:root {
  --text-5: #1d2129;
  --text-4: #4e5969;
  --text-3: #86909c;
  --text-2: #c9cdd4;
  --primary-6: #242a2c;
  --brand: #165dff;
  --brand-red: #e62f43;
  --page-bg: #f5f5f5;
  --fill-1: #f7f8fa;
  --fill-2: #f2f3f5;
  --white: #ffffff;
  --shadow: 0 8px 32px rgba(29, 33, 41, 0.08);
  --radius-lg: 16px;
  --radius-pill: 100px;
  --max-w: 1080px;
}

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

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Helvetica Neue",
    "Microsoft YaHei", sans-serif;
  background: var(--page-bg);
  color: var(--text-5);
  line-height: 1.6;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
}

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

a:hover {
  text-decoration: underline;
}

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

.container {
  width: min(100% - 32px, var(--max-w));
  margin-inline: auto;
}

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--fill-2);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 0;
  gap: 16px;
}

.brand-mark {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--text-5);
  font-weight: 600;
  font-size: 18px;
  text-decoration: none;
}

.brand-mark:hover {
  text-decoration: none;
}

.brand-mark img,
.brand-mark .brand-logo {
  height: 32px;
  width: auto;
  display: block;
}

.nav {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 20px;
  font-size: 14px;
}

.nav a {
  color: var(--text-4);
  text-decoration: none;
}

.nav a:hover {
  color: var(--text-5);
}

/* 汉堡按钮：桌面端隐藏 */
.nav-toggle {
  display: none;
  width: 44px;
  height: 44px;
  padding: 10px;
  margin-right: -6px;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 5px;
  background: none;
  border: 0;
  cursor: pointer;
}

.nav-toggle span {
  display: block;
  width: 20px;
  height: 2px;
  background: var(--text-5);
  border-radius: 2px;
  transition: transform 0.2s ease, opacity 0.2s ease;
}

.nav-toggle[aria-expanded="true"] span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.nav-toggle[aria-expanded="true"] span:nth-child(2) {
  opacity: 0;
}

.nav-toggle[aria-expanded="true"] span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* Hero */
.hero {
  position: relative;
  overflow: hidden;
  padding: 48px 0 64px;
  background: linear-gradient(
    165deg,
    #ededed 0%,
    #f1f1f1 14%,
    #f5f5f5 39%
  );
}

.hero::before {
  content: "";
  position: absolute;
  width: 480px;
  height: 480px;
  right: -120px;
  top: -80px;
  background: radial-gradient(
    circle,
    rgba(22, 93, 255, 0.08) 0%,
    transparent 70%
  );
  pointer-events: none;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 40px;
  align-items: center;
}

@media (min-width: 880px) {
  .hero-grid {
    grid-template-columns: 1.05fr 0.95fr;
    gap: 48px;
  }
  .hero {
    padding: 72px 0 88px;
  }
}

.hero-logo {
  width: min(100%, 280px);
  margin-bottom: 20px;
}

.hero-tagline {
  font-size: clamp(22px, 4vw, 28px);
  font-weight: 600;
  color: var(--text-5);
  margin-bottom: 12px;
  letter-spacing: 0.02em;
}

.hero-desc {
  font-size: 16px;
  color: var(--text-4);
  max-width: 32em;
  margin-bottom: 28px;
}

/* 手机端使用精简文案 */
.hero-desc-short {
  display: none;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 24px;
  border-radius: var(--radius-pill);
  font-size: 15px;
  font-weight: 500;
  border: none;
  cursor: pointer;
  text-decoration: none;
  transition: transform 0.15s ease, box-shadow 0.15s ease;
}

.btn:hover {
  text-decoration: none;
  transform: translateY(-1px);
}

.btn-primary {
  background: var(--primary-6);
  color: var(--white);
  box-shadow: 0 4px 4px rgba(29, 33, 41, 0.12);
}

.btn-secondary {
  background: var(--white);
  color: var(--text-5);
  border: 1px solid var(--fill-2);
}

.hero-visual {
  background: var(--white);
  border-radius: 20px;
  padding: 20px;
  box-shadow: var(--shadow);
}

.hero-visual img {
  border-radius: 12px;
  width: 100%;
}

/* Sections */
section {
  padding: 56px 0;
}

.section-title {
  font-size: clamp(22px, 3vw, 26px);
  font-weight: 600;
  text-align: center;
  margin-bottom: 8px;
}

.section-sub {
  text-align: center;
  color: var(--text-3);
  font-size: 15px;
  margin-bottom: 36px;
  max-width: 36em;
  margin-inline: auto;
}

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

.feature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 20px;
}

.feature-card {
  background: var(--fill-1);
  border-radius: var(--radius-lg);
  padding: 24px 20px;
  border: 1px solid transparent;
  transition: border-color 0.2s, box-shadow 0.2s;
}

.feature-card:hover {
  border-color: var(--fill-2);
  box-shadow: 0 4px 16px rgba(29, 33, 41, 0.06);
}

.feature-card h3 {
  font-size: 17px;
  font-weight: 600;
  margin-bottom: 8px;
}

.feature-card p {
  font-size: 14px;
  color: var(--text-4);
  line-height: 1.55;
}

.platforms-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(88px, 1fr));
  gap: 16px;
  max-width: 720px;
  margin-inline: auto;
}

.platform-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  padding: 16px 8px;
  background: var(--white);
  border-radius: 12px;
  box-shadow: 0 1px 4px rgba(0, 0, 0, 0.04);
}

.platform-item img {
  width: 36px;
  height: 36px;
  object-fit: contain;
}

.platform-item span {
  font-size: 12px;
  color: var(--text-4);
  text-align: center;
}

.steps {
  display: grid;
  gap: 20px;
  max-width: 640px;
  margin-inline: auto;
}

.step {
  display: flex;
  gap: 16px;
  align-items: flex-start;
  background: var(--white);
  padding: 20px 22px;
  border-radius: var(--radius-lg);
  box-shadow: 0 1px 4px rgba(0, 0, 0, 0.04);
}

.step-num {
  flex-shrink: 0;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: var(--primary-6);
  color: var(--white);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 15px;
  font-weight: 600;
}

.step h3 {
  font-size: 16px;
  margin-bottom: 4px;
}

.step p {
  font-size: 14px;
  color: var(--text-4);
}

.safety {
  background: var(--fill-1);
}

.safety-card {
  background: var(--white);
  border-radius: var(--radius-lg);
  padding: 28px 24px;
  max-width: 720px;
  margin-inline: auto;
  border-left: 4px solid var(--brand);
}

.safety-card p {
  color: var(--text-4);
  font-size: 15px;
  margin-bottom: 12px;
}

.safety-card p:last-child {
  margin-bottom: 0;
}

.contact-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 20px;
}

.contact-card {
  background: var(--white);
  border-radius: var(--radius-lg);
  padding: 24px;
  box-shadow: 0 1px 4px rgba(0, 0, 0, 0.04);
}

.contact-card h3 {
  font-size: 14px;
  color: var(--text-3);
  font-weight: 500;
  margin-bottom: 6px;
}

.contact-card p,
.contact-card a {
  font-size: 16px;
  color: var(--text-5);
}

.disclosure {
  margin-top: 24px;
  padding: 16px 18px;
  background: #f0f7ff;
  border: 1px solid #b5d6ff;
  border-radius: 12px;
  font-size: 13px;
  color: #2d4c73;
  max-width: 720px;
  margin-inline: auto;
}

.site-footer {
  background: var(--primary-6);
  color: rgba(255, 255, 255, 0.75);
  padding: 32px 0 calc(32px + env(safe-area-inset-bottom));
  font-size: 13px;
  text-align: center;
}

.site-footer a {
  color: rgba(255, 255, 255, 0.9);
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 8px 20px;
  margin-bottom: 12px;
}

/* ===== 锚点定位不被吸顶 header 遮挡 ===== */
section[id] {
  scroll-margin-top: 76px;
}

/* ===== 下载按钮 ===== */
.btn-download {
  gap: 10px;
  min-height: 48px;
  padding: 12px 26px;
  background: var(--primary-6);
  color: var(--white);
  box-shadow: 0 4px 12px rgba(29, 33, 41, 0.18);
}

.btn-download:hover {
  box-shadow: 0 6px 16px rgba(29, 33, 41, 0.22);
}

.btn-download svg {
  width: 20px;
  height: 20px;
  flex-shrink: 0;
}

.btn-download .icon-android {
  fill: #3ddc84;
}

.btn-download .icon-apple {
  fill: #ffffff;
}

.btn-download.is-disabled {
  opacity: 0.55;
  cursor: not-allowed;
}

/* ===== 导航高亮「下载 App」 ===== */
.nav-cta {
  color: var(--brand) !important;
  font-weight: 600;
}

.nav-cta:hover {
  color: var(--brand) !important;
}

/* ===== 下载区块 ===== */
.download {
  background: var(--page-bg);
}

.download-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 20px;
  max-width: 780px;
  margin-inline: auto;
}

@media (min-width: 720px) {
  .download-grid {
    grid-template-columns: 1fr 1fr;
  }
}

.download-card {
  background: var(--white);
  border-radius: var(--radius-lg);
  padding: 28px 24px;
  box-shadow: 0 1px 4px rgba(0, 0, 0, 0.04);
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  gap: 12px;
  transition: transform 0.15s ease, box-shadow 0.15s ease;
}

.download-card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow);
}

.download-card-icon {
  width: 64px;
  height: 64px;
  border-radius: 18px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.download-card-icon svg {
  width: 32px;
  height: 32px;
}

.download-card-icon.android {
  background: rgba(61, 220, 132, 0.15);
}

.download-card-icon.android svg {
  fill: #16a34a;
}

.download-card-icon.ios {
  background: rgba(36, 42, 44, 0.08);
}

.download-card-icon.ios svg {
  fill: var(--text-5);
}

.download-card h3 {
  font-size: 18px;
  font-weight: 600;
}

.download-card p {
  font-size: 14px;
  color: var(--text-4);
  line-height: 1.55;
}

.download-card .btn {
  margin-top: auto;
  width: 100%;
  max-width: 260px;
}

.download-card .download-note {
  width: 100%;
  margin: 2px 0 0;
  display: flex;
  align-items: flex-start;
  gap: 8px;
  background: #fff8ec;
  border: 1px solid #ffe1ad;
  border-radius: 12px;
  padding: 10px 12px;
  font-size: 12.5px;
  color: #7a4d0f;
  line-height: 1.55;
  text-align: left;
}

.download-card .download-note svg {
  width: 16px;
  height: 16px;
  flex-shrink: 0;
  margin-top: 3px;
  fill: #d48806;
}

/* ===== 弹窗 ===== */
.modal {
  position: fixed;
  inset: 0;
  z-index: 200;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
}

.modal[hidden] {
  display: none;
}

.modal-mask {
  position: absolute;
  inset: 0;
  background: rgba(15, 20, 25, 0.45);
}

.modal-dialog {
  position: relative;
  background: var(--white);
  border-radius: 18px;
  width: min(100%, 440px);
  max-height: calc(100vh - 48px);
  overflow: auto;
  padding: 24px;
  box-shadow: 0 12px 48px rgba(0, 0, 0, 0.18);
  animation: modal-in 0.18s ease-out;
}

@keyframes modal-in {
  from {
    opacity: 0;
    transform: translateY(14px);
  }
  to {
    opacity: 1;
    transform: none;
  }
}

.modal-dialog h3 {
  font-size: 18px;
  font-weight: 600;
  margin-bottom: 12px;
}

.modal-body p {
  font-size: 14px;
  color: var(--text-4);
  margin-bottom: 10px;
  line-height: 1.65;
}

.modal-highlight {
  background: #f0f7ff;
  border: 1px solid #b5d6ff;
  border-radius: 10px;
  padding: 12px 14px;
  color: #2d4c73 !important;
}

.modal-tip {
  font-size: 12.5px;
  color: var(--text-3) !important;
  margin-bottom: 0;
}

.modal-actions {
  display: flex;
  gap: 12px;
  margin-top: 18px;
}

.modal-actions .btn {
  flex: 1;
  min-height: 46px;
}

/* ===== Toast ===== */
.toast {
  position: fixed;
  left: 50%;
  bottom: calc(28px + env(safe-area-inset-bottom));
  transform: translate(-50%, 12px);
  z-index: 300;
  max-width: min(90vw, 420px);
  padding: 10px 20px;
  border-radius: var(--radius-pill);
  background: rgba(29, 33, 41, 0.92);
  color: #fff;
  font-size: 14px;
  text-align: center;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.2s ease, transform 0.2s ease, visibility 0.2s;
  pointer-events: none;
}

.toast.show {
  opacity: 1;
  visibility: visible;
  transform: translate(-50%, 0);
}

/* ===== 手机端适配 ===== */
@media (max-width: 640px) {
  body {
    font-size: 15px;
  }

  /* 头部折叠：品牌 + 汉堡按钮，导航下拉展开 */
  .header-inner {
    position: relative;
    flex-wrap: nowrap;
    padding: 8px 0;
  }

  .nav-toggle {
    display: flex;
  }

  .nav {
    display: none;
    position: absolute;
    top: 100%;
    left: -16px;
    right: -16px;
    flex-direction: column;
    gap: 0;
    background: var(--white);
    border-bottom: 1px solid var(--fill-2);
    box-shadow: 0 12px 24px rgba(29, 33, 41, 0.08);
    padding: 6px 16px 12px;
    z-index: 99;
  }

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

  .nav a {
    padding: 13px 4px;
    font-size: 15px;
    border-bottom: 1px solid var(--fill-1);
  }

  .nav a:last-child {
    border-bottom: none;
  }

  section {
    padding: 34px 0;
  }

  .hero {
    padding: 18px 0 30px;
  }

  .hero-grid {
    gap: 16px;
  }

  /* 手机上隐藏大 Logo（头部已有品牌标识） */
  .hero-logo {
    display: none;
  }

  .hero-tagline {
    font-size: 21px;
    margin-bottom: 8px;
  }

  .hero-desc {
    font-size: 15px;
    margin-bottom: 14px;
  }

  .hero-desc-full {
    display: none;
  }

  .hero-desc-short {
    display: inline;
  }

  .hero-visual {
    padding: 10px;
    border-radius: 14px;
  }

  .section-sub {
    margin-bottom: 22px;
  }

  .feature-grid,
  .download-grid,
  .download-card,
  .steps {
    gap: 14px;
  }

  .feature-card {
    padding: 18px 16px;
  }

  .download-card {
    padding: 20px 16px;
  }

  .download-card .download-note {
    padding: 10px 12px;
  }

  .step {
    padding: 14px 16px;
  }

  .safety-card {
    padding: 18px 16px;
  }

  /* 弹窗变为底部弹出，更贴近手机习惯 */
  .modal {
    align-items: flex-end;
    padding: 12px;
    padding-bottom: calc(12px + env(safe-area-inset-bottom));
  }

  .modal-dialog {
    border-radius: 18px;
    padding: 22px 20px;
  }

  .modal-actions {
    flex-direction: column-reverse;
  }

  .modal-actions .btn {
    width: 100%;
  }

  .site-footer {
    padding: 28px 0 calc(28px + env(safe-area-inset-bottom));
  }
}

/* 减少动态效果偏好 */
@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  .modal-dialog {
    animation: none;
  }
  .btn,
  .download-card,
  .toast {
    transition: none;
  }
}