:root,
[data-theme="light"] {
  --bg: #fafafa;
  --bg-alt: #ffffff;
  --bg-card: rgba(255, 255, 255, 0.7);
  --bg-nav: rgba(250, 250, 250, 0.8);
  --text: #111111;
  --text-2: #444444;
  --text-3: #888888;
  --border: rgba(0, 0, 0, 0.08);
  --border-hover: rgba(0, 0, 0, 0.15);
  --accent-1: #6366f1;
  --accent-2: #8b5cf6;
  --accent-3: #ec4899;
  --accent-bg: rgba(99, 102, 241, 0.06);
  --accent-bg-hover: rgba(99, 102, 241, 0.1);
  --tag-bg: #f3f4f6;
  --tag-text: #555;
  --glow-1: rgba(99, 102, 241, 0.15);
  --glow-2: rgba(236, 72, 153, 0.1);
  --hero-grid: rgba(0, 0, 0, 0.03);
  --stat-bg: linear-gradient(135deg, #f8f9ff 0%, #f0f0ff 100%);
  --card-shadow: 0 1px 3px rgba(0,0,0,0.04), 0 8px 32px rgba(0,0,0,0.04);
  --card-shadow-hover: 0 4px 12px rgba(0,0,0,0.06), 0 16px 48px rgba(0,0,0,0.08);
}

[data-theme="dark"] {
  --bg: #09090b;
  --bg-alt: #0f0f14;
  --bg-card: rgba(22, 22, 34, 0.7);
  --bg-nav: rgba(9, 9, 11, 0.85);
  --text: #f0f0f4;
  --text-2: #a0a0b4;
  --text-3: #5a5a72;
  --border: rgba(255, 255, 255, 0.06);
  --border-hover: rgba(255, 255, 255, 0.12);
  --accent-1: #818cf8;
  --accent-2: #a78bfa;
  --accent-3: #f472b6;
  --accent-bg: rgba(129, 140, 248, 0.08);
  --accent-bg-hover: rgba(129, 140, 248, 0.14);
  --tag-bg: rgba(255, 255, 255, 0.05);
  --tag-text: #a0a0b4;
  --glow-1: rgba(129, 140, 248, 0.12);
  --glow-2: rgba(244, 114, 182, 0.08);
  --hero-grid: rgba(255, 255, 255, 0.02);
  --stat-bg: linear-gradient(135deg, rgba(129,140,248,0.08) 0%, rgba(167,139,250,0.06) 100%);
  --card-shadow: 0 1px 3px rgba(0,0,0,0.2), 0 8px 32px rgba(0,0,0,0.2);
  --card-shadow-hover: 0 4px 12px rgba(0,0,0,0.3), 0 16px 48px rgba(0,0,0,0.3);
}

*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  font-family: 'Inter', 'Noto Sans SC', -apple-system, BlinkMacSystemFont, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  transition: background 0.5s ease, color 0.5s ease;
  overflow-x: hidden;
}
a { color: inherit; text-decoration: none; }
::selection { background: var(--accent-1); color: #fff; }

/* ===== Nav ===== */
.nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  background: transparent;
  backdrop-filter: blur(20px); -webkit-backdrop-filter: blur(20px);
  transition: background 0.5s ease;
}
.nav-inner {
  max-width: 1000px; margin: 0 auto; padding: 0 32px;
  height: 64px; display: flex; align-items: center; justify-content: space-between;
}
.nav-logo {
  font-size: 1.5rem; font-weight: 800;
  background: linear-gradient(135deg, var(--accent-1), var(--accent-2));
  -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text;
}
.nav-links { display: flex; gap: 32px; }
.nav-links a {
  font-size: 0.85rem; font-weight: 500; color: var(--text-3);
  transition: color 0.2s ease; letter-spacing: 0.01em;
}
.nav-links a:hover { color: var(--text); }
.nav-controls { display: flex; gap: 8px; align-items: center; }

.lang-toggle, .theme-toggle {
  width: 38px; height: 38px; border-radius: 10px;
  border: 1px solid var(--border); background: transparent;
  color: var(--text-3); cursor: pointer;
  display: flex; align-items: center; justify-content: center;
  transition: all 0.2s ease; font-size: 0.8rem; font-weight: 600;
  font-family: 'Noto Sans SC', 'Inter', sans-serif;
}
.lang-toggle:hover, .theme-toggle:hover {
  border-color: var(--accent-1); color: var(--accent-1); background: var(--accent-bg);
}
[data-theme="light"] .icon-moon { display: none; }
[data-theme="dark"] .icon-sun { display: none; }
[data-theme="light"] .icon-sun { display: block; }
[data-theme="dark"] .icon-moon { display: block; }
[data-lang="en"] [data-lang-show="zh"] { display: none; }
[data-lang="zh"] [data-lang-show="en"] { display: none; }
[data-lang="en"] [data-lang-show="en"] { display: inline; }
[data-lang="zh"] [data-lang-show="zh"] { display: inline; }

/* ===== Intro ===== */
.main {
  padding-top: 72px;
  min-height: 100vh;
  background: var(--bg-alt);
}
.intro {
  padding: 32px 0 48px;
  border-bottom: 1px solid var(--border);
  margin-bottom: 48px;
  text-align: center;
}
.intro-name {
  font-size: 2.2rem; font-weight: 800;
  letter-spacing: -0.03em; line-height: 1;
  margin-bottom: 8px;
  background: linear-gradient(135deg, var(--accent-1) 0%, var(--accent-2) 50%, var(--accent-3) 100%);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  background-clip: text;
}
.intro-desc {
  font-size: 0.88rem; color: var(--text-3); line-height: 1.6;
}

/* ===== Sections ===== */
.container { max-width: 860px; margin: 0 auto; padding: 0 32px; }
.section { padding: 80px 0; }
.section-alt { background: var(--bg-alt); }
.section-header { margin-bottom: 40px; }
.section-label {
  display: inline-block; font-size: 0.75rem; font-weight: 600;
  letter-spacing: 0.12em; text-transform: uppercase;
  color: var(--accent-1); margin-bottom: 12px;
  padding: 4px 12px; border-radius: 6px; background: var(--accent-bg);
}
.section-title {
  font-size: clamp(1.8rem, 4vw, 2.4rem); font-weight: 700;
  letter-spacing: -0.03em; color: var(--text); line-height: 1.2;
}
.section-subtitle {
  font-size: 1.05rem; color: var(--text-3); margin-top: 16px;
  line-height: 1.7; max-width: 520px;
}

/* ===== About ===== */
.about-grid {
  display: grid; grid-template-columns: 1fr 1fr; gap: 48px;
  align-items: start; margin-bottom: 40px;
}
.about-text p {
  font-size: 1rem; color: var(--text-2); line-height: 1.85; margin-bottom: 16px;
}
.about-text p:last-child { margin-bottom: 0; }
.about-stats { display: flex; flex-direction: column; gap: 12px; }
.stat-card {
  padding: 20px 24px; border-radius: 14px;
  background: var(--stat-bg);
  border: 1px solid var(--border);
  display: flex; align-items: baseline; gap: 12px;
  transition: border-color 0.2s ease;
}
.stat-card:hover { border-color: var(--border-hover); }
.stat-number {
  font-size: 1.6rem; font-weight: 800;
  background: linear-gradient(135deg, var(--accent-1), var(--accent-2));
  -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text;
}
.stat-label { font-size: 0.85rem; font-weight: 500; color: var(--text-3); }

.skills { display: flex; flex-wrap: wrap; gap: 8px; }
.skill-tag {
  padding: 6px 14px; font-size: 0.78rem; font-weight: 500;
  color: var(--tag-text); background: var(--tag-bg);
  border-radius: 8px; border: 1px solid transparent;
  transition: all 0.2s ease;
}
.skill-tag:hover {
  border-color: var(--accent-1); color: var(--accent-1); background: var(--accent-bg);
}

/* ===== Projects ===== */
.project-card {
  margin-bottom: 32px; border-radius: 20px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  backdrop-filter: blur(16px); -webkit-backdrop-filter: blur(16px);
  box-shadow: var(--card-shadow);
  transition: all 0.35s ease;
  overflow: hidden;
}
.project-card:last-child { margin-bottom: 0; }
.project-card:hover {
  border-color: var(--border-hover);
  box-shadow: var(--card-shadow-hover);
  transform: translateY(-4px);
}
.project-card-inner { padding: 32px; position: relative; }
.project-card-accent {
  position: absolute; top: 0; left: 0; right: 0; height: 3px;
  background: linear-gradient(90deg, var(--accent-1), var(--accent-2));
  opacity: 0; transition: opacity 0.35s ease;
}
.accent-alt { background: linear-gradient(90deg, var(--accent-2), var(--accent-3)); }
.project-card:hover .project-card-accent { opacity: 1; }

.project-top {
  display: flex; align-items: center; justify-content: space-between;
  margin-bottom: 24px;
}
.project-meta { display: flex; align-items: center; gap: 12px; }
.project-number {
  font-size: 0.75rem; font-weight: 700; color: var(--text-3);
  font-variant-numeric: tabular-nums;
}
.project-badge {
  font-size: 0.72rem; font-weight: 600; color: var(--accent-1);
  background: var(--accent-bg); padding: 3px 10px; border-radius: 6px;
}
.project-icon { color: var(--accent-1); opacity: 0.6; }
.project-name {
  font-size: 1.5rem; font-weight: 700; color: var(--text);
  margin-bottom: 6px; letter-spacing: -0.02em;
}
.project-link {
  color: var(--text); text-decoration: none;
  transition: color 0.2s ease;
}
.project-link:hover { color: var(--accent-1); }
.link-arrow {
  font-size: 0.85em; opacity: 0.4; margin-left: 4px;
  display: inline-block; transition: all 0.2s ease;
}
.project-link:hover .link-arrow { opacity: 1; transform: translate(2px, -2px); }
.project-tagline {
  font-size: 0.9rem; font-weight: 500; color: var(--accent-1);
  margin-bottom: 16px;
}
.project-desc {
  font-size: 0.95rem; color: var(--text-2); line-height: 1.8; margin-bottom: 0;
}

.project-highlights {
  display: flex; gap: 40px; margin-bottom: 28px;
  padding: 24px 0;
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}
.highlight { display: flex; flex-direction: column; align-items: center; gap: 4px; }
.highlight-value {
  font-size: 1.3rem; font-weight: 800;
  background: linear-gradient(135deg, var(--accent-1), var(--accent-2));
  -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text;
}
.highlight-label {
  font-size: 0.7rem; font-weight: 600; color: var(--text-3);
  text-transform: uppercase; letter-spacing: 0.08em;
}

.project-tags { display: flex; flex-wrap: wrap; gap: 6px; }
.tag {
  font-size: 0.7rem; font-weight: 500; color: var(--tag-text);
  background: var(--tag-bg); padding: 4px 10px; border-radius: 6px;
}
.project-credit {
  text-align: right; margin-top: 16px;
  font-size: 0.8rem; font-weight: 500; color: var(--text-3);
  letter-spacing: 0.02em;
}

/* ===== Contact ===== */
.social-grid {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 12px;
}
.social-card {
  display: flex; align-items: center; gap: 12px;
  padding: 20px 24px; border-radius: 16px;
  border: 1px solid var(--border);
  background: var(--bg-card);
  backdrop-filter: blur(8px);
  color: var(--text-2);
  transition: all 0.25s ease;
}
.social-card:hover {
  border-color: var(--accent-1); color: var(--accent-1);
  background: var(--accent-bg); transform: translateY(-2px);
  box-shadow: var(--card-shadow);
}
.social-card svg { flex-shrink: 0; width: 20px; height: 20px; }
.social-name { font-size: 0.88rem; font-weight: 600; flex: 1; }
.social-arrow {
  font-size: 0.85rem; opacity: 0;
  transform: translateX(-4px);
  transition: all 0.25s ease;
}
.social-card:hover .social-arrow { opacity: 1; transform: translateX(0); }
.social-card-wrap { position: relative; }
.bubble {
  position: absolute; bottom: calc(100% + 10px); left: 50%;
  transform: translateX(-50%) scale(0.9);
  padding: 8px 16px; border-radius: 10px;
  background: var(--text); color: var(--bg);
  font-size: 0.82rem; font-weight: 500; white-space: nowrap;
  font-family: 'Inter', monospace;
  opacity: 0; pointer-events: none;
  transition: opacity 0.2s ease, transform 0.2s ease;
  box-shadow: 0 4px 16px rgba(0,0,0,0.12);
}
.bubble::after {
  content: ''; position: absolute; top: 100%; left: 50%;
  transform: translateX(-50%);
  border: 6px solid transparent;
  border-top-color: var(--text);
}
.bubble.show {
  opacity: 1; pointer-events: auto;
  transform: translateX(-50%) scale(1);
}

/* ===== Footer ===== */
.footer { border-top: 1px solid var(--border); padding: 32px 0; }
.footer-inner {
  display: flex; justify-content: space-between; align-items: center;
}
.footer p { font-size: 0.8rem; color: var(--text-3); }
.footer-domain { font-size: 0.78rem; color: var(--text-3); opacity: 0.5; }

/* ===== Animations ===== */
.fade-in {
  opacity: 0; transform: translateY(28px);
  transition: opacity 0.8s cubic-bezier(0.16, 1, 0.3, 1),
              transform 0.8s cubic-bezier(0.16, 1, 0.3, 1);
}
.fade-in.visible { opacity: 1; transform: translateY(0); }

/* ===== Responsive ===== */
@media (max-width: 768px) {
  .nav-links { display: none; }
  .nav-inner { padding: 0 20px; }
  .main { padding-top: 80px; }
  .section { padding: 60px 0; }
  .container { padding: 0 20px; }
  .project-card-inner { padding: 24px; }
  .social-grid { grid-template-columns: 1fr 1fr; }
  .footer-inner { flex-direction: column; gap: 4px; text-align: center; }
}

@media (max-width: 480px) {
  .social-grid { grid-template-columns: 1fr; }
}