid var(--line);
}

.station-meta div {
  display: flex;
  flex-direction: column;
  gap: 0.1rem;
}

.station-meta dt {
  font-family: var(--mono);
  font-size: 0.56rem;
  letter-spacing: 0.12em;
  color: var(--muted);
}

.station-meta dd {
  margin: 0;
  font-size: 0.72rem;
  color: var(--ink-soft);
}

/* ---------- Sections ---------- */

.section {
  max-width: var(--max);
  margin: 0 auto;
  padding: clamp(4rem, 8vw, 7rem) var(--gutter);
  border-top: 1px solid var(--line);
}

.section-head {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(280px, 0.9fr);
  gap: clamp(1.5rem, 4vw, 4rem);
  align-items: start;
  margin-bottom: clamp(2.5rem, 5vw, 4rem);
}

.section-head .mono {
  grid-column: 1 / -1;
  margin: 0 0 1rem;
  color: var(--muted);
}

.section-head h2 {
  margin: 0;
  font-family: var(--display);
  font-size: clamp(2rem, 3.6vw, 3.4rem);
  font-weight: 600;
  line-height: 1.12;
  letter-spacing: -0.03em;
}

.section-lede {
  margin: 0;
  color: var(--ink-soft);
  line-height: 1.9;
}

.note-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 0;
  border-top: 1px solid var(--line-strong);
}

.note-card {
  padding: 1.6rem 1.8rem 2rem 0;
  border-right: 1px solid var(--line);
}

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

.note-index {
  margin: 0 0 1.4rem;
  color: var(--muted);
}

.note-card h3 {
  margin: 0 0 0.8rem;
  font-family: var(--display);
  font-size: clamp(1.3rem, 1.8vw, 1.65rem);
  font-weight: 600;
  letter-spacing: -0.02em;
}

.note-card p:last-child {
  margin: 0;
  color: var(--ink-soft);
  font-size: 0.92rem;
  line-height: 1.85;
}

.statement {
  max-width: var(--max);
  margin: 0 auto;
  padding: clamp(3.5rem, 7vw, 6rem) var(--gutter);
  border-top: 1px solid var(--line);
}

.statement .mono {
  margin: 0 0 1.6rem;
  color: var(--muted);
}

.statement-line {
  margin: 0;
  padding-left: clamp(1rem, 3vw, 2.5rem);
  border-left: 2px solid var(--teal);
  font-family: var(--display);
  font-size: clamp(1.8rem, 4vw, 3.6rem);
  font-weight: 600;
  line-height: 1.35;
  letter-spacing: -0.03em;
}

/* ---------- Notify ---------- */

.notify {
  background: var(--ink);
  color: var(--paper);
}

.notify-inner {
  max-width: var(--max);
  margin: 0 auto;
  padding: clamp(4rem, 8vw, 7rem) var(--gutter);
}

.notify .mono {
  margin: 0 0 1.2rem;
  color: rgba(238, 245, 241, 0.55);
}

.notify h2 {
  margin: 0 0 1rem;
  font-family: var(--display);
  font-size: clamp(2.2rem, 5vw, 4.6rem);
  font-weight: 600;
  line-height: 1.05;
  letter-spacing: -0.035em;
}

.notify p {
  max-width: 36rem;
  margin: 0;
  color: rgba(238, 245, 241, 0.72);
}

.notify-domain {
  margin-top: 2.4rem !important;
  font-family: var(--mono);
  font-size: clamp(1rem, 2vw, 1.5rem);
  letter-spacing: 0.08em;
  color: var(--paper) !important;
  background: linear-gradient(90deg, var(--teal), var(--violet), var(--coral));
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

/* ---------- Footer ---------- */

.site-footer {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  max-width: var(--max);
  margin: 0 auto;
  padding: 1.6rem var(--gutter);
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 0.72rem;
}

.site-footer p {
  margin: 0;
}

/* ---------- Motion ---------- */

.js .reveal {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity 0.8s cubic-bezier(0.2, 0.7, 0.2, 1), transform 0.8s cubic-bezier(0.2, 0.7, 0.2, 1);
}

.js .reveal.is-visible {
  opacity: 1;
  transform: none;
}

@keyframes drift {
  0% { transform: translate3d(-2%, 1%, 0) rotate(-2deg) scale(1.02); }
  50% { transform: translate3d(2%, -2%, 0) rotate(1.5deg) scale(1.05); }
  100% { transform: translate3d(-1%, 2%, 0) rotate(-1deg) scale(1.03); }
}

@keyframes pulse {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.55; transform: scale(0.82); }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .ribbon, .status-dot { animation: none; }
  .js .reveal { opacity: 1; transform: none; transition: none; }
  .button:hover { transform: none; }
}

/* ---------- Responsive ---------- */

@media (max-width: 980px) {
  .hero {
    grid-template-columns: 1fr;
    gap: 3rem;
  }

  .hero-visual {
    max-width: 520px;
  }

  .section-head {
    grid-template-columns: 1fr;
    gap: 1.2rem;
  }

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

  .note-card {
    padding: 1.4rem 0 1.8rem;
    border-right: 0;
    border-bottom: 1px solid var(--line);
  }

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

@media (max-width: 720px) {
  .site-header {
    gap: 1rem;
    padding-block: 0.9rem;
  }

  .site-nav {
    display: none;
  }

  .status-pill {
    margin-left: auto;
  }

  .hero {
    padding-top: 2.5rem;
  }

  .hero h1 {
    font-size: clamp(2.5rem, 12.2vw, 4.2rem);
    letter-spacing: -0.05em;
  }

  .station-card {
    position: relative;
    left: 0;
    bottom: 0;
    width: 100%;
    margin-top: -3rem;
    margin-left: 1rem;
    margin-right: -1rem;
  }

  .window-caption {
    display: none;
  }

  .site-footer {
    flex-direction: column;
  }
}