/* ========== 1. Reset ========== */
*,
*::before,
*::after { box-sizing: border-box; }

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

body, 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 { display: block; max-width: 100%; }
button, input, select, textarea { font: inherit; color: inherit; }
button { background: none; border: 0; padding: 0; cursor: pointer; }
a { color: inherit; text-decoration: none; }
table { border-collapse: collapse; width: 100%; }
[hidden] { display: none !important; }

/* ========== 2. Tokens ========== */
:root {
  --ink-950: #04150F;
  --ink-900: #072A20;
  --ink-700: #0C4234;
  --glass-green: rgba(12, 66, 52, 0.58);
  --cyan-400: #2BF5C8;
  --cyan-200: #A6FFE8;
  --yellow-400: #FFD24A;
  --carbon-900: #1B221F;
  --paper: #F3F7F2;
  --mist-500: #6D7C75;

  --hair-cyan: 1px solid rgba(43, 245, 200, 0.26);
  --hair-cyan-soft: 1px solid rgba(43, 245, 200, 0.14);
  --hair-ink: 1px solid rgba(27, 34, 31, 0.16);

  --r-sm: 4px;
  --r-md: 8px;
  --r-pill: 999px;

  --wrap-max: 1280px;
  --gutter: 24px;
  --bar-h: 68px;
  --strip-h: 36px;

  --font-body: "PingFang SC", "Hiragino Sans GB", "Source Han Sans SC", "Noto Sans SC", "Microsoft YaHei", system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-display: "PingFang SC", "Hiragino Sans GB", "Source Han Sans SC", "Noto Sans SC", "Microsoft YaHei", system-ui, sans-serif;
  --font-mono: ui-monospace, "JetBrains Mono", "Roboto Mono", "SFMono-Regular", Menlo, Consolas, monospace;

  --ease: cubic-bezier(0.22, 0.68, 0.3, 1);
}

/* ========== 3. Base typography ========== */
body {
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.75;
  color: var(--cyan-200);
  background-color: var(--ink-950);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-display);
  font-weight: 800;
  letter-spacing: -0.02em;
  line-height: 1.12;
}

:focus-visible {
  outline: 2px solid var(--yellow-400);
  outline-offset: 3px;
  border-radius: 2px;
}

.band--paper :focus-visible,
.paper-panel :focus-visible {
  outline-color: var(--ink-700);
}

/* ========== 4. Layout ========== */
.wrap {
  width: 100%;
  max-width: var(--wrap-max);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.band { padding-block: 64px; }
.band--ink { background-color: var(--ink-900); color: var(--cyan-200); }
.band--deep { background-color: var(--ink-950); color: var(--cyan-200); }
.band--paper { background-color: var(--paper); color: var(--carbon-900); }

.grid {
  display: grid;
  gap: 24px;
}

.grid--12 { grid-template-columns: repeat(12, minmax(0, 1fr)); }

@media (max-width: 1024px) {
  .grid--12 { grid-template-columns: repeat(8, minmax(0, 1fr)); }
  .band { padding-block: 48px; }
}

@media (max-width: 640px) {
  :root { --gutter: 18px; }
  .grid--12 { grid-template-columns: repeat(4, minmax(0, 1fr)); }
  .band { padding-block: 40px; }
}

/* ========== 5. Header ========== */
.skip-link {
  position: absolute;
  left: 8px;
  top: -72px;
  z-index: 200;
  display: inline-block;
  padding: 10px 18px;
  border-radius: var(--r-sm);
  background-color: var(--cyan-400);
  color: var(--ink-950);
  font-size: 14px;
  font-weight: 700;
  transition: top 0.18s var(--ease);
}
.skip-link:focus {
  top: 8px;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 60;
  background-color: var(--ink-950);
  border-bottom: var(--hair-cyan);
}

.header-strip {
  background-image: linear-gradient(90deg, var(--ink-950), var(--ink-900));
  border-bottom: 1px solid rgba(43, 245, 200, 0.12);
}

.header-strip__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  min-height: var(--strip-h);
}

.brand-line {
  font-size: 12px;
  letter-spacing: 0.18em;
  color: rgba(166, 255, 232, 0.82);
  white-space: nowrap;
}

.tick-preview {
  display: flex;
  align-items: center;
  gap: 12px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: rgba(166, 255, 232, 0.62);
}

.tick-preview__label {
  white-space: nowrap;
  color: rgba(166, 255, 232, 0.55);
}

.tick-preview__ruler {
  display: block;
  width: 132px;
  height: 12px;
  background-image:
    repeating-linear-gradient(90deg, rgba(43, 245, 200, 0.78) 0 1px, transparent 1px 11px),
    linear-gradient(rgba(166, 255, 232, 0.28), rgba(166, 255, 232, 0.28));
  background-repeat: no-repeat;
  background-position: top left, bottom left;
  background-size: 100% 6px, 100% 1px;
}

.tick-preview__value {
  font-variant-numeric: tabular-nums;
  color: var(--yellow-400);
  white-space: nowrap;
}

.header-main {
  position: relative;
  background-color: var(--ink-900);
}

.header-main__inner {
  display: flex;
  align-items: center;
  gap: 28px;
  min-height: var(--bar-h);
}

/* -- brand mark: CSS-drawn ruler glyph -- */
.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  flex: 0 0 auto;
}

.brand__glyph {
  position: relative;
  width: 34px;
  height: 34px;
  flex: 0 0 auto;
  border: 1px solid rgba(43, 245, 200, 0.55);
  border-radius: var(--r-sm);
  background-image: linear-gradient(160deg, rgba(43, 245, 200, 0.22), rgba(12, 66, 52, 0.12) 62%);
}
.brand__glyph::before {
  content: "";
  position: absolute;
  left: 6px;
  right: 6px;
  bottom: 7px;
  height: 9px;
  background-image: repeating-linear-gradient(90deg, var(--cyan-400) 0 1px, transparent 1px 5px);
}
.brand__glyph::after {
  content: "";
  position: absolute;
  left: 6px;
  right: 6px;
  bottom: 6px;
  height: 1px;
  background-color: var(--yellow-400);
}

.brand__text {
  display: flex;
  flex-direction: column;
  line-height: 1.1;
}

.brand__name {
  font-family: var(--font-display);
  font-size: 17px;
  font-weight: 800;
  letter-spacing: -0.01em;
  color: var(--paper);
  white-space: nowrap;
}

.brand__sub {
  margin-top: 4px;
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.24em;
  color: var(--cyan-400);
  white-space: nowrap;
}

/* -- primary navigation -- */
.site-nav {
  flex: 1 1 auto;
  display: flex;
  min-width: 0;
}

.site-nav__list {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 2px;
}

.site-nav__item { display: flex; }

.site-nav__link {
  position: relative;
  display: block;
  padding: 8px 14px;
  border-radius: var(--r-sm);
  font-size: 14px;
  line-height: 1.4;
  color: rgba(166, 255, 232, 0.78);
  white-space: nowrap;
  transition: color 0.18s var(--ease), background-color 0.18s var(--ease);
}
.site-nav__link:hover {
  color: var(--paper);
  background-color: rgba(43, 245, 200, 0.1);
}
.site-nav__link[aria-current="page"] {
  color: var(--cyan-400);
  background-color: rgba(43, 245, 200, 0.08);
  font-weight: 700;
}
.site-nav__link[aria-current="page"]::after {
  content: "";
  position: absolute;
  left: 14px;
  right: 14px;
  bottom: 2px;
  height: 2px;
  border-radius: 2px;
  background-color: var(--cyan-400);
}

/* -- utility tools -- */
.header-tools {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-left: auto;
  flex: 0 0 auto;
}

.tool-search {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  padding: 9px 16px;
  border: 1px solid rgba(43, 245, 200, 0.42);
  border-radius: var(--r-pill);
  background-color: var(--glass-green);
  -webkit-backdrop-filter: blur(8px);
  backdrop-filter: blur(8px);
  color: var(--cyan-200);
  font-size: 13px;
  letter-spacing: 0.04em;
  white-space: nowrap;
  transition: border-color 0.18s var(--ease), background-color 0.18s var(--ease), color 0.18s var(--ease);
}
.tool-search:hover {
  border-color: var(--cyan-400);
  background-color: rgba(43, 245, 200, 0.16);
  color: var(--paper);
}

.tool-search__gl {
  position: relative;
  width: 12px;
  height: 12px;
  flex: 0 0 auto;
  border: 1.5px solid currentColor;
  border-radius: 50%;
}
.tool-search__gl::after {
  content: "";
  position: absolute;
  right: -4px;
  bottom: -3px;
  width: 6px;
  height: 1.5px;
  background-color: currentColor;
  transform: rotate(45deg);
  transform-origin: left center;
}

.tool-search__label { display: inline; }

.tool-help {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 9px 16px;
  border: 1px solid rgba(255, 210, 74, 0.5);
  border-radius: var(--r-pill);
  background-color: rgba(255, 210, 74, 0.12);
  color: var(--yellow-400);
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.04em;
  white-space: nowrap;
  transition: background-color 0.18s var(--ease), border-color 0.18s var(--ease);
}
.tool-help::before {
  content: "";
  width: 6px;
  height: 6px;
  flex: 0 0 auto;
  border-radius: 50%;
  background-color: var(--yellow-400);
}
.tool-help:hover {
  border-color: var(--yellow-400);
  background-color: rgba(255, 210, 74, 0.22);
}

/* -- mobile toggle -- */
.nav-toggle {
  display: none;
  position: relative;
  width: 42px;
  height: 42px;
  flex: 0 0 auto;
  border: 1px solid rgba(43, 245, 200, 0.42);
  border-radius: var(--r-sm);
  background-color: rgba(12, 66, 52, 0.5);
}

.nav-toggle__bar {
  position: absolute;
  left: 11px;
  right: 11px;
  height: 1.5px;
  background-color: var(--cyan-400);
  transition: transform 0.2s var(--ease), opacity 0.2s var(--ease);
}
.nav-toggle__bar:nth-child(1) { top: 15px; }
.nav-toggle__bar:nth-child(2) { top: 20px; }
.nav-toggle__bar:nth-child(3) { top: 25px; }

.nav-toggle[aria-expanded="true"] .nav-toggle__bar:nth-child(1) { transform: translateY(5px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle__bar:nth-child(2) { opacity: 0; }
.nav-toggle[aria-expanded="true"] .nav-toggle__bar:nth-child(3) { transform: translateY(-5px) rotate(-45deg); }

/* -- scroll meter -- */
.scroll-meter {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 2px;
  background-color: rgba(43, 245, 200, 0.14);
  overflow: hidden;
}

.scroll-meter__fill {
  display: block;
  width: 100%;
  height: 100%;
  transform: scaleX(0);
  transform-origin: 0 50%;
  background-image: linear-gradient(90deg, var(--cyan-400), var(--yellow-400));
  will-change: transform;
}

/* ========== 6. Footer ========== */
.site-footer {
  position: relative;
  padding-bottom: 32px;
  background-color: var(--ink-950);
  color: rgba(166, 255, 232, 0.72);
  border-top: 1px solid rgba(43, 245, 200, 0.18);
}

.footer-ruler {
  height: 22px;
  background-color: var(--ink-950);
  background-image:
    repeating-linear-gradient(90deg, rgba(43, 245, 200, 0.45) 0 1px, transparent 1px 24px),
    linear-gradient(rgba(43, 245, 200, 0.3), rgba(43, 245, 200, 0.3));
  background-repeat: no-repeat;
  background-position: top left, bottom left;
  background-size: 100% 7px, 100% 1px;
}

.footer-top {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 2fr);
  gap: 48px;
  padding-block: 44px 36px;
}

.footer-brand__name {
  font-family: var(--font-display);
  font-size: 20px;
  font-weight: 800;
  letter-spacing: -0.01em;
  color: var(--paper);
}

.footer-brand__desc {
  margin-top: 12px;
  font-size: 14px;
  line-height: 1.75;
  color: rgba(166, 255, 232, 0.66);
  max-width: 34ch;
}

.footer-brand__note {
  margin-top: 14px;
  padding-left: 12px;
  border-left: 1px solid rgba(43, 245, 200, 0.3);
  font-size: 12px;
  line-height: 1.7;
  color: rgba(166, 255, 232, 0.5);
}

.footer-brand__cta {
  margin-top: 20px;
}

.footer-cols {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 28px 24px;
}

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

.footer-col__title {
  margin-bottom: 12px;
  padding-bottom: 8px;
  border-bottom: var(--hair-cyan-soft);
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.18em;
  color: var(--cyan-400);
}

.footer-col__list {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.footer-link {
  display: inline-block;
  padding: 4px 0;
  font-size: 14px;
  color: rgba(166, 255, 232, 0.72);
  transition: color 0.16s var(--ease), transform 0.16s var(--ease);
}
.footer-link:hover {
  color: var(--cyan-400);
  transform: translateX(2px);
}

.footer-contact {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 28px;
  padding-block: 18px;
  border-top: var(--hair-cyan-soft);
  border-bottom: var(--hair-cyan-soft);
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.02em;
  color: rgba(166, 255, 232, 0.6);
}

.footer-contact__item {
  display: inline-flex;
  flex-wrap: wrap;
  gap: 8px;
  align-items: baseline;
}

.footer-contact__k {
  padding: 1px 6px;
  border: 1px solid rgba(43, 245, 200, 0.24);
  border-radius: var(--r-sm);
  font-size: 10px;
  letter-spacing: 0.12em;
  color: var(--cyan-400);
}

.footer-legal {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 12px 24px;
  padding-block: 18px 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.04em;
  color: rgba(166, 255, 232, 0.46);
}

.footer-legal__links {
  display: flex;
  flex-wrap: wrap;
  gap: 18px;
}
.footer-legal__links a {
  color: rgba(166, 255, 232, 0.66);
  transition: color 0.16s var(--ease);
}
.footer-legal__links a:hover { color: var(--cyan-400); }

.footer-icp { color: rgba(166, 255, 232, 0.5); }

.footer-legal__copy {
  font-variant-numeric: tabular-nums;
  color: rgba(166, 255, 232, 0.4);
}

/* ========== 7. Reusable blocks ========== */
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.18em;
  color: var(--cyan-400);
}
.eyebrow::before {
  content: "";
  width: 18px;
  height: 1px;
  flex: 0 0 auto;
  background-color: currentColor;
}
.band--paper .eyebrow { color: var(--ink-700); }

.section-title {
  font-size: clamp(26px, 3.6vw, 44px);
  line-height: 1.08;
  letter-spacing: -0.025em;
  color: inherit;
}

.section-lead {
  max-width: 56ch;
  font-size: 16px;
  line-height: 1.8;
  opacity: 0.82;
}

.prose {
  max-width: 68ch;
  font-size: 17px;
  line-height: 1.8;
}
.prose p + p { margin-top: 1em; }

.num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  letter-spacing: -0.01em;
}

.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 3px 8px;
  border-radius: var(--r-sm);
  background-color: var(--cyan-400);
  color: var(--ink-950);
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.08em;
  line-height: 1.5;
}
.tag--ghost {
  background-color: transparent;
  border: 1px solid rgba(43, 245, 200, 0.4);
  color: var(--cyan-400);
}
.tag--yellow {
  background-color: var(--yellow-400);
  color: var(--carbon-900);
}
.band--paper .tag--ghost {
  border-color: rgba(12, 66, 52, 0.35);
  color: var(--ink-700);
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 22px;
  border: 1px solid transparent;
  border-radius: var(--r-sm);
  font-size: 15px;
  font-weight: 600;
  line-height: 1.2;
  text-align: center;
  transition: background-color 0.18s var(--ease), border-color 0.18s var(--ease), color 0.18s var(--ease);
}
.btn--primary {
  background-color: var(--cyan-400);
  color: var(--ink-950);
}
.btn--primary:hover { background-color: var(--cyan-200); }
.btn--ghost {
  border-color: rgba(43, 245, 200, 0.45);
  background-color: rgba(12, 66, 52, 0.5);
  color: var(--cyan-200);
}
.btn--ghost:hover {
  border-color: var(--cyan-400);
  background-color: rgba(43, 245, 200, 0.14);
  color: var(--paper);
}
.btn--paper {
  background-color: var(--ink-900);
  color: var(--paper);
}
.btn--paper:hover { background-color: var(--ink-700); }

.panel {
  padding: 24px;
  border: var(--hair-cyan);
  border-radius: var(--r-md);
  background-color: var(--ink-900);
}

.glass {
  padding: 20px;
  border: 1px solid rgba(43, 245, 200, 0.35);
  border-radius: var(--r-md);
  background-color: var(--glass-green);
  -webkit-backdrop-filter: blur(10px);
  backdrop-filter: blur(10px);
}

.paper-panel {
  padding: 24px;
  border: var(--hair-ink);
  border-radius: var(--r-md);
  background-color: #FFFFFF;
  color: var(--carbon-900);
}

.stat {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 14px 16px;
  border: var(--hair-cyan-soft);
  border-radius: var(--r-md);
  background-color: rgba(12, 66, 52, 0.38);
}
.stat__value {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 26px;
  line-height: 1.1;
  color: var(--yellow-400);
}
.stat__label {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  color: rgba(166, 255, 232, 0.6);
}
.band--paper .stat {
  border-color: rgba(27, 34, 31, 0.16);
  background-color: rgba(12, 66, 52, 0.05);
}
.band--paper .stat__value { color: var(--ink-700); }
.band--paper .stat__label { color: var(--mist-500); }

/* ========== 8. Media containers ========== */
.media {
  position: relative;
  overflow: hidden;
  border: var(--hair-cyan);
  border-radius: 0 0 var(--r-md) var(--r-md);
  background-color: var(--ink-700);
  background-image: linear-gradient(150deg, var(--ink-700), var(--ink-950));
}
.media--4x3 { aspect-ratio: 4 / 3; }
.media--16x9 { aspect-ratio: 16 / 9; }
.media > img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.media__caption {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  padding: 10px 14px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--cyan-200);
  background-image: linear-gradient(to top, rgba(4, 21, 15, 0.92), rgba(4, 21, 15, 0));
}

/* ========== 9. Breadcrumb ========== */
.breadcrumb {
  padding-block: 16px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
}
.breadcrumb__list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
}
.breadcrumb__list li {
  display: flex;
  align-items: center;
  gap: 8px;
}
.breadcrumb__list li:not(:last-child)::after {
  content: "/";
  opacity: 0.4;
}
.breadcrumb a {
  color: var(--cyan-400);
  transition: opacity 0.16s var(--ease);
}
.breadcrumb a:hover { opacity: 0.75; }
.breadcrumb [aria-current="page"] {
  color: inherit;
  opacity: 0.72;
}

/* ========== 10. Reveal ========== */
[data-reveal] {
  opacity: 0;
  transform: translateY(8px);
  transition: opacity 0.32s var(--ease), transform 0.32s var(--ease);
}
[data-reveal].is-revealed {
  opacity: 1;
  transform: none;
}
.reveal { will-change: opacity, transform; }

/* ========== 11. Responsive header / footer ========== */
@media (max-width: 900px) {
  .header-main__inner {
    gap: 14px;
    min-height: 60px;
  }

  .nav-toggle { display: block; }

  .site-nav {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    display: none;
    flex-direction: column;
    max-height: calc(100vh - 100px);
    overflow-y: auto;
    padding: 10px var(--gutter) 22px;
    background-color: var(--ink-950);
    border-bottom: 1px solid rgba(43, 245, 200, 0.3);
  }

  .site-nav[data-open="true"] { display: flex; }

  .site-nav__list {
    flex-direction: column;
    align-items: stretch;
    gap: 2px;
  }

  .site-nav__link {
    padding: 12px 12px;
    border-left: 2px solid transparent;
    border-radius: 0 var(--r-sm) var(--r-sm) 0;
    font-size: 15px;
  }

  .site-nav__link[aria-current="page"] {
    border-left-color: var(--cyan-400);
    border-radius: 0 var(--r-sm) var(--r-sm) 0;
  }

  .site-nav__link[aria-current="page"]::after { display: none; }

  .footer-top {
    grid-template-columns: 1fr;
    gap: 32px;
    padding-block: 36px 28px;
  }

  .footer-cols { grid-template-columns: repeat(2, minmax(0, 1fr)); }

  .footer-brand__desc { max-width: none; }
}

@media (max-width: 640px) {
  .header-strip { display: none; }
  .tick-preview { display: none; }
  .brand__sub { display: none; }
  .brand__name { font-size: 16px; }
  .tool-search { padding: 9px 12px; }
  .tool-search__label { display: none; }
  .tool-help { padding: 9px 12px; font-size: 12px; }
  .footer-cols { grid-template-columns: 1fr; gap: 22px; }
  .footer-legal { flex-direction: column; align-items: flex-start; }
  .footer-contact { flex-direction: column; gap: 8px; }
}

/* ========== 12. Reduced motion ========== */
@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;
  }
  [data-reveal] {
    opacity: 1;
    transform: none;
  }
  .footer-link:hover { transform: none; }
}