/* ============================================
   yeahtech · 业以科技 官网样式
   暗黑底 + 极简留白 + 抽象动效
   ============================================ */

* { margin: 0; padding: 0; box-sizing: border-box; }

:root {
  --bg: #050505;
  --bg-soft: #0a0a0a;
  --fg: #f0f0f0;
  --fg-dim: #888;
  --fg-faint: #444;
  --accent-cyan: #7df9ff;
  --accent-violet: #c8a2ff;
  --line: rgba(240, 240, 240, 0.08);
  --line-bright: rgba(240, 240, 240, 0.18);
  --font-mono: 'JetBrains Mono', ui-monospace, monospace;
  --font-sans: 'Space Grotesk', 'Noto Sans SC', system-ui, sans-serif;
  --font-cn: 'Noto Sans SC', 'PingFang SC', 'Microsoft YaHei', system-ui, sans-serif;
}

html, body {
  background: var(--bg);
  color: var(--fg);
  font-family: var(--font-sans);
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
  cursor: none;
}

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

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

/* ===== 自定义光标 ===== */
.cursor {
  position: fixed;
  top: 0; left: 0;
  width: 6px; height: 6px;
  background: var(--fg);
  border-radius: 50%;
  pointer-events: none;
  z-index: 9999;
  transform: translate(-50%, -50%);
  transition: width .25s, height .25s, background .25s;
  mix-blend-mode: difference;
}
.cursor-aura {
  position: fixed;
  top: 0; left: 0;
  width: 40px; height: 40px;
  border: 1px solid rgba(240,240,240,0.3);
  border-radius: 50%;
  pointer-events: none;
  z-index: 9998;
  transform: translate(-50%, -50%);
  transition: width .35s ease, height .35s ease, border-color .35s ease;
}
.cursor.is-hover { width: 0; height: 0; }
.cursor-aura.is-hover {
  width: 70px; height: 70px;
  border-color: var(--accent-cyan);
}

/* ===== 噪点叠层 ===== */
.noise {
  position: fixed; inset: 0;
  pointer-events: none;
  z-index: 9000;
  opacity: 0.035;
  background-image: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='200' height='200'><filter id='n'><feTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='2' stitchTiles='stitch'/></filter><rect width='100%' height='100%' filter='url(%23n)'/></svg>");
  mix-blend-mode: overlay;
}

/* ===== 顶部导航 ===== */
.nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  padding: 28px 48px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.1em;
  mix-blend-mode: difference;
}
.nav-mark {
  display: flex;
  align-items: center;
  gap: 10px;
}
.mark-glyph {
  font-size: 18px;
  animation: rotate 12s linear infinite;
  display: inline-block;
}
@keyframes rotate { to { transform: rotate(360deg); } }
.mark-text {
  letter-spacing: 0.15em;
  font-weight: 500;
}
.nav-links {
  display: flex;
  gap: 36px;
}
.nav-links a {
  color: var(--fg);
  position: relative;
  transition: opacity .3s;
  opacity: 0.7;
}
.nav-links a:hover { opacity: 1; }
.nav-links a::before {
  content: '';
  position: absolute;
  left: -14px; top: 50%;
  width: 4px; height: 1px;
  background: var(--fg);
  transform: translateY(-50%) scaleX(0);
  transform-origin: left;
  transition: transform .3s;
}
.nav-links a:hover::before { transform: translateY(-50%) scaleX(1); }

/* ===== HERO ===== */
.hero {
  position: relative;
  height: 100vh;
  min-height: 720px;
  width: 100%;
  overflow: hidden;
  display: flex;
  align-items: center;
  justify-content: center;
}
#particles {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  z-index: 1;
}
.hero-frame {
  position: absolute;
  inset: 48px;
  pointer-events: none;
  z-index: 3;
}
.hero-frame span {
  position: absolute;
  width: 28px; height: 28px;
  border-color: var(--line-bright);
  border-style: solid;
  border-width: 0;
}
.frame-tl { top: 0; left: 0; border-top-width: 1px; border-left-width: 1px; }
.frame-tr { top: 0; right: 0; border-top-width: 1px; border-right-width: 1px; }
.frame-bl { bottom: 0; left: 0; border-bottom-width: 1px; border-left-width: 1px; }
.frame-br { bottom: 0; right: 0; border-bottom-width: 1px; border-right-width: 1px; }

.hero-content {
  position: relative;
  z-index: 2;
  text-align: center;
  padding: 0 24px;
}
.hero-meta {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.3em;
  color: var(--fg-dim);
  margin-bottom: 36px;
  opacity: 0;
  animation: fadeUp 1.2s 0.2s forwards;
}
.meta-dot {
  width: 6px; height: 6px;
  background: var(--accent-cyan);
  border-radius: 50%;
  box-shadow: 0 0 12px var(--accent-cyan);
  animation: pulse 2s ease-in-out infinite;
}
@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.3; }
}

.hero-title {
  font-family: var(--font-sans);
  font-size: clamp(52px, 11vw, 168px);
  font-weight: 300;
  letter-spacing: -0.04em;
  line-height: 0.95;
  margin-bottom: 24px;
}
.title-line {
  display: inline-block;
  position: relative;
  opacity: 0;
  animation: titleReveal 1.6s 0.4s cubic-bezier(.2,.8,.2,1) forwards;
}
.title-line::after {
  content: attr(data-text);
  position: absolute;
  left: 0; top: 0;
  color: transparent;
  background: linear-gradient(90deg, var(--accent-cyan), var(--accent-violet));
  -webkit-background-clip: text;
  background-clip: text;
  opacity: 0;
  transition: opacity .6s;
}
.title-line:hover::after { opacity: 1; }

@keyframes titleReveal {
  0% { opacity: 0; transform: translateY(40px); filter: blur(12px); }
  100% { opacity: 1; transform: translateY(0); filter: blur(0); }
}
@keyframes fadeUp {
  0% { opacity: 0; transform: translateY(20px); }
  100% { opacity: 1; transform: translateY(0); }
}

.hero-sub {
  font-family: var(--font-cn);
  font-size: clamp(14px, 1.4vw, 18px);
  font-weight: 300;
  color: var(--fg-dim);
  margin-bottom: 56px;
  opacity: 0;
  animation: fadeUp 1.2s 0.8s forwards;
}
.sub-cn {
  letter-spacing: 0.6em;
  padding-left: 0.6em;
}

.hero-keywords {
  display: inline-flex;
  align-items: center;
  gap: 16px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.25em;
  color: var(--fg-dim);
  opacity: 0;
  animation: fadeUp 1.2s 1.1s forwards;
}
.kw-divider {
  color: var(--fg-faint);
}

.hero-scroll {
  position: absolute;
  bottom: 48px; left: 50%;
  transform: translateX(-50%);
  z-index: 3;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.4em;
  color: var(--fg-dim);
}
.scroll-line {
  display: block;
  width: 1px;
  height: 48px;
  background: linear-gradient(to bottom, transparent, var(--fg-dim));
  position: relative;
  overflow: hidden;
}
.scroll-line::after {
  content: '';
  position: absolute;
  top: -100%;
  left: 0;
  width: 100%;
  height: 100%;
  background: var(--accent-cyan);
  animation: scrollDown 2.4s ease-in-out infinite;
}
@keyframes scrollDown {
  0% { top: -100%; }
  100% { top: 100%; }
}

/* ===== 通用区块 ===== */
section {
  position: relative;
  padding: 160px 48px;
}

.section-index {
  position: absolute;
  top: 80px;
  left: 48px;
  display: flex;
  flex-direction: column;
  gap: 6px;
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.3em;
  color: var(--fg-faint);
}
.idx-num {
  font-size: 11px;
  color: var(--fg-dim);
}

/* ===== 入场动画 ===== */
.reveal {
  opacity: 0;
  transform: translateY(40px);
  transition: opacity 1.2s cubic-bezier(.2,.8,.2,1), transform 1.2s cubic-bezier(.2,.8,.2,1);
}
.reveal.is-visible {
  opacity: 1;
  transform: translateY(0);
}

/* ===== Domains ===== */
.domains {
  border-top: 1px solid var(--line);
}
.domains-grid {
  max-width: 1240px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}
.domain {
  background: var(--bg);
  padding: 80px 56px;
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  position: relative;
  transition: background .6s;
  overflow: hidden;
}
.domain::before {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(circle at 50% 50%, rgba(125,249,255,0.06), transparent 60%);
  opacity: 0;
  transition: opacity .8s;
  pointer-events: none;
}
.domain[data-domain="ai"]::before {
  background: radial-gradient(circle at 50% 50%, rgba(200,162,255,0.06), transparent 60%);
}
.domain:hover::before { opacity: 1; }

.domain-visual {
  width: 200px;
  height: 200px;
  margin-bottom: 48px;
}
.domain-svg {
  width: 100%;
  height: 100%;
}
.ring {
  transform-origin: center;
  animation: ringRotate 24s linear infinite;
}
.ring-2 { animation-duration: 18s; animation-direction: reverse; }
.ring-3 { animation-duration: 12s; }
@keyframes ringRotate {
  from { stroke-dashoffset: 0; transform: rotate(0deg); }
  to { stroke-dashoffset: 0; transform: rotate(360deg); }
}
.ai-graph .node {
  animation: nodePulse 3s ease-in-out infinite;
}
.ai-graph .node:nth-child(8) { animation-delay: 0.2s; }
.ai-graph .node:nth-child(9) { animation-delay: 0.4s; }
.ai-graph .node:nth-child(10) { animation-delay: 0.6s; }
.ai-graph .node:nth-child(11) { animation-delay: 0.8s; }
.ai-graph .node:nth-child(12) { animation-delay: 1.0s; }
.ai-graph .node-center { animation-duration: 2s; }
@keyframes nodePulse {
  0%, 100% { opacity: 0.4; }
  50% { opacity: 1; }
}

.domain-num {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.25em;
  color: var(--fg-faint);
  margin-bottom: 12px;
}
.domain-name {
  font-size: 96px;
  font-weight: 300;
  letter-spacing: -0.02em;
  line-height: 1;
  margin-bottom: 18px;
}
.domain[data-domain="xr"] .domain-name {
  background: linear-gradient(180deg, var(--fg) 60%, var(--accent-cyan));
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}
.domain[data-domain="ai"] .domain-name {
  background: linear-gradient(180deg, var(--fg) 60%, var(--accent-violet));
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}
.domain-desc {
  font-family: var(--font-cn);
  font-size: 12px;
  font-weight: 300;
  letter-spacing: 0.12em;
  color: var(--fg-dim);
  line-height: 2;
}

/* ===== Philosophy ===== */
.philosophy {
  border-top: 1px solid var(--line);
  min-height: 80vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  position: relative;
  overflow: hidden;
}
.philosophy-content {
  max-width: 1100px;
  margin: 0 auto;
  width: 100%;
  position: relative;
  z-index: 2;
}
.philosophy-line {
  display: flex;
  align-items: baseline;
  gap: 28px;
  margin-bottom: 32px;
}
.philosophy-line:nth-child(1) {
  font-family: var(--font-cn);
  font-size: clamp(28px, 4vw, 56px);
  font-weight: 300;
  letter-spacing: 0.12em;
  color: var(--fg);
}
.philosophy-line:nth-child(2) {
  font-family: var(--font-sans);
  font-size: clamp(16px, 1.6vw, 22px);
  font-weight: 300;
  letter-spacing: 0.02em;
  color: var(--fg-dim);
  margin-left: 60px;
}
.line-bullet {
  color: var(--accent-cyan);
  font-weight: 300;
}
.philosophy-grid {
  position: absolute;
  inset: 0;
  z-index: 1;
  pointer-events: none;
}
.grid-line {
  position: absolute;
  background: var(--line);
}
.grid-line:nth-child(1) { left: 16.66%; top: 0; width: 1px; height: 100%; }
.grid-line:nth-child(2) { left: 50%; top: 0; width: 1px; height: 100%; }
.grid-line:nth-child(3) { left: 83.33%; top: 0; width: 1px; height: 100%; }
.grid-line:nth-child(4) {
  left: 0; top: 50%;
  width: 100%; height: 1px;
  background: linear-gradient(90deg, transparent, var(--line) 30%, var(--line) 70%, transparent);
}

/* ===== Footer ===== */
.footer {
  border-top: 1px solid var(--line);
  padding: 160px 48px 40px;
  position: relative;
}
.footer-content {
  max-width: 1240px;
  margin: 0 auto;
}
.footer-mail {
  display: inline-flex;
  align-items: baseline;
  gap: 18px;
  font-family: var(--font-sans);
  font-size: clamp(36px, 6vw, 88px);
  font-weight: 300;
  letter-spacing: -0.02em;
  color: var(--fg);
  position: relative;
  margin-bottom: 96px;
  transition: color .4s;
}
.footer-mail:hover { color: var(--accent-cyan); }
.mail-text {
  position: relative;
}
.mail-text::after {
  content: '';
  position: absolute;
  left: 0; bottom: 0.1em;
  width: 100%;
  height: 1px;
  background: currentColor;
  transform: scaleX(0);
  transform-origin: left;
  transition: transform .6s cubic-bezier(.2,.8,.2,1);
}
.footer-mail:hover .mail-text::after { transform: scaleX(1); }
.mail-arrow {
  font-size: 0.5em;
  font-weight: 300;
  transition: transform .4s;
}
.footer-mail:hover .mail-arrow { transform: translate(8px, -8px); }

.footer-meta {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 56px;
  padding-bottom: 60px;
  border-bottom: 1px solid var(--line);
}
.meta-col {
  display: flex;
  flex-direction: column;
  gap: 12px;
}
.meta-key {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.3em;
  color: var(--fg-faint);
}
.meta-val {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.05em;
  color: var(--fg-dim);
  display: flex;
  align-items: center;
  gap: 8px;
}
.status-dot {
  width: 6px; height: 6px;
  background: var(--accent-cyan);
  border-radius: 50%;
  box-shadow: 0 0 10px var(--accent-cyan);
  animation: pulse 2s ease-in-out infinite;
}

.footer-bottom {
  max-width: 1240px;
  margin: 32px auto 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.2em;
  color: var(--fg-faint);
}
.footer-icp {
  font-family: var(--font-cn);
  font-size: 11px;
  font-weight: 300;
  letter-spacing: 0.05em;
  color: var(--fg-faint);
  transition: color .3s;
}
.footer-icp:hover { color: var(--fg-dim); }

/* ===== 响应式 ===== */
@media (max-width: 768px) {
  .nav { padding: 20px 24px; }
  .nav-links { gap: 20px; font-size: 11px; }
  section { padding: 120px 24px; }
  .section-index { left: 24px; top: 60px; }
  .hero-frame { inset: 24px; }
  .domains-grid { grid-template-columns: 1fr; }
  .domain { padding: 60px 32px; }
  .domain-name { font-size: 72px; }
  .footer { padding: 120px 24px 32px; }
  .footer-meta { grid-template-columns: 1fr; gap: 32px; }
  .philosophy-line:nth-child(2) { margin-left: 0; }
  html, body { cursor: auto; }
  .cursor, .cursor-aura { display: none; }
}