/* ===== 全局变量 ===== */
:root {
  --primary: #E4393C;
  --primary-dark: #CC2E31;
  --primary-light: #FF5A54;
  --text-main: #333333;
  --text-sub: #666666;
  --text-light: #999999;
  --bg-white: #FFFFFF;
  --bg-page: #FFFFFF;
  --bg-light: #F8F9FA;
  --border: #EEEEEE;
  --shadow: 0 2px 12px rgba(0,0,0,.08);
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  color: var(--text-main);
  background: var(--bg-page);
  line-height: 1.6;
}

.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 24px;
}

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

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

/* ===== Header ===== */
.header {
  background: var(--bg-white);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
}
.header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}
.logo img { height: 32px; }
.nav { display: flex; gap: 36px; }
.nav a {
  font-size: 15px;
  color: var(--text-sub);
  transition: color .2s;
  padding: 4px 0;
}
.nav a:hover,
.nav a.active { color: var(--primary); }
.mobile-menu-btn {
  display:none;
  align-items:center; justify-content:center;
  width:36px; height:36px;
  border:none; background:transparent;
  cursor:pointer; padding:6px;
}
.mobile-menu-btn svg {
  width:22px; height:22px;
  stroke:var(--text-sub);
  stroke-width:2;
  fill:none;
}
.mobile-menu-btn:hover svg { stroke:var(--primary); }
.nav.mobile-open {
  display:flex; flex-direction:column;
  position:absolute; top:64px; left:0; right:0;
  background:rgba(255,255,255,0.98);
  backdrop-filter:blur(12px);
  border-bottom:1px solid var(--border);
  padding:16px 24px 24px;
  gap:16px; z-index:99;
  box-shadow:0 10px 30px rgba(0,0,0,0.08);
}

/* ===== Hero Section ===== */
.hero-section {
  position: relative;
  width: 100%;
  height: 759px;
  overflow: hidden;
}
.hero-banner {
  width: 100%;
  height: 759px;
  object-fit: cover;
  position: absolute;
  top: -48px;
  z-index: 0;
}
.hero-content {
  position: absolute;
  top: 133px;
  left: 50%;
  transform: translateX(-50%);
  width: 1200px;
  text-align: center;
  z-index: 1;
}
.hero-logo {
  width: auto;
  height: 38px;
  display: block;
  margin: 48px auto 0 auto;
}
.hero-title {
  width: auto;
  height: 84px;
  margin: 25px auto 40px auto;
}
.hero-tips-img {
  width: auto;
  height: 16px;
  position: absolute;
  right: 7.6%;
  top: 190px;
}
.hero-computer {
  position: absolute;
  left: 50%;
  transform: translateX(-50%);
  z-index: -1;
  width: 823px;
  height: auto;
  top: 0;
}
.hero-download-area {
  display: inline-block;
  margin-top: 20px;
}
.hero-dl-row {
  display: flex;
  gap: 12px;
  justify-content: center;
  align-items: center;
}
.hero-dl-btn {
  height: auto;
  cursor: pointer;
}
.hero-ms-btn {
  /* Microsoft store button */
}
.hero-links {
  margin-top: 14px;
  font-size: 13px;
  color: #999;
  display: flex;
  gap: 24px;
  justify-content: center;
}
.hero-links span {
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 4px;
  transition: color .2s;
}
.hero-links span:hover { color: var(--primary); }
.link-icon {
  width: 10px;
  height: 10px;
}
.hero-sub-links {
  display: flex;
  gap: 24px;
  justify-content: center;
  margin-top: 10px;
}
.hero-sub-links a {
  font-size: 13px;
  color: var(--text-light);
  transition: color .2s;
  display: flex;
  align-items: center;
  gap: 4px;
}
.hero-sub-links a:hover { color: var(--primary); }

/* ===== 让AI助力知识研究 ===== */
.ai-research {
  padding: 70px 0;
  background: var(--bg-white);
}
.ai-research h2 {
  font-size: 28px;
  font-weight: 700;
  text-align: center;
  margin-bottom: 8px;
  color: var(--text-main);
}
.sub-desc {
  text-align: center;
  color: var(--text-light);
  font-size: 13px;
  margin-bottom: 40px;
  letter-spacing: .5px;
}
.research-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: center;
}
.research-text h3 {
  font-size: 22px;
  font-weight: 700;
  color: var(--text-main);
  margin-bottom: 6px;
}
.research-subtitle {
  font-size: 14px;
  color: var(--text-sub);
  margin-bottom: 24px;
}
.infos-list { list-style: none; }
.infos-list li {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  margin-bottom: 18px;
  line-height: 1.7;
}
.info-tag {
  display: inline-block;
  background: linear-gradient(135deg, #E4393C, #FF5A54);
  color: #fff;
  font-size: 12px;
  font-weight: 600;
  padding: 2px 10px;
  border-radius: 10px;
  white-space: nowrap;
  flex-shrink: 0;
  line-height: 20px;
}
.info-desc {
  font-size: 14px;
  color: var(--text-sub);
}
.research-img img {
  border-radius: 12px;
  box-shadow: var(--shadow);
}

/* ===== 用AI重新定义翻译 ===== */
.ai-define {
  padding: 70px 0;
  background: var(--bg-light);
}
.ai-define h2 {
  font-size: 28px;
  font-weight: 700;
  text-align: center;
  margin-bottom: 8px;
  color: var(--text-main);
}
.define-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: center;
  margin-bottom: 60px;
}
.define-left img {
  border-radius: 12px;
  box-shadow: var(--shadow);
}
.define-right h3 {
  font-size: 22px;
  font-weight: 700;
  margin-bottom: 6px;
  color: var(--text-main);
}
.define-right p {
  color: var(--text-sub);
  margin-bottom: 16px;
  line-height: 1.7;
  font-size: 14px;
}
.define-sub {
  margin-top: 48px;
  padding-top: 48px;
  border-top: 1px solid var(--border);
}
.define-sub:first-of-type {
  border-top: none;
  padding-top: 0;
  margin-top: 0;
}

/* ===== Feature Block (文档/写作) ===== */
.feature-block {
  padding: 70px 0;
}
.feature-block:nth-child(even) { background: var(--bg-white); }
.feature-block:nth-child(odd) { background: var(--bg-light); }
.feature-layout {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: center;
}
.feature-layout.reverse { direction: rtl; }
.feature-layout.reverse > * { direction: ltr; }
.feature-visual img {
  border-radius: 12px;
  box-shadow: var(--shadow);
}
.feature-info h3 {
  font-size: 22px;
  font-weight: 700;
  margin-bottom: 16px;
  color: var(--text-main);
}
.feature-info p {
  color: var(--text-sub);
  line-height: 1.8;
  margin-bottom: 20px;
}
.feature-info ul { list-style: none; }
.feature-info li {
  padding: 6px 0;
  color: var(--text-sub);
  font-size: 15px;
}

/* ===== 各种翻译（首页横向布局） ===== */
.translate-types {
  padding: 70px 0;
  background: var(--bg-white);
}
.translate-types h2 {
  font-size: 28px;
  font-weight: 700;
  text-align: center;
  margin-bottom: 48px;
  color: var(--text-main);
}
.types-rows {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
  margin-bottom: 48px;
}
.type-row {
  display: flex;
  flex-direction: column;
  gap: 16px;
  padding: 28px 24px;
  background: var(--bg-light);
  border-radius: 12px;
  border: 1px solid var(--border);
  transition: all .3s;
}
.type-row:hover {
  box-shadow: var(--shadow);
  border-color: transparent;
}
.type-row-text h3 {
  font-size: 18px;
  font-weight: 700;
  color: var(--text-main);
  margin-bottom: 8px;
}
.type-row-text p {
  font-size: 13px;
  color: var(--text-sub);
  line-height: 1.7;
}
.type-row-img {
  max-width: 100%;
  height: auto;
  border-radius: 8px;
  order: 1;
}
/* 截图翻译跨2列 */
.type-row-full {
  grid-column: 1 / -1;
  flex-direction: row;
  align-items: center;
}
.type-row-full .type-row-text {
  flex: 1;
}
.type-row-full .type-row-img {
  max-width: 45%;
  order: 0;
}

/* 底部4工具（在 translate-types 区域内） */
.bottom-infos {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
}
.bottom-info-item {
  display: flex;
  align-items: flex-start;
  gap: 16px;
  background: var(--bg-light);
  border-radius: 12px;
  padding: 24px;
  border: 1px solid var(--border);
  transition: all .3s;
}
.bottom-info-item:hover {
  box-shadow: var(--shadow);
  border-color: transparent;
}
.bottom-info-icon {
  width: 56px;
  height: 56px;
  object-fit: contain;
  flex-shrink: 0;
  border-radius: 10px;
  background: #fff;
  padding: 6px;
}
.bottom-info-text h4 {
  font-size: 16px;
  font-weight: 600;
  color: var(--text-main);
  margin-bottom: 6px;
}
.bottom-info-text p {
  font-size: 13px;
  color: var(--text-sub);
  line-height: 1.7;
}

/* ===== 底部CTA（首页） ===== */
/* 底部CTA（照抄yd7）*/
.bottom-cta {
  width: 100%;
  height: 750px;
  background: url(../images/cta_bg.jpg) no-repeat;
  background-size: cover;
}
.bottom-cta-inner {
  max-width: 1200px;
  text-align: center;
  padding-top: 120px;
  margin: 0 auto;
}
.bottom-cta-title {
  font-weight: 600;
  font-size: 48px;
  line-height: 55px;
  letter-spacing: .008em;
  color: #2a2b2e;
}
.bottom-cta-honor {
  display: flex;
  justify-content: space-between;
  width: 1200px;
  height: auto;
  margin: 60px auto;
}
.honor-item {
  width: 224px;
  height: 270px;
}
.bottom-cta-dl-btn {
  width: 226px;
  height: auto;
  cursor: pointer;
}

/* ===== Footer (参考有道官网) ===== */
.site-footer {
  background: #F1F6FF;
  padding: 48px 0 0;
  font-size: 11px;
  color: #333;
}
.ft-main {
  display: flex;
  justify-content: space-between;
  gap: 40px;
  padding-bottom: 32px;
  border-bottom: 1px solid #DDE6F6;
}
.ft-left {
  flex-shrink: 0;
  width: 180px;
}
.ft-logo {
  height: 32px;
  margin-bottom: 16px;
}
.ft-qrcode-wrap {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 16px;
}
.ft-qrcode {
  height: 72px;
  border-radius: 6px;
}
.ft-qrcode-text {
  font-size: 10px;
  color: #666;
  line-height: 1.5;
}
.ft-channels {
  margin-top: 8px;
}
.ft-channel-title {
  font-size: 10px;
  color: #999;
  display: block;
  margin-bottom: 8px;
}
.ft-channel-icons {
  display: flex;
  gap: 10px;
}
.ch-icon {
  height: 24px;
  width: 24px;
  cursor: pointer;
}
.ft-links {
  display: flex;
  gap: 40px;
  flex: 1;
  justify-content: flex-end;
}
.ft-list {
  list-style: none;
  min-width: 90px;
}
.ft-title {
  font-weight: 600;
  font-size: 12px;
  color: #222;
  margin-bottom: 12px;
}
.ft-list li {
  margin-bottom: 8px;
}
.ft-list a {
  font-size: 11px;
  color: #666;
  transition: color .2s;
}
.ft-list a:hover {
  color: #E4393C;
}
.ft-copyright {
  text-align: center;
  padding: 16px 0 8px;
  font-size: 10px;
  color: #999;
  display: flex;
  justify-content: center;
  gap: 16px;
  flex-wrap: wrap;
}
.ft-copyright a {
  color: #999;
  font-size: 10px;
}
.ft-copyright a:hover { color: #E4393C; }
.ft-report {
  text-align: center;
  padding: 4px 0 20px;
  font-size: 10px;
  color: #999;
  display: flex;
  justify-content: center;
  gap: 20px;
  flex-wrap: wrap;
  border-bottom: 1px solid #DDE6F6;
  margin-bottom: 0;
}
.ft-report a {
  color: #999;
  font-size: 10px;
}
.ft-report a:hover { color: #E4393C; }

/* ===== 多平台下载页面 ===== */
.dl-page {
  padding: 60px 0 80px;
  background: #fff;
}
.dl-title {
  font-size: 40px;
  font-weight: 400;
  color: #2A2B2E;
  text-align: center;
  margin-bottom: 8px;
}
.dl-divider {
  width: 100%;
  height: 1px;
  background: linear-gradient(90deg, transparent, #E4E7ED, transparent);
  margin-bottom: 16px;
}
.dl-protocol {
  text-align: center;
  font-size: 13px;
  color: #666;
  margin-bottom: 6px;
}
.dl-link {
  color: #4A90D9;
  text-decoration: none;
}
.dl-link:hover { text-decoration: underline; }
.dl-changelog {
  display: block;
  text-align: center;
  font-size: 13px;
  color: #4A90D9;
  text-decoration: none;
  margin-bottom: 40px;
}
.dl-changelog:hover { text-decoration: underline; }

/* 下载项：左侧设备图 + 右侧信息 */
.dl-item {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 80px;
  padding: 32px 129px;
  margin-bottom: 32px;
  background: rgba(244,245,247,0.5);
  border-radius: 16px;
}
.dl-preview {
  width: 371px;
  height: auto;
  flex-shrink: 0;
}
.dl-info {
  min-width: 300px;
}
.dl-os-name {
  font-size: 28px;
  font-weight: 400;
  color: #2A2B2E;
  margin-bottom: 24px;
}
.dl-desc {
  font-size: 14px;
  color: #999;
  margin-bottom: 12px;
}

/* 按钮组 */
.dl-btns {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-top: 32px;
}
.dl-btns-grid {
  display: grid;
  grid-template-columns: repeat(2, 192px);
  gap: 10px;
  margin-top: 2px;
}
.dl-btn-img {
  height: 48px;
  cursor: pointer;
  transition: opacity .2s;
  border: none;
  background: none;
  padding: 0;
}
.dl-btn-img:hover { opacity: .85; }

/* Linux 包按钮 */
.dl-pkg-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 192px;
  height: 48px;
  background: #5B8DEF;
  color: #fff;
  border-radius: 6px;
  font-size: 13px;
  cursor: pointer;
  transition: background .2s;
  text-align: center;
  line-height: 1.2;
  padding: 4px 12px;
  box-sizing: border-box;
}
.dl-pkg-btn:hover {
  background: #4A7DD9;
}

/* ===== Release Notes (更新日志) ===== */
.cl-page {
  padding: 60px 0 80px;
  background: #fff;
}
.cl-title {
  font-size: 40px;
  font-weight: 400;
  color: #2A2B2E;
  text-align: center;
  margin-bottom: 40px;
}
.cl-box {
  max-width: 800px;
  margin: 0 auto;
  padding: 0 20px;
}
.cl-item {
  padding-bottom: 31px;
  margin-top: 32px;
  border-bottom: 1px dashed rgba(220,223,229,0.6);
}
.cl-item:first-child { margin-top: 0; }
.cl-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 12px;
}
.cl-ver {
  font-size: 18px;
  font-weight: 600;
  color: #2A2B2E;
}
.cl-date {
  font-size: 14px;
  color: #626469;
}
.cl-desc {
  list-style: none;
  padding: 0;
  margin: 0;
}
.cl-desc li {
  font-size: 14px;
  color: #626469;
  line-height: 21px;
  padding: 3px 0;
  position: relative;
  padding-left: 16px;
}
.cl-desc li::before {
  content: '-';
  position: absolute;
  left: 0;
  color: #999;
}

/* ===== 法律页面（服务条款/隐私政策） ===== */
.legal-page {
  padding: 60px 0 80px;
  background: #fff;
}
.legal-title {
  font-size: 32px;
  font-weight: 400;
  color: #2A2B2E;
  text-align: center;
  margin-bottom: 40px;
}
.legal-body {
  max-width: 800px;
  margin: 0 auto;
  padding: 0 20px;
  font-size: 14px;
  color: #555;
  line-height: 1.8;
}
.legal-body p { margin-bottom: 16px; }
.legal-body h3 {
  font-size: 18px;
  font-weight: 600;
  color: #2A2B2E;
  margin: 28px 0 12px;
}
.legal-body h4 {
  font-size: 16px;
  font-weight: 600;
  color: #333;
  margin: 24px 0 10px;
}
.legal-body ul {
  padding-left: 20px;
  margin-bottom: 16px;
}
.legal-body ul li {
  line-height: 1.8;
  color: #555;
}


/* ===== About 页面 ===== */
.about-banner {
  padding: 80px 0 60px;
  background: linear-gradient(180deg, #FFF5F5 0%, #FFFFFF 100%);
  text-align: center;
}
.about-banner h1 {
  font-size: 36px;
  font-weight: 700;
  color: #2A2B2E;
  margin-bottom: 12px;
}
.about-banner p {
  font-size: 18px;
  color: var(--text-light);
}

/* 公司介绍 */
.about-intro {
  padding: 80px 0;
  background: #fff;
}
.about-intro-inner {
  display: grid;
  grid-template-columns: 1fr 320px;
  gap: 60px;
  align-items: start;
}
.about-intro-text h2 {
  font-size: 28px;
  font-weight: 700;
  color: var(--primary);
  margin-bottom: 20px;
}
.about-intro-lead {
  font-size: 18px;
  font-weight: 600;
  color: var(--text-main);
  line-height: 1.6;
  margin-bottom: 16px;
}
.about-intro-text p {
  font-size: 15px;
  color: var(--text-sub);
  line-height: 1.8;
  margin-bottom: 12px;
}
.highlight {
  color: var(--primary);
  font-weight: 600;
}
.about-intro-stats {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
}
.stat-item {
  background: var(--bg-light);
  border-radius: 12px;
  padding: 24px 20px;
  text-align: center;
}
.stat-num {
  display: block;
  font-size: 32px;
  font-weight: 700;
  color: var(--primary);
  margin-bottom: 4px;
}
.stat-label {
  font-size: 14px;
  color: var(--text-light);
}

/* 产品功能 */
.about-product {
  padding: 80px 0;
  background: var(--bg-light);
}
.section-title {
  font-size: 28px;
  font-weight: 700;
  text-align: center;
  color: #2A2B2E;
  margin-bottom: 8px;
}
.section-subtitle {
  font-size: 16px;
  color: var(--text-light);
  text-align: center;
  margin-bottom: 48px;
}
.product-features {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}
.pf-card {
  background: #fff;
  border-radius: 12px;
  padding: 32px 24px;
  text-align: center;
  transition: box-shadow 0.2s;
}
.pf-card:hover {
  box-shadow: var(--shadow);
}
.pf-icon {
  font-size: 36px;
  margin-bottom: 16px;
}
.pf-card h3 {
  font-size: 18px;
  font-weight: 600;
  color: #2A2B2E;
  margin-bottom: 12px;
}
.pf-card p {
  font-size: 14px;
  color: var(--text-sub);
  line-height: 1.6;
}

/* 产品生态 */
.about-ecosystem {
  padding: 80px 0;
  background: #fff;
}
.eco-category {
  margin-bottom: 48px;
}
.eco-category:last-child {
  margin-bottom: 0;
}
.eco-category-title {
  font-size: 20px;
  font-weight: 600;
  color: #2A2B2E;
  margin-bottom: 20px;
  padding-left: 12px;
  border-left: 4px solid var(--primary);
}
.eco-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
}
.eco-card {
  background: var(--bg-light);
  border-radius: 10px;
  padding: 20px;
  transition: box-shadow 0.2s;
}
.eco-card:hover {
  box-shadow: var(--shadow);
}
.eco-card h4 {
  font-size: 15px;
  font-weight: 600;
  color: #2A2B2E;
  margin-bottom: 6px;
}
.eco-card p {
  font-size: 13px;
  color: var(--text-light);
  line-height: 1.5;
}

/* FAQ */
.about-faq {
  padding: 80px 0;
  background: var(--bg-light);
}
.faq-list {
  max-width: 720px;
  margin: 0 auto;
}
.faq-item {
  background: #fff;
  border-radius: 10px;
  margin-bottom: 12px;
  overflow: hidden;
}
.faq-question {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 18px 24px;
  cursor: pointer;
  font-size: 15px;
  font-weight: 500;
  color: #2A2B2E;
  transition: background 0.2s;
}
.faq-question:hover {
  background: #fafafa;
}
.faq-arrow {
  font-size: 12px;
  color: var(--text-light);
  transition: transform 0.2s;
}
.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease, padding 0.3s ease;
}
.faq-answer p {
  padding: 0 24px 18px;
  font-size: 14px;
  color: var(--text-sub);
  line-height: 1.7;
}
.faq-answer a {
  color: var(--primary);
}
.faq-item.active .faq-answer {
  max-height: 200px;
}
.faq-item.active .faq-arrow {
  transform: rotate(180deg);
}

/* 联系我们 */
.about-contact {
  padding: 80px 0;
  background: #fff;
}
.contact-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
  max-width: 900px;
  margin: 0 auto;
}
.contact-card {
  text-align: center;
  padding: 32px 16px;
  background: var(--bg-light);
  border-radius: 12px;
}
.contact-icon {
  font-size: 32px;
  margin-bottom: 12px;
}
.contact-card h4 {
  font-size: 15px;
  font-weight: 600;
  color: #2A2B2E;
  margin-bottom: 8px;
}
.contact-card p {
  font-size: 14px;
  color: var(--text-sub);
}
.contact-card a {
  color: var(--primary);
}
.contact-qr {
  margin-top: 12px;
}
.contact-qr img {
  width: 80px;
  height: 80px;
  border-radius: 6px;
}
.contact-qr span {
  display: block;
  font-size: 12px;
  color: var(--text-light);
  margin-top: 6px;
}

/* ===== 响应式 ===== */
@media (max-width: 900px) {
  .research-grid,
  .define-grid,
  .feature-layout {
    grid-template-columns: 1fr;
    gap: 32px;
  }
  .feature-layout.reverse { direction: ltr; }
  .type-row { text-align: center; }
  .type-row-full { grid-column: 1 / -1; flex-direction: column; }
  .type-row-full .type-row-img { max-width: 100%; }
  .bottom-infos { grid-template-columns: 1fr; }
  .ft-main { flex-direction: column; gap: 32px; }
  .ft-links { gap: 24px; flex-wrap: wrap; justify-content: flex-start; }
  .ft-left { width: 100%; }
  /* 下载页响应式 */
  .dl-item { flex-direction: column; padding: 40px 24px; gap: 24px; text-align: center; }
  .dl-preview { width: 280px; }
  .dl-btns { justify-content: center; }
  .dl-btns-grid { grid-template-columns: repeat(2, 160px); gap: 8px; }
  .dl-pkg-btn { width: 160px; height: 42px; font-size: 12px; }
  /* About 页面响应式 */
  .about-intro-inner { grid-template-columns: 1fr; gap: 40px; }
  .about-intro-stats { grid-template-columns: repeat(2, 1fr); }
  .product-features { grid-template-columns: repeat(2, 1fr); }
  .eco-grid { grid-template-columns: repeat(2, 1fr); }
  .contact-grid { grid-template-columns: repeat(2, 1fr); }
  .about-banner h1 { font-size: 28px; }
}
@media (max-width: 640px) {
  .container { padding:0 16px; }
  .nav { display:none; }
  .mobile-menu-btn { display:flex; }
  .header .container { position:relative; }
  .hero-section { height: auto; padding: 40px 0 30px; }
  .hero-banner { position: relative; top: 0; height: auto; }
  .hero-content { position: relative; top: 0; left: 0; transform: none; width: 100%; padding: 0 16px; }
  .hero-logo { height: 28px; margin: 20px auto 0; }
  .hero-title { height: 50px; margin: 15px auto 20px; }
  .hero-tips-img { position: static; margin-bottom: 10px; }
  .hero-computer { position: static; transform: none; width: 100%; max-width: 500px; }
  .hero-dl-row { flex-direction: column; gap: 8px; align-items: center; }
  .hero-dl-btn { max-width: 200px; }
  .hero-links { flex-direction: column; gap: 6px; }
  /* About 页面超小屏 */
  .product-features { grid-template-columns: 1fr; }
  .eco-grid { grid-template-columns: 1fr; }
  .contact-grid { grid-template-columns: 1fr; }
  .about-intro-stats { grid-template-columns: 1fr 1fr; }
  .stat-num { font-size: 24px; }
  .bottom-cta { height: auto; padding: 40px 0; background-size: cover; }
  .bottom-cta-inner { padding-top: 40px; width: 100%; }
  .bottom-cta-title { font-size: 24px; line-height: 32px; }
  .bottom-cta-honor { width: 100%; flex-wrap: wrap; justify-content: center; gap: 12px; margin: 30px auto; }
  .honor-item { width: 140px; height: 170px; }
  .bottom-cta-dl-btn { width: 180px; }
  /* Footer 超小屏 */
  .ft-main { flex-direction: column; }
  .ft-left { width: 100%; }
  .ft-links { gap: 20px; flex-wrap: wrap; }
  .ft-qrcode-wrap { display: none; }
  .ft-copyright, .ft-report { font-size: 9px; }
  /* 下载页超小屏 */
  .dl-item { padding: 24px 16px; }
  .dl-preview { width: 200px; }
  .dl-btns-grid { grid-template-columns: 1fr; max-width: 200px; }
  /* Features 页面超小屏 */
  .section-title { font-size: 22px; }
  .define-grid, .feature-layout { gap: 20px; }
  .type-row { flex-direction: column; }
  .type-row-img { max-width: 100%; }
  /* Terms/Privacy 页面 */
  .content-page { padding: 30px 0; }
  .content-page h2 { font-size: 20px; }
}