/* 幻世AI 官网 - QQ 品牌设计系统 */
:root {
  --qq: #12b7f5;
  --qq-deep: #0a5bd3;
  --navy: #071a33;
  --navy-2: #0a2547;
  --ink: #17233b;
  --ink-2: #5a6b85;
  --line: #e7edf6;
  --grad: linear-gradient(120deg, #12b7f5, #0a5bd3);
  --radius: 18px;
}
* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { font-family: 'PingFang SC', 'Microsoft YaHei', 'Helvetica Neue', Arial, sans-serif; color: var(--ink); background: #fff; -webkit-font-smoothing: antialiased; }
a { text-decoration: none; color: inherit; }
.wrap { max-width: 1180px; margin: 0 auto; padding: 0 24px; }
.grad { background: var(--grad); -webkit-background-clip: text; background-clip: text; color: transparent; }

/* ===== 导航 ===== */
.nav { position: fixed; top: 0; left: 0; right: 0; z-index: 100; padding: 16px 0; transition: all 0.3s; background: transparent; }
.nav.scrolled { background: rgba(7, 26, 51, 0.92); backdrop-filter: blur(14px); padding: 10px 0; box-shadow: 0 4px 24px rgba(2, 10, 30, 0.35); }
.nav-inner { display: flex; align-items: center; justify-content: space-between; }
.logo { display: flex; align-items: center; gap: 10px; font-size: 21px; font-weight: 800; color: #fff; }
.logo-mark { width: 38px; height: 38px; border-radius: 11px; background: var(--grad); display: flex; align-items: center; justify-content: center; box-shadow: 0 6px 18px rgba(18, 183, 245, 0.5); }
.nav-links { display: flex; gap: 30px; }
.nav-links a { color: rgba(255, 255, 255, 0.78); font-size: 14px; transition: color 0.2s; }
.nav-links a:hover { color: #fff; }
.nav-cta { display: flex; gap: 12px; }
.btn-primary { background: var(--grad); color: #fff; padding: 11px 24px; border-radius: 10px; font-size: 14px; font-weight: 600; display: inline-block; transition: all 0.25s; box-shadow: 0 8px 22px rgba(18, 183, 245, 0.38); }
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 12px 30px rgba(18, 183, 245, 0.5); }
.btn-primary.big { padding: 15px 36px; font-size: 16px; border-radius: 12px; }
.btn-ghost { color: #fff; padding: 11px 22px; border-radius: 10px; font-size: 14px; border: 1px solid rgba(255, 255, 255, 0.35); transition: all 0.25s; }
.btn-ghost:hover { background: rgba(255, 255, 255, 0.1); border-color: rgba(255, 255, 255, 0.6); }
.btn-ghost.big { padding: 15px 32px; font-size: 16px; border-radius: 12px; }

/* ===== Hero ===== */
.hero { position: relative; min-height: 100vh; background: linear-gradient(165deg, #071a33 0%, #0a2a5c 55%, #0d3d85 100%); display: flex; align-items: center; padding: 130px 0 90px; overflow: hidden; }
.hero-bg { position: absolute; inset: 0; }
.orb { position: absolute; border-radius: 50%; filter: blur(90px); opacity: 0.5; }
.orb.o1 { width: 520px; height: 520px; background: #12b7f5; top: -180px; left: -140px; }
.orb.o2 { width: 420px; height: 420px; background: #4f8dff; bottom: -160px; right: -80px; opacity: 0.4; }
.orb.o3 { width: 240px; height: 240px; background: #22e0c8; top: 30%; left: 46%; opacity: 0.22; }
.dots { position: absolute; inset: 0; background-image: radial-gradient(rgba(255, 255, 255, 0.09) 1px, transparent 1px); background-size: 26px 26px; }
.hero-inner { position: relative; display: flex; align-items: center; gap: 60px; }
.hero-left { flex: 1; color: #fff; }
.badge { display: inline-flex; align-items: center; gap: 8px; background: rgba(18, 183, 245, 0.14); border: 1px solid rgba(18, 183, 245, 0.4); color: #8addfa; padding: 8px 16px; border-radius: 99px; font-size: 13px; margin-bottom: 26px; }
.badge .dot { width: 8px; height: 8px; border-radius: 50%; background: #22e0c8; box-shadow: 0 0 10px #22e0c8; }
.hero h1 { font-size: 52px; font-weight: 800; line-height: 1.3; letter-spacing: 1px; }
.hero .sub { margin: 24px 0 36px; font-size: 17px; line-height: 1.9; color: rgba(255, 255, 255, 0.75); max-width: 560px; }
.hero .sub b { color: #8addfa; }
.hero-cta { display: flex; gap: 16px; margin-bottom: 36px; }
.trust { display: flex; gap: 26px; flex-wrap: wrap; }
.trust span { display: flex; align-items: center; gap: 7px; font-size: 13px; color: rgba(255, 255, 255, 0.65); }

/* 聊天窗口 mock */
.hero-right { flex: 1; position: relative; display: flex; justify-content: center; }
.chat-mock { width: 400px; max-width: 92%; background: #fff; border-radius: 22px; overflow: hidden; box-shadow: 0 40px 100px rgba(2, 10, 30, 0.6); transform: rotate(-2deg); }
.cm-head { display: flex; align-items: center; gap: 12px; padding: 16px 20px; background: linear-gradient(120deg, #12b7f5, #0a5bd3); color: #fff; }
.cm-avatar { width: 40px; height: 40px; border-radius: 50%; background: rgba(255, 255, 255, 0.25); display: flex; align-items: center; justify-content: center; font-weight: 800; }
.cm-head b { font-size: 15px; display: block; }
.cm-head small { font-size: 11px; opacity: 0.85; }
.cm-live { margin-left: auto; font-size: 10px; background: rgba(255, 255, 255, 0.22); padding: 4px 10px; border-radius: 99px; letter-spacing: 1px; }
.cm-body { padding: 22px 18px; min-height: 330px; background: #f4f8fd; display: flex; flex-direction: column; gap: 14px; }
.msg { max-width: 86%; padding: 12px 16px; border-radius: 14px; font-size: 13.5px; line-height: 1.7; animation: fadeUp 0.5s ease; }
.msg.user { align-self: flex-end; background: var(--grad); color: #fff; border-bottom-right-radius: 4px; }
.msg.bot { align-self: flex-start; background: #fff; color: var(--ink); border-bottom-left-radius: 4px; box-shadow: 0 3px 12px rgba(10, 40, 90, 0.08); }
.msg .src { display: block; margin-top: 8px; font-size: 11px; color: var(--ink-2); }
.cm-input { display: flex; align-items: center; gap: 10px; padding: 14px 16px; border-top: 1px solid var(--line); font-size: 13px; }
.cm-input > span:first-child { color: var(--qq-deep); font-weight: 700; white-space: nowrap; }
.cm-placeholder { flex: 1; color: #a8b6cc; }
.cm-send { background: var(--grad); color: #fff; padding: 6px 16px; border-radius: 8px; font-size: 12px; font-weight: 600; }
.float-chip { position: absolute; background: #fff; padding: 10px 18px; border-radius: 12px; font-size: 13px; font-weight: 700; color: var(--ink); box-shadow: 0 12px 32px rgba(2, 10, 30, 0.35); animation: float 4s ease-in-out infinite; }
.f1 { top: -4%; left: 4%; }
.f2 { bottom: 10%; left: -6%; animation-delay: 1.2s; }
.f3 { top: 38%; right: -4%; animation-delay: 0.6s; }
@keyframes float { 0%, 100% { transform: translateY(0); } 50% { transform: translateY(-12px); } }
@keyframes fadeUp { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: translateY(0); } }

/* ===== 数据条 ===== */
.stats { background: #fff; position: relative; z-index: 2; }
.stats-inner { display: flex; justify-content: space-between; padding: 44px 24px; margin-top: -46px; background: #fff; border-radius: 20px; box-shadow: 0 20px 60px rgba(10, 40, 90, 0.1); flex-wrap: wrap; gap: 20px; }
.stat { text-align: center; flex: 1; min-width: 150px; }
.stat b { display: block; font-size: 34px; font-weight: 800; background: var(--grad); -webkit-background-clip: text; background-clip: text; color: transparent; }
.stat span { font-size: 13px; color: var(--ink-2); }

/* ===== 区块通用 ===== */
section { padding: 90px 0; }
.sec-title { font-size: 36px; font-weight: 800; text-align: center; margin-bottom: 14px; }
.sec-sub { text-align: center; color: var(--ink-2); font-size: 15px; margin-bottom: 54px; }

/* ===== 功能 ===== */
.features { background: #f7fafd; }
.feat-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.feat-card { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 30px 26px; transition: all 0.3s; }
.feat-card:hover { transform: translateY(-6px); box-shadow: 0 18px 44px rgba(10, 40, 90, 0.12); }
.f-icon { width: 54px; height: 54px; border-radius: 15px; display: flex; align-items: center; justify-content: center; margin-bottom: 18px; }
.i1 { background: rgba(18, 183, 245, 0.12); }
.i2 { background: rgba(139, 123, 255, 0.12); }
.i3 { background: rgba(34, 197, 139, 0.12); }
.i4 { background: rgba(255, 154, 61, 0.12); }
.i5 { background: rgba(245, 86, 109, 0.12); }
.i6 { background: rgba(23, 200, 183, 0.12); }
.feat-card h3 { font-size: 18px; margin-bottom: 10px; }
.feat-card p { font-size: 14px; line-height: 1.8; color: var(--ink-2); }

/* ===== 场景 ===== */
.scene-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; }
.scene-card { border: 1px solid var(--line); border-radius: var(--radius); padding: 28px 24px; transition: all 0.3s; background: linear-gradient(180deg, #fff, #f9fcff); }
.scene-card:hover { border-color: #9adcfb; transform: translateY(-6px); box-shadow: 0 16px 40px rgba(10, 40, 90, 0.1); }
.s-tag { display: inline-block; font-size: 12px; color: var(--qq-deep); background: rgba(18, 183, 245, 0.1); padding: 4px 12px; border-radius: 99px; margin-bottom: 14px; font-weight: 600; }
.scene-card h3 { font-size: 17px; margin-bottom: 10px; }
.scene-card p { font-size: 13.5px; line-height: 1.8; color: var(--ink-2); }

/* ===== 流程 ===== */
.how { background: linear-gradient(165deg, #071a33, #0a2a5c); }
.how .sec-title { color: #fff; }
.how .sec-sub { color: rgba(255, 255, 255, 0.6); }
.steps { display: flex; align-items: center; justify-content: center; gap: 26px; flex-wrap: wrap; margin-bottom: 50px; }
.step { background: rgba(255, 255, 255, 0.06); border: 1px solid rgba(255, 255, 255, 0.14); border-radius: 18px; padding: 30px 28px; width: 240px; text-align: center; color: #fff; backdrop-filter: blur(8px); }
.step-num { width: 44px; height: 44px; border-radius: 50%; background: var(--grad); display: flex; align-items: center; justify-content: center; margin: 0 auto 16px; font-weight: 800; font-size: 19px; box-shadow: 0 8px 20px rgba(18, 183, 245, 0.5); }
.step h3 { font-size: 17px; margin-bottom: 8px; }
.step p { font-size: 13px; color: rgba(255, 255, 255, 0.65); line-height: 1.7; }
.step-arrow { color: #12b7f5; font-size: 26px; }
.how-cta { text-align: center; }

/* ===== FAQ ===== */
.faq { background: #f7fafd; }
.faq-wrap { max-width: 820px; }
.faq-list details { background: #fff; border: 1px solid var(--line); border-radius: 14px; margin-bottom: 14px; overflow: hidden; transition: all 0.2s; }
.faq-list details[open] { border-color: #9adcfb; box-shadow: 0 10px 28px rgba(10, 40, 90, 0.08); }
.faq-list summary { padding: 18px 24px; font-weight: 600; font-size: 15px; cursor: pointer; list-style: none; display: flex; justify-content: space-between; align-items: center; }
.faq-list summary::after { content: '+'; font-size: 20px; color: var(--qq); transition: transform 0.2s; }
.faq-list details[open] summary::after { transform: rotate(45deg); }
.faq-list p { padding: 0 24px 20px; font-size: 14px; line-height: 1.9; color: var(--ink-2); }

/* ===== Footer ===== */
.footer { background: #06182e; color: rgba(255, 255, 255, 0.7); padding: 64px 0 40px; }
.foot-inner { display: flex; gap: 60px; flex-wrap: wrap; }
.f-brand { flex: 1.6; min-width: 240px; }
.f-brand p { margin-top: 16px; font-size: 13px; line-height: 1.9; color: rgba(255, 255, 255, 0.5); }
.logo.light { color: #fff; }
.f-col { display: flex; flex-direction: column; gap: 12px; min-width: 120px; }
.f-col h4 { color: #fff; font-size: 14px; margin-bottom: 6px; }
.f-col a, .f-col span { font-size: 13px; color: rgba(255, 255, 255, 0.55); transition: color 0.2s; }
.f-col a:hover { color: #8addfa; }
.icp { font-size: 12px; color: rgba(255, 255, 255, 0.35); }

@media (max-width: 1024px) {
  .hero-inner { flex-direction: column; text-align: center; padding-top: 40px; }
  .hero h1 { font-size: 38px; }
  .hero .sub { margin: 20px auto 30px; }
  .hero-cta, .trust { justify-content: center; }
  .feat-grid { grid-template-columns: repeat(2, 1fr); }
  .scene-grid { grid-template-columns: repeat(2, 1fr); }
  .nav-links { display: none; }
  .chat-mock { margin-top: 40px; }
}
@media (max-width: 640px) {
  .feat-grid, .scene-grid { grid-template-columns: 1fr; }
  .stats-inner { flex-direction: column; }
  .hero h1 { font-size: 30px; }
}