/* ========================================================
   有道翻译官网 · 清新蓝绿学习风 · 第1套样式
   ======================================================== */
:root {
  --c-primary: #0E9F8E;
  --c-primary-dark: #0A7C6E;
  --c-secondary: #2E7CF6;
  --c-accent: #FFB020;
  --c-bg: #F4FBF9;
  --c-bg-alt: #EAF7F3;
  --c-text: #1B2B2A;
  --c-text-light: #5B7472;
  --c-border: #D9EEE8;
  --c-white: #FFFFFF;
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 22px;
  --shadow-sm: 0 2px 8px rgba(14, 159, 142, 0.08);
  --shadow-md: 0 8px 24px rgba(14, 159, 142, 0.12);
  --shadow-lg: 0 16px 40px rgba(14, 159, 142, 0.16);
  --max-width: 1180px;
}

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

html { scroll-behavior: smooth; }

body {
  font-family: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  background: var(--c-bg);
  color: var(--c-text);
  line-height: 1.7;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
}

a { color: inherit; text-decoration: none; }
ul { list-style: none; }
img, svg { display: block; }

.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

/* ============ 导航栏：顶部固定，居中导航项 ============ */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--c-border);
}

.nav-wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 20px;
  font-weight: 700;
  color: var(--c-primary-dark);
}

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

.main-nav {
  display: flex;
  align-items: center;
  gap: 6px;
  background: var(--c-bg-alt);
  border-radius: 999px;
  padding: 6px;
}

.main-nav a {
  padding: 10px 22px;
  border-radius: 999px;
  font-size: 15px;
  font-weight: 500;
  color: var(--c-text-light);
  transition: all 0.2s ease;
}

.main-nav a:hover { color: var(--c-primary-dark); }

.main-nav a.active {
  background: var(--c-primary);
  color: #fff;
  box-shadow: var(--shadow-sm);
}

.nav-cta {
  padding: 11px 24px;
  border-radius: 999px;
  background: var(--c-secondary);
  color: #fff;
  font-weight: 600;
  font-size: 14px;
  border: none;
  cursor: pointer;
  transition: transform 0.15s ease, box-shadow 0.15s ease;
}

.nav-cta:hover { transform: translateY(-2px); box-shadow: var(--shadow-md); }
.nav-cta:disabled { opacity: 0.7; cursor: default; transform: none; }

/* ============ Hero：居中大标题 ============ */
.hero {
  padding: 88px 0 96px;
  text-align: center;
  background: radial-gradient(ellipse at top, var(--c-bg-alt) 0%, var(--c-bg) 70%);
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 18px;
  border-radius: 999px;
  background: var(--c-white);
  box-shadow: var(--shadow-sm);
  font-size: 13px;
  color: var(--c-primary-dark);
  font-weight: 600;
  margin-bottom: 28px;
}

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

.hero h1 {
  font-size: 46px;
  font-weight: 800;
  line-height: 1.35;
  color: var(--c-text);
  max-width: 820px;
  margin: 0 auto 20px;
}

.hero h1 span { color: var(--c-primary); }

.hero-sub {
  font-size: 18px;
  color: var(--c-text-light);
  max-width: 640px;
  margin: 0 auto 36px;
}

.hero-actions {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 16px;
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 15px 32px;
  border-radius: var(--radius-md);
  font-size: 16px;
  font-weight: 700;
  border: none;
  cursor: pointer;
  transition: transform 0.15s ease, box-shadow 0.15s ease;
}

.btn svg { width: 20px; height: 20px; }

.btn-primary {
  background: linear-gradient(135deg, var(--c-primary), var(--c-secondary));
  color: #fff;
  box-shadow: var(--shadow-md);
}

.btn-primary:hover { transform: translateY(-3px); box-shadow: var(--shadow-lg); }
.btn-primary:disabled { opacity: 0.75; cursor: default; transform: none; }

.btn-outline {
  background: var(--c-white);
  color: var(--c-primary-dark);
  border: 1.5px solid var(--c-border);
}

.btn-outline:hover { border-color: var(--c-primary); color: var(--c-primary); }

.hero-note {
  margin-top: 18px;
  font-size: 13px;
  color: var(--c-text-light);
}

.hero-stats {
  display: flex;
  justify-content: center;
  gap: 56px;
  margin-top: 56px;
  flex-wrap: wrap;
}

.hero-stat b {
  display: block;
  font-size: 30px;
  font-weight: 800;
  color: var(--c-primary-dark);
}

.hero-stat span {
  font-size: 13px;
  color: var(--c-text-light);
}

/* ============ 通用区块 ============ */
.section { padding: 84px 0; }
.section-alt { background: var(--c-white); }

.section-head {
  text-align: center;
  max-width: 680px;
  margin: 0 auto 52px;
}

.section-tag {
  display: inline-block;
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.5px;
  color: var(--c-secondary);
  text-transform: uppercase;
  margin-bottom: 12px;
}

.section-head h2 {
  font-size: 32px;
  font-weight: 800;
  margin-bottom: 14px;
}

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

/* ============ 特性卡片网格 ============ */
.feature-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.feature-card {
  background: var(--c-white);
  border: 1px solid var(--c-border);
  border-radius: var(--radius-lg);
  padding: 32px 28px;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.feature-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-md);
  border-color: transparent;
}

.feature-icon {
  width: 52px;
  height: 52px;
  border-radius: var(--radius-sm);
  background: var(--c-bg-alt);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 20px;
}

.feature-icon svg { width: 26px; height: 26px; color: var(--c-primary); }

.feature-card h3 {
  font-size: 19px;
  font-weight: 700;
  margin-bottom: 10px;
}

.feature-card p {
  font-size: 14.5px;
  color: var(--c-text-light);
}

/* ============ 多平台下载 ============ */
.platform-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
}

.platform-card {
  background: var(--c-bg-alt);
  border-radius: var(--radius-lg);
  padding: 28px 22px;
  text-align: center;
}

.platform-icon {
  width: 56px;
  height: 56px;
  margin: 0 auto 16px;
  border-radius: 50%;
  background: var(--c-white);
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow-sm);
}

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

.platform-card h4 { font-size: 16px; margin-bottom: 6px; }
.platform-card p { font-size: 13px; color: var(--c-text-light); margin-bottom: 18px; min-height: 40px; }

.btn-block {
  width: 100%;
  justify-content: center;
  padding: 12px 0;
  border-radius: var(--radius-sm);
  font-size: 14px;
}

/* ============ 详细功能段落（图文交替） ============ */
.detail-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: center;
  margin-bottom: 76px;
}

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

.detail-row.reverse { direction: rtl; }
.detail-row.reverse > * { direction: ltr; }

.detail-visual {
  background: linear-gradient(150deg, var(--c-bg-alt), var(--c-white));
  border-radius: var(--radius-lg);
  padding: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 260px;
  border: 1px solid var(--c-border);
}

.detail-visual svg { width: 120px; height: 120px; color: var(--c-primary); }

.detail-num {
  font-size: 13px;
  font-weight: 700;
  color: var(--c-secondary);
  margin-bottom: 12px;
}

.detail-text h3 {
  font-size: 25px;
  font-weight: 800;
  margin-bottom: 16px;
}

.detail-text p {
  color: var(--c-text-light);
  margin-bottom: 12px;
  font-size: 15px;
}

/* ============ 评价 ============ */
.review-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 22px;
}

.review-card {
  background: var(--c-white);
  border: 1px solid var(--c-border);
  border-radius: var(--radius-lg);
  padding: 26px;
}

.review-stars { display: flex; gap: 3px; margin-bottom: 14px; }
.review-stars svg { width: 16px; height: 16px; color: var(--c-accent); }

.review-card p { font-size: 14.5px; color: var(--c-text); margin-bottom: 18px; }

.review-user { display: flex; align-items: center; gap: 10px; }

.review-avatar {
  width: 38px;
  height: 38px;
  border-radius: 50%;
  background: var(--c-bg-alt);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  color: var(--c-primary-dark);
  font-size: 14px;
}

.review-user b { font-size: 14px; display: block; }
.review-user span { font-size: 12px; color: var(--c-text-light); }

/* ============ 对比表格 ============ */
.compare-table-wrap { overflow-x: auto; border-radius: var(--radius-lg); border: 1px solid var(--c-border); }

table.compare-table {
  width: 100%;
  border-collapse: collapse;
  background: var(--c-white);
  min-width: 640px;
}

.compare-table th, .compare-table td {
  padding: 16px 20px;
  text-align: center;
  border-bottom: 1px solid var(--c-border);
  font-size: 14px;
}

.compare-table th {
  background: var(--c-bg-alt);
  font-weight: 700;
  color: var(--c-text);
}

.compare-table td:first-child, .compare-table th:first-child {
  text-align: left;
  font-weight: 600;
}

.compare-table .col-youdao { background: rgba(14, 159, 142, 0.06); color: var(--c-primary-dark); font-weight: 700; }

.tag-yes { color: var(--c-primary-dark); font-weight: 700; }
.tag-no { color: #c2513f; }

/* ============ FAQ ============ */
.faq-list { max-width: 780px; margin: 0 auto; }

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

.faq-item summary {
  padding: 20px 24px;
  font-weight: 700;
  font-size: 15.5px;
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

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

.faq-item summary .faq-icon {
  width: 20px;
  height: 20px;
  flex-shrink: 0;
  transition: transform 0.2s ease;
  color: var(--c-primary);
}

.faq-item[open] summary .faq-icon { transform: rotate(45deg); }

.faq-item .faq-body {
  padding: 0 24px 20px;
  color: var(--c-text-light);
  font-size: 14.5px;
}

/* ============ CTA 区块 ============ */
.cta-band {
  background: linear-gradient(120deg, var(--c-primary), var(--c-secondary));
  border-radius: var(--radius-lg);
  padding: 56px;
  text-align: center;
  color: #fff;
}

.cta-band h2 { font-size: 28px; font-weight: 800; margin-bottom: 12px; }
.cta-band p { opacity: 0.92; margin-bottom: 28px; font-size: 15px; }
.cta-band .btn-primary { background: #fff; color: var(--c-primary-dark); box-shadow: none; }
.cta-band .btn-primary:hover { transform: translateY(-3px); box-shadow: 0 10px 24px rgba(0,0,0,0.18); }

/* ============ 下载页专用 ============ */
.download-hero {
  padding: 64px 0 48px;
  text-align: center;
}

.download-main-card {
  background: var(--c-white);
  border: 1px solid var(--c-border);
  border-radius: var(--radius-lg);
  padding: 44px;
  max-width: 640px;
  margin: 0 auto;
  box-shadow: var(--shadow-md);
}

.download-main-card .platform-icon { width: 72px; height: 72px; margin-bottom: 20px; }
.download-main-card .platform-icon svg { width: 36px; height: 36px; }

.version-meta {
  display: flex;
  justify-content: center;
  gap: 26px;
  margin: 20px 0 28px;
  flex-wrap: wrap;
}

.version-meta div { text-align: center; }
.version-meta b { display: block; font-size: 18px; color: var(--c-text); }
.version-meta span { font-size: 12.5px; color: var(--c-text-light); }

.steps-list {
  counter-reset: step;
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 18px;
}

.step-item {
  counter-increment: step;
  background: var(--c-white);
  border: 1px solid var(--c-border);
  border-radius: var(--radius-md);
  padding: 24px 16px;
  text-align: center;
  position: relative;
}

.step-item::before {
  content: counter(step);
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: var(--c-primary);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  margin: 0 auto 14px;
  font-size: 14px;
}

.step-item h4 { font-size: 14.5px; margin-bottom: 6px; }
.step-item p { font-size: 12.5px; color: var(--c-text-light); }

.req-table-wrap { border: 1px solid var(--c-border); border-radius: var(--radius-lg); overflow: hidden; }

table.req-table { width: 100%; border-collapse: collapse; background: var(--c-white); }
.req-table th, .req-table td { padding: 14px 20px; font-size: 13.5px; border-bottom: 1px solid var(--c-border); text-align: left; }
.req-table th { background: var(--c-bg-alt); }

.changelog-list { max-width: 760px; margin: 0 auto; }

.changelog-item {
  display: flex;
  gap: 24px;
  padding: 24px 0;
  border-bottom: 1px dashed var(--c-border);
}

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

.changelog-ver {
  flex-shrink: 0;
  width: 130px;
}

.changelog-ver b { display: block; font-size: 16px; color: var(--c-primary-dark); }
.changelog-ver span { font-size: 12.5px; color: var(--c-text-light); }

.changelog-body ul { padding-left: 18px; list-style: disc; }
.changelog-body li { font-size: 14px; color: var(--c-text-light); margin-bottom: 6px; }

.security-band {
  display: flex;
  align-items: center;
  gap: 22px;
  background: var(--c-bg-alt);
  border-radius: var(--radius-lg);
  padding: 30px 34px;
}

.security-band svg { width: 44px; height: 44px; color: var(--c-primary); flex-shrink: 0; }
.security-band h4 { font-size: 16px; margin-bottom: 6px; }
.security-band p { font-size: 13.5px; color: var(--c-text-light); }

/* ============ 中文页专用 ============ */
.article-content { max-width: 760px; margin: 0 auto; }
.article-content h2 { font-size: 24px; margin: 44px 0 16px; font-weight: 800; }
.article-content h2:first-child { margin-top: 0; }
.article-content h3 { font-size: 18px; margin: 28px 0 12px; font-weight: 700; color: var(--c-primary-dark); }
.article-content p { color: var(--c-text-light); margin-bottom: 14px; font-size: 15px; }
.article-content ul { padding-left: 20px; list-style: disc; margin-bottom: 14px; }
.article-content li { margin-bottom: 8px; color: var(--c-text-light); font-size: 15px; }

.tip-box {
  background: var(--c-bg-alt);
  border-left: 4px solid var(--c-primary);
  border-radius: var(--radius-sm);
  padding: 18px 22px;
  margin: 20px 0;
  font-size: 14.5px;
  color: var(--c-text);
}

/* ============ 页脚 ============ */
.site-footer {
  background: #0F2926;
  color: rgba(255,255,255,0.72);
  padding: 56px 0 30px;
  margin-top: 40px;
}

.footer-top {
  display: flex;
  justify-content: space-between;
  gap: 40px;
  flex-wrap: wrap;
  padding-bottom: 32px;
  border-bottom: 1px solid rgba(255,255,255,0.12);
}

.footer-brand { max-width: 320px; }
.footer-brand .logo { color: #fff; margin-bottom: 12px; }
.footer-brand p { font-size: 13.5px; line-height: 1.8; }

.footer-links { display: flex; gap: 56px; }
.footer-col h5 { color: #fff; font-size: 14px; margin-bottom: 16px; }
.footer-col a { display: block; font-size: 13.5px; margin-bottom: 10px; color: rgba(255,255,255,0.68); }
.footer-col a:hover { color: #fff; }

.footer-bottom {
  margin-top: 24px;
  font-size: 12.5px;
  line-height: 1.9;
  text-align: center;
}

.footer-security {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  margin-bottom: 10px;
  color: rgba(255,255,255,0.85);
}

.footer-security svg { width: 16px; height: 16px; }

/* ============ Loading Spinner 动画 ============ */
@keyframes spin { from { transform: rotate(0deg); } to { transform: rotate(360deg); } }

/* ============ 响应式 ============ */
@media (max-width: 980px) {
  .feature-grid { grid-template-columns: repeat(2, 1fr); }
  .platform-grid { grid-template-columns: repeat(2, 1fr); }
  .review-grid { grid-template-columns: repeat(2, 1fr); }
  .detail-row { grid-template-columns: 1fr; gap: 28px; }
  .detail-row.reverse { direction: ltr; }
  .steps-list { grid-template-columns: repeat(3, 1fr); }
  .main-nav { display: none; }
}

@media (max-width: 640px) {
  .hero h1 { font-size: 32px; }
  .feature-grid { grid-template-columns: 1fr; }
  .platform-grid { grid-template-columns: 1fr; }
  .review-grid { grid-template-columns: 1fr; }
  .steps-list { grid-template-columns: repeat(2, 1fr); }
  .footer-top { flex-direction: column; }
  .footer-links { gap: 32px; }
  .hero-stats { gap: 30px; }
}