/* ============================================================
   HobbyAI · hobbyaiapp.com.cn 单页官网样式
   主题：深色青蓝科技风（AI互动故事）
   ============================================================ */

:root {
  --bg: #0f1115;
  --bg-2: #161920;
  --card: rgba(255, 255, 255, 0.045);
  --card-2: rgba(255, 255, 255, 0.07);
  --line: rgba(255, 255, 255, 0.09);
  --text: #f0f4f8;
  --muted: #8a93a6;
  --primary: #2dd4bf;
  --primary-2: #0ea5e9;
  --grad: linear-gradient(135deg, #2dd4bf 0%, #0ea5e9 100%);
  --radius: 18px;
  --shadow: 0 20px 60px rgba(45, 212, 191, 0.18);
  --ease: cubic-bezier(.22, .61, .36, 1);
}

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

html { scroll-behavior: smooth; scroll-padding-top: 80px; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
button { font-family: inherit; cursor: pointer; border: none; background: none; color: inherit; }

.container { width: min(1200px, 92%); margin: 0 auto; }

.grad-text {
  background: var(--grad);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  color: transparent;
}

/* ============ 按钮 ============ */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  border-radius: 999px;
  font-weight: 600;
  transition: transform .25s var(--ease), box-shadow .25s var(--ease), background .25s;
  white-space: nowrap;
}
.btn:hover { transform: translateY(-2px); }
.btn:active { transform: translateY(0); }

.btn-primary {
  background: var(--grad);
  color: #06202a;
  box-shadow: 0 10px 30px rgba(45, 212, 191, .35);
}
.btn-primary:hover { box-shadow: 0 14px 40px rgba(14, 165, 233, .45); }

.btn-ghost {
  background: rgba(255, 255, 255, .06);
  border: 1px solid var(--line);
  color: var(--text);
}
.btn-ghost:hover { background: rgba(255, 255, 255, .12); border-color: var(--primary); }

.btn-sm { padding: 9px 20px; font-size: 14px; }
.btn-lg { padding: 15px 30px; font-size: 16px; }
.btn-xl { padding: 18px 44px; font-size: 17px; }
.ico { flex: 0 0 auto; }

/* ============ 导航 ============ */
.nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  transition: background .3s, box-shadow .3s, backdrop-filter .3s;
}
.nav.scrolled {
  background: rgba(15, 17, 21, .82);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  box-shadow: 0 4px 30px rgba(0, 0, 0, .4);
}
.nav-inner {
  width: min(1200px, 92%);
  margin: 0 auto;
  height: 68px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}
.brand { display: flex; align-items: center; gap: 10px; font-weight: 800; font-size: 19px; }
.brand-logo {
  width: 38px; height: 38px;
  border-radius: 10px;
  object-fit: cover;
  box-shadow: 0 4px 14px rgba(45, 212, 191, .4);
}
.nav-links { display: flex; gap: 28px; }
.nav-link { font-size: 15px; color: var(--muted); transition: color .2s; position: relative; }
.nav-link:hover { color: var(--text); }
.nav-link::after {
  content: "";
  position: absolute;
  left: 0; bottom: -6px;
  width: 0; height: 2px;
  background: var(--grad);
  border-radius: 2px;
  transition: width .25s var(--ease);
}
.nav-link:hover::after { width: 100%; }

.nav-toggle { display: none; flex-direction: column; gap: 5px; padding: 8px; }
.nav-toggle span { width: 22px; height: 2px; background: var(--text); border-radius: 2px; transition: .3s; }

/* ============ Hero ============ */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  padding-top: 68px;
  overflow: hidden;
}
.hero-bg {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse 60% 50% at 82% 18%, rgba(45, 212, 191, .22), transparent 60%),
    radial-gradient(ellipse 50% 50% at 12% 82%, rgba(14, 165, 233, .18), transparent 60%),
    var(--bg);
  z-index: -1;
}
.hero-inner {
  display: grid;
  grid-template-columns: 1.1fr .9fr;
  gap: 40px;
  align-items: center;
  padding: 60px 0;
}
.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 7px 16px;
  border-radius: 999px;
  background: rgba(45, 212, 191, .12);
  border: 1px solid rgba(45, 212, 191, .3);
  color: #5eead4;
  font-size: 13px;
  margin-bottom: 22px;
}
.hero-badge .dot {
  width: 8px; height: 8px;
  border-radius: 50%;
  background: var(--primary);
  animation: pulse 1.8s infinite;
}
@keyframes pulse {
  0% { box-shadow: 0 0 0 0 rgba(45, 212, 191, .6); }
  70% { box-shadow: 0 0 0 10px rgba(45, 212, 191, 0); }
  100% { box-shadow: 0 0 0 0 rgba(45, 212, 191, 0); }
}
.hero-title {
  font-size: clamp(34px, 5.5vw, 58px);
  line-height: 1.15;
  font-weight: 800;
  margin-bottom: 22px;
  letter-spacing: -1px;
}
.hero-desc { font-size: 17px; color: var(--muted); max-width: 540px; margin-bottom: 22px; }
.hero-tags { display: flex; flex-wrap: wrap; gap: 10px; margin-bottom: 30px; }
.hero-tags span {
  padding: 6px 14px;
  border-radius: 999px;
  background: var(--card);
  border: 1px solid var(--line);
  font-size: 13px;
  color: var(--muted);
}
.hero-btns { display: flex; flex-wrap: wrap; gap: 14px; margin-bottom: 22px; }
.hero-meta { font-size: 13px; color: var(--muted); opacity: .8; }

/* 手机模型 */
.hero-phone { position: relative; display: flex; justify-content: center; }
.phone {
  position: relative;
  width: 300px;
  height: 600px;
  background: #000;
  border-radius: 42px;
  padding: 10px;
  box-shadow: 0 30px 80px rgba(45, 212, 191, .28), inset 0 0 0 2px rgba(255, 255, 255, .08);
}
.phone-notch {
  position: absolute;
  top: 16px; left: 50%;
  transform: translateX(-50%);
  width: 100px; height: 24px;
  background: #000;
  border-radius: 14px;
  z-index: 3;
}
.phone-screen {
  width: 100%; height: 100%;
  border-radius: 32px;
  overflow: hidden;
  position: relative;
  background: #000;
}
.phone-img { width: 100%; height: 100%; object-fit: cover; object-position: top center; }
.phone-glow {
  position: absolute;
  inset: -40px;
  background: radial-gradient(circle, rgba(45, 212, 191, .28), transparent 70%);
  z-index: -1;
  filter: blur(30px);
}

/* ============ 数据统计 ============ */
.stats {
  padding: 50px 0;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  background: var(--bg-2);
}
.stats-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; text-align: center; }
.stat-num {
  font-size: clamp(30px, 4vw, 46px);
  font-weight: 800;
  background: var(--grad);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}
.stat-label { color: var(--muted); font-size: 14px; margin-top: 6px; }

/* ============ 通用 Section ============ */
.section { padding: 100px 0; }
.section-head { text-align: center; max-width: 680px; margin: 0 auto 56px; }
.section-eyebrow { font-size: 13px; letter-spacing: 3px; color: var(--primary); font-weight: 700; margin-bottom: 12px; }
.section-title { font-size: clamp(28px, 4vw, 42px); font-weight: 800; margin-bottom: 16px; }
.section-desc { color: var(--muted); font-size: 16px; }

/* ============ 核心能力 ============ */
.features-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 22px; }
.feature-card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 30px 24px;
  transition: transform .3s var(--ease), border-color .3s, background .3s;
}
.feature-card:hover {
  transform: translateY(-6px);
  border-color: rgba(45, 212, 191, .4);
  background: var(--card-2);
}
.feature-ico {
  width: 54px; height: 54px;
  border-radius: 14px;
  background: var(--grad);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #06202a;
  margin-bottom: 18px;
  box-shadow: 0 8px 22px rgba(45, 212, 191, .3);
}
.feature-card h3 { font-size: 18px; margin-bottom: 10px; }
.feature-card p { color: var(--muted); font-size: 14px; }

/* ============ 角色实拍 ============ */
.preview { background: var(--bg-2); }
.preview-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 22px; }
.preview-card {
  border-radius: var(--radius);
  overflow: hidden;
  border: 1px solid var(--line);
  background: var(--card);
  transition: transform .3s var(--ease), box-shadow .3s;
}
.preview-card:hover { transform: translateY(-6px); box-shadow: var(--shadow); }
.preview-card img {
  width: 100%;
  height: 420px;
  object-fit: cover;
  object-position: top center;
}
.preview-card figcaption { padding: 14px 18px; font-size: 14px; color: var(--muted); text-align: center; }

/* ============ 两种玩法 ============ */
.modes-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 24px; max-width: 960px; margin: 0 auto; }
.mode-card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 36px 32px;
  transition: transform .3s var(--ease), border-color .3s;
}
.mode-card:hover { transform: translateY(-6px); border-color: rgba(45, 212, 191, .4); }
.mode-icon { font-size: 36px; margin-bottom: 16px; }
.mode-card h3 { font-size: 22px; margin-bottom: 12px; }
.mode-card p { color: var(--muted); margin-bottom: 16px; }
.mode-list { list-style: none; }
.mode-list li {
  padding: 8px 0 8px 26px;
  position: relative;
  color: var(--text);
  font-size: 14.5px;
}
.mode-list li::before {
  content: "✓";
  position: absolute;
  left: 0;
  color: var(--primary);
  font-weight: 700;
}

/* ============ 认识 Hobby ============ */
.about { background: var(--bg-2); }
.about-inner {
  display: grid;
  grid-template-columns: .8fr 1.2fr;
  gap: 50px;
  align-items: center;
}
.about-poster {
  border-radius: 24px;
  overflow: hidden;
  box-shadow: var(--shadow);
  border: 1px solid var(--line);
  background: #000;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 40px;
}
.about-poster img { width: 160px; height: 160px; object-fit: cover; border-radius: 24px; }
.about-text h2 { font-size: clamp(24px, 3.5vw, 36px); font-weight: 800; margin-bottom: 16px; }
.about-text p { color: var(--muted); margin-bottom: 20px; }
.about-tags { display: flex; gap: 12px; margin-bottom: 20px; flex-wrap: wrap; }
.about-tag {
  padding: 8px 18px;
  border-radius: 999px;
  background: var(--card);
  border: 1px solid var(--line);
  font-size: 14px;
}
.about-note { font-size: 13px; opacity: .7; }

/* ============ FAQ ============ */
.faq-list { max-width: 800px; margin: 0 auto; display: flex; flex-direction: column; gap: 14px; }
.faq-item {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 14px;
  overflow: hidden;
}
.faq-q {
  width: 100%;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 20px 24px;
  font-size: 16px;
  font-weight: 600;
  text-align: left;
}
.faq-arrow {
  font-style: normal;
  font-size: 24px;
  color: var(--primary);
  transition: transform .3s var(--ease);
  flex: 0 0 auto;
}
.faq-item.open .faq-arrow { transform: rotate(45deg); }
.faq-a {
  max-height: 0;
  overflow: hidden;
  transition: max-height .35s var(--ease), padding .35s;
  padding: 0 24px;
  color: var(--muted);
  font-size: 14.5px;
}
.faq-item.open .faq-a { max-height: 260px; padding: 0 24px 20px; }

/* ============ 下载 CTA ============ */
.download-card {
  position: relative;
  text-align: center;
  padding: 70px 30px;
  border-radius: 28px;
  background:
    radial-gradient(ellipse 60% 80% at 50% 0%, rgba(45, 212, 191, .22), transparent 70%),
    var(--card);
  border: 1px solid var(--line);
  overflow: hidden;
}
.download-card h2 { font-size: clamp(26px, 4vw, 38px); margin-bottom: 16px; }
.download-card p { color: var(--muted); margin-bottom: 30px; }
.download-meta { margin-top: 18px; font-size: 13px; color: var(--muted); }

/* ============ 页脚 ============ */
.footer { border-top: 1px solid var(--line); padding: 40px 0; background: var(--bg-2); }
.footer-top {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 20px;
  margin-bottom: 24px;
}
.footer-brand { display: flex; align-items: center; gap: 10px; color: var(--muted); font-size: 14px; }
.footer-brand .brand-logo { width: 32px; height: 32px; }
.footer-links { display: flex; gap: 22px; flex-wrap: wrap; }
.footer-links a { color: var(--muted); font-size: 14px; transition: color .2s; }
.footer-links a:hover { color: var(--primary); }
.footer-bottom {
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 10px;
  padding-top: 20px;
  border-top: 1px solid var(--line);
  font-size: 12.5px;
  color: var(--muted);
}

/* ============ 回到顶部 ============ */
.back-top {
  position: fixed;
  right: 24px;
  bottom: 24px;
  width: 46px;
  height: 46px;
  border-radius: 50%;
  background: var(--grad);
  color: #06202a;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 10px 26px rgba(45, 212, 191, .4);
  opacity: 0;
  visibility: hidden;
  transform: translateY(10px);
  transition: .3s;
  z-index: 90;
}
.back-top.show { opacity: 1; visibility: visible; transform: none; }

/* ============ 滚动显现 ============ */
.reveal { opacity: 0; transform: translateY(28px); transition: opacity .7s var(--ease), transform .7s var(--ease); }
.reveal.in { opacity: 1; transform: none; }

/* ============ 响应式 ============ */
@media (max-width: 1080px) {
  .preview-grid { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 960px) {
  .hero-inner { grid-template-columns: 1fr; text-align: center; padding: 40px 0; }
  .hero-text { display: flex; flex-direction: column; align-items: center; }
  .hero-phone { margin-top: 30px; }
  .features-grid { grid-template-columns: repeat(2, 1fr); }
  .modes-grid { grid-template-columns: 1fr; }
  .about-inner { grid-template-columns: 1fr; gap: 30px; }
}
@media (max-width: 720px) {
  .nav-links {
    position: fixed;
    top: 68px; left: 0; right: 0;
    flex-direction: column;
    background: rgba(15, 17, 21, .97);
    backdrop-filter: blur(14px);
    padding: 20px 6%;
    gap: 18px;
    border-bottom: 1px solid var(--line);
    transform: translateY(-130%);
    transition: transform .3s var(--ease);
  }
  .nav-links.open { transform: none; }
  .nav-toggle { display: flex; }
  .nav .btn-sm { display: none; }

  .stats-grid { grid-template-columns: repeat(2, 1fr); gap: 30px; }
  .features-grid { grid-template-columns: 1fr; }
  .preview-grid { grid-template-columns: 1fr; }
  .preview-card img { height: 460px; }
  .section { padding: 70px 0; }
  .phone { width: 260px; height: 520px; }
  .footer-bottom { justify-content: center; text-align: center; }
}