/* =========================================================
   尔曰BB 官方网站 — 深空科技风样式
   品牌色: space-black #0c0f1e / nebula-purple #7b61ff
           telemetry-blue #1ea7ff / plasma-green #00ffc3
   品牌渐变: linear-gradient(135deg,#7b61ff,#1ea7ff,#00ffc3)
   ========================================================= */

:root {
  --space-black: #0c0f1e;
  --space-deep: #080b16;
  --cosmic-white: #f5faff;
  --nebula-purple: #7b61ff;
  --telemetry-blue: #1ea7ff;
  --plasma-green: #00ffc3;
  --text-dim: rgba(245, 250, 255, .62);
  --text-faint: rgba(245, 250, 255, .45);
  --glass: rgba(255, 255, 255, .05);
  --glass-border: rgba(255, 255, 255, .1);
  --grad: linear-gradient(135deg, #7b61ff, #1ea7ff, #00ffc3);
  --grad-soft: linear-gradient(135deg, rgba(123,97,255,.5), rgba(30,167,255,.5), rgba(0,255,195,.5));
  --font-orbitron: 'Orbitron', monospace;
  --font-exo: 'Exo', sans-serif;
  --font-mono: 'Share Tech Mono', monospace;
  --ease: cubic-bezier(.4, 0, .2, 1);
}

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

/* 滚动淡入 */
.reveal { opacity: 0; transform: translateY(28px); transition: opacity .8s var(--ease), transform .8s var(--ease); }
.revealed { opacity: 1; transform: translateY(0); }

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

body {
  font-family: var(--font-exo);
  background: var(--space-black);
  color: var(--cosmic-white);
  overflow-x: hidden;
  line-height: 1.6;
}

a { color: inherit; text-decoration: none; }
ul { list-style: none; }
img, svg { display: block; max-width: 100%; }

.container {
  width: min(1200px, 92%);
  margin: 0 auto;
  position: relative;
  z-index: 2;
}

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

/* ============ 星空背景 ============ */
.stars-bg {
  position: fixed; inset: 0; z-index: 0; pointer-events: none;
  background-image:
    radial-gradient(1px 1px at 20% 30%, #fff, transparent),
    radial-gradient(1px 1px at 40% 70%, rgba(255,255,255,.8), transparent),
    radial-gradient(1.5px 1.5px at 60% 20%, rgba(255,255,255,.6), transparent),
    radial-gradient(1px 1px at 80% 50%, #fff, transparent),
    radial-gradient(1px 1px at 30% 80%, rgba(255,255,255,.7), transparent),
    radial-gradient(1.5px 1.5px at 70% 85%, rgba(255,255,255,.5), transparent),
    radial-gradient(1px 1px at 90% 15%, #fff, transparent),
    radial-gradient(1px 1px at 10% 55%, rgba(255,255,255,.6), transparent);
  opacity: .35;
}

.aurora {
  position: fixed; top: -30%; left: -10%; width: 120%; height: 90%; z-index: 0;
  pointer-events: none; filter: blur(90px); opacity: .25;
  background:
    radial-gradient(circle at 20% 30%, #7b61ff, transparent 50%),
    radial-gradient(circle at 80% 50%, #1ea7ff, transparent 45%),
    radial-gradient(circle at 50% 90%, #00ffc3, transparent 40%);
  animation: auroraShift 18s ease-in-out infinite alternate;
}
@keyframes auroraShift {
  0% { transform: translate(0, 0) rotate(0deg); }
  100% { transform: translate(-3%, 2%) rotate(3deg); }
}

/* ============ 导航栏 ============ */
.navbar {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  background: rgba(12, 15, 30, .72);
  backdrop-filter: blur(14px); -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid transparent;
  transition: border-color .3s var(--ease), background .3s var(--ease);
}
.navbar.scrolled { border-bottom-color: var(--glass-border); }
.nav-inner { display: flex; align-items: center; justify-content: space-between; height: 72px; }

.brand { display: flex; align-items: center; gap: .6rem; }
.brand-logo { width: 40px; height: 40px; }
.brand-logo.sm { width: 32px; height: 32px; }
.brand-name { font-family: var(--font-orbitron); font-weight: 700; font-size: 1.15rem; letter-spacing: .05em; }
.brand-bb { color: var(--plasma-green); }

.nav-links { display: flex; gap: 2.2rem; }
.nav-links a {
  font-size: .92rem; color: var(--text-dim); position: relative;
  transition: color .25s var(--ease);
}
.nav-links a::after {
  content: ''; position: absolute; left: 0; bottom: -6px; height: 2px; width: 0;
  background: var(--grad); border-radius: 2px; transition: width .3s var(--ease);
}
.nav-links a:hover { color: var(--cosmic-white); }
.nav-links a:hover::after { width: 100%; }

.nav-cta { display: flex; align-items: center; gap: 1rem; }

/* ============ 按钮 ============ */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: .5rem;
  font-family: var(--font-exo); font-weight: 600; border-radius: 12px;
  cursor: pointer; transition: transform .25s var(--ease), box-shadow .25s var(--ease), background .25s var(--ease);
  white-space: nowrap;
}
.btn-primary { background: var(--grad); color: #0a0e1a; box-shadow: 0 0 24px rgba(123,97,255,.35); }
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 0 36px rgba(30,167,255,.5); }
.btn-ghost { background: transparent; color: var(--cosmic-white); border: 1px solid var(--glass-border); }
.btn-ghost:hover { border-color: var(--telemetry-blue); transform: translateY(-2px); }
.btn-lg { padding: .95rem 1.9rem; font-size: 1.02rem; }
.btn-sm { padding: .6rem 1.25rem; font-size: .88rem; }
.ico { width: 18px; height: 18px; }

.nav-toggle { display: none; flex-direction: column; gap: 5px; background: none; border: 0; cursor: pointer; padding: 6px; }
.nav-toggle span { width: 22px; height: 2px; background: var(--cosmic-white); border-radius: 2px; transition: .3s var(--ease); }

/* ============ HERO ============ */
.hero { position: relative; min-height: 100vh; display: flex; align-items: center; padding: 120px 0 80px; overflow: hidden; }
.hero-content { max-width: 680px; }
.hero-badge {
  display: inline-flex; align-items: center; gap: .55rem;
  padding: .45rem 1rem; border-radius: 999px; font-size: .82rem;
  background: var(--glass); border: 1px solid var(--glass-border);
  color: var(--text-dim); margin-bottom: 1.8rem;
}
.pulse-dot { width: 8px; height: 8px; border-radius: 50%; background: var(--plasma-green); box-shadow: 0 0 12px var(--plasma-green); animation: pulse 2s infinite; }
@keyframes pulse { 0%,100% { opacity: 1; transform: scale(1);} 50% { opacity: .5; transform: scale(.8);} }

.hero-title {
  font-family: var(--font-orbitron); font-weight: 900;
  font-size: clamp(2.6rem, 6vw, 4.4rem); line-height: 1.12; margin-bottom: 1.5rem;
  text-shadow: 0 0 40px rgba(123,97,255,.25);
}
.hero-sub { font-size: 1.12rem; color: var(--text-dim); margin-bottom: 2.4rem; line-height: 1.75; }
.hero-actions { display: flex; gap: 1rem; flex-wrap: wrap; margin-bottom: 3rem; }

.hero-stats { display: flex; gap: 3rem; flex-wrap: wrap; }
.stat { display: flex; flex-direction: column; gap: .25rem; }
.stat strong { font-family: var(--font-orbitron); font-size: 2.2rem; font-weight: 700; }
.stat span { font-size: .82rem; color: var(--text-faint); }

/* 聊天气泡视觉 */
.hero-visual { position: absolute; right: 4%; top: 50%; transform: translateY(-50%); width: 400px; z-index: 1; }
.chat-mock { display: flex; flex-direction: column; gap: 1rem; }
.chat-msg {
  max-width: 90%; padding: 1rem 1.3rem; border-radius: 18px; font-size: 1rem;
  opacity: 0; animation: msgIn .7s var(--ease) forwards;
  background: rgba(255,255,255,.06); border: 1px solid var(--glass-border);
}
.chat-msg.out { align-self: flex-end; background: linear-gradient(135deg, rgba(123,97,255,.35), rgba(30,167,255,.35)); }
.chat-msg.grad-border { border-color: rgba(0,255,195,.5); }
.chat-msg:nth-child(1) { animation-delay: .3s; }
.chat-msg:nth-child(2) { animation-delay: .9s; }
.chat-msg:nth-child(3) { animation-delay: 1.5s; }
@keyframes msgIn { from { opacity: 0; transform: translateY(14px);} to { opacity: 1; transform: translateY(0);} }

.scroll-hint { position: absolute; bottom: 2.2rem; left: 50%; transform: translateX(-50%); }
.scroll-hint span { display: block; width: 26px; height: 42px; border: 2px solid var(--text-faint); border-radius: 16px; position: relative; }
.scroll-hint span::before { content: ''; position: absolute; top: 8px; left: 50%; transform: translateX(-50%); width: 4px; height: 8px; border-radius: 2px; background: var(--plasma-green); animation: scrollDot 1.8s infinite; }
@keyframes scrollDot { 0% { opacity: 1; top: 8px; } 70% { opacity: 0; top: 22px;} 100% { opacity: 0; } }

/* ============ 通用区块 ============ */
.section { padding: 110px 0; position: relative; }
.section-alt { background: var(--space-deep); }
.center { text-align: center; }

.section-head { text-align: center; margin-bottom: 3.5rem; }
.eyebrow { font-family: var(--font-mono); letter-spacing: .25em; font-size: .78rem; display: block; margin-bottom: 1rem; }
.section-title { font-family: var(--font-orbitron); font-weight: 700; font-size: clamp(1.8rem, 3.5vw, 2.6rem); margin-bottom: 1rem; line-height: 1.25; }
.section-sub { color: var(--text-dim); font-size: 1.05rem; max-width: 640px; margin: 0 auto; }

/* ============ 产品能力 ============ */
.grid-features { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1.6rem; }
.feat-card {
  padding: 2.2rem 1.8rem; border-radius: 18px; background: var(--glass);
  border: 1px solid var(--glass-border); transition: transform .3s var(--ease), box-shadow .3s var(--ease), border-color .3s var(--ease);
}
.feat-card:hover { transform: translateY(-6px); border-color: rgba(123,97,255,.5); box-shadow: 0 16px 40px rgba(123,97,255,.18); }
.feat-icon {
  width: 54px; height: 54px; border-radius: 14px; display: flex; align-items: center; justify-content: center;
  font-size: 1.6rem; margin-bottom: 1.2rem; box-shadow: 0 0 20px rgba(30,167,255,.35);
}
.feat-card h3 { font-family: var(--font-orbitron); font-size: 1.12rem; margin-bottom: .7rem; }
.feat-card p { color: var(--text-dim); font-size: .94rem; line-height: 1.7; }

/* ============ 极致体验 ============ */
.split { display: grid; grid-template-columns: 1fr 1fr; gap: 4rem; align-items: center; }
.lead { color: var(--text-dim); font-size: 1.12rem; line-height: 1.8; margin-bottom: 1.8rem; }
.check-list li { padding: .7rem 0 .7rem 1.9rem; position: relative; color: var(--text-dim); }
.check-list li::before { content: '✓'; position: absolute; left: 0; color: var(--plasma-green); font-weight: 700; }

.glass-card {
  border-radius: 24px; background: var(--glass); border: 1px solid var(--glass-border);
  padding: 2.5rem; position: relative; overflow: hidden;
}
.devices { display: flex; flex-direction: column; gap: 1.2rem; }
.device { padding: 1.2rem 1.6rem; border-radius: 14px; background: rgba(255,255,255,.05); border: 1px solid var(--glass-border); font-family: var(--font-orbitron); font-weight: 500; }
.sync-line { height: 1px; background: var(--grad); margin: 1.6rem 0; box-shadow: 0 0 20px rgba(0,255,195,.5); }
.sync-label { text-align: center; letter-spacing: .15em; }

/* ============ 安全 ============ */
.grid-security { display: grid; grid-template-columns: repeat(4, 1fr); gap: 1.4rem; }
.sec-card { padding: 1.8rem; border-radius: 16px; background: var(--glass); border: 1px solid var(--glass-border); transition: transform .3s var(--ease); }
.sec-card:hover { transform: translateY(-5px); }
.sec-num { font-family: var(--font-orbitron); font-weight: 700; font-size: 1.8rem; margin-bottom: .8rem; }
.sec-card h4 { font-family: var(--font-orbitron); margin-bottom: .5rem; }
.sec-card p { color: var(--text-dim); font-size: .88rem; line-height: 1.6; }

/* ============ 全平台 ============ */
.platform-list { display: grid; grid-template-columns: repeat(6, 1fr); gap: 1.2rem; margin-top: 2rem; }
.pf {
  display: flex; flex-direction: column; align-items: center; gap: .7rem; padding: 1.8rem 1rem;
  border-radius: 16px; background: var(--glass); border: 1px solid var(--glass-border);
  font-size: .92rem; transition: transform .3s var(--ease), border-color .3s var(--ease);
}
.pf:hover { transform: translateY(-5px); border-color: rgba(0,255,195,.4); }
.pf-ico { font-size: 1.8rem; }

/* ============ 愿景 ============ */
.vision { padding: 130px 0; }
.vision-quote {
  font-family: var(--font-orbitron); font-weight: 700;
  font-size: clamp(1.8rem, 4vw, 3rem); line-height: 1.4; margin-bottom: 1.8rem;
  text-shadow: 0 0 40px rgba(0,255,195,.15);
}
.vision-text { max-width: 720px; margin: 0 auto; color: var(--text-dim); font-size: 1.12rem; line-height: 2; }

/* ============ 下载 ============ */
.download-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 1.4rem; margin-top: 1rem; }
.dl-card {
  display: flex; flex-direction: column; align-items: center; gap: .55rem; padding: 2.4rem 1.4rem;
  border-radius: 18px; background: var(--glass); border: 1px solid var(--glass-border);
  transition: transform .3s var(--ease), box-shadow .3s var(--ease), border-color .3s var(--ease);
}
.dl-card:hover { transform: translateY(-6px); border-color: rgba(123,97,255,.5); box-shadow: 0 16px 40px rgba(123,97,255,.18); }
a.dl-card { cursor: pointer; }
.dl-ico { font-size: 2.2rem; }
.dl-card strong { font-family: var(--font-orbitron); font-size: 1.05rem; }
.dl-meta { color: var(--text-faint); font-size: .82rem; }
.dl-go { color: var(--plasma-green); font-size: .88rem; margin-top: .4rem; }
.dl-coming { color: var(--text-faint); font-size: .82rem; margin-top: .4rem; }
.dl-note { margin-top: 1.4rem; color: var(--text-faint); font-size: .84rem; line-height: 1.9; }
.dl-note a { color: var(--plasma-green); text-decoration: none; border-bottom: 1px dashed rgba(0,255,195,.4); }
.dl-note a:hover { border-bottom-style: solid; }

/* ---- 扫码下载（手机端秒装） ---- */
.dl-qr {
  margin: 2.2rem auto 0; max-width: 620px;
  display: flex; align-items: center; gap: 1.6rem;
  padding: 1.4rem; border-radius: 20px;
  background: var(--glass); border: 1px solid var(--glass-border);
  text-align: left;
}
.dl-qr-img {
  flex: 0 0 auto; display: block; padding: 8px; border-radius: 14px;
  background: #fff; line-height: 0;
  box-shadow: 0 10px 30px rgba(0,0,0,.35);
}
.dl-qr-img img { display: block; width: 176px; height: 176px; }
.dl-qr-text { display: flex; flex-direction: column; gap: .45rem; }
.dl-qr-text strong { font-family: var(--font-orbitron); font-size: 1.05rem; }
.dl-qr-text span { color: var(--text-dim); font-size: .86rem; line-height: 1.7; }
.dl-qr-tip { color: var(--text-faint) !important; font-size: .8rem !important; }
.dl-qr-link { color: var(--plasma-green); text-decoration: none; font-size: .88rem; }
.dl-qr-link:hover { text-decoration: underline; }

@media (max-width: 640px) {
  .dl-qr { flex-direction: column; text-align: center; gap: 1.1rem; }
  .dl-qr-img img { width: 200px; height: 200px; }
}

/* ============ 关于我们 ============ */
.about-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 1.6rem; }
.about-card { padding: 2.2rem; border-radius: 18px; background: var(--glass); border: 1px solid var(--glass-border); transition: transform .3s var(--ease); }
.about-card:hover { transform: translateY(-5px); }
.about-card h3 { font-family: var(--font-orbitron); font-size: 1.1rem; margin-bottom: 1rem; }
.about-card p { color: var(--text-dim); line-height: 1.85; }

/* ============ 页脚 ============ */
.footer { background: var(--space-deep); border-top: 1px solid var(--glass-border); padding: 3.5rem 0 2rem; }
.footer-grid { display: grid; grid-template-columns: 1.6fr 1fr 1fr 1fr; gap: 2.5rem; margin-bottom: 2.5rem; }
.footer-brand p { color: var(--text-dim); font-size: .9rem; margin-top: 1rem; line-height: 1.8; }
.footer-col { display: flex; flex-direction: column; gap: .6rem; }
.footer-col h5 { font-family: var(--font-orbitron); font-size: .95rem; margin-bottom: .4rem; color: var(--cosmic-white); }
.footer-col a, .footer-col span { color: var(--text-dim); font-size: .9rem; transition: color .25s var(--ease); }
.footer-col a:hover { color: var(--plasma-green); }
.footer-bottom { display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap; gap: 1rem; padding-top: 1.6rem; border-top: 1px solid var(--glass-border); }
.footer-bottom span { color: var(--text-faint); font-size: .82rem; }

/* ============ 响应式 ============ */
@media (max-width: 1024px) {
  .grid-features { grid-template-columns: repeat(2, 1fr); }
  .grid-security { grid-template-columns: repeat(2, 1fr); }
  .platform-list { grid-template-columns: repeat(3, 1fr); }
  .download-grid { grid-template-columns: repeat(2, 1fr); }
  .hero-visual { display: none; }
}
@media (max-width: 768px) {
  .nav-links { display: none; position: fixed; top: 72px; left: 0; right: 0; flex-direction: column; background: rgba(8,11,22,.98); padding: 1.5rem 8%; gap: 1.2rem; border-bottom: 1px solid var(--glass-border); }
  .nav-links.open { display: flex; }
  .nav-toggle { display: flex; }
  .split { grid-template-columns: 1fr; gap: 2.5rem; }
  .grid-features, .grid-security, .about-grid, .download-grid { grid-template-columns: 1fr; }
  .platform-list { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .hero { padding-top: 110px; }
  .hero-actions { flex-direction: column; }
  .btn-lg { width: 100%; }
}
@media (max-width: 480px) {
  .platform-list { grid-template-columns: 1fr 1fr; }
  .hero-stats { gap: 1.6rem; }
}