:root {
  --bg: #edf3f8;
  --text: #12263a;
  --muted: #486581;
  --line: #d8e1ea;
  --primary: #0077b6;
  --primary-deep: #023e8a;
  --surface: #ffffff;
  --surface-dark: #0f2b3a;
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  font-family: "Noto Sans SC", "Microsoft YaHei UI", "Segoe UI", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.65;
}

.container {
  width: min(1140px, 92vw);
  margin: 0 auto;
}

.header {
  position: sticky;
  top: 0;
  z-index: 30;
  background: rgba(255, 255, 255, 0.95);
  border-bottom: 1px solid var(--line);
  backdrop-filter: blur(8px);
}

.nav-bar {
  min-height: 74px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.logo {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: var(--text);
}

.logo-mark {
  width: 42px;
  height: 42px;
  border-radius: 9px;
  display: grid;
  place-items: center;
  color: #fff;
  font-weight: 800;
  background: linear-gradient(135deg, var(--primary), var(--primary-deep));
}

.logo-text {
  font-weight: 800;
  letter-spacing: 0.3px;
  font-size: 1.15rem;
}

.menu-btn {
  display: none;
}

.lang-switch {
  display: flex;
  gap: 6px;
  margin-left: auto;
  margin-right: 14px;
}

.lang-btn {
  border: 1px solid var(--line);
  background: #fff;
  color: var(--text);
  border-radius: 6px;
  padding: 0.22rem 0.5rem;
  font-weight: 700;
  cursor: pointer;
}

.lang-btn.active {
  background: var(--primary);
  color: #fff;
  border-color: var(--primary);
}

.nav-links {
  display: flex;
  gap: 22px;
}

.nav-links a {
  text-decoration: none;
  color: var(--text);
  font-weight: 600;
  font-size: 0.95rem;
}

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

.hero {
  position: relative;
  min-height: 75vh;
  display: grid;
  align-items: center;
  overflow: hidden;
  background:
    radial-gradient(circle at 18% 22%, rgba(47, 171, 255, 0.2), transparent 52%),
    radial-gradient(circle at 84% 8%, rgba(12, 73, 130, 0.45), transparent 48%),
    linear-gradient(118deg, #0b2740, #0f4f75 46%, #1375aa 100%);
}

.hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(255,255,255,0.09) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,0.09) 1px, transparent 1px);
  background-size: 40px 40px;
  mix-blend-mode: soft-light;
}

.hero-layer {
  position: absolute;
  inset: 0;
  background: linear-gradient(180deg, rgba(1, 24, 43, 0.18), rgba(1, 24, 43, 0.58));
}

.hero-content {
  position: relative;
  z-index: 1;
  color: #f2f9ff;
}

.hero-tag {
  margin: 0;
  text-transform: uppercase;
  letter-spacing: 0.14em;
  opacity: 0.9;
  font-weight: 700;
  font-size: 0.86rem;
}

.hero h1 {
  margin: 0.35rem 0 0.8rem;
  max-width: 980px;
  font-size: clamp(2rem, 3.8vw, 3.5rem);
  line-height: 1.15;
}

.hero-desc {
  max-width: 760px;
  color: #d5ecff;
  font-size: 1.05rem;
}

.hero-cta {
  margin-top: 1.4rem;
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

.btn {
  display: inline-block;
  border-radius: 8px;
  padding: 0.72rem 1.18rem;
  text-decoration: none;
  font-weight: 700;
}

.btn-primary {
  color: #fff;
  background: linear-gradient(135deg, #00a6fb, #0077b6);
}

.btn-outline {
  color: #e7f6ff;
  border: 1px solid #a7d8f7;
}

.section {
  padding: 66px 0;
}

.page-hero {
  padding: 72px 0 46px;
  background:
    radial-gradient(circle at 88% 8%, rgba(26, 140, 211, 0.18), transparent 42%),
    linear-gradient(180deg, #f7fbff, #e8f1f8);
  border-bottom: 1px solid var(--line);
}

.page-hero h1 {
  margin: 0;
  font-size: clamp(1.9rem, 3.1vw, 2.8rem);
}

.page-hero p {
  margin-top: 0.5rem;
  color: var(--muted);
}

.section-head h2 {
  margin: 0;
  font-size: clamp(1.65rem, 3vw, 2.45rem);
}

.section-head p {
  margin-top: 0.4rem;
  color: var(--muted);
}

.feature-grid {
  margin-top: 18px;
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 14px;
}

.feature-card {
  border: 1px solid var(--line);
  border-radius: 12px;
  background: var(--surface);
  padding: 1rem;
  box-shadow: 0 10px 24px rgba(18, 38, 58, 0.06);
}

.feature-card h3 { margin-top: 0; margin-bottom: 0.35rem; }
.feature-card p { margin: 0; color: var(--muted); }

.section-dark {
  color: #f1f8ff;
  background: linear-gradient(180deg, #0b3046, #124661);
}

.section-dark .section-head p {
  color: #b9d8eb;
}

.timeline {
  margin: 16px 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 11px;
}

.timeline li {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 0.85rem 0.95rem;
  background: rgba(255, 255, 255, 0.09);
  border: 1px solid rgba(255, 255, 255, 0.2);
  border-radius: 10px;
}

.timeline .step-badge {
  width: 34px;
  height: 34px;
  display: grid;
  place-items: center;
  border-radius: 7px;
  background: #2ca6e0;
  font-weight: 800;
  color: #fff;
  flex-shrink: 0;
}

.timeline .step-text {
  display: inline;
  width: auto;
  height: auto;
  background: transparent;
  border-radius: 0;
  color: inherit;
  font-weight: 600;
}

.timeline code {
  background: rgba(0, 0, 0, 0.2);
  padding: 0.08rem 0.35rem;
  border-radius: 4px;
}

.result-grid {
  margin-top: 16px;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}

.result-block {
  border: 1px solid var(--line);
  border-radius: 12px;
  background: var(--surface);
  padding: 1rem;
}

.result-block h3 { margin-top: 0; margin-bottom: 0.35rem; }
.result-block p { margin: 0; color: var(--muted); }

.result-media {
  margin-top: 14px;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: var(--surface);
  padding: 1rem;
}

.result-media h3 {
  margin-top: 0;
  margin-bottom: 0.6rem;
}

.result-media img {
  width: 100%;
  border-radius: 10px;
  border: 1px solid #c8d7e6;
  display: block;
}

.preview-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  align-items: stretch;
}

.preview-item {
  margin: 0;
  display: flex;
  flex-direction: column;
  height: 100%;
  border: 1px solid #c8d7e6;
  border-radius: 10px;
  background: #f8fbff;
  overflow: hidden;
}

.preview-item img {
  height: 360px;
  width: 100%;
  object-fit: contain;
  background: #f4f7fb;
  border: 0;
  border-bottom: 1px solid #d7e3ef;
}

.preview-item figcaption {
  margin-top: 0;
  padding: 0.55rem 0.7rem;
  color: var(--muted);
  font-size: 0.9rem;
}

.section-news {
  background: #e2eef7;
}

.faq details {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 0.75rem 0.9rem;
  margin-bottom: 10px;
}

.faq summary {
  font-weight: 700;
  cursor: pointer;
}

.faq p {
  margin: 0.45rem 0 0;
  color: var(--muted);
}

.download-list {
  display: grid;
  gap: 12px;
}

.download-item {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 1rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
}

.download-item h3 {
  margin: 0 0 0.25rem;
}

.download-item p {
  margin: 0;
  color: var(--muted);
}

.news-wrap {
  display: grid;
  gap: 16px;
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.news-col {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 1rem;
}

.news-col h2 {
  margin-top: 0;
  margin-bottom: 0.5rem;
}

.news-col ul {
  margin: 0;
  padding-left: 1rem;
}

.news-col li {
  margin-bottom: 0.4rem;
}

.section-cta {
  text-align: center;
  background: linear-gradient(180deg, #d3e7f5, #c8e0f1);
}

.contributors {
  margin-top: 14px;
  display: grid;
  gap: 12px;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  text-align: left;
}

.contrib-card {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 0.85rem 0.95rem;
}

.contrib-card h3 {
  margin: 0 0 0.35rem;
  font-size: 1rem;
}

.contrib-card p {
  margin: 0.2rem 0;
  color: var(--muted);
  word-break: break-word;
}

.contrib-card a {
  color: var(--primary-deep);
  font-weight: 700;
  text-decoration: none;
}

.contrib-card a:hover {
  text-decoration: underline;
}

.footer {
  background: #fff;
  border-top: 1px solid var(--line);
  padding: 18px 0;
}

.footer-wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.footer-wrap p {
  margin: 0;
  color: #5b748d;
}

.footer-wrap a {
  text-decoration: none;
  color: var(--primary);
  font-weight: 700;
}

.reveal {
  opacity: 0;
  transform: translateY(10px);
  transition: opacity 0.55s ease, transform 0.55s ease;
}

.reveal.show {
  opacity: 1;
  transform: translateY(0);
}

@media (max-width: 980px) {
  .feature-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 760px) {
  .menu-btn {
    display: inline-block;
    border: 1px solid var(--line);
    background: #fff;
    border-radius: 8px;
    padding: 0.42rem 0.72rem;
    font-weight: 700;
  }

  .nav-links {
    display: none;
    position: absolute;
    top: 74px;
    left: 4vw;
    right: 4vw;
    background: #fff;
    border: 1px solid var(--line);
    border-radius: 10px;
    padding: 10px;
    flex-direction: column;
    gap: 10px;
  }

  .lang-switch {
    margin-left: 10px;
    margin-right: 10px;
  }

  .nav-links.open {
    display: flex;
  }

  .feature-grid,
  .result-grid,
  .news-wrap,
  .contributors {
    grid-template-columns: 1fr;
  }

  .preview-grid {
    grid-template-columns: 1fr;
  }

  .preview-item img {
    height: 300px;
  }

  .download-item {
    flex-direction: column;
    align-items: flex-start;
  }
}