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

html {
  font-size: 62.5%;
  overflow-x: hidden;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  font-size: 1.5rem;
  color: #333;
  background: linear-gradient(180deg, #f0f4ff 0%, #e8eef8 40%, #f5f7fb 100%);
  min-height: 100vh;
  -webkit-tap-highlight-color: transparent;
}

a { text-decoration: none; color: inherit; }
ul { list-style: none; }

header {
  width: 100%;
  padding: 4rem 2rem 1.6rem;
}

.header {
  max-width: 750px;
  margin: 0 auto;
  text-align: center;
  padding: 1rem 1rem 0;
}

.app-logo {
  width: 11rem;
  height: 11rem;
  border-radius: 24%;
  margin: 0 auto;
  display: block;
  object-fit: cover;
  border: 2px solid #edf4ff;
  box-shadow: 0 10px 28px rgba(60, 106, 220, .18);
  background: #fff;
}

.header h1 {
  font-size: 2.1rem;
  font-weight: 700;
  line-height: 1.45;
  margin-top: 1.2rem;
  color: #1d1d1f;
}

.header-notice {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: .8rem;
  max-width: 52rem;
  margin: 1.4rem auto 1.2rem;
  padding: .8rem 1.2rem;
  border: 1px solid rgba(82, 168, 255, .35);
  background: linear-gradient(180deg, #f6fbff, #eef6ff);
  border-radius: 999px;
  color: #2a5ea8;
  box-shadow: 0 10px 24px rgba(63, 126, 247, .12);
  overflow: hidden;
}

.notice-icon { font-size: 1.4rem; flex-shrink: 0; }

.notice-text {
  font-size: 1.3rem;
  white-space: nowrap;
  animation: marquee 14s linear infinite;
}

@keyframes marquee {
  0% { transform: translateX(100%); }
  100% { transform: translateX(-100%); }
}

.invite-line {
  font-size: 1.5rem;
  font-weight: bold;
  line-height: 2;
  margin-bottom: 1.2rem;
}

.invite-code {
  color: #fd5a2c;
  cursor: pointer;
}

#copyBtn {
  display: inline-block;
  padding: .2rem .9rem;
  margin-left: .4rem;
  border-radius: 999px;
  border: 1px solid rgba(101, 156, 255, .45);
  background: linear-gradient(135deg, #eef5ff, #e9f4ff);
  color: #2f63be;
  cursor: pointer;
  font-size: 1.4rem;
  transition: all .2s ease;
}

#copyBtn:active {
  background: linear-gradient(135deg, #3b82f6, #6758ff);
  color: #fff;
  box-shadow: 0 10px 24px rgba(59, 130, 246, .32);
}

.header-btn ul {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 1rem 0;
}

.header-btn li {
  width: 50%;
  padding: 0 .3rem;
  margin-bottom: 1rem;
}

.header-btn li a {
  display: block;
  width: calc(100% - 1rem);
  max-width: 25rem;
  margin: 0 auto;
  border: 1px solid #dfeaff;
  border-radius: 1.4rem;
  overflow: hidden;
  box-shadow: 0 10px 24px rgba(22, 44, 120, .12);
  transition: transform .15s ease, box-shadow .15s ease;
}

.header-btn li a:active {
  transform: scale(.98);
  box-shadow: 0 6px 16px rgba(22, 44, 120, .1);
}

.btn-top {
  display: flex;
  height: 5.2rem;
  padding: 0 1.2rem;
  justify-content: center;
  align-items: center;
  gap: .8rem;
  color: #fff;
  font-size: 1.65rem;
  font-weight: 700;
  text-shadow: 0 1px 2px rgba(0, 0, 0, .15);
}

.btn-top svg {
  width: 2.2rem;
  height: 2.2rem;
  fill: #fff;
  flex-shrink: 0;
}

.btn-bottom {
  display: block;
  height: 3.2rem;
  line-height: 3.2rem;
  font-size: 1.25rem;
  text-align: center;
  color: #5870b8;
  background: linear-gradient(180deg, #f7faff, #edf3ff);
  border-top: 1px solid #dbe7ff;
  font-weight: 600;
}

.header-btn li:nth-child(1) .btn-top { background: linear-gradient(135deg, #2bb7ff, #4d6dff); }
.header-btn li:nth-child(2) .btn-top { background: linear-gradient(135deg, #3b82f6, #6758ff); }
.header-btn li:nth-child(3) .btn-top { background: linear-gradient(135deg, #00c6ff, #0072ff); }
.header-btn li:nth-child(4) .btn-top { background: linear-gradient(135deg, #4facfe, #5f72ff); }

main {
  max-width: 750px;
  margin: 0 auto;
  padding: .4rem 2rem 3rem;
}

.seo-content {
  margin-top: 1.6rem;
}

.seo-block {
  background: #fff;
  border-radius: 1.2rem;
  padding: 1.6rem 1.8rem;
  margin-bottom: 1rem;
  box-shadow: 0 8px 20px rgba(35, 56, 160, .08);
  border: 1px solid #eef2ff;
}

.seo-block h2 {
  font-size: 1.65rem;
  font-weight: 700;
  color: #1e3a8a;
  margin-bottom: .8rem;
  line-height: 1.5;
}

.seo-block p {
  font-size: 1.35rem;
  line-height: 1.85;
  color: #4b5563;
}

.seo-block strong {
  color: #ea580c;
  font-weight: 700;
}

.faq-section {
  margin-top: 1.6rem;
  background: #fff;
  border-radius: 1.2rem;
  padding: 1.8rem 1.8rem 1.2rem;
  box-shadow: 0 8px 20px rgba(35, 56, 160, .08);
  border: 1px solid #eef2ff;
}

.faq-section > h2 {
  font-size: 1.75rem;
  font-weight: 700;
  color: #1e3a8a;
  margin-bottom: 1.2rem;
  text-align: center;
}

.faq-item {
  padding: 1.2rem 0;
  border-bottom: 1px solid #f0f4ff;
}

.faq-item:last-child {
  border-bottom: none;
  padding-bottom: .4rem;
}

.faq-item h3 {
  font-size: 1.45rem;
  font-weight: 700;
  color: #1d4ed8;
  margin-bottom: .6rem;
  line-height: 1.5;
}

.faq-item p {
  font-size: 1.32rem;
  line-height: 1.85;
  color: #4b5563;
}

footer {
  margin-top: 2.4rem;
  color: #9d9292;
  text-align: center;
  padding-top: 1rem;
  font-size: 1.2rem;
  line-height: 1.7;
}

.toast {
  display: none;
  position: fixed;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  background: rgba(0, 0, 0, .78);
  color: #fff;
  padding: 1.2rem 2.4rem;
  border-radius: 1rem;
  font-size: 1.4rem;
  z-index: 20000;
}

.toast.show { display: block; }