/* Site Set 2 — Modern Ocean Tech */
:root {
  --primary: #1565C0;
  --primary-dark: #0D47A1;
  --primary-light: #42A5F5;
  --accent: #00897B;
  --accent-light: #26A69A;
  --bg: #E3F2FD;
  --bg-soft: #F5FAFE;
  --white: #FFFFFF;
  --text: #1A2B3C;
  --text-secondary: #4A6278;
  --text-muted: #78909C;
  --border: #BBDEFB;
  --border-soft: #E1F0FA;
  --radius: 12px;
  --shadow-soft: 0 2px 12px rgba(21, 101, 192, 0.08);
  --nav-h: 64px;
  --font: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", "Source Han Sans SC", sans-serif;
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font);
  font-weight: 500;
  color: var(--text);
  background: var(--bg-soft);
  line-height: 1.7;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--primary);
  text-decoration: none;
  transition: color 0.2s ease, background 0.2s ease, border-color 0.2s ease, box-shadow 0.2s ease;
}

a:hover {
  color: var(--accent);
}

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

ul,
ol {
  list-style: none;
}

button {
  font-family: inherit;
  font-weight: 500;
  cursor: pointer;
  border: none;
  background: none;
}

.container {
  width: min(1120px, 92%);
  margin: 0 auto;
}

/* ——— Header / Nav ——— */
.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  height: var(--nav-h);
  background: linear-gradient(90deg, rgba(21, 101, 192, 0.92), rgba(0, 137, 123, 0.92));
  backdrop-filter: blur(10px);
  border-bottom: 1px solid rgba(255, 255, 255, 0.18);
  transition: background 0.25s ease, box-shadow 0.25s ease;
}

.site-header.is-solid {
  background: linear-gradient(90deg, #1565C0, #00897B);
  box-shadow: 0 2px 16px rgba(13, 71, 161, 0.18);
}

.nav-inner {
  height: var(--nav-h);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  color: #fff;
  font-size: 18px;
  font-weight: 600;
  letter-spacing: 0.02em;
  flex-shrink: 0;
}

.logo svg {
  width: 32px;
  height: 32px;
}

.logo:hover {
  color: #fff;
  opacity: 0.92;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 6px;
  flex-wrap: wrap;
  justify-content: flex-end;
}

.nav-links a {
  color: rgba(255, 255, 255, 0.92);
  padding: 7px 14px;
  border-radius: 20px;
  font-size: 14px;
  border: 1px solid transparent;
  transition: background 0.2s ease, color 0.2s ease, border-color 0.2s ease;
}

.nav-links a:hover {
  background: rgba(255, 255, 255, 0.14);
  color: #fff;
  border-color: rgba(255, 255, 255, 0.22);
}

.nav-links a.active {
  background: var(--primary);
  color: #fff;
  border-color: rgba(255, 255, 255, 0.35);
  box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.15);
}

.nav-toggle {
  display: none;
  width: 40px;
  height: 40px;
  border-radius: 10px;
  border: 1px solid rgba(255, 255, 255, 0.35);
  align-items: center;
  justify-content: center;
  color: #fff;
}

.nav-toggle svg {
  width: 22px;
  height: 22px;
}

/* ——— Hero ——— */
.hero {
  position: relative;
  padding: 72px 0 56px;
  background:
    radial-gradient(ellipse 80% 60% at 50% -10%, rgba(66, 165, 245, 0.35), transparent 60%),
    linear-gradient(180deg, #E3F2FD 0%, #F5FAFE 70%, #FFFFFF 100%);
  text-align: center;
  overflow: hidden;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 14px;
  border-radius: 20px;
  background: rgba(21, 101, 192, 0.08);
  border: 1px solid var(--border);
  color: var(--primary);
  font-size: 13px;
  margin-bottom: 18px;
}

.hero-badge svg {
  width: 16px;
  height: 16px;
}

.hero h1 {
  font-size: clamp(28px, 4.5vw, 42px);
  font-weight: 600;
  color: var(--text);
  line-height: 1.3;
  letter-spacing: 0.01em;
  max-width: 820px;
  margin: 0 auto 16px;
}

.hero-lead {
  font-size: 17px;
  color: var(--text-secondary);
  max-width: 640px;
  margin: 0 auto 28px;
  font-weight: 500;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  justify-content: center;
  margin-bottom: 36px;
}

.hero-wave {
  width: min(720px, 94%);
  margin: 0 auto;
  color: var(--primary);
  opacity: 0.85;
}

.hero-wave svg {
  width: 100%;
  height: auto;
}

/* ——— Buttons ——— */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 24px;
  border-radius: var(--radius);
  font-size: 15px;
  font-weight: 500;
  border: 1px solid transparent;
  transition: background 0.2s ease, color 0.2s ease, border-color 0.2s ease, transform 0.15s ease;
}

.btn svg {
  width: 18px;
  height: 18px;
  flex-shrink: 0;
}

.btn:hover {
  transform: translateY(-1px);
}

.btn:disabled {
  opacity: 0.75;
  cursor: wait;
  transform: none;
}

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

.btn-primary:hover {
  background: var(--primary-dark);
  color: #fff;
}

.btn-accent {
  background: var(--accent);
  color: #fff;
  border-color: #00695C;
}

.btn-accent:hover {
  background: #00695C;
  color: #fff;
}

.btn-outline {
  background: var(--white);
  color: var(--primary);
  border-color: var(--border);
}

.btn-outline:hover {
  border-color: var(--primary);
  color: var(--primary-dark);
  background: #F0F7FF;
}

.btn-lg {
  padding: 14px 28px;
  font-size: 16px;
}

.btn-block {
  width: 100%;
}

/* ——— Sections ——— */
.section {
  padding: 64px 0;
}

.section-alt {
  background: var(--bg);
}

.section-white {
  background: var(--white);
}

.section-head {
  text-align: center;
  max-width: 680px;
  margin: 0 auto 40px;
}

.section-head h2 {
  font-size: clamp(22px, 3vw, 30px);
  font-weight: 600;
  color: var(--text);
  margin-bottom: 12px;
}

.section-head p {
  color: var(--text-secondary);
  font-size: 15px;
}

.section-label {
  display: inline-block;
  color: var(--accent);
  font-size: 13px;
  margin-bottom: 8px;
  letter-spacing: 0.04em;
}

/* ——— Feature cards (6-grid) ——— */
.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}

.feature-card {
  background: var(--white);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius);
  padding: 28px 24px;
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.feature-card:hover {
  border-color: var(--border);
  box-shadow: var(--shadow-soft);
}

.feature-icon {
  width: 48px;
  height: 48px;
  border-radius: var(--radius);
  background: linear-gradient(135deg, rgba(21, 101, 192, 0.1), rgba(0, 137, 123, 0.1));
  border: 1px solid var(--border-soft);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 16px;
  color: var(--primary);
}

.feature-icon svg {
  width: 24px;
  height: 24px;
}

.feature-card h3 {
  font-size: 17px;
  font-weight: 600;
  margin-bottom: 8px;
  color: var(--text);
}

.feature-card p {
  font-size: 14px;
  color: var(--text-secondary);
  line-height: 1.65;
}

/* ——— Timeline ——— */
.timeline {
  max-width: 720px;
  margin: 0 auto;
  position: relative;
  padding-left: 36px;
}

.timeline::before {
  content: "";
  position: absolute;
  left: 11px;
  top: 8px;
  bottom: 8px;
  width: 2px;
  background: linear-gradient(180deg, var(--primary), var(--accent));
  border-radius: 2px;
}

.timeline-item {
  position: relative;
  padding: 0 0 32px 24px;
}

.timeline-item:last-child {
  padding-bottom: 0;
}

.timeline-dot {
  position: absolute;
  left: -36px;
  top: 4px;
  width: 24px;
  height: 24px;
  border-radius: 50%;
  background: var(--white);
  border: 2px solid var(--primary);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1;
}

.timeline-dot span {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--accent);
}

.timeline-item h3 {
  font-size: 18px;
  font-weight: 600;
  margin-bottom: 8px;
  color: var(--text);
}

.timeline-item p {
  font-size: 14px;
  color: var(--text-secondary);
}

.timeline-tag {
  display: inline-block;
  font-size: 12px;
  color: var(--primary);
  background: rgba(21, 101, 192, 0.08);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 2px 10px;
  margin-bottom: 8px;
}

/* ——— Platforms ——— */
.platforms-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 18px;
}

.platform-card {
  background: var(--white);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius);
  padding: 28px 20px;
  text-align: center;
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.platform-card:hover {
  border-color: var(--border);
  box-shadow: var(--shadow-soft);
}

.platform-icon {
  width: 56px;
  height: 56px;
  margin: 0 auto 14px;
  border-radius: var(--radius);
  background: var(--bg);
  border: 1px solid var(--border-soft);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--primary);
}

.platform-icon svg {
  width: 28px;
  height: 28px;
}

.platform-card h3 {
  font-size: 16px;
  font-weight: 600;
  margin-bottom: 6px;
}

.platform-card p {
  font-size: 13px;
  color: var(--text-muted);
  margin-bottom: 16px;
  min-height: 40px;
}

/* ——— Stats ——— */
.stats-strip {
  background: linear-gradient(90deg, var(--primary), var(--accent));
  color: #fff;
  padding: 40px 0;
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
  text-align: center;
}

.stat-item strong {
  display: block;
  font-size: clamp(26px, 3.5vw, 36px);
  font-weight: 600;
  margin-bottom: 6px;
  letter-spacing: 0.02em;
}

.stat-item span {
  font-size: 14px;
  opacity: 0.9;
}

/* ——— Reviews ——— */
.reviews-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}

.review-card {
  background: var(--white);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius);
  padding: 24px;
  transition: border-color 0.2s ease;
}

.review-card:hover {
  border-color: var(--border);
}

.review-stars {
  display: flex;
  gap: 3px;
  color: #F9A825;
  margin-bottom: 12px;
}

.review-stars svg {
  width: 16px;
  height: 16px;
}

.review-card blockquote {
  font-size: 14px;
  color: var(--text-secondary);
  margin-bottom: 16px;
  line-height: 1.7;
}

.review-meta {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 13px;
  color: var(--text-muted);
}

.review-avatar {
  width: 36px;
  height: 36px;
  border-radius: 10px;
  background: linear-gradient(135deg, var(--primary-light), var(--accent-light));
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 13px;
  font-weight: 600;
}

.review-meta strong {
  display: block;
  color: var(--text);
  font-weight: 600;
}

/* ——— FAQ Accordion ——— */
.faq-list {
  max-width: 800px;
  margin: 0 auto;
}

.faq-item {
  background: var(--white);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius);
  margin-bottom: 12px;
  overflow: hidden;
}

.faq-item summary {
  padding: 16px 20px;
  cursor: pointer;
  font-weight: 600;
  font-size: 15px;
  color: var(--text);
  list-style: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  transition: background 0.2s ease;
}

.faq-item summary::-webkit-details-marker {
  display: none;
}

.faq-item summary::after {
  content: "";
  width: 10px;
  height: 10px;
  border-right: 2px solid var(--primary);
  border-bottom: 2px solid var(--primary);
  transform: rotate(45deg);
  flex-shrink: 0;
  transition: transform 0.2s ease;
  margin-top: -4px;
}

.faq-item[open] summary::after {
  transform: rotate(-135deg);
  margin-top: 4px;
}

.faq-item summary:hover {
  background: var(--bg-soft);
}

.faq-item .faq-body {
  padding: 0 20px 18px;
  font-size: 14px;
  color: var(--text-secondary);
  border-top: 1px solid var(--border-soft);
  padding-top: 14px;
  margin: 0 0 0;
}

/* ——— Comparison table ——— */
.table-wrap {
  overflow-x: auto;
  border: 1px solid var(--border-soft);
  border-radius: var(--radius);
  background: var(--white);
}

.compare-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 14px;
  min-width: 640px;
}

.compare-table th,
.compare-table td {
  padding: 14px 18px;
  text-align: left;
  border-bottom: 1px solid var(--border-soft);
}

.compare-table th {
  background: linear-gradient(90deg, rgba(21, 101, 192, 0.08), rgba(0, 137, 123, 0.08));
  font-weight: 600;
  color: var(--text);
}

.compare-table tr:last-child td {
  border-bottom: none;
}

.compare-table td:not(:first-child) {
  text-align: center;
}

.compare-table .check {
  color: var(--accent);
  font-weight: 600;
}

.compare-table .cross {
  color: var(--text-muted);
}

/* ——— Download page ——— */
.download-hero {
  padding: 56px 0 48px;
  background:
    radial-gradient(ellipse 70% 50% at 50% 0%, rgba(66, 165, 245, 0.3), transparent 55%),
    var(--bg);
  text-align: center;
}

.download-hero h1 {
  font-size: clamp(26px, 4vw, 38px);
  font-weight: 600;
  margin-bottom: 12px;
}

.download-hero .hero-lead {
  margin-bottom: 28px;
}

.download-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 16px 28px;
  justify-content: center;
  margin-top: 20px;
  font-size: 13px;
  color: var(--text-secondary);
}

.download-meta span {
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.download-meta svg {
  width: 16px;
  height: 16px;
  color: var(--accent);
}

.guide-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}

.guide-card {
  background: var(--white);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius);
  padding: 24px;
}

.guide-card .step-num {
  width: 32px;
  height: 32px;
  border-radius: 10px;
  background: var(--primary);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 14px;
  font-weight: 600;
  margin-bottom: 14px;
}

.guide-card h3 {
  font-size: 16px;
  margin-bottom: 8px;
}

.guide-card p,
.guide-card ol {
  font-size: 14px;
  color: var(--text-secondary);
}

.guide-card ol {
  list-style: decimal;
  padding-left: 18px;
}

.guide-card ol li {
  margin-bottom: 6px;
}

.req-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
}

.req-card {
  background: var(--white);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius);
  padding: 24px 28px;
}

.req-card h3 {
  font-size: 17px;
  margin-bottom: 14px;
  display: flex;
  align-items: center;
  gap: 8px;
  color: var(--primary);
}

.req-card h3 svg {
  width: 20px;
  height: 20px;
}

.req-card ul li {
  font-size: 14px;
  color: var(--text-secondary);
  padding: 6px 0;
  border-bottom: 1px solid var(--border-soft);
  display: flex;
  justify-content: space-between;
  gap: 12px;
}

.req-card ul li:last-child {
  border-bottom: none;
}

.req-card ul li strong {
  color: var(--text);
  font-weight: 500;
}

.changelog {
  background: var(--white);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius);
  padding: 8px 0;
}

.changelog-item {
  padding: 20px 28px;
  border-bottom: 1px solid var(--border-soft);
}

.changelog-item:last-child {
  border-bottom: none;
}

.changelog-item h3 {
  font-size: 16px;
  margin-bottom: 6px;
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
}

.changelog-ver {
  background: rgba(0, 137, 123, 0.1);
  color: var(--accent);
  font-size: 12px;
  padding: 2px 10px;
  border-radius: 8px;
  border: 1px solid rgba(0, 137, 123, 0.25);
}

.changelog-date {
  font-size: 13px;
  color: var(--text-muted);
  font-weight: 500;
}

.changelog-item ul {
  margin-top: 10px;
}

.changelog-item ul li {
  font-size: 14px;
  color: var(--text-secondary);
  padding: 4px 0 4px 16px;
  position: relative;
}

.changelog-item ul li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 11px;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--primary-light);
}

.security-box {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
}

.security-card {
  background: var(--white);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius);
  padding: 28px;
}

.security-card h3 {
  font-size: 17px;
  margin-bottom: 10px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.security-card h3 svg {
  width: 22px;
  height: 22px;
  color: var(--accent);
}

.security-card p {
  font-size: 14px;
  color: var(--text-secondary);
}

/* ——— Article (zh-cn) ——— */
.article-hero {
  padding: 48px 0 32px;
  background: linear-gradient(180deg, var(--bg) 0%, var(--bg-soft) 100%);
  text-align: center;
}

.article-hero h1 {
  font-size: clamp(24px, 3.5vw, 34px);
  font-weight: 600;
  margin-bottom: 12px;
  max-width: 800px;
  margin-left: auto;
  margin-right: auto;
}

.article-hero .hero-lead {
  margin-bottom: 0;
}

.article {
  max-width: 800px;
  margin: 0 auto;
  padding: 40px 0 64px;
}

.article h2 {
  font-size: 22px;
  font-weight: 600;
  margin: 36px 0 14px;
  color: var(--text);
  padding-bottom: 8px;
  border-bottom: 1px solid var(--border-soft);
}

.article h3 {
  font-size: 17px;
  font-weight: 600;
  margin: 24px 0 10px;
  color: var(--primary-dark);
}

.article p {
  font-size: 15px;
  color: var(--text-secondary);
  margin-bottom: 14px;
  line-height: 1.85;
}

.article ul {
  margin: 0 0 16px 0;
}

.article ul li {
  font-size: 15px;
  color: var(--text-secondary);
  padding: 6px 0 6px 18px;
  position: relative;
  line-height: 1.75;
}

.article ul li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 14px;
  width: 7px;
  height: 7px;
  border-radius: 2px;
  background: var(--accent);
}

.cta-banner {
  margin-top: 40px;
  padding: 32px;
  border-radius: var(--radius);
  background: linear-gradient(135deg, rgba(21, 101, 192, 0.08), rgba(0, 137, 123, 0.1));
  border: 1px solid var(--border);
  text-align: center;
}

.cta-banner h2 {
  border: none;
  padding: 0;
  margin: 0 0 10px;
  font-size: 20px;
}

.cta-banner p {
  margin-bottom: 20px;
}

/* ——— Footer ——— */
.site-footer {
  background: #0D3B66;
  color: rgba(255, 255, 255, 0.85);
  padding: 40px 0 28px;
  font-size: 13px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 32px;
  margin-bottom: 28px;
}

.footer-brand {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.footer-brand .logo {
  color: #fff;
}

.footer-brand p {
  color: rgba(255, 255, 255, 0.7);
  line-height: 1.7;
  max-width: 360px;
}

.footer-col h4 {
  color: #fff;
  font-size: 14px;
  font-weight: 600;
  margin-bottom: 12px;
}

.footer-col a {
  display: block;
  color: rgba(255, 255, 255, 0.7);
  padding: 4px 0;
  font-size: 13px;
}

.footer-col a:hover {
  color: #fff;
}

.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.12);
  padding-top: 20px;
  text-align: center;
  color: rgba(255, 255, 255, 0.6);
  line-height: 1.8;
}

.footer-bottom p {
  margin-bottom: 4px;
}

/* ——— Spin (download loading) ——— */
@keyframes spin {
  from { transform: rotate(0deg); }
  to { transform: rotate(360deg); }
}

/* ——— Utilities ——— */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  border: 0;
}

.text-center {
  text-align: center;
}

.mt-24 {
  margin-top: 24px;
}

/* ——— Responsive ——— */
@media (max-width: 960px) {
  .features-grid,
  .reviews-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .platforms-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .stats-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 24px;
  }

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

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

@media (max-width: 720px) {
  .nav-toggle {
    display: inline-flex;
  }

  .nav-links {
    display: none;
    position: absolute;
    top: var(--nav-h);
    left: 0;
    right: 0;
    background: linear-gradient(180deg, #1565C0, #00897B);
    flex-direction: column;
    align-items: stretch;
    padding: 12px 16px 20px;
    gap: 4px;
    border-bottom: 1px solid rgba(255, 255, 255, 0.15);
  }

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

  .nav-links a {
    padding: 12px 16px;
  }

  .features-grid,
  .reviews-grid,
  .platforms-grid,
  .req-grid,
  .security-box {
    grid-template-columns: 1fr;
  }

  .footer-grid {
    grid-template-columns: 1fr;
    gap: 24px;
  }

  .hero {
    padding: 48px 0 40px;
  }

  .section {
    padding: 48px 0;
  }
}