/* ===== 听力先行者 · 设计系统 ===== */
:root {
  --c-primary: #0f8b8d;
  --c-primary-dark: #0b6e70;
  --c-accent: #2ec4b6;
  --c-ink: #12313a;
  --c-body: #4a626a;
  --c-bg: #f7fbfa;
  --c-surface: #ffffff;
  --c-line: #e4efec;
  --c-hero-bg: linear-gradient(160deg, #0b6e70 0%, #0f8b8d 55%, #2ec4b6 100%);
  --radius: 16px;
  --radius-sm: 10px;
  --shadow: 0 20px 50px -20px rgba(15, 139, 141, 0.35);
  --shadow-sm: 0 8px 24px -12px rgba(18, 49, 58, 0.18);
  --maxw: 1140px;
  --font: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--font);
  color: var(--c-ink);
  background: var(--c-bg);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}
a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }

.container { max-width: var(--maxw); margin: 0 auto; padding: 0 24px; }
.container.narrow { max-width: 820px; }

/* ===== Header ===== */
.site-header {
  position: sticky; top: 0; z-index: 100;
  background: rgba(255, 255, 255, 0.9);
  backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid var(--c-line);
}
.header-inner { display: flex; align-items: center; justify-content: space-between; height: 68px; }
.brand { display: flex; align-items: center; gap: 10px; font-weight: 700; font-size: 18px; color: var(--c-ink); }
.brand-logo { width: 34px; height: 34px; }
.brand-name { letter-spacing: 0.5px; }
.main-nav { display: flex; align-items: center; gap: 28px; }
.main-nav a { font-size: 15px; color: var(--c-body); transition: color .2s; }
.main-nav a:hover { color: var(--c-primary); }
.nav-cta { background: var(--c-primary); color: #fff !important; padding: 8px 20px; border-radius: 999px; font-weight: 600; transition: background .2s, transform .2s; }
.nav-cta:hover { background: var(--c-primary-dark); transform: translateY(-1px); }
.nav-toggle { display: none; background: none; border: none; cursor: pointer; flex-direction: column; gap: 5px; }
.nav-toggle span { width: 24px; height: 2px; background: var(--c-ink); border-radius: 2px; transition: .3s; }

/* ===== Hero ===== */
.hero { background: var(--c-hero-bg); color: #fff; overflow: hidden; position: relative; }
.hero-inner { display: grid; grid-template-columns: 1.1fr 0.9fr; gap: 48px; align-items: center; padding: 96px 24px; }
.hero-text .eyebrow { color: var(--c-accent); }
.hero-text h1 { font-size: 52px; line-height: 1.15; margin: 16px 0 20px; letter-spacing: -1px; }
.hero-text h1 .accent { color: #ffd166; }
.hero-desc { font-size: 17px; color: rgba(255, 255, 255, 0.9); max-width: 520px; }
.hero-actions { display: flex; gap: 14px; margin: 32px 0 40px; flex-wrap: wrap; }
.hero-stats { display: flex; gap: 40px; flex-wrap: wrap; }
.hero-stats .stat { display: flex; flex-direction: column; }
.hero-stats .stat strong { font-size: 24px; font-weight: 700; }
.hero-stats .stat span { font-size: 13px; color: rgba(255, 255, 255, 0.75); }

.btn { display: inline-block; padding: 13px 30px; border-radius: 999px; font-weight: 600; font-size: 15px; transition: transform .2s, box-shadow .2s, background .2s; }
.btn:hover { transform: translateY(-2px); }
.btn-primary { background: #ffd166; color: #12313a; box-shadow: 0 12px 30px -10px rgba(255, 209, 102, 0.6); }
.btn-primary:hover { background: #ffc93c; }
.btn-ghost { background: rgba(255, 255, 255, 0.14); color: #fff; border: 1px solid rgba(255, 255, 255, 0.35); }
.btn-ghost:hover { background: rgba(255, 255, 255, 0.24); }
.btn-light { background: #fff; color: var(--c-primary-dark); }
.btn-light:hover { box-shadow: var(--shadow-sm); }

/* 声波动画 */
.hero-visual { position: relative; display: flex; align-items: center; justify-content: center; min-height: 320px; }
.soundwave { display: flex; align-items: center; gap: 6px; height: 200px; }
.soundwave span {
  width: 10px; border-radius: 6px; background: rgba(255, 255, 255, 0.85);
  height: var(--h); animation: wave 1.6s ease-in-out infinite alternate;
}
.soundwave span:nth-child(2n) { animation-delay: .15s; }
.soundwave span:nth-child(3n) { animation-delay: .3s; }
.soundwave span:nth-child(5n) { animation-delay: .45s; }
@keyframes wave { from { transform: scaleY(0.4); } to { transform: scaleY(1.05); } }
.ear-chip {
  position: absolute; background: rgba(255, 255, 255, 0.16); border: 1px solid rgba(255, 255, 255, 0.3);
  padding: 8px 18px; border-radius: 999px; font-size: 14px; font-weight: 600;
  backdrop-filter: blur(6px);
}
.chip-1 { top: 8%; left: 6%; }
.chip-2 { bottom: 10%; right: 8%; }
.chip-3 { top: 30%; right: 0; }

/* ===== Sections ===== */
.section { padding: 96px 0; }
.section-head { text-align: center; max-width: 640px; margin: 0 auto 56px; }
.section-head h2 { font-size: 38px; letter-spacing: -0.5px; margin: 12px 0; }
.section-sub { color: var(--c-body); font-size: 16px; }
.eyebrow { color: var(--c-primary); font-weight: 700; font-size: 13px; letter-spacing: 2px; text-transform: uppercase; }

/* Cards */
.cards-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; }
.card { background: var(--c-surface); border: 1px solid var(--c-line); border-radius: var(--radius); padding: 30px 26px; box-shadow: var(--shadow-sm); transition: transform .25s, box-shadow .25s; }
.card:hover { transform: translateY(-6px); box-shadow: var(--shadow); }
.card-icon { font-size: 34px; margin-bottom: 14px; }
.card h3 { font-size: 19px; margin-bottom: 10px; }
.card p { color: var(--c-body); font-size: 14.5px; }

/* Features */
.features { background: #fff; }
.features-list { display: flex; flex-direction: column; gap: 40px; }
.feature { display: grid; grid-template-columns: 1fr 1fr; gap: 48px; align-items: center; }
.feature.reverse .feature-text { order: 2; }
.feature.reverse .feature-visual { order: 1; }
.feature-text h3 { font-size: 26px; margin-bottom: 12px; }
.feature-text p { color: var(--c-body); font-size: 16px; }
.feature-visual {
  background: linear-gradient(150deg, #e6f7f4, #d5f1ee); border-radius: var(--radius);
  min-height: 220px; display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 16px; padding: 30px;
}
.level-bar { width: 220px; height: 34px; background: #fff; border-radius: 8px; overflow: hidden; box-shadow: var(--shadow-sm); }
.level-bar span { display: flex; align-items: center; justify-content: flex-end; padding-right: 12px; height: 100%; background: linear-gradient(90deg, var(--c-accent), var(--c-primary)); color: #fff; font-size: 12px; font-weight: 700; border-radius: 8px; }
.player { display: flex; align-items: center; gap: 18px; }
.play-btn { width: 64px; height: 64px; border-radius: 50%; border: none; background: var(--c-primary); color: #fff; font-size: 22px; cursor: pointer; box-shadow: var(--shadow); }
.player-wave { width: 160px; height: 40px; background: linear-gradient(90deg, var(--c-accent), var(--c-primary)); border-radius: 20px; opacity: .5; }
.badge { background: #fff; padding: 12px 22px; border-radius: 10px; font-weight: 600; color: var(--c-primary-dark); box-shadow: var(--shadow-sm); }

/* Path */
.path { background: linear-gradient(160deg, #0b6e70, #0f8b8d); color: #fff; }
.path .eyebrow { color: #ffd166; }
.path .section-sub { color: rgba(255, 255, 255, 0.8); }
.steps { list-style: none; display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; counter-reset: step; }
.step { background: rgba(255, 255, 255, 0.08); border: 1px solid rgba(255, 255, 255, 0.18); border-radius: var(--radius); padding: 30px 24px; }
.step-num { font-size: 40px; font-weight: 800; color: #ffd166; opacity: .9; }
.step h3 { margin: 12px 0 8px; font-size: 20px; }
.step p { color: rgba(255, 255, 255, 0.82); font-size: 14.5px; }

/* FAQ */
.faq-list { display: flex; flex-direction: column; gap: 14px; }
.faq-item { background: var(--c-surface); border: 1px solid var(--c-line); border-radius: var(--radius-sm); padding: 6px 24px; box-shadow: var(--shadow-sm); }
.faq-item summary { cursor: pointer; font-weight: 600; padding: 16px 0; list-style: none; display: flex; justify-content: space-between; align-items: center; }
.faq-item summary::after { content: "+"; font-size: 24px; color: var(--c-primary); font-weight: 400; transition: transform .2s; }
.faq-item[open] summary::after { transform: rotate(45deg); }
.faq-item p { padding: 0 0 18px; color: var(--c-body); font-size: 15px; }

/* CTA */
.cta { background: var(--c-hero-bg); color: #fff; text-align: center; }
.cta h2 { font-size: 38px; margin-bottom: 12px; }
.cta p { color: rgba(255, 255, 255, 0.9); margin-bottom: 28px; }
.cta-btns { display: flex; gap: 14px; justify-content: center; flex-wrap: wrap; }

/* Footer */
.site-footer { background: #0c2b31; color: rgba(255, 255, 255, 0.75); padding: 56px 0 32px; }
.footer-inner { text-align: center; }
.footer-brand { display: flex; align-items: center; justify-content: center; gap: 10px; font-size: 18px; font-weight: 700; color: #fff; margin-bottom: 14px; }
.footer-brand .brand-logo { width: 28px; height: 28px; }
.footer-desc { max-width: 460px; margin: 0 auto 24px; font-size: 14px; }
.footer-links { display: flex; justify-content: center; gap: 24px; flex-wrap: wrap; margin-bottom: 24px; font-size: 14px; }
.footer-links a:hover { color: #fff; }
.copyright { font-size: 13px; opacity: .7; }
.beian { margin-top: 8px; font-size: 13px; }
.beian a { color: rgba(255, 255, 255, 0.6); }
.beian a:hover { color: #fff; }

/* ===== 滚动出现动画 ===== */
.reveal { opacity: 0; transform: translateY(24px); transition: opacity .6s ease, transform .6s ease; }
.reveal.in-view { opacity: 1; transform: translateY(0); }

/* ===== Responsive ===== */
@media (max-width: 960px) {
  .hero-inner { grid-template-columns: 1fr; text-align: center; padding: 64px 24px; }
  .hero-desc { margin: 0 auto; }
  .hero-actions, .hero-stats { justify-content: center; }
  .hero-visual { min-height: 220px; }
  .cards-grid, .steps { grid-template-columns: repeat(2, 1fr); }
  .feature { grid-template-columns: 1fr; gap: 24px; }
  .feature.reverse .feature-text { order: 1; }
  .feature.reverse .feature-visual { order: 2; }
}
@media (max-width: 640px) {
  .main-nav { position: fixed; top: 68px; right: 0; left: 0; background: #fff; flex-direction: column; padding: 20px 24px; gap: 18px; border-bottom: 1px solid var(--c-line); transform: translateY(-130%); transition: transform .3s; }
  .main-nav.open { transform: translateY(0); }
  .nav-toggle { display: flex; }
  .hero-text h1 { font-size: 38px; }
  .cards-grid, .steps { grid-template-columns: 1fr; }
  .section-head h2, .cta h2 { font-size: 30px; }
}