/* ========== Root Variables ========== */
:root {
  --brand-red: #e60012;
  --brand-red-dark: #c4000f;
  --brand-red-light: #ff4d5a;
  --text-primary: #1a1a1a;
  --text-secondary: #4a4a4a;
  --text-muted: #777;
  --bg-white: #ffffff;
  --bg-light: #f7f8fa;
  --bg-gray: #f0f1f5;
  --border-color: #e5e6eb;
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.06);
  --shadow-md: 0 4px 16px rgba(0,0,0,0.08);
  --shadow-lg: 0 12px 32px rgba(0,0,0,0.12);
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --max-width: 1180px;
  --font-stack: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", sans-serif;
  --transition: all 0.25s ease;
}

/* ========== Reset & Base ========== */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: var(--font-stack);
  color: var(--text-primary);
  background: var(--bg-white);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--brand-red);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

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

ul, ol {
  list-style: none;
}

/* ========== Spin Animation ========== */
@keyframes spin {
  from { transform: rotate(0deg); }
  to   { transform: rotate(360deg); }
}

@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(24px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes float {
  0%, 100% { transform: translateY(0); }
  50%      { transform: translateY(-8px); }
}

@keyframes pulse-soft {
  0%, 100% { box-shadow: 0 0 0 0 rgba(230, 0, 18, 0.3); }
  50%      { box-shadow: 0 0 0 12px rgba(230, 0, 18, 0); }
}

/* ========== Layout ========== */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 20px;
}

.section {
  padding: 72px 0;
}

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

.section-title {
  font-size: 2rem;
  font-weight: 700;
  text-align: center;
  margin-bottom: 12px;
  color: var(--text-primary);
}

.section-subtitle {
  font-size: 1.05rem;
  text-align: center;
  color: var(--text-muted);
  margin-bottom: 48px;
  max-width: 640px;
  margin-left: auto;
  margin-right: auto;
}

/* ========== Buttons ========== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  font-size: 1rem;
  font-weight: 600;
  padding: 14px 32px;
  border-radius: var(--radius-md);
  border: none;
  cursor: pointer;
  transition: var(--transition);
  font-family: inherit;
}

.btn-primary {
  background: var(--brand-red);
  color: #fff;
}

.btn-primary:hover {
  background: var(--brand-red-dark);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

.btn-primary:active {
  transform: translateY(0);
}

.btn-secondary {
  background: #fff;
  color: var(--brand-red);
  border: 2px solid var(--brand-red);
}

.btn-secondary:hover {
  background: var(--brand-red);
  color: #fff;
}

.btn-lg {
  padding: 16px 40px;
  font-size: 1.1rem;
}

.btn-sm {
  padding: 10px 20px;
  font-size: 0.9rem;
}

/* ========== Navigation ========== */
.navbar {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: rgba(255,255,255,0.96);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border-color);
}

.navbar .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 1.2rem;
  color: var(--text-primary);
}

.nav-brand svg {
  width: 32px;
  height: 32px;
  flex-shrink: 0;
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: 32px;
}

.nav-menu a {
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--text-secondary);
  transition: var(--transition);
  position: relative;
}

.nav-menu a:hover {
  color: var(--brand-red);
  text-decoration: none;
}

.nav-menu a.active {
  color: var(--brand-red);
  font-weight: 700;
}

.nav-menu a.active::after {
  content: "";
  position: absolute;
  bottom: -6px;
  left: 0;
  width: 100%;
  height: 3px;
  background: var(--brand-red);
  border-radius: 2px;
}

/* ========== Footer ========== */
.footer {
  background: #1a1a1a;
  color: #aaa;
  padding: 40px 0 28px;
  font-size: 0.9rem;
}

.footer-disclaimer {
  text-align: center;
  line-height: 1.8;
}

.footer-disclaimer strong {
  color: #fff;
  display: block;
  margin-bottom: 6px;
}

/* ========== Hero (index) ========== */
.hero {
  background: linear-gradient(135deg, #fff 0%, #fff5f5 60%, #ffeaea 100%);
  padding: 90px 0 80px;
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: "";
  position: absolute;
  top: -120px;
  right: -120px;
  width: 480px;
  height: 480px;
  background: radial-gradient(circle, rgba(230,0,18,0.06) 0%, transparent 70%);
  border-radius: 50%;
  pointer-events: none;
}

.hero-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 48px;
  position: relative;
  z-index: 1;
}

.hero-text {
  flex: 1;
  max-width: 560px;
}

.hero-text h1 {
  font-size: 2.8rem;
  font-weight: 800;
  line-height: 1.2;
  margin-bottom: 16px;
}

.hero-text .accent {
  color: var(--brand-red);
}

.hero-text p {
  font-size: 1.15rem;
  color: var(--text-secondary);
  margin-bottom: 32px;
  line-height: 1.7;
}

.hero-actions {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}

.hero-visual {
  flex-shrink: 0;
  width: 420px;
  position: relative;
}

.hero-visual .device-mockup {
  width: 100%;
  background: linear-gradient(145deg, #ffffff, #f5f5f5);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  padding: 24px;
  animation: float 6s ease-in-out infinite;
}

/* ========== Feature Cards ========== */
.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.feature-card {
  background: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 32px 24px;
  transition: var(--transition);
}

.feature-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
  border-color: transparent;
}

.feature-icon {
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(230, 0, 18, 0.08);
  border-radius: var(--radius-sm);
  margin-bottom: 16px;
}

.feature-icon svg {
  width: 24px;
  height: 24px;
  color: var(--brand-red);
}

.feature-card h3 {
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: 10px;
}

.feature-card p {
  font-size: 0.92rem;
  color: var(--text-muted);
  line-height: 1.65;
}

/* ========== Platform Download Area ========== */
.platforms-row {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
}

.platform-card {
  background: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 28px 20px;
  text-align: center;
  transition: var(--transition);
}

.platform-card:hover {
  border-color: var(--brand-red);
  box-shadow: var(--shadow-md);
  transform: translateY(-3px);
}

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

.platform-icon svg {
  width: 28px;
  height: 28px;
  color: var(--text-primary);
}

.platform-card h4 {
  font-size: 1.05rem;
  font-weight: 600;
  margin-bottom: 6px;
}

.platform-card p {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: 16px;
}

/* ========== Detailed Feature Sections ========== */
.detail-block {
  display: flex;
  align-items: center;
  gap: 48px;
  margin-bottom: 64px;
}

.detail-block:nth-child(even) {
  flex-direction: row-reverse;
}

.detail-block:last-child {
  margin-bottom: 0;
}

.detail-text {
  flex: 1;
}

.detail-text h3 {
  font-size: 1.4rem;
  font-weight: 700;
  margin-bottom: 14px;
  color: var(--text-primary);
}

.detail-text p {
  font-size: 0.98rem;
  color: var(--text-secondary);
  margin-bottom: 12px;
  line-height: 1.8;
}

.detail-text ul {
  margin-top: 12px;
}

.detail-text ul li {
  position: relative;
  padding-left: 22px;
  margin-bottom: 8px;
  font-size: 0.95rem;
  color: var(--text-secondary);
}

.detail-text ul li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 9px;
  width: 8px;
  height: 8px;
  background: var(--brand-red);
  border-radius: 2px;
}

.detail-visual {
  flex-shrink: 0;
  width: 420px;
  height: 280px;
  background: var(--bg-gray);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  overflow: hidden;
}

/* ========== Reviews ========== */
.reviews-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.review-card {
  background: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 28px 24px;
}

.review-header {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 14px;
}

.review-avatar {
  width: 42px;
  height: 42px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--brand-red-light), var(--brand-red));
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-weight: 700;
  font-size: 0.9rem;
  flex-shrink: 0;
}

.review-meta h4 {
  font-size: 0.95rem;
  font-weight: 600;
}

.review-stars {
  display: flex;
  gap: 2px;
  margin-top: 2px;
}

.review-stars svg {
  width: 14px;
  height: 14px;
  color: #ffb800;
}

.review-card p {
  font-size: 0.92rem;
  color: var(--text-secondary);
  line-height: 1.7;
}

/* ========== Stats ========== */
.stats-row {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
}

.stat-item {
  text-align: center;
  padding: 28px 16px;
  background: var(--bg-white);
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
}

.stat-number {
  font-size: 2.2rem;
  font-weight: 800;
  color: var(--brand-red);
  line-height: 1;
  margin-bottom: 8px;
}

.stat-label {
  font-size: 0.9rem;
  color: var(--text-muted);
}

/* ========== Comparison Table ========== */
.comparison-table-wrap {
  overflow-x: auto;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
}

.comparison-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.95rem;
  background: var(--bg-white);
}

.comparison-table th,
.comparison-table td {
  padding: 16px 20px;
  text-align: left;
  border-bottom: 1px solid var(--border-color);
}

.comparison-table thead th {
  background: var(--bg-gray);
  font-weight: 600;
  color: var(--text-primary);
}

.comparison-table tbody tr:hover {
  background: var(--bg-light);
}

.comparison-table .yes {
  color: #2e9d5e;
  font-weight: 600;
}

.comparison-table .no {
  color: #d33;
}

.comparison-table .highlight {
  background: rgba(230, 0, 18, 0.04);
}

/* ========== FAQ ========== */
.faq-list {
  max-width: 820px;
  margin: 0 auto;
}

.faq-item {
  background: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  margin-bottom: 14px;
  overflow: hidden;
}

.faq-question {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 18px 22px;
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-primary);
  background: none;
  border: none;
  cursor: pointer;
  text-align: left;
  font-family: inherit;
}

.faq-question svg {
  width: 20px;
  height: 20px;
  color: var(--brand-red);
  flex-shrink: 0;
  transition: transform 0.25s ease;
}

.faq-item.open .faq-question svg {
  transform: rotate(180deg);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease, padding 0.3s ease;
}

.faq-item.open .faq-answer {
  max-height: 500px;
}

.faq-answer-inner {
  padding: 0 22px 18px;
  font-size: 0.95rem;
  color: var(--text-secondary);
  line-height: 1.75;
}

/* ========== Download Page Specific ========== */
.download-hero {
  background: linear-gradient(135deg, #fff 0%, #fff5f5 60%, #ffeaea 100%);
  padding: 70px 0 60px;
  text-align: center;
}

.download-hero h1 {
  font-size: 2.4rem;
  font-weight: 800;
  margin-bottom: 12px;
}

.download-hero > p {
  font-size: 1.05rem;
  color: var(--text-secondary);
  margin-bottom: 32px;
}

.download-main-card {
  max-width: 540px;
  margin: 0 auto;
  background: var(--bg-white);
  border: 2px solid var(--brand-red);
  border-radius: var(--radius-lg);
  padding: 40px 32px;
  box-shadow: var(--shadow-lg);
  position: relative;
}

.download-main-card .badge {
  position: absolute;
  top: -12px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--brand-red);
  color: #fff;
  font-size: 0.75rem;
  font-weight: 700;
  padding: 5px 14px;
  border-radius: 20px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.download-main-card .platform-icon-large {
  width: 72px;
  height: 72px;
  margin: 0 auto 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(230,0,18,0.08);
  border-radius: 18px;
}

.download-main-card .platform-icon-large svg {
  width: 36px;
  height: 36px;
  color: var(--brand-red);
}

.download-main-card h3 {
  font-size: 1.3rem;
  font-weight: 700;
  margin-bottom: 6px;
}

.download-meta {
  font-size: 0.88rem;
  color: var(--text-muted);
  margin-bottom: 24px;
}

.download-meta span {
  margin: 0 8px;
}

.download-btn-wrap {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.download-btn-wrap .btn {
  width: 100%;
}

/* Platform Cards in download page */
.platform-grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.platform-download-card {
  background: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 32px 24px;
  transition: var(--transition);
}

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

.platform-download-card .platform-icon {
  margin-bottom: 16px;
}

.platform-download-card h4 {
  font-size: 1.1rem;
  font-weight: 700;
  margin-bottom: 4px;
}

.platform-download-card .version {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: 12px;
}

.platform-download-card .sysreq {
  font-size: 0.82rem;
  color: var(--text-muted);
  margin-bottom: 16px;
  line-height: 1.6;
}

.platform-download-card ol {
  list-style: decimal;
  padding-left: 18px;
  font-size: 0.88rem;
  color: var(--text-secondary);
  margin-bottom: 16px;
}

.platform-download-card ol li {
  margin-bottom: 6px;
  line-height: 1.5;
}

/* Install Guide Steps */
.steps-list {
  max-width: 720px;
  margin: 0 auto;
}

.step-item {
  display: flex;
  gap: 20px;
  margin-bottom: 32px;
}

.step-item:last-child {
  margin-bottom: 0;
}

.step-num {
  flex-shrink: 0;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--brand-red);
  color: #fff;
  font-weight: 700;
  font-size: 1.1rem;
  display: flex;
  align-items: center;
  justify-content: center;
}

.step-content h4 {
  font-size: 1.05rem;
  font-weight: 600;
  margin-bottom: 6px;
  margin-top: 10px;
}

.step-content p {
  font-size: 0.95rem;
  color: var(--text-secondary);
  line-height: 1.7;
}

/* System Requirements Table */
.sysreq-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.92rem;
  background: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  overflow: hidden;
}

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

.sysreq-table thead th {
  background: var(--bg-gray);
  font-weight: 600;
}

/* Changelog */
.changelog-list {
  max-width: 780px;
  margin: 0 auto;
}

.changelog-item {
  background: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 22px 26px;
  margin-bottom: 14px;
}

.changelog-item .cl-header {
  display: flex;
  align-items: baseline;
  gap: 12px;
  margin-bottom: 10px;
}

.changelog-item .cl-version {
  font-weight: 700;
  color: var(--brand-red);
  font-size: 1.05rem;
}

.changelog-item .cl-date {
  font-size: 0.85rem;
  color: var(--text-muted);
}

.changelog-item ul {
  list-style: disc;
  padding-left: 20px;
  font-size: 0.92rem;
  color: var(--text-secondary);
  line-height: 1.7;
}

.changelog-item ul li {
  margin-bottom: 4px;
}

/* Security Badge */
.security-block {
  display: flex;
  align-items: flex-start;
  gap: 20px;
  max-width: 680px;
  margin: 0 auto;
  background: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 28px 28px;
}

.security-icon {
  flex-shrink: 0;
  width: 52px;
  height: 52px;
  background: rgba(46, 157, 94, 0.1);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
}

.security-icon svg {
  width: 26px;
  height: 26px;
  color: #2e9d5e;
}

.security-text h4 {
  font-size: 1.05rem;
  font-weight: 600;
  margin-bottom: 6px;
}

.security-text p {
  font-size: 0.92rem;
  color: var(--text-secondary);
  line-height: 1.7;
}

/* ========== zh-cn Page Specific ========== */
.seo-hero {
  background: linear-gradient(135deg, #fff 0%, #fff5f5 60%, #ffeaea 100%);
  padding: 80px 0 70px;
  text-align: center;
}

.seo-hero h1 {
  font-size: 2.2rem;
  font-weight: 800;
  margin-bottom: 14px;
  line-height: 1.3;
}

.seo-hero p {
  font-size: 1.05rem;
  color: var(--text-secondary);
  max-width: 640px;
  margin: 0 auto 28px;
  line-height: 1.7;
}

.article-content {
  max-width: 780px;
  margin: 0 auto;
  font-size: 1rem;
  line-height: 1.85;
  color: var(--text-secondary);
}

.article-content h2 {
  font-size: 1.4rem;
  font-weight: 700;
  color: var(--text-primary);
  margin: 48px 0 18px;
  padding-bottom: 10px;
  border-bottom: 2px solid var(--border-color);
}

.article-content h3 {
  font-size: 1.15rem;
  font-weight: 600;
  color: var(--text-primary);
  margin: 28px 0 12px;
}

.article-content p {
  margin-bottom: 14px;
}

.article-content ul {
  list-style: disc;
  padding-left: 24px;
  margin-bottom: 16px;
}

.article-content ul li {
  margin-bottom: 8px;
}

.article-content strong {
  color: var(--text-primary);
}

.seo-cta-box {
  background: linear-gradient(135deg, rgba(230,0,18,0.06), rgba(230,0,18,0.02));
  border: 2px solid var(--brand-red);
  border-radius: var(--radius-lg);
  padding: 36px 32px;
  text-align: center;
  margin-top: 40px;
}

.seo-cta-box h3 {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 10px;
  color: var(--text-primary);
}

.seo-cta-box p {
  font-size: 0.98rem;
  color: var(--text-secondary);
  margin-bottom: 20px;
}

/* ========== Responsive ========== */
@media (max-width: 1024px) {
  .hero-inner {
    flex-direction: column;
    text-align: center;
  }
  .hero-text {
    max-width: 100%;
  }
  .hero-actions {
    justify-content: center;
  }
  .hero-visual {
    width: 100%;
    max-width: 460px;
  }
  .detail-block,
  .detail-block:nth-child(even) {
    flex-direction: column;
  }
  .detail-visual {
    width: 100%;
    max-width: 500px;
  }
}

@media (max-width: 768px) {
  .section {
    padding: 52px 0;
  }
  .section-title {
    font-size: 1.6rem;
  }
  .hero-text h1 {
    font-size: 2rem;
  }
  .features-grid {
    grid-template-columns: 1fr;
  }
  .platforms-row {
    grid-template-columns: repeat(2, 1fr);
  }
  .reviews-grid {
    grid-template-columns: 1fr;
  }
  .stats-row {
    grid-template-columns: repeat(2, 1fr);
  }
  .platform-grid-3 {
    grid-template-columns: 1fr;
  }
  .nav-menu {
    gap: 18px;
  }
  .navbar .container {
    height: 56px;
  }
}

@media (max-width: 480px) {
  .platforms-row,
  .stats-row {
    grid-template-columns: 1fr;
  }
  .download-main-card {
    padding: 32px 20px;
  }
  .hero-actions {
    flex-direction: column;
    align-items: stretch;
  }
  .hero-actions .btn {
    width: 100%;
  }
}