@import url('https://fonts.googleapis.com/css2?family=Instrument+Sans:opsz,wght@14..32,400;500;600&family=Space+Grotesk:wght@400;500;600;700&display=swap');

:root {
  --font-display: "Space Grotesk", "PingFang SC", "Microsoft YaHei", "Noto Sans SC", "Heiti SC", sans-serif;
  --font-body: "Instrument Sans", "PingFang SC", "Microsoft YaHei", "Noto Sans SC", "Heiti SC", sans-serif;
  --canvas: #f6f1e7;
  --surface: #ffffff;
  --ink: #111b1f;
  --muted: #55636b;
  --accent: #e76f51;
  --accent-2: #2a9d8f;
  --accent-3: #e9c46a;
  --border: rgba(17, 27, 31, 0.12);
  --shadow: 0 24px 48px rgba(17, 27, 31, 0.12);
  --shadow-soft: 0 14px 32px rgba(17, 27, 31, 0.1);
  --radius-xl: 32px;
  --radius-lg: 20px;
  --radius-md: 14px;
  --radius-sm: 10px;
  --space-1: 8px;
  --space-2: 12px;
  --space-3: 16px;
  --space-4: 24px;
  --space-5: 32px;
  --space-6: 48px;
  --space-7: 72px;
}

html:lang(zh) {
  --font-display: "PingFang SC", "Microsoft YaHei", "Noto Sans SC", "Heiti SC", sans-serif;
  --font-body: "PingFang SC", "Microsoft YaHei", "Noto Sans SC", "Heiti SC", sans-serif;
}

html:lang(zh) .brand,
html:lang(zh) .lang-link,
html:lang(zh) .eyebrow {
  letter-spacing: 0;
}

html:lang(zh) .eyebrow {
  text-transform: none;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: var(--font-body);
  color: var(--ink);
  background:
    radial-gradient(600px 400px at 10% 10%, rgba(231, 111, 81, 0.18), transparent 70%),
    radial-gradient(700px 500px at 90% 20%, rgba(42, 157, 143, 0.2), transparent 65%),
    linear-gradient(180deg, #f8f2e8 0%, #f2eadf 100%);
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  background-image: linear-gradient(rgba(17, 27, 31, 0.08) 1px, transparent 1px);
  background-size: 1px 160px;
  pointer-events: none;
  opacity: 0.4;
}

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

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

.container {
  width: min(1120px, 100% - 48px);
  margin: 0 auto;
}

.site-header {
  padding: var(--space-4) 0 var(--space-2);
  position: relative;
  z-index: 2;
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3);
}

.brand {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.2rem;
  letter-spacing: 0.5px;
}

.nav-links {
  display: flex;
  gap: var(--space-3);
  font-weight: 500;
  color: var(--muted);
}

.nav-links a {
  position: relative;
  padding-bottom: 4px;
}

.nav-links a::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: 100%;
  height: 2px;
  background: var(--accent-2);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.3s ease;
}

.nav-links a:hover::after {
  transform: scaleX(1);
}

.nav-cta {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 18px;
  border-radius: 999px;
  border: 1px solid var(--ink);
  font-weight: 600;
  background: var(--surface);
  box-shadow: var(--shadow-soft);
}

.lang-switch {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px;
  border-radius: 999px;
  background: rgba(17, 27, 31, 0.08);
}

.lang-link {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 6px 10px;
  border-radius: 999px;
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.5px;
  color: var(--muted);
}

.lang-link.is-active {
  background: var(--ink);
  color: #fefcf8;
}

.hero {
  display: grid;
  grid-template-columns: minmax(0, 1.1fr) minmax(0, 0.9fr);
  gap: var(--space-6);
  align-items: center;
  padding: var(--space-6) 0 var(--space-7);
}

.hero-content h1 {
  font-family: var(--font-display);
  font-size: clamp(2.5rem, 3vw + 1.6rem, 4.1rem);
  margin: 12px 0;
}

.hero-content p {
  font-size: 1.1rem;
  color: var(--muted);
  line-height: 1.6;
}

.eyebrow {
  text-transform: uppercase;
  letter-spacing: 2px;
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--accent-2);
}

.hero-actions {
  display: flex;
  gap: var(--space-2);
  margin-top: var(--space-4);
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 22px;
  border-radius: 999px;
  font-weight: 600;
  border: none;
  background: var(--ink);
  color: #fefcf8;
  box-shadow: var(--shadow-soft);
}

.btn.ghost {
  background: transparent;
  color: var(--ink);
  border: 1px solid var(--ink);
  box-shadow: none;
}

.hero-panel {
  background: var(--surface);
  border-radius: var(--radius-xl);
  padding: var(--space-5);
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
  position: relative;
  overflow: hidden;
}

.hero-panel::before {
  content: "";
  position: absolute;
  inset: 0;
  background: radial-gradient(200px 200px at 20% 10%, rgba(233, 196, 106, 0.35), transparent 60%),
    radial-gradient(220px 220px at 80% 90%, rgba(42, 157, 143, 0.25), transparent 65%);
  opacity: 0.8;
  pointer-events: none;
}

.highlight-grid {
  display: grid;
  gap: var(--space-3);
  position: relative;
  z-index: 1;
}

.highlight-card {
  padding: var(--space-3);
  border-radius: var(--radius-md);
  background: rgba(255, 255, 255, 0.78);
  border: 1px solid var(--border);
  backdrop-filter: blur(6px);
}

.highlight-card p {
  margin: 0;
  font-size: 0.85rem;
  color: var(--muted);
}

.highlight-card h3 {
  margin: 6px 0 0;
  font-family: var(--font-display);
  font-size: 1.15rem;
}

.hero-note {
  margin-top: var(--space-4);
  position: relative;
  z-index: 1;
}

.hero-note h3 {
  margin: 0 0 8px;
  font-family: var(--font-display);
}

.hero-note ul {
  padding-left: 18px;
  margin: 0;
  color: var(--muted);
}

.section {
  padding: var(--space-6) 0;
}

.section-head {
  display: flex;
  justify-content: space-between;
  align-items: flex-end;
  gap: var(--space-4);
  margin-bottom: var(--space-4);
}

.section-head h2 {
  margin: 6px 0;
  font-family: var(--font-display);
  font-size: clamp(1.8rem, 2vw + 1rem, 2.6rem);
}

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

.pill {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 12px;
  border-radius: 999px;
  background: rgba(17, 27, 31, 0.08);
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--muted);
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: var(--space-4);
}

.card {
  position: relative;
  display: flex;
  flex-direction: column;
  padding: var(--space-4);
  border-radius: var(--radius-lg);
  border: 1px solid var(--border);
  background: var(--surface);
  box-shadow: var(--shadow-soft);
  transition: transform 0.3s ease, box-shadow 0.3s ease;
  overflow: hidden;
}

.card::before {
  content: "";
  position: absolute;
  inset: 0;
  border-top: 4px solid var(--accent, var(--accent));
  pointer-events: none;
}

.card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow);
}

.card h3 {
  margin: 12px 0 8px;
  font-family: var(--font-display);
  font-size: 1.25rem;
}

.card p {
  margin: 0 0 var(--space-3);
  color: var(--muted);
  line-height: 1.5;
}

.card-meta {
  display: flex;
  gap: var(--space-2);
  flex-wrap: wrap;
  font-size: 0.85rem;
  color: var(--muted);
}

.tag-list {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-top: auto;
}

.tag {
  display: inline-flex;
  padding: 4px 10px;
  border-radius: 999px;
  background: rgba(17, 27, 31, 0.08);
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--muted);
}

.knowledge-group {
  margin-bottom: var(--space-6);
}

.knowledge-group h3 {
  font-family: var(--font-display);
  font-size: 1.5rem;
  margin-bottom: 6px;
}

.knowledge-group p {
  color: var(--muted);
  margin-top: 0;
}

.detail-hero {
  display: grid;
  grid-template-columns: minmax(0, 1.3fr) minmax(0, 0.7fr);
  gap: var(--space-5);
  padding: var(--space-6) 0 var(--space-4);
}

.detail-copy h1 {
  margin: 8px 0 12px;
  font-family: var(--font-display);
  font-size: clamp(2rem, 2.5vw + 1.4rem, 3rem);
}

.detail-copy p {
  color: var(--muted);
  line-height: 1.6;
}

.meta {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin: var(--space-3) 0;
}

.meta span {
  padding: 6px 10px;
  border-radius: 999px;
  background: rgba(17, 27, 31, 0.08);
  font-size: 0.8rem;
  color: var(--muted);
}

.detail-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: var(--space-4);
  box-shadow: var(--shadow-soft);
  position: relative;
  overflow: hidden;
}

.detail-card::before {
  content: "";
  position: absolute;
  inset: 0;
  border-left: 4px solid var(--accent, var(--accent));
  pointer-events: none;
}

.detail-card h3 {
  font-family: var(--font-display);
  margin-top: 0;
}

.detail-card ul {
  padding-left: 18px;
  margin: 0;
  color: var(--muted);
}

.detail-section {
  padding-bottom: var(--space-6);
}

.detail-block {
  background: var(--surface);
  border-radius: var(--radius-lg);
  border: 1px solid var(--border);
  padding: var(--space-4);
  margin-bottom: var(--space-4);
  box-shadow: var(--shadow-soft);
}

.detail-block h3 {
  margin-top: 0;
  font-family: var(--font-display);
}

.structure-grid {
  display: grid;
  gap: var(--space-3);
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
}

.structure-step {
  background: rgba(17, 27, 31, 0.04);
  border-radius: var(--radius-md);
  padding: var(--space-3);
}

.structure-step h4 {
  margin: 0 0 8px;
  font-family: var(--font-display);
  font-size: 1rem;
}

.structure-step ul {
  padding-left: 18px;
  margin: 0;
  color: var(--muted);
}

.drill-grid {
  display: grid;
  gap: var(--space-3);
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
}

.drill-card {
  border-radius: var(--radius-md);
  padding: var(--space-3);
  background: rgba(17, 27, 31, 0.04);
}

.drill-card h4 {
  margin: 0 0 8px;
  font-family: var(--font-display);
}

.drill-card p {
  margin: 0 0 8px;
  color: var(--muted);
  font-size: 0.9rem;
}

.empty-state {
  padding: var(--space-5);
  border: 1px dashed var(--border);
  border-radius: var(--radius-lg);
  text-align: center;
  color: var(--muted);
}

.site-footer {
  padding: var(--space-6) 0 var(--space-5);
  background: rgba(17, 27, 31, 0.06);
  margin-top: var(--space-6);
}

.footer-grid {
  display: flex;
  justify-content: space-between;
  gap: var(--space-4);
  flex-wrap: wrap;
}

.footer-brand h3 {
  margin-top: 0;
  font-family: var(--font-display);
}

.footer-brand p {
  color: var(--muted);
  margin-bottom: 0;
}

.footer-links {
  display: flex;
  gap: var(--space-3);
  align-items: center;
  color: var(--muted);
}

.reveal {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity 0.8s ease, transform 0.8s ease;
}

.reveal.is-visible {
  opacity: 1;
  transform: translateY(0);
}

.reveal[data-delay] {
  transition-delay: var(--delay, 0ms);
}

@media (max-width: 960px) {
  .hero {
    grid-template-columns: 1fr;
  }

  .detail-hero {
    grid-template-columns: 1fr;
  }

  .nav-cta {
    display: none;
  }
}

@media (max-width: 720px) {
  .container {
    width: min(100% - 32px, 960px);
  }

  .nav {
    flex-direction: column;
    align-items: flex-start;
    gap: 12px;
  }

  .nav-links {
    flex-wrap: wrap;
    font-size: 0.95rem;
  }

  .hero-actions {
    flex-direction: column;
    align-items: flex-start;
  }

  .section-head {
    flex-direction: column;
    align-items: flex-start;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation: none !important;
    transition: none !important;
    scroll-behavior: auto !important;
  }

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