/* liangyiOS site — shared color, type, chrome, orbit */

:root {
  --bg: #0b1010;
  --panel: #121918;
  --text: #eef2ea;
  --muted: #a8b6af;
  --accent: #caf593;
  --line: #2e3b35;
  --button-text: #152014;
  --radius: 6px;
  --stroke: 1px;
  --font: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --pad-x: 7%;
  --max: 1440px;
  --fs-12: 12px;
  --fs-14: 14px;
  --fs-17: 17px;
  --fs-24: 24px;
  --fs-40: 40px;
  --fs-64: 64px;
}

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

html {
  scroll-padding-top: 88px;
  font-synthesis: none;
  line-break: strict;
  overflow-wrap: break-word;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  font-size: var(--fs-17);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

img,
svg {
  max-width: 100%;
  display: block;
}

a {
  color: inherit;
  text-underline-offset: 4px;
}

button {
  font: inherit;
  color: inherit;
  cursor: pointer;
}

button,
a {
  -webkit-tap-highlight-color: transparent;
}

button:focus-visible,
a:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
}

::selection {
  background: var(--accent);
  color: var(--bg);
}

.skip {
  position: fixed;
  left: 16px;
  top: -88px;
  z-index: 100;
  background: var(--text);
  color: var(--bg);
  padding: 10px 14px;
  text-decoration: none;
  font-size: var(--fs-14);
  font-weight: 600;
}

.skip:focus {
  top: 12px;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.progress {
  height: 2px;
  background: var(--accent);
  position: fixed;
  left: 0;
  top: 0;
  z-index: 40;
  width: 0;
}

.wrap {
  max-width: var(--max);
  margin: 0 auto;
}

.masthead {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 24px;
  padding: 16px var(--pad-x);
  border-bottom: var(--stroke) solid var(--line);
  position: relative;
  z-index: 10;
  background: var(--bg);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  margin: 0;
  font-size: 28px;
  font-weight: 600;
  letter-spacing: -0.045em;
  line-height: 1;
  text-decoration: none;
  color: var(--text);
  white-space: nowrap;
}

.brand-mark {
  width: 28px;
  height: 28px;
  color: var(--accent);
  flex-shrink: 0;
}

.brand-os {
  color: var(--accent);
}

.masthead-nav {
  display: flex;
  gap: 22px;
  align-items: center;
  flex-shrink: 0;
}

.masthead-nav a {
  font-size: var(--fs-14);
  text-decoration: none;
  color: var(--muted);
}

.masthead-nav a:hover,
.masthead-nav a[aria-current="page"] {
  color: var(--text);
}

.chapter-nav {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 10px 20px;
  position: sticky;
  top: 0;
  z-index: 9;
  background: var(--bg);
  border-bottom: var(--stroke) solid var(--line);
  padding: 12px 20px;
}

.chapter-nav a {
  font-size: var(--fs-12);
  letter-spacing: 0.06em;
  text-decoration: none;
  color: var(--muted);
  white-space: nowrap;
}

.chapter-nav a.is-active,
.chapter-nav a[aria-current="location"] {
  color: var(--accent);
}

.chapter {
  padding: 80px var(--pad-x);
  border-bottom: var(--stroke) solid var(--line);
  scroll-margin-top: 20px;
}

.eyebrow {
  color: var(--accent);
  font-size: var(--fs-12);
  letter-spacing: 0.14em;
  font-weight: 600;
  display: block;
  margin-bottom: 20px;
}

.section-head {
  margin-bottom: 40px;
  max-width: 760px;
}

.section-head h2 {
  font-size: clamp(24px, 3vw, 40px);
  font-weight: 600;
  line-height: 1.28;
  letter-spacing: -0.035em;
  margin: 0 0 16px;
  text-wrap: balance;
}

.section-head p {
  margin: 0;
  color: var(--muted);
  font-size: var(--fs-17);
}

.hero {
  display: grid;
  grid-template-columns: 1.12fr 1fr;
  gap: 56px;
  align-items: center;
  min-height: calc(100vh - 64px);
  padding-top: 48px;
  padding-bottom: 56px;
}

.hero h1 {
  font-size: clamp(40px, 5vw, 64px);
  line-height: 1.16;
  letter-spacing: -0.04em;
  font-weight: 600;
  margin: 12px 0 20px;
  text-wrap: balance;
}

.hero h1 .accent {
  color: var(--accent);
}

.hero-lead {
  font-size: var(--fs-17);
  color: var(--muted);
  max-width: 36em;
  line-height: 1.8;
  margin: 0;
}

.hero-foot {
  display: flex;
  flex-wrap: wrap;
  gap: 16px 24px;
  align-items: center;
  margin-top: 32px;
}

.hero-note {
  font-size: var(--fs-12);
  color: var(--muted);
  margin: 24px 0 0;
}

.concept-note {
  max-width: 44em;
  font-size: 14px;
  line-height: 1.65;
}

.button {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  background: var(--accent);
  color: var(--button-text);
  padding: 12px 20px;
  border: 0;
  border-radius: var(--radius);
  text-decoration: none;
  font-weight: 600;
  font-size: var(--fs-14);
}

.button-ghost {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  background: transparent;
  color: var(--text);
  padding: 11px 18px;
  border: var(--stroke) solid var(--line);
  border-radius: var(--radius);
  text-decoration: none;
  font-size: var(--fs-14);
}

.button-ghost:hover,
.button:hover {
  filter: brightness(1.05);
}

.text-link {
  color: var(--accent);
  text-decoration: none;
  font-size: 15px;
  font-weight: 500;
}

.text-link:hover {
  text-decoration: underline;
}

.orbit {
  --ring-inset: 12%;
  width: 100%;
  max-width: 440px;
  aspect-ratio: 1;
  position: relative;
  margin: 0 auto;
}

.orbit-ring {
  position: absolute;
  border: var(--stroke) solid var(--line);
  border-radius: 50%;
  pointer-events: none;
}

.orbit-ring-outer {
  inset: var(--ring-inset);
}

.orbit-ring-inner {
  inset: 28%;
  border-style: dashed;
}

.orbit-core {
  position: absolute;
  left: 50%;
  top: 50%;
  width: 36%;
  aspect-ratio: 1;
  transform: translate(-50%, -50%);
  border: var(--stroke) solid var(--accent);
  border-radius: 50%;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  background: var(--panel);
  text-align: center;
  padding: 10px;
}

.orbit-core b {
  font-size: var(--fs-24);
  letter-spacing: -0.04em;
  font-weight: 600;
  line-height: 1.2;
}

.orbit-core span {
  font-size: var(--fs-12);
  color: var(--muted);
  letter-spacing: 0.08em;
  margin-top: 6px;
}

.orbit-label {
  position: absolute;
  left: var(--lx);
  top: var(--ly);
  transform: translate(-50%, -50%);
  background: var(--bg);
  border: var(--stroke) solid var(--line);
  padding: 6px 12px;
  border-radius: 999px;
  font-size: var(--fs-14);
  line-height: 1.2;
  white-space: nowrap;
  z-index: 1;
}

.orbit-label::before {
  content: "";
  display: inline-block;
  width: 5px;
  height: 5px;
  margin-right: 6px;
  border-radius: 50%;
  background: var(--accent);
  vertical-align: 1px;
}

.orbit-track {
  position: absolute;
  inset: var(--ring-inset);
  border-radius: 50%;
  pointer-events: none;
}

.orbit-dot {
  position: absolute;
  left: 50%;
  top: 0;
  width: 7px;
  height: 7px;
  transform: translate(-50%, -50%);
  border-radius: 50%;
  background: var(--accent);
}

.orbit-caption {
  text-align: center;
  font-size: var(--fs-12);
  color: var(--muted);
  margin: 24px 0 0;
  letter-spacing: 0.06em;
}

.note {
  font-size: 13px;
  color: var(--muted);
  margin-top: 28px;
  max-width: 52em;
}

.statement {
  font-size: clamp(22px, 2.4vw, 32px);
  font-weight: 500;
  line-height: 1.45;
  letter-spacing: -0.02em;
  margin: 48px 0 0;
  padding: 32px 0 0;
  border-top: var(--stroke) solid var(--line);
  max-width: 22em;
}

.statement .accent {
  color: var(--accent);
}

.closing {
  padding: 88px var(--pad-x);
  text-align: center;
}

.closing h2 {
  font-weight: 600;
  line-height: 1.4;
  font-size: clamp(24px, 3.2vw, 40px);
  letter-spacing: -0.03em;
  margin: 12px auto 16px;
  max-width: 16em;
  text-wrap: balance;
}

.closing p {
  color: var(--muted);
  font-size: 15px;
  margin: 0 auto;
  max-width: 36em;
}

.site-footer {
  padding: 36px var(--pad-x) 28px;
  border-top: var(--stroke) solid var(--line);
}

.footer-brand {
  text-align: center;
  padding-bottom: 20px;
  margin-bottom: 18px;
  border-bottom: var(--stroke) solid var(--line);
}

.footer-product {
  margin: 0 0 6px;
  font-size: var(--fs-17);
  font-weight: 600;
  letter-spacing: -0.03em;
  color: var(--text);
}

.footer-vision {
  margin: 0;
  font-size: var(--fs-14);
  color: var(--muted);
}

.footer-legal {
  text-align: center;
}

.footer-host,
.footer-icp {
  margin: 0;
  font-size: 13px;
  line-height: 1.65;
  color: var(--muted);
}

.footer-host {
  margin-bottom: 4px;
}

.footer-icp a {
  color: var(--muted);
}

.footer-icp a:hover {
  color: var(--text);
}

@media (min-width: 1440px) {
  .hero {
    min-height: 760px;
  }
}

@media (max-width: 1080px) {
  .hero {
    gap: 36px;
    min-height: 0;
    padding-left: 5%;
    padding-right: 5%;
  }

  .chapter,
  .closing,
  .masthead,
  .site-footer {
    padding-left: 5%;
    padding-right: 5%;
  }

  .orbit-core b {
    font-size: 20px;
  }
}

@media (max-width: 700px) {
  body {
    font-size: 16px;
  }

  .masthead {
    padding: 14px 22px;
    align-items: center;
    gap: 16px;
  }

  .brand {
    font-size: 26px;
    gap: 8px;
  }

  .brand-mark {
    width: 24px;
    height: 24px;
  }

  .masthead-nav {
    gap: 16px;
  }

  .chapter-nav {
    justify-content: flex-start;
    gap: 8px 14px;
    padding: 12px 22px;
  }

  .chapter,
  .closing {
    padding: 56px 22px;
  }

  .hero {
    grid-template-columns: 1fr;
    gap: 40px;
    padding: 36px 22px 48px;
    min-height: 0;
  }

  .hero h1 {
    font-size: 40px;
    letter-spacing: -0.03em;
  }

  .hero-lead {
    font-size: var(--fs-17);
  }

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

  .hero-foot .hero-note {
    margin: 0;
    text-align: center;
  }

  .button,
  .button-ghost {
    justify-content: center;
  }

  .orbit {
    max-width: 300px;
  }

  .orbit-label {
    font-size: var(--fs-12);
    padding: 5px 9px;
  }

  .orbit-core b {
    font-size: 16px;
  }

  .orbit-core span {
    font-size: var(--fs-12);
    letter-spacing: 0.04em;
  }

  .section-head h2 {
    font-size: 28px;
  }

  .site-footer {
    padding: 28px 22px 24px;
  }
}

@media (prefers-reduced-motion: no-preference) {
  html {
    scroll-behavior: smooth;
  }

  .orbit-dot {
    left: auto;
    top: auto;
    transform: none;
    offset-path: circle(closest-side at center);
    offset-anchor: center;
    offset-rotate: 0deg;
    animation: orbit-run 28s linear infinite;
  }

  .progress {
    transition: width 80ms linear;
  }
}

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

  *,
  *::before,
  *::after {
    animation: none !important;
    transition: none !important;
  }
}

@keyframes orbit-run {
  to {
    offset-distance: 100%;
  }
}

@media print {
  body {
    background: #fff;
    color: #18221a;
    --bg: #fff;
    --panel: #f4f6f1;
    --text: #18221a;
    --muted: #455247;
    --accent: #285638;
    --line: #bfc8bf;
    --button-text: #fff;
  }

  .skip,
  .progress,
  .chapter-nav,
  .hero-foot,
  .orbit,
  .sys-wires {
    display: none !important;
  }

  a {
    text-decoration: none;
  }

  .chapter,
  .hero,
  .closing {
    min-height: 0;
    background: none;
    break-inside: avoid;
  }
}