:root {
  --ink: #07131F;
  --ink-2: #0D2233;
  --green: #22E06B;
  --green-deep: #0B8F45;
  --orange: #FF7A1A;
  --orange-soft: #FFB067;
  --paper: #F3F7F2;
  --gray: #9BB0BC;
  --black: #03070B;
  --cyan: #4CC9F0;

  --content-w: 1200px;
  --note-w: 240px;
  --radius: 2px;

  --font-sans: "Noto Sans SC", "Source Han Sans SC", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", system-ui, -apple-system, sans-serif;
  --font-mono: "JetBrains Mono", "Barlow Condensed", "DIN Condensed", "SFMono-Regular", ui-monospace, Menlo, Consolas, monospace;
}

/* ---------- reset ---------- */
*,
*::before,
*::after { box-sizing: border-box; }

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: 150px;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.8;
  color: var(--paper);
  background-color: var(--ink);
  background-image:
    radial-gradient(62% 48% at 84% -6%, rgba(34, 224, 107, 0.13), transparent 70%),
    radial-gradient(46% 40% at 0% 12%, rgba(255, 122, 26, 0.09), transparent 72%);
  background-repeat: no-repeat;
  background-attachment: fixed;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

h1, h2, h3, h4, h5, h6, p, figure, blockquote, dl, dd { margin: 0; }
ul, ol { margin: 0; padding: 0; list-style: none; }
img, svg, video { max-width: 100%; height: auto; display: block; }
button { font: inherit; color: inherit; }
a { color: inherit; text-decoration: none; }
[id] { scroll-margin-top: 150px; }

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

:focus-visible {
  outline: 2px solid var(--green);
  outline-offset: 3px;
}

/* ---------- skip link ---------- */
.skip-link {
  position: fixed;
  top: -120px;
  left: 1rem;
  z-index: 200;
  padding: 0.6rem 1.1rem;
  background: var(--green);
  color: var(--ink);
  font-size: 0.85rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  border-radius: var(--radius);
  transition: top 0.18s ease;
}
.skip-link:focus { top: 0.75rem; }

/* ---------- header ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 90;
  background: var(--ink);
  border-bottom: 1px solid rgba(34, 224, 107, 0.32);
}

.read-progress {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: rgba(155, 176, 188, 0.16);
  overflow: hidden;
}
.read-progress-bar {
  display: block;
  height: 100%;
  width: 100%;
  transform: scaleX(0);
  transform-origin: 0 50%;
  background: linear-gradient(90deg, var(--green-deep), var(--green) 55%, var(--orange));
}

.header-inner {
  width: 100%;
  max-width: var(--content-w);
  margin-inline: auto;
  padding-inline: clamp(1rem, 4vw, 2.5rem);
}

.header-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  padding-block: 0.5rem;
  border-bottom: 1px solid rgba(155, 176, 188, 0.15);
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.2em;
}

.header-tag {
  color: var(--gray);
  white-space: nowrap;
}

.header-cta {
  color: var(--orange);
  letter-spacing: 0.14em;
  border-bottom: 1px solid currentColor;
  padding-bottom: 1px;
  white-space: nowrap;
  transition: color 0.16s ease;
}
.header-cta:hover { color: var(--green); }

.nav-toggle {
  display: none;
  align-items: center;
  gap: 0.5rem;
  padding: 0.3rem 0.6rem;
  background: transparent;
  border: 1px solid rgba(34, 224, 107, 0.5);
  border-radius: var(--radius);
  color: var(--paper);
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.16em;
  cursor: pointer;
}
.nav-toggle:hover { border-color: var(--green); color: var(--green); }

.nav-toggle-box {
  display: inline-flex;
  flex-direction: column;
  justify-content: space-between;
  width: 16px;
  height: 11px;
}
.nav-toggle-box span {
  display: block;
  height: 2px;
  width: 100%;
  background: var(--green);
  transition: transform 0.16s ease, opacity 0.16s ease;
}
.nav-toggle[aria-expanded="true"] .nav-toggle-box span:nth-child(1) { transform: translateY(4.5px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle-box span:nth-child(2) { opacity: 0; }
.nav-toggle[aria-expanded="true"] .nav-toggle-box span:nth-child(3) { transform: translateY(-4.5px) rotate(-45deg); }

.nav-toggle-label { line-height: 1; }

.masthead {
  display: flex;
  align-items: center;
  gap: clamp(0.75rem, 3vw, 1.75rem);
  padding-block: clamp(0.55rem, 1.4vw, 0.9rem);
}

.masthead-rule {
  flex: 1 1 auto;
  height: 1px;
  min-width: 1.5rem;
  background: linear-gradient(90deg, transparent, rgba(155, 176, 188, 0.45));
}
.masthead-rule--end {
  background: linear-gradient(270deg, transparent, rgba(155, 176, 188, 0.45));
}

.brand {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.15rem;
  text-align: center;
  transition: opacity 0.16s ease;
}
.brand:hover { opacity: 0.85; }

.brand-name {
  font-size: clamp(1.6rem, 4vw, 2.9rem);
  font-weight: 200;
  letter-spacing: 0.14em;
  line-height: 1.05;
  color: var(--paper);
}

.brand-sub {
  font-family: var(--font-mono);
  font-size: 0.6rem;
  letter-spacing: 0.28em;
  color: var(--green);
  white-space: nowrap;
}

.site-nav {
  border-top: 1px solid rgba(155, 176, 188, 0.15);
}

.nav-list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: clamp(0.5rem, 2vw, 1.9rem);
  padding-block: 0.5rem;
}

.nav-link {
  position: relative;
  display: inline-block;
  padding: 0.35rem 0.1rem;
  font-size: 0.84rem;
  letter-spacing: 0.12em;
  color: rgba(243, 247, 242, 0.76);
  transition: color 0.16s ease;
}
.nav-link::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: -2px;
  height: 3px;
  background: var(--green);
  transform: scaleX(0) skewX(-18deg);
  transform-origin: left center;
  transition: transform 0.16s ease;
}
.nav-link:hover { color: var(--paper); }
.nav-link:hover::after { transform: scaleX(1) skewX(-18deg); }

.nav-link[aria-current="page"] {
  color: var(--green);
  font-weight: 700;
}
.nav-link[aria-current="page"]::after {
  transform: scaleX(1) skewX(-18deg);
  background: var(--orange);
}

/* ---------- footer ---------- */
.site-footer {
  position: relative;
  margin-top: clamp(2.5rem, 7vw, 5rem);
  background: var(--black);
  color: var(--paper);
}

.footer-slice {
  height: 6px;
  background: linear-gradient(
    90deg,
    var(--green) 0 26%,
    var(--orange) 26% 36%,
    rgba(243, 247, 242, 0.16) 36% 100%
  );
}

.footer-inner {
  width: 100%;
  max-width: var(--content-w);
  margin-inline: auto;
  padding: clamp(2rem, 5vw, 3.5rem) clamp(1rem, 4vw, 2.5rem) 1.5rem;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.5fr 1fr 1fr 1.5fr;
  gap: clamp(1.25rem, 3vw, 2.5rem);
}

.footer-col { min-width: 0; }

.footer-brandline {
  margin-bottom: 0.6rem;
  font-size: 1.05rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  color: var(--paper);
}

.footer-note {
  margin-bottom: 1rem;
  font-size: 0.8rem;
  line-height: 1.75;
  color: var(--gray);
  max-width: 24em;
}

.footer-icp {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.08em;
  color: var(--orange-soft);
}

.footer-heading {
  margin-bottom: 0.85rem;
  font-family: var(--font-mono);
  font-size: 0.68rem;
  font-weight: 500;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--green);
}

.footer-links {
  display: flex;
  flex-direction: column;
  gap: 0.45rem;
}

.footer-link {
  display: inline-block;
  font-size: 0.85rem;
  color: rgba(243, 247, 242, 0.72);
  transition: color 0.16s ease, padding-left 0.16s ease;
}
.footer-link:hover {
  color: var(--green);
  padding-left: 0.35rem;
}

.footer-contact {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.footer-contact-row {
  display: flex;
  align-items: baseline;
  gap: 0.6rem;
}

.footer-contact-label {
  flex: 0 0 4.4em;
  font-family: var(--font-mono);
  font-size: 0.65rem;
  letter-spacing: 0.14em;
  color: var(--gray);
}

.footer-contact-value {
  font-family: var(--font-mono);
  font-size: 0.76rem;
  line-height: 1.6;
  color: var(--paper);
  word-break: break-word;
}

.footer-bottom {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  margin-top: clamp(1.5rem, 4vw, 2.5rem);
  padding-top: 1rem;
  border-top: 1px solid rgba(155, 176, 188, 0.18);
}

.footer-copy {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.06em;
  color: var(--gray);
}

.footer-legal {
  display: flex;
  flex-wrap: wrap;
  gap: 1.15rem;
}

/* ---------- layout ---------- */
.container {
  width: 100%;
  max-width: var(--content-w);
  margin-inline: auto;
  padding-inline: clamp(1rem, 4vw, 2.5rem);
}

.section {
  padding-block: clamp(2.5rem, 6vw, 4.5rem);
}
.section--ink { background: var(--ink-2); }
.section--paper {
  background: var(--paper);
  color: var(--ink);
}

.section-head {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-end;
  justify-content: space-between;
  gap: 0.75rem 1.5rem;
  margin-bottom: clamp(1.25rem, 3vw, 2rem);
  padding-bottom: 0.85rem;
  border-bottom: 1px solid rgba(155, 176, 188, 0.25);
}
.section--paper .section-head { border-bottom-color: rgba(7, 19, 31, 0.16); }

.grid { display: grid; gap: clamp(1rem, 2.5vw, 1.75rem); }
.grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid--4 { grid-template-columns: repeat(4, minmax(0, 1fr)); }

.split {
  display: grid;
  grid-template-columns: 7fr 5fr;
  gap: clamp(1.25rem, 3vw, 2.5rem);
  align-items: start;
}

.stack > * + * { margin-top: 1rem; }

.divider {
  height: 1px;
  border: 0;
  margin-block: clamp(1.5rem, 4vw, 2.5rem);
  background: rgba(155, 176, 188, 0.25);
}

/* ---------- typography ---------- */
.eyebrow {
  margin-bottom: 0.5rem;
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.28em;
  text-transform: uppercase;
  color: var(--orange);
}

.section-index {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(2rem, 5vw, 3.2rem);
  font-weight: 700;
  line-height: 1;
  letter-spacing: 0.02em;
  color: rgba(34, 224, 107, 0.3);
}
.section--paper .section-index { color: rgba(11, 143, 69, 0.35); }

.section-title {
  margin-bottom: 0.7rem;
  font-size: clamp(1.45rem, 3.4vw, 2.25rem);
  font-weight: 800;
  line-height: 1.15;
  letter-spacing: 0.01em;
}

.lede {
  margin-bottom: 1.25rem;
  max-width: 34em;
  font-size: 1.02rem;
  line-height: 1.85;
  color: rgba(243, 247, 242, 0.82);
}
.section--paper .lede { color: rgba(7, 19, 31, 0.8); }

.note {
  max-width: 30em;
  font-size: 0.78rem;
  line-height: 1.75;
  letter-spacing: 0.02em;
  color: var(--gray);
}
.section--paper .note { color: rgba(7, 19, 31, 0.6); }

.num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  letter-spacing: 0.04em;
}

/* ---------- buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.7rem 1.35rem;
  border: 1px solid transparent;
  border-radius: var(--radius);
  font-size: 0.87rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  line-height: 1.4;
  cursor: pointer;
  transition: background-color 0.16s ease, color 0.16s ease, border-color 0.16s ease, transform 0.16s ease;
}
.btn:active { transform: translateY(1px); }

.btn--primary { background: var(--green); color: var(--ink); }
.btn--primary:hover { background: var(--green-deep); color: var(--paper); }

.btn--accent { background: var(--orange); color: var(--ink); }
.btn--accent:hover { background: var(--orange-soft); }

.btn--ghost {
  background: transparent;
  border-color: rgba(243, 247, 242, 0.35);
  color: var(--paper);
}
.btn--ghost:hover { border-color: var(--green); color: var(--green); }

/* ---------- tags ---------- */
.tag {
  display: inline-block;
  padding: 0.16rem 0.55rem;
  font-family: var(--font-mono);
  font-size: 0.66rem;
  letter-spacing: 0.14em;
  background: rgba(155, 176, 188, 0.18);
  color: var(--paper);
  border: 1px solid transparent;
  border-radius: var(--radius);
}
.tag--green { background: var(--green); color: var(--ink); }
.tag--orange { background: var(--orange); color: var(--ink); }
.tag--outline {
  background: transparent;
  border-color: rgba(34, 224, 107, 0.55);
  color: var(--green);
}

/* ---------- cards & panels ---------- */
.card {
  position: relative;
  padding: clamp(1rem, 2.4vw, 1.5rem);
  background: var(--ink-2);
  border: 1px solid rgba(155, 176, 188, 0.22);
  border-radius: var(--radius);
}
.card--paper {
  background: var(--paper);
  color: var(--ink);
  border-color: rgba(7, 19, 31, 0.14);
}
.card--slant::after {
  content: "";
  position: absolute;
  right: -1px;
  bottom: -1px;
  width: 22px;
  height: 22px;
  background: linear-gradient(to bottom right, transparent 48%, var(--green) 49%, var(--green) 100%);
  pointer-events: none;
}

.panel {
  padding: clamp(1rem, 2.6vw, 1.75rem);
  background: var(--ink-2);
  border: 1px solid rgba(155, 176, 188, 0.22);
  border-left: 3px solid var(--green);
}

/* ---------- breadcrumb ---------- */
.breadcrumb {
  padding-block: 0.9rem;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.12em;
  color: var(--gray);
}
.breadcrumb ol {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
}
.breadcrumb li + li::before {
  content: "/";
  margin-right: 0.45rem;
  color: rgba(155, 176, 188, 0.5);
}
.breadcrumb a { transition: color 0.16s ease; }
.breadcrumb a:hover { color: var(--green); }

/* ---------- media frames ---------- */
.media-frame {
  position: relative;
  overflow: hidden;
  aspect-ratio: 16 / 10;
  background: var(--ink-2);
  border: 1px solid rgba(155, 176, 188, 0.24);
}
.media-frame img,
.media-frame svg {
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.media-frame::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 1;
  pointer-events: none;
  background-image:
    linear-gradient(rgba(76, 201, 240, 0.13) 1px, transparent 1px),
    linear-gradient(90deg, rgba(76, 201, 240, 0.13) 1px, transparent 1px);
  background-size: 32px 32px;
}
.media-frame::after {
  content: attr(data-watermark);
  position: absolute;
  right: 0.7rem;
  bottom: 0.35rem;
  z-index: 2;
  font-family: var(--font-mono);
  font-size: 0.66rem;
  letter-spacing: 0.22em;
  color: rgba(243, 247, 242, 0.5);
  pointer-events: none;
}
.media-frame--slant {
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 26px), calc(100% - 26px) 100%, 0 100%);
}
.media-frame--tall { aspect-ratio: 4 / 5; }
.media-frame--wide { aspect-ratio: 21 / 9; }

/* ---------- responsive ---------- */
@media (max-width: 1024px) {
  .footer-grid { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 980px) {
  .grid--3, .grid--4 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .split { grid-template-columns: minmax(0, 1fr); }
}

@media (max-width: 860px) {
  html { scroll-padding-top: 132px; }
  [id] { scroll-margin-top: 132px; }

  .nav-toggle { display: inline-flex; }

  .site-nav {
    display: none;
    border-top: 1px solid rgba(155, 176, 188, 0.15);
  }
  .site-nav[data-open] { display: block; }

  .nav-list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding-block: 0.25rem 0.75rem;
  }
  .nav-item { border-bottom: 1px solid rgba(155, 176, 188, 0.12); }
  .nav-item:last-child { border-bottom: 0; }

  .nav-link {
    display: block;
    padding: 0.8rem 0.25rem;
    font-size: 0.95rem;
  }
  .nav-link::after {
    bottom: 0;
    height: 2px;
  }

  .grid--2 { grid-template-columns: minmax(0, 1fr); }
  .footer-bottom { flex-direction: column; align-items: flex-start; }
}

@media (max-width: 620px) {
  .header-bar { font-size: 0.64rem; letter-spacing: 0.14em; }
  .brand-sub { letter-spacing: 0.18em; font-size: 0.55rem; }
  .grid--3, .grid--4 { grid-template-columns: minmax(0, 1fr); }
  .footer-grid { grid-template-columns: minmax(0, 1fr); }
  .footer-legal { gap: 0.75rem; }
  .footer-contact-row { flex-direction: column; gap: 0.1rem; }
  .footer-contact-label { flex: none; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
    scroll-behavior: auto !important;
  }
  .nav-link::after,
  .read-progress-bar,
  .skip-link { transition: none; }
}