/* ============================================================
   EverCheck – Shared Stylesheet
   ============================================================ */

/* ===== RESET & BASE ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: 'DM Sans', system-ui, -apple-system, sans-serif;
  color: var(--brand-black);
  background: var(--white);
  font-size: 16px;
  line-height: 1.75;
  font-weight: 400;
  -webkit-font-smoothing: antialiased;
}
a { text-decoration: none; color: inherit; }
ul { list-style: none; }
img { max-width: 100%; height: auto; display: block; }

/* ===== DESIGN TOKENS ===== */
:root {
  --brand-blue: #80bce2;
  --brand-blue-dark: #5a9fd0;
  --brand-black: #333333;
  --brand-gray: #666666;
  --brand-light-gray: #f5f7fa;
  --brand-border: #e8ecf1;
  --white: #ffffff;
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-pill: 48px;
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.04);
  --shadow-md: 0 4px 20px rgba(0,0,0,0.06);
  --shadow-lg: 0 8px 40px rgba(0,0,0,0.08);
}

/* ===== LAYOUT ===== */
.container { max-width: 1200px; margin: 0 auto; padding: 0 24px; }
.section { padding: 80px 0; }
.section-alt { background: var(--brand-light-gray); }
.section-header { text-align: center; max-width: 700px; margin: 0 auto 64px; }
.section-header h2 {
  font-size: 36px; font-weight: 700; letter-spacing: -0.5px;
  margin-bottom: 16px; color: var(--brand-black);
}
.section-header p { font-size: 17px; color: var(--brand-gray); line-height: 1.7; }

/* ===== NAVIGATION ===== */
.nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 1000;
  background: rgba(255,255,255,0.92); backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--brand-border);
}
.nav-inner {
  display: flex; align-items: center; justify-content: space-between;
  height: 72px;
}
.logo { font-size: 20px; font-weight: 600; color: var(--brand-black); letter-spacing: -0.5px; }
.logo span { color: var(--brand-blue); }
.logo-img { height: 32px; width: auto; display: block; }
.footer-logo .logo-img { height: 28px; }

.nav-links { display: flex; gap: 48px; align-items: center; }
.nav-links > a {
  font-size: 16px; font-weight: 400; color: var(--brand-black);
  transition: color 0.2s;
}
.nav-links > a:hover { color: var(--brand-blue); }

/* Dropdown */
.nav-item { position: relative; }
.nav-item > a {
  display: flex; align-items: center; gap: 4px;
  font-size: 16px; font-weight: 400; color: var(--brand-black);
  transition: color 0.2s;
}
.nav-item > a:hover { color: var(--brand-blue); }
.nav-item > a .arrow {
  display: inline-block; width: 0; height: 0;
  border-left: 4px solid transparent; border-right: 4px solid transparent;
  border-top: 5px solid var(--brand-gray);
  transition: transform 0.2s; margin-top: 1px;
}
.nav-item:hover > a .arrow { transform: rotate(180deg); }
.nav-dropdown {
  position: absolute; top: calc(100% + 8px); left: 50%; transform: translateX(-50%);
  background: var(--white); border-radius: var(--radius-md);
  box-shadow: 0 12px 40px rgba(0,0,0,0.12); border: 1px solid var(--brand-border);
  min-width: 200px; padding: 8px 0;
  opacity: 0; visibility: hidden;
  transition: opacity 0.2s, visibility 0.2s, transform 0.2s;
  transform: translateX(-50%) translateY(-4px);
  z-index: 1001;
}
.nav-item:hover .nav-dropdown {
  opacity: 1; visibility: visible;
  transform: translateX(-50%) translateY(0);
}
.nav-dropdown a {
  display: block; padding: 10px 20px; font-size: 14px;
  color: var(--brand-black); transition: background 0.15s, color 0.15s;
  white-space: nowrap;
}
.nav-dropdown a:hover { background: var(--brand-light-gray); color: var(--brand-blue); }

/* Hamburger */
.nav-toggle {
  display: none; flex-direction: column; gap: 5px;
  cursor: pointer; padding: 6px; background: none; border: none;
  z-index: 1002;
}
.nav-toggle span {
  display: block; width: 22px; height: 2px;
  background: var(--brand-black); border-radius: 2px;
  transition: all 0.25s ease;
}
.nav-toggle.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle.open span:nth-child(2) { opacity: 0; }
.nav-toggle.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* Mobile menu overlay */
.nav-mobile {
  display: none; position: fixed; top: 72px; left: 0; right: 0;
  background: var(--white); border-top: 1px solid var(--brand-border);
  padding: 24px; z-index: 999;
  box-shadow: 0 8px 32px rgba(0,0,0,0.08);
  max-height: calc(100vh - 72px); overflow-y: auto;
}
.nav-mobile.open { display: block; }
.nav-mobile-item { border-bottom: 1px solid var(--brand-border); }
.nav-mobile-item:last-child { border-bottom: none; }
.nav-mobile-item > a {
  display: block; padding: 14px 0; font-size: 16px; font-weight: 500;
  color: var(--brand-black);
}
.nav-mobile-sub { padding: 0 0 12px 16px; }
.nav-mobile-sub a {
  display: block; padding: 8px 0; font-size: 14px; color: var(--brand-gray);
}
.nav-mobile-sub a:hover { color: var(--brand-blue); }
.nav-mobile .btn-primary { display: block; text-align: center; margin-top: 20px; }

/* ===== BUTTONS ===== */
.btn {
  display: inline-flex; align-items: center; justify-content: center;
  padding: 12px 28px; border-radius: var(--radius-pill);
  font-size: 14px; font-weight: 600; font-family: inherit;
  text-decoration: none; transition: all 0.25s ease;
  cursor: pointer; border: none; white-space: nowrap;
}
.btn-primary {
  background: var(--brand-blue); color: var(--white);
  box-shadow: 0 4px 16px rgba(128,188,226,0.35);
}
.btn-primary:hover {
  background: var(--brand-blue-dark); transform: translateY(-1px);
  box-shadow: 0 6px 24px rgba(128,188,226,0.45);
}
.btn-outline {
  background: transparent; color: var(--brand-black);
  border: 1.5px solid var(--brand-border);
}
.btn-outline:hover { border-color: var(--brand-blue); color: var(--brand-blue); }
.btn-white {
  background: var(--white); color: var(--brand-black);
}
.btn-white:hover { background: var(--brand-light-gray); }

/* ===== LINK ARROW ===== */
.link-arrow {
  display: inline-flex; align-items: center; gap: 8px;
  font-size: 15px; font-weight: 600; color: var(--brand-blue);
  transition: gap 0.2s;
}
.link-arrow:hover { gap: 12px; }
.link-arrow svg { width: 16px; height: 16px; flex-shrink: 0; }

/* ===== FOOTER CTA ===== */
.footer-cta {
  background: linear-gradient(135deg, var(--brand-black) 0%, #1a1a2e 100%);
  border-radius: var(--radius-lg); padding: 80px 60px; text-align: center;
  color: var(--white); position: relative; overflow: hidden;
}
.footer-cta::before {
  content: ''; position: absolute; top: -100px; right: -100px;
  width: 400px; height: 400px; border-radius: 50%;
  background: radial-gradient(circle, rgba(128,188,226,0.1) 0%, transparent 70%);
  pointer-events: none;
}
.footer-cta h2 {
  font-size: 36px; font-weight: 700; margin-bottom: 16px;
  position: relative; z-index: 1; letter-spacing: -0.6px; color: var(--white);
}
.footer-cta p {
  font-size: 17px; color: rgba(255,255,255,0.7); max-width: 560px;
  margin: 0 auto 32px; position: relative; z-index: 1; line-height: 1.7;
}
.footer-cta .btn-primary {
  position: relative; z-index: 1;
  box-shadow: 0 4px 24px rgba(128,188,226,0.3);
}

/* ===== FOOTER ===== */
.footer { padding: 80px 0 48px; border-top: 1px solid var(--brand-border); margin-top: 80px; }
.footer-grid { display: grid; grid-template-columns: 1.4fr 1fr 1fr 1fr; gap: 48px; }
.footer-brand .logo { font-size: 22px; font-weight: 600; margin-bottom: 20px; }
.footer-brand p {
  font-size: 14px; line-height: 1.75; color: var(--brand-gray);
  margin-bottom: 24px; max-width: 280px;
}
.footer-social { display: flex; gap: 12px; }
.footer-social a {
  width: 36px; height: 36px; border-radius: 50%;
  background: var(--brand-light-gray); display: flex;
  align-items: center; justify-content: center;
  transition: all 0.2s;
}
.footer-social a:hover { background: var(--brand-blue); }
.footer-social a:hover svg { stroke: var(--white); }
.footer-social a svg { width: 16px; height: 16px; stroke: var(--brand-gray); fill: none; stroke-width: 2; }
.footer-col h4 {
  font-size: 14px; font-weight: 600; color: var(--brand-black);
  margin-bottom: 20px; letter-spacing: 0.3px; text-transform: uppercase;
}
.footer-col ul li { margin-bottom: 12px; }
.footer-col ul li a { font-size: 14px; color: var(--brand-gray); transition: color 0.2s; }
.footer-col ul li a:hover { color: var(--brand-black); }
.footer-bottom {
  margin-top: 64px; padding-top: 24px;
  border-top: 1px solid var(--brand-border);
  display: flex; justify-content: space-between; align-items: center;
}
.footer-bottom p { font-size: 13px; color: var(--brand-gray); }
.footer-bottom-links { display: flex; gap: 24px; }
.footer-bottom-links a { font-size: 13px; color: var(--brand-gray); transition: color 0.2s; }
.footer-bottom-links a:hover { color: var(--brand-black); }

/* ===== FAQ ACCORDION ===== */
.faq-list { display: flex; flex-direction: column; gap: 12px; }
.faq-item {
  background: var(--white); border: 1px solid var(--brand-border);
  border-radius: var(--radius-md); overflow: hidden;
  transition: box-shadow 0.2s;
}
.faq-item.open { box-shadow: var(--shadow-md); }
.faq-question {
  display: flex; align-items: center; justify-content: space-between;
  padding: 20px 24px; cursor: pointer;
  background: none; border: none; width: 100%; text-align: left;
  font-family: inherit; font-size: 16px; font-weight: 600; color: var(--brand-black);
  gap: 16px;
}
.faq-text { flex: 1; text-align: left; }
.faq-icon { flex-shrink: 0; }
.faq-question:hover { color: var(--brand-blue); }
.faq-icon {
  width: 24px; height: 24px; flex-shrink: 0; border-radius: 50%;
  background: rgba(128,188,226,0.12); display: flex;
  align-items: center; justify-content: center; transition: transform 0.25s;
}
.faq-item.open .faq-icon { transform: rotate(45deg); background: var(--brand-blue); }
.faq-icon svg { width: 14px; height: 14px; stroke: var(--brand-blue); fill: none; stroke-width: 2; }
.faq-item.open .faq-icon svg { stroke: var(--white); }
.faq-answer { display: none; padding: 0 24px 20px; }
.faq-answer p, .faq-answer ul, .faq-answer ol {
  font-size: 15px; color: var(--brand-gray); line-height: 1.7;
  margin: 0;
}
.faq-item.open .faq-answer { display: block; }

/* ===== SCROLL ANIMATION ===== */
.fade-up {
  opacity: 0; transform: translateY(24px);
  transition: opacity 0.5s ease, transform 0.5s ease;
}
.fade-up.visible { opacity: 1; transform: translateY(0); }

/* ===== RESPONSIVE ===== */
@media (max-width: 1024px) {
  .section { padding: 64px 0; }
}

@media (max-width: 900px) {
  .section-header h2 { font-size: 28px; }
  .footer-cta { padding: 60px 32px; }
  .footer-cta h2 { font-size: 28px; }
  .footer-grid { grid-template-columns: 1fr 1fr; gap: 40px 32px; }
  .footer-bottom { flex-direction: column; gap: 12px; text-align: center; }
}

@media (max-width: 768px) {
  .nav-links { display: none; }
  .nav-toggle { display: flex; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 480px) {
  .container { padding: 0 16px; }
  .footer-grid { grid-template-columns: 1fr; }
  .footer-cta { padding: 48px 24px; }
  .footer-cta h2 { font-size: 24px; }
}

/* ============================================================
   MOBILE RESPONSIVE — 全局补丁
   ============================================================ */

/* 防止任何元素横向溢出 */
@media (max-width: 768px) {
  body { overflow-x: hidden; }

  /* 所有两列以上的 grid 强制单列 */
  [style*="grid-template-columns"],
  .grid-2, .grid-3, .grid-4,
  .two-col, .three-col,
  .product-hero-grid,
  .anatomy-grid,
  .specs-grid,
  .steps-grid,
  .why-grid,
  .comm-grid,
  .comm-grid.col2,
  .scenario-grid,
  .dual-grid,
  .overview-layout {
    grid-template-columns: 1fr !important;
  }

  /* app-feature 图文并排 → 单列，且重置 RTL */
  .app-feature-row .app-feature-inner {
    grid-template-columns: 1fr !important;
    gap: 32px !important;
    padding: 40px 16px !important;
    direction: ltr !important;
  }
  .app-feature-row.reverse .app-feature-inner {
    direction: ltr !important;
  }
  .app-feature-img { order: -1; }
  .app-feature-img img {
    max-width: 240px !important;
    max-height: 380px !important;
    margin: 0 auto;
  }
  .app-feature-text h3 { font-size: 22px !important; }

  /* 表格：可横向滚动，防止截断 */
  .specs-table-wrap,
  .table-wrap,
  [class*="table-wrap"] {
    overflow-x: auto !important;
    -webkit-overflow-scrolling: touch;
  }
  table {
    min-width: 400px;
  }
  .specs-table td {
    font-size: 13px !important;
    padding: 12px 14px !important;
    white-space: normal !important;
    word-break: break-word;
  }
  .specs-table td:first-child {
    min-width: 160px;
  }

  /* hero 文字 */
  .hero-text h1,
  .product-hero-content h1 { font-size: 28px !important; letter-spacing: -0.5px !important; }
  .hero-text p { font-size: 15px !important; }
  .hero-cta { flex-direction: column; align-items: stretch; }
  .hero-cta .btn { text-align: center; justify-content: center; }

  /* section 标题 */
  .section-header h2 { font-size: 24px !important; white-space: normal !important; }
  .section-header p { font-size: 15px !important; }
  .section { padding: 48px 0 !important; }

  /* container padding */
  .container { padding: 0 16px !important; }

  /* footer CTA */
  .footer-cta { padding: 48px 20px !important; }
  .footer-cta h2 { font-size: 22px !important; }
  .footer-grid { grid-template-columns: 1fr 1fr !important; gap: 32px 24px !important; }

  /* overview layout（patient-app 注释图）*/
  .overview-layout {
    grid-template-columns: 1fr !important;
    gap: 24px !important;
  }
  .overview-annotations.right { text-align: left !important; }
  .overview-phone img { height: 360px !important; margin: 0 auto; display: block; }
}

@media (max-width: 480px) {
  .footer-grid { grid-template-columns: 1fr !important; }
  .hero-text h1,
  .product-hero-content h1 { font-size: 24px !important; }
  .section-header h2 { font-size: 20px !important; }
  .app-feature-img img {
    max-width: 200px !important;
    max-height: 320px !important;
  }
  /* 表格字体再小一点 */
  .specs-table td { font-size: 12px !important; padding: 10px 12px !important; }
  .comm-card, .scenario-card { padding: 24px 16px !important; }
  .footer-cta { padding: 36px 16px !important; }
  .footer-cta h2 { font-size: 20px !important; }
  .btn { padding: 11px 20px !important; font-size: 13px !important; }
}

/* ============================================================
   动画安全兜底：手机端所有动画初始状态强制可见
   防止 IntersectionObserver 未触发时内容透明不可见
   ============================================================ */
@media (max-width: 768px) {
  .fade-up,
  .receive-card,
  .require-card,
  .process-step,
  .app-feature-inner {
    opacity: 1 !important;
    transform: none !important;
    transition: none !important;
  }
}