:root {
  --bg: #070a13;
  --bg-soft: #0b1020;
  --panel: rgba(255, 255, 255, 0.035);
  --line: rgba(255, 255, 255, 0.09);
  --text: #eef2ff;
  --muted: #94a1c6;
  --accent: #6ee7ff;
  --accent-2: #9b8cff;
  --gold: #ffd166;
  --max: 1180px;
}

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

html { scroll-behavior: smooth; }

body {
  background: var(--bg);
  color: var(--text);
  font-family: "PingFang SC", "HarmonyOS Sans SC", "Microsoft YaHei",
               -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

/* 背景光晕 + 颗粒 */
body::before {
  content: "";
  position: fixed;
  inset: 0;
  background:
    radial-gradient(900px 600px at 15% -10%, rgba(110, 231, 255, 0.13), transparent 60%),
    radial-gradient(800px 700px at 90% 10%, rgba(155, 140, 255, 0.12), transparent 60%),
    radial-gradient(700px 500px at 50% 100%, rgba(255, 209, 102, 0.05), transparent 60%);
  pointer-events: none;
  z-index: 0;
}

.grain {
  position: fixed;
  inset: 0;
  opacity: 0.035;
  pointer-events: none;
  z-index: 1;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='200' height='200'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.85' numOctaves='3'/%3E%3C/filter%3E%3Crect width='200' height='200' filter='url(%23n)'/%3E%3C/svg%3E");
}

main, .nav, .footer { position: relative; z-index: 2; }

/* ---------------- 导航 ---------------- */
.nav {
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  align-items: center;
  gap: 28px;
  padding: 18px clamp(20px, 5vw, 56px);
  backdrop-filter: blur(18px);
  background: rgba(7, 10, 19, 0.55);
  border-bottom: 1px solid transparent;
  transition: border-color .3s ease, background .3s ease;
}

.nav.scrolled {
  border-bottom-color: var(--line);
  background: rgba(7, 10, 19, 0.82);
}

.logo {
  display: flex;
  align-items: center;
  gap: 9px;
  color: var(--text);
  text-decoration: none;
  font-family: Georgia, "Times New Roman", serif;
  font-size: 19px;
  letter-spacing: 0.4px;
}

.logo-mark { color: var(--accent); font-size: 21px; }

.nav-links {
  display: flex;
  gap: 26px;
  margin-left: auto;
}

.nav-links a {
  color: var(--muted);
  text-decoration: none;
  font-size: 14px;
  transition: color .2s ease;
}

.nav-links a:hover { color: var(--text); }

.nav-cta {
  padding: 9px 18px;
  border-radius: 999px;
  font-size: 13px;
  color: #06101f;
  background: linear-gradient(135deg, var(--accent), #a5f3ff);
  text-decoration: none;
  font-weight: 700;
  transition: transform .2s ease, box-shadow .2s ease;
}

.nav-cta:hover {
  transform: translateY(-1px);
  box-shadow: 0 10px 28px rgba(110, 231, 255, 0.28);
}

/* ---------------- 通用 ---------------- */
section[id] { scroll-margin-top: 84px; }

.section {
  max-width: var(--max);
  margin: 0 auto;
  padding: clamp(72px, 11vw, 128px) clamp(20px, 5vw, 40px);
}

.section-head { margin-bottom: 46px; }

.num {
  display: inline-block;
  font-family: Georgia, serif;
  font-size: 13px;
  letter-spacing: 3px;
  color: var(--accent);
  margin-bottom: 14px;
}

.section-head h2 {
  font-size: clamp(30px, 5vw, 46px);
  font-weight: 800;
  letter-spacing: -0.5px;
  line-height: 1.15;
}

.section-head p {
  margin-top: 12px;
  color: var(--muted);
  font-size: 15px;
}

/* ---------------- Hero ---------------- */
.hero {
  max-width: var(--max);
  margin: 0 auto;
  padding: clamp(70px, 12vw, 140px) clamp(20px, 5vw, 40px) 0;
  position: relative;
}

.hero-glow {
  position: absolute;
  top: -80px;
  left: 50%;
  width: 700px;
  height: 500px;
  transform: translateX(-50%);
  background: radial-gradient(closest-side, rgba(110, 231, 255, 0.18), transparent);
  filter: blur(30px);
  pointer-events: none;
}

.eyebrow {
  font-size: 12px;
  letter-spacing: 5px;
  color: var(--accent);
  text-transform: uppercase;
  margin-bottom: 26px;
}

.hero h1 {
  font-size: clamp(46px, 9vw, 96px);
  font-weight: 900;
  line-height: 1.04;
  letter-spacing: -2px;
}

.grad {
  background: linear-gradient(100deg, #6ee7ff 0%, #9b8cff 55%, #ffd166 110%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.lede {
  margin-top: 28px;
  max-width: 560px;
  font-size: clamp(15px, 2.2vw, 18px);
  color: var(--muted);
}

.actions {
  display: flex;
  gap: 14px;
  margin-top: 40px;
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  padding: 14px 26px;
  border-radius: 999px;
  font-size: 15px;
  font-weight: 700;
  text-decoration: none;
  transition: transform .2s ease, box-shadow .25s ease, background .2s ease;
}

.btn.primary {
  color: #06101f;
  background: linear-gradient(135deg, var(--accent), #b8f3ff);
  box-shadow: 0 12px 34px rgba(110, 231, 255, 0.25);
}

.btn.primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 16px 40px rgba(110, 231, 255, 0.38);
}

.btn.ghost {
  color: var(--text);
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid var(--line);
}

.btn.ghost:hover { background: rgba(255, 255, 255, 0.08); }

.arrow { transition: transform .2s ease; }
.btn:hover .arrow { transform: translateX(4px); }

/* Hero 数据条 */
.hero-stats {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1px;
  margin-top: clamp(56px, 8vw, 88px);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  background: var(--line);
}

.stat {
  background: var(--bg);
  padding: 28px 10px;
  text-align: center;
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.stat b {
  font-family: Georgia, serif;
  font-size: clamp(28px, 4vw, 40px);
  font-weight: 400;
  color: var(--text);
  line-height: 1;
}

.stat span { font-size: 12px; color: var(--muted); letter-spacing: 1px; }

/* ---------------- 卡片 ---------------- */
.grid.three {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(230px, 1fr));
  gap: 20px;
}

.card {
  position: relative;
  padding: 30px 28px 26px;
  border-radius: 20px;
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.05), rgba(255, 255, 255, 0.02));
  border: 1px solid var(--line);
  overflow: hidden;
  transition: transform .3s ease, border-color .3s ease, background .3s ease;
}

.card::after {
  content: "";
  position: absolute;
  inset: 0;
  background: radial-gradient(400px 200px at 20% 0%, rgba(110, 231, 255, 0.10), transparent 70%);
  opacity: 0;
  transition: opacity .35s ease;
  pointer-events: none;
}

.card:hover {
  transform: translateY(-5px);
  border-color: rgba(110, 231, 255, 0.28);
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.07), rgba(255, 255, 255, 0.025));
}

.card:hover::after { opacity: 1; }

.card-top {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 26px;
}

.tag {
  font-size: 11px;
  letter-spacing: 2px;
  color: var(--muted);
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 4px 10px;
}

.icon {
  font-size: 22px;
  color: var(--accent);
  opacity: 0.85;
}

.card h3 {
  font-size: 20px;
  font-weight: 800;
  letter-spacing: 0.2px;
  margin-bottom: 10px;
}

.card p {
  color: var(--muted);
  font-size: 14px;
  line-height: 1.7;
  min-height: 48px;
}

.card-link {
  display: inline-block;
  margin-top: 20px;
  font-size: 13px;
  color: var(--accent);
  text-decoration: none;
  letter-spacing: 0.5px;
}

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

/* ---------------- 作品列表 ---------------- */
.works {
  border-top: 1px solid var(--line);
}

.work {
  display: grid;
  grid-template-columns: 56px 1fr auto;
  align-items: center;
  gap: 22px;
  padding: 26px 6px;
  border-bottom: 1px solid var(--line);
  text-decoration: none;
  color: var(--text);
  transition: padding .25s ease, background .25s ease;
}

.work:hover {
  padding-left: 16px;
  background: linear-gradient(90deg, rgba(110, 231, 255, 0.05), transparent 60%);
}

.work-idx {
  font-family: Georgia, serif;
  color: var(--muted);
  font-size: 14px;
  letter-spacing: 2px;
}

.work h3 { font-size: clamp(17px, 2.4vw, 21px); font-weight: 700; }

.work p { color: var(--muted); font-size: 13px; margin-top: 3px; }

.work-meta {
  font-size: 12px;
  color: var(--muted);
  letter-spacing: 1px;
  white-space: nowrap;
}

.work:hover .work-meta { color: var(--accent); }

/* ---------------- 关于 ---------------- */
.about-grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr;
  gap: 56px;
  align-items: start;
}

.about-text {
  font-size: clamp(18px, 2.6vw, 24px);
  line-height: 1.75;
  color: #cfd8f5;
  font-weight: 300;
}

.about-text b { color: var(--text); font-weight: 700; }

.about-meta { display: flex; flex-direction: column; gap: 18px; }

.about-meta div {
  display: flex;
  justify-content: space-between;
  gap: 20px;
  padding-bottom: 14px;
  border-bottom: 1px solid var(--line);
}

.about-meta span { color: var(--muted); font-size: 13px; }
.about-meta b { font-size: 14px; font-weight: 600; }

/* ---------------- 联系 ---------------- */
.contact { padding-bottom: 60px; }

.contact-inner {
  text-align: center;
  padding: clamp(56px, 9vw, 96px) 24px;
  border-radius: 28px;
  background:
    radial-gradient(600px 300px at 50% 0%, rgba(155, 140, 255, 0.14), transparent 70%),
    linear-gradient(180deg, rgba(255, 255, 255, 0.05), rgba(255, 255, 255, 0.015));
  border: 1px solid var(--line);
}

.contact-inner h2 {
  font-size: clamp(28px, 5vw, 44px);
  font-weight: 800;
  letter-spacing: -0.5px;
}

.contact-inner p {
  color: var(--muted);
  margin-top: 14px;
  font-size: 15px;
}

.contact-inner .actions { justify-content: center; }

/* ---------------- 页脚 ---------------- */
.footer {
  max-width: var(--max);
  margin: 0 auto;
  padding: 28px clamp(20px, 5vw, 40px) 40px;
  color: var(--muted);
  font-size: 12px;
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  gap: 6px;
}

.footer .dot { opacity: 0.5; }

/* ---------------- 动画 ---------------- */
.reveal {
  opacity: 0;
  transform: translateY(22px);
  transition: opacity .7s cubic-bezier(.2, .7, .3, 1),
              transform .7s cubic-bezier(.2, .7, .3, 1);
}

.reveal.in {
  opacity: 1;
  transform: none;
}

/* ---------------- 响应式 ---------------- */
@media (max-width: 900px) {
  .grid.three { grid-template-columns: 1fr; }
  .about-grid { grid-template-columns: 1fr; gap: 36px; }
  .nav-links { display: none; }
  .nav { justify-content: space-between; }
}

@media (max-width: 620px) {
  .hero-stats { grid-template-columns: repeat(2, 1fr); }
  .work { grid-template-columns: 36px 1fr; }
  .work-meta { grid-column: 2; justify-self: start; margin-top: 4px; }
  .footer { flex-wrap: wrap; }
}

@media (prefers-reduced-motion: reduce) {
  .reveal { opacity: 1; transform: none; transition: none; }
  html { scroll-behavior: auto; }
}

/* ===== 学习路径（按使用频率分档） ===== */
.path-steps {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 16px;
  margin-top: 10px;
}

.step {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 26px 24px 22px;
  border-radius: 18px;
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.05), rgba(255, 255, 255, 0.02));
  border: 1px solid var(--line);
  text-decoration: none;
  color: inherit;
  transition: transform .3s ease, border-color .3s ease, background .3s ease;
}

.step:hover {
  transform: translateY(-3px);
  border-color: rgba(110, 231, 255, 0.4);
  background: linear-gradient(180deg, rgba(110, 231, 255, 0.08), rgba(255, 255, 255, 0.02));
}

.step-no {
  font-size: 11px;
  letter-spacing: .18em;
  font-weight: 600;
  color: var(--accent);
}

.step h3 {
  font-size: 19px;
  font-weight: 600;
  letter-spacing: .01em;
}

.step p {
  font-size: 13.5px;
  line-height: 1.7;
  color: var(--muted);
}

.step-cta {
  margin-top: auto;
  padding-top: 12px;
  font-size: 13px;
  color: var(--accent-2);
}

.path-note {
  margin-top: 20px;
  max-width: 780px;
  font-size: 13px;
  line-height: 1.85;
  color: var(--muted);
}

.path-note b {
  color: var(--text);
  font-weight: 600;
}

/* ===== 品牌标语 ===== */
.logo-img {
  width: 30px;
  height: 30px;
  border-radius: 8px;
  display: block;
}

.hero-slogan {
  margin-top: 18px;
  font-size: 15px;
  letter-spacing: .12em;
  color: var(--muted);
}

.hero-slogan-en {
  display: block;
  margin-top: 6px;
  font-size: 12px;
  letter-spacing: .08em;
  opacity: .6;
}

.footer-brand {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  font-size: 13px;
  color: var(--text);
}

.footer-logo {
  border-radius: 6px;
  opacity: .85;
}

.footer-name {
  font-weight: 600;
  letter-spacing: .02em;
}

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

.footer-sub {
  margin-top: 6px;
  font-size: 11.5px;
  letter-spacing: .06em;
  color: var(--muted);
  opacity: .7;
}

.footer-meta {
  margin-top: 12px;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: 6px;
  row-gap: 2px;
  font-size: 12px;
  color: var(--muted);
  opacity: .75;
}

.footer-meta > span { white-space: nowrap; }

.footer-legal {
  margin-top: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 14px;
  font-size: 12px;
  color: var(--muted);
  opacity: .8;
}

.footer-legal a {
  color: inherit;
  text-decoration: none;
}

.footer-legal a:hover {
  color: var(--text);
  text-decoration: underline;
}

/* 备案号行：居中、不换行 */
.footer-legal a { white-space: nowrap; }