/* ============================================================
   ailife 功能介绍页（SEO 落地页）样式
   复用 style.css 变量与账号栏，补充长文排版
   ============================================================ */

.account-bar {
  position: fixed; top: calc(14px + env(safe-area-inset-top)); right: calc(16px + env(safe-area-inset-right));
  display: flex; align-items: center; gap: 10px; z-index: 10;
}
.account-bar a, .account-bar button {
  font: inherit; font-size: 14px; font-weight: 600; color: var(--text);
  text-decoration: none; cursor: pointer; border: none; background: none; padding: 0;
}
.account-login {
  padding: 7px 16px; border-radius: 999px; background: var(--surface-solid);
  box-shadow: var(--shadow); color: var(--text);
}
.account-avatar { width: 30px; height: 30px; border-radius: 50%; object-fit: cover; background: var(--separator); }
.account-name { max-width: 120px; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.account-logout { color: var(--text-secondary); font-size: 13px; }

.icon-score { background: linear-gradient(160deg, #ff9500 0%, #ff2d55 100%); }
.icon-days{ background: linear-gradient(160deg, #ff9500 0%, #ff375f 100%); }

.intro {
  max-width: 720px;
  margin: 0 auto;
  padding: calc(72px + env(safe-area-inset-top)) 22px 40px;
}

.intro-hero {
  text-align: center;
  margin-bottom: 48px;
}
.intro-icon {
  width: 96px; height: 96px;
  border-radius: var(--icon-radius);
  display: inline-flex; align-items: center; justify-content: center;
  font-size: 48px;
  box-shadow: var(--shadow);
  margin-bottom: 20px;
}
.intro-hero h1 {
  font-size: clamp(32px, 7vw, 48px);
  font-weight: 700;
  letter-spacing: -0.02em;
}
.intro-tagline {
  margin-top: 10px;
  font-size: clamp(15px, 3.5vw, 19px);
  color: var(--text-secondary);
}
.intro-cta {
  display: inline-block;
  margin-top: 26px;
  padding: 12px 30px;
  border-radius: 999px;
  background: linear-gradient(160deg, #007aff, #0056d6);
  color: #fff;
  font-size: 16px; font-weight: 600;
  text-decoration: none;
  box-shadow: var(--shadow);
  transition: transform .2s ease, box-shadow .2s ease;
}
.intro-cta:hover { transform: translateY(-2px); box-shadow: var(--shadow-hover); }
.intro-cta:active { transform: scale(.97); }

.intro-section { margin-bottom: 36px; }
.intro-section h2, .intro-faq h2 {
  font-size: 22px;
  font-weight: 700;
  margin-bottom: 14px;
  letter-spacing: -0.01em;
}
.intro-section p {
  font-size: 16px;
  line-height: 1.75;
  color: var(--text);
}
.intro-list {
  list-style: none;
  display: flex; flex-direction: column; gap: 12px;
}
.intro-list li {
  font-size: 16px; line-height: 1.65;
  padding: 14px 18px;
  background: var(--surface-solid);
  border-radius: 14px;
  box-shadow: var(--shadow);
}
.intro-list strong { color: var(--text); }

.intro-faq { margin-bottom: 36px; }
.intro-faq details {
  background: var(--surface-solid);
  border-radius: 14px;
  box-shadow: var(--shadow);
  padding: 14px 18px;
  margin-bottom: 12px;
}
.intro-faq summary {
  font-size: 16px; font-weight: 600; cursor: pointer;
  list-style: none;
}
.intro-faq summary::-webkit-details-marker { display: none; }
.intro-faq summary::after { content: " +"; color: var(--text-secondary); }
.intro-faq details[open] summary::after { content: " −"; }
.intro-faq details p {
  margin-top: 10px;
  font-size: 15px; line-height: 1.7;
  color: var(--text-secondary);
}

.intro-back { text-align: center; margin-top: 8px; }
.intro-back a { color: var(--text-secondary); text-decoration: none; font-size: 15px; }
.intro-back a:hover { color: var(--text); }

.intro-footer {
  text-align: center; padding: 20px 12px calc(20px + env(safe-area-inset-bottom));
  font-size: 12px; color: var(--text-secondary);
}
.intro-footer a { color: var(--text-secondary); text-decoration: none; }