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

/* ─── Oriental Minimalism 色彩系统 ─── */
:root {
  --warm-white: #f7f4f0;
  --cream: #f5f2ed;
  --sand: rgba(200,180,150,0.08);
  --sand-stronger: rgba(200,180,150,0.15);
  --water: rgba(120,160,190,0.15);
  --water-line: rgba(120,160,190,0.25);
  --water-line-strong: rgba(100,140,170,0.4);
  --water-glow: rgba(220,200,170,0.04);
  --glow-warm: rgba(220,200,170,0.04);

  /* 文字层 — 提升对比度 */
  --text-primary: rgba(35,35,35,0.85);
  --text-body: rgba(45,45,45,0.72);
  --text-muted: rgba(55,55,55,0.5);
  --text-light: rgba(70,70,70,0.35);

  /* 辅助色 */
  --accent-teal: rgba(20,184,166,0.7);
  --accent-blue: rgba(37,99,235,0.65);
  --accent-warm: rgba(234,88,12,0.6);
  --accent-green: rgba(22,163,74,0.65);

  /* 卡片 — 提高不透明度 */
  --card-bg: rgba(255,255,255,0.75);
  --card-border: rgba(120,160,190,0.12);
  --card-shadow: 0 2px 16px rgba(0,0,0,0.04);
}

body {
  font-family: "PingFang SC", "Noto Sans SC", -apple-system, BlinkMacSystemFont, sans-serif;
  background: var(--warm-white);
  color: var(--text-body);
  line-height: 1.9;
  overflow-x: hidden;
  font-weight: 400;
  position: relative;
}

/* ─── Flow Mesh Gradient Background (below hero only) ─── */
.flow-bg {
  position: fixed;
  inset: 0;
  z-index: 0;
  overflow: hidden;
  pointer-events: none;
  background: var(--warm-white);
}

.flow-blob {
  position: absolute;
  border-radius: 50%;
  filter: blur(120px);
  opacity: 0.6;
  animation: flow-drift 90s ease-in-out infinite alternate;
}

.flow-blob-1 {
  width: 700px;
  height: 700px;
  top: -15%;
  left: -10%;
  background: radial-gradient(circle, rgba(100,160,200,0.7) 0%, transparent 70%);
  animation-duration: 100s;
}

.flow-blob-2 {
  width: 600px;
  height: 600px;
  top: 25%;
  right: -15%;
  background: radial-gradient(circle, rgba(200,180,150,0.65) 0%, transparent 70%);
  animation-duration: 120s;
  animation-delay: -30s;
}

.flow-blob-3 {
  width: 550px;
  height: 550px;
  bottom: 15%;
  left: 5%;
  background: radial-gradient(circle, rgba(140,180,170,0.6) 0%, transparent 70%);
  animation-duration: 110s;
  animation-delay: -60s;
}

.flow-blob-4 {
  width: 650px;
  height: 650px;
  top: 55%;
  right: 15%;
  background: radial-gradient(circle, rgba(160,140,190,0.5) 0%, transparent 70%);
  animation-duration: 130s;
  animation-delay: -45s;
}

.flow-blob-5 {
  width: 500px;
  height: 500px;
  top: 45%;
  left: 40%;
  background: radial-gradient(circle, rgba(120,160,190,0.55) 0%, transparent 70%);
  animation-duration: 90s;
  animation-delay: -15s;
}

.flow-blob-6 {
  width: 450px;
  height: 450px;
  bottom: -10%;
  right: 25%;
  background: radial-gradient(circle, rgba(180,160,140,0.55) 0%, transparent 70%);
  animation-duration: 115s;
  animation-delay: -70s;
}

@keyframes flow-drift {
  0% {
    transform: translate(0, 0) scale(1);
  }
  25% {
    transform: translate(80px, -60px) scale(1.1);
  }
  50% {
    transform: translate(-40px, 100px) scale(0.95);
  }
  75% {
    transform: translate(60px, 40px) scale(1.05);
  }
  100% {
    transform: translate(-30px, -80px) scale(1);
  }
}

/* Respect reduced motion */
@media (prefers-reduced-motion: reduce) {
  .flow-blob {
    animation: none;
    opacity: 0.15;
  }
}

/* ========= HERO ========= */
.hero {
  position: relative;
  z-index: 2;
  min-height: 100vh;
  display: flex; align-items: center; justify-content: center;
  text-align: center;
  overflow: hidden;
  background: var(--warm-white);
  color: var(--text-primary);
}

.hero canvas {
  position: absolute; inset: 0;
  width: 100%; height: 100%;
  z-index: 0;
}

.hero-inner {
  position: relative; z-index: 1;
  max-width: 640px; padding: 36px 40px 40px;
  background: rgba(247,244,240,0.65);
  backdrop-filter: blur(12px); -webkit-backdrop-filter: blur(12px);
  border-radius: 16px;
  text-align: center;
}

.hackathon-badge {
  display: inline-flex;
  align-items: center;
  height: 26px;
  margin: 0;
  font-size: 12px; font-weight: 500;
  letter-spacing: 0.08em;
  padding: 0 12px;
  border-radius: 6px;
  background: rgba(100,140,170,0.06);
  border: 1px solid rgba(100,140,170,0.1);
  color: var(--text-body);
}

.hero-badges {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  flex-wrap: wrap;
  margin-bottom: 28px;
}

.github-badge {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  font-size: 12px;
  font-weight: 500;
  height: 26px;
  padding: 0 12px;
  border-radius: 6px;
  background: rgba(30,30,30,0.04);
  border: 1px solid rgba(30,30,30,0.08);
  color: var(--text-body);
  text-decoration: none;
  transition: all 0.2s;
  line-height: 1;
}
.github-badge svg {
  flex-shrink: 0;
}
.github-badge:hover {
  background: rgba(30,30,30,0.08);
  border-color: rgba(30,30,30,0.15);
  color: rgba(30,30,30,0.85);
}

.hero-logo {
  font-family: "Songti SC", "Noto Serif CJK SC", "STSong", "SimSun", "Source Han Serif SC", serif;
  font-size: clamp(48px, 8vw, 72px);
  font-weight: 200;
  margin-bottom: 20px;
  color: rgba(30,30,30,0.85);
  line-height: 1.2;
}

.hero h1 {
  font-size: clamp(18px, 3vw, 24px);
  font-weight: 400;
  letter-spacing: 0.08em;
  line-height: 1.6;
  margin-bottom: 48px;
  color: rgba(30,30,30,0.8);
}
.hero h1 .flow { color: rgba(90,130,160,0.8); }

.hero-stats {
  display: flex; justify-content: center; gap: 48px; flex-wrap: wrap;
}
.hero-stat { text-align: center; }
.hero-stat-num {
  font-size: 20px; font-weight: 600;
  color: rgba(80,120,150,0.85);
  letter-spacing: 0.03em;
}
.hero-stat-label {
  font-size: 10px; color: var(--text-muted); margin-top: 4px;
  letter-spacing: 0.05em; font-weight: 400;
}

.scroll-hint {
  position: absolute; bottom: 2.5rem; left: 50%; transform: translateX(-50%);
  z-index: 2; display: flex; flex-direction: column; align-items: center; gap: 0;
}
.scroll-hint .arrow {
  width: 1px; height: 32px;
  background: linear-gradient(to bottom, var(--text-body), transparent);
}

/* ========= SECTIONS ========= */
.container { max-width: 720px; margin: 0 auto; padding: 0 24px; position: relative; z-index: 1; }
section { padding: 100px 0; position: relative; z-index: 1; }
section + section { padding-top: 0; }

.section-tag {
  display: inline-block;
  color: var(--text-body);
  font-size: 11px; font-weight: 600;
  letter-spacing: 0.18em; margin-bottom: 14px;
  padding: 4px 12px;
  background: rgba(100,140,170,0.08);
  border-radius: 4px;
  border: 1px solid rgba(100,140,170,0.1);
}
.section-title {
  font-size: clamp(22px, 3.8vw, 30px);
  font-weight: 600; color: rgba(30,30,30,0.9);
  margin-bottom: 10px; letter-spacing: 0.02em;
  line-height: 1.45;
}
.section-sub {
  font-size: 15px; color: var(--text-body); margin-bottom: 48px;
  font-weight: 400; letter-spacing: 0.02em;
  line-height: 1.6;
}

/* Divider */
.divider {
  width: 40px; height: 1px;
  background: var(--water-line);
  margin: 60px 0;
  opacity: 0.3;
}

/* Scroll animations base */
.section-animate {
  opacity: 0;
}

/* ========= RESPONSIVE ========= */
@media (max-width: 640px) {
  .hero-stats { gap: 24px; }
  .hero-inner { padding: 28px 24px; }
  .hero-badges { flex-direction: column; gap: 8px; margin-bottom: 24px; }
  .hero-tagline { font-size: 12px; margin-bottom: 24px; }
  .back-link { top: 12px; left: 12px; padding: 6px 12px; font-size: 12px; }
}