/* 官网:和 App 一个调子 —— 黑底、灰字、橙色只做小点缀 */
@font-face {
  font-family: 'Inter';
  font-style: normal;
  font-weight: 400 800;
  font-display: swap;
  src: url(/assets/fonts/inter-latin.woff2) format('woff2');
  unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
}

:root {
  --bg: #000;
  --surface: #121215;
  --surface-2: #1a1a1f;
  --line: rgba(255, 255, 255, 0.08);
  --line-strong: rgba(255, 255, 255, 0.14);
  --text: #f5f5f7;
  --muted: #a1a1aa;
  --dim: #71717a;
  --accent: #f97316;
  --maxw: 1120px;
  --gutter: clamp(16px, 4vw, 40px);
  color-scheme: dark;
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; scroll-padding-top: 76px; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: Inter, -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans', 'Noto Sans CJK SC', 'Noto Sans JP', sans-serif;
  font-size: 16px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  overflow-x: clip;
}
body.lang-zh { font-family: Inter, -apple-system, BlinkMacSystemFont, 'PingFang SC', 'Noto Sans SC', 'Microsoft YaHei', sans-serif; }
body.lang-ja { font-family: Inter, -apple-system, BlinkMacSystemFont, 'Hiragino Sans', 'Noto Sans JP', 'Yu Gothic', sans-serif; }
img { max-width: 100%; display: block; }
a { color: inherit; }
h1, h2, h3 { margin: 0; font-weight: 750; letter-spacing: -0.025em; }
.lang-zh h1, .lang-zh h2, .lang-zh h3, .lang-ja h1, .lang-ja h2, .lang-ja h3 { letter-spacing: 0; }
p { margin: 0; text-wrap: pretty; }
h1, h2 { text-wrap: balance; }
.clause { display: inline-block; }

/* --- 顶栏 --- */
.top {
  position: sticky; top: 0; z-index: 10;
  display: flex; align-items: center; gap: 24px;
  height: 64px; padding: 0 var(--gutter);
  background: rgba(0, 0, 0, 0.72);
  -webkit-backdrop-filter: saturate(160%) blur(18px);
  backdrop-filter: saturate(160%) blur(18px);
  border-bottom: 1px solid var(--line);
}
.brand { display: flex; align-items: center; gap: 10px; text-decoration: none; font-weight: 700; font-size: 15px; }
.brand img { border-radius: 8px; }
.top-nav { display: flex; gap: 28px; margin-left: auto; font-size: 14px; }
.top-nav a { color: var(--muted); text-decoration: none; }
.top-nav a:hover { color: var(--text); }
.lang-switch { display: flex; padding: 3px; border: 1px solid var(--line-strong); border-radius: 999px; font-size: 13px; line-height: 1; }
.lang-switch a, .lang-switch span { display: grid; place-items: center; min-width: 34px; height: 28px; padding: 0 8px; border-radius: 999px; text-decoration: none; }
.lang-switch a { color: var(--muted); }
.lang-switch a:hover { color: var(--text); }
.lang-switch span { color: var(--text); background: var(--surface-2); font-weight: 600; }
.top-cta {
  padding: 7px 16px; border-radius: 999px; border: 1px solid var(--line-strong);
  font-size: 14px; font-weight: 600; text-decoration: none;
}
.top-cta:hover { border-color: var(--text); }

main { overflow-x: clip; }

/* --- 首屏 --- */
.hero {
  position: relative;
  display: grid; grid-template-columns: 1.05fr 1fr; align-items: center; gap: 40px;
  max-width: var(--maxw); margin: 0 auto;
  padding: clamp(48px, 8vw, 96px) var(--gutter) 56px;
}
.hero::before {
  /* 首屏右边一点暖光,托住手机;很淡 */
  content: ''; position: absolute; z-index: -1; right: -10%; top: 6%;
  width: 70%; height: 90%;
  background: radial-gradient(closest-side, rgba(249, 115, 22, 0.13), rgba(249, 115, 22, 0) 70%);
  pointer-events: none;
}
.eyebrow { display: flex; align-items: center; gap: 10px; color: var(--muted); font-size: 14px; font-weight: 500; }
.eyebrow::before { content: ''; width: 6px; height: 6px; border-radius: 50%; background: var(--accent); flex: none; }
h1 { margin-top: 18px; font-size: clamp(40px, 5.6vw, 66px); line-height: 1.04; }
.lang-zh h1, .lang-ja h1 { line-height: 1.22; font-size: clamp(34px, 4.2vw, 54px); }
.lead { margin-top: 22px; max-width: 34em; color: var(--muted); font-size: 18px; line-height: 1.65; }
.download { display: flex; flex-wrap: wrap; align-items: center; gap: 16px 20px; margin-top: 32px; }
.store-badge img { height: 48px; width: auto; }
.android { color: var(--dim); font-size: 14px; }
.note { margin-top: 18px; color: var(--dim); font-size: 13px; }

.hero-media { position: relative; }
.hero-devices { position: relative; height: 640px; }
/* 前面那台是 Apple 官方框(截图已经合成进去):原样显示,不倾斜、不加阴影、不被别的东西盖住 */
.device { display: block; width: 300px; max-width: 100%; height: auto; }
.hero-devices .front { position: absolute; left: 4%; top: 0; z-index: 2; }
.hero-devices .back { position: absolute; right: 0; top: 54px; --w: 262px; transform: rotate(5deg); z-index: 1; }

/* 后面倾斜那台:自己画的黑色钛金属外框 + 黑玻璃边 + 侧键(不是 Apple 的素材) */
.mock {
  position: relative; margin: 0; width: var(--w, 262px);
  padding: calc(var(--w, 262px) * 0.016);
  border-radius: 15% / 7.2%;
  background: linear-gradient(140deg, #5c5c62 0%, #2a2a2e 12%, #17171a 40%, #2f2f34 62%, #141416 86%, #4e4e54 100%);
  box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.14), 0 40px 90px rgba(0, 0, 0, 0.6);
}
.mock-glass {
  display: block; padding: 3.6%; border-radius: 13.8% / 6.6%;
  background: #040405; box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.05);
}
.mock-glass img { display: block; width: 100%; height: auto; border-radius: 11.8% / 5.5%; background: #000; }
.mock-btn { position: absolute; width: 1.4%; background: linear-gradient(90deg, #55555b, #1d1d20); }
.mock-btn.action, .mock-btn.vol-up, .mock-btn.vol-down { left: -1.2%; border-radius: 2px 0 0 2px; }
.mock-btn.action { top: 17%; height: 4.4%; }
.mock-btn.vol-up { top: 24.5%; height: 7.4%; }
.mock-btn.vol-down { top: 33.5%; height: 7.4%; }
.mock-btn.side { right: -1.2%; top: 27%; height: 11%; border-radius: 0 2px 2px 0; background: linear-gradient(270deg, #55555b, #1d1d20); }

/* 和弦卡片:放在「学和声」那段文字下面;几个和弦叠在同一格里轮流渐显 */
.decode {
  position: relative; margin-top: 32px; width: 100%; max-width: 300px;
  padding: 16px 18px 12px; border-radius: 18px;
  background: rgba(22, 22, 26, 0.86);
  -webkit-backdrop-filter: blur(18px); backdrop-filter: blur(18px);
  border: 1px solid var(--line-strong);
  box-shadow: 0 24px 60px rgba(0, 0, 0, 0.55);
  cursor: pointer; -webkit-user-select: none; user-select: none; -webkit-tap-highlight-color: transparent;
}
.decode:focus-visible { outline: 2px solid var(--muted); outline-offset: 3px; }
.decode-label { color: var(--dim); font-size: 12px; }
.decode-stack { display: grid; }
.decode-slide { grid-area: 1 / 1; opacity: 0; transition: opacity 0.7s ease; }
.decode-slide.is-active { opacity: 1; }
.decode-chord { margin-top: 4px; font-size: 30px; font-weight: 750; letter-spacing: -0.02em; }
.decode dl { margin: 10px 0 0; }
.decode dl > div { display: flex; justify-content: space-between; align-items: baseline; gap: 12px; padding: 7px 0; border-top: 1px solid var(--line); font-size: 13.5px; }
.decode dt { color: var(--muted); flex: none; }
.decode dd { margin: 0; font-weight: 600; white-space: pre-wrap; text-align: right; }
.decode-shape { align-items: center !important; }
.decode-foot { display: flex; justify-content: space-between; align-items: center; gap: 12px; padding-top: 10px; border-top: 1px solid var(--line); }
.decode-dots { display: flex; gap: 5px; }
.decode-dots i { width: 4px; height: 4px; border-radius: 50%; background: var(--line-strong); transition: background-color 0.7s ease; }
.decode-dots i.on { background: var(--muted); }
.decode-hint { color: var(--dim); font-size: 11px; }
.shape { width: 92px; height: auto; display: block; }
.shape line { stroke: var(--dim); stroke-width: 1.1; }
.shape line.nut { stroke: var(--muted); stroke-width: 3; }
.shape circle { fill: var(--text); }
.shape circle.root { fill: var(--accent); }
.shape circle.open { fill: none; stroke: var(--muted); stroke-width: 1.3; }
.shape circle.open.root { stroke: var(--accent); }
.shape text { fill: var(--muted); font-size: 11px; text-anchor: middle; font-family: Inter, sans-serif; }
.shape text.fret { text-anchor: start; }


/* --- 一行承诺 --- */
.trust {
  display: flex; flex-wrap: wrap; justify-content: center; gap: 10px;
  max-width: var(--maxw); margin: 24px auto 0; padding: 0 var(--gutter); list-style: none;
}
.trust li { padding: 6px 14px; border: 1px solid var(--line); border-radius: 999px; color: var(--muted); font-size: 13px; }

/* --- 功能 --- */
.feature {
  display: grid; grid-template-columns: 1fr 1fr; align-items: center; gap: clamp(32px, 6vw, 88px);
  max-width: var(--maxw); margin: 0 auto; padding: clamp(72px, 10vw, 128px) var(--gutter) 0;
}
.feature.flip .feature-text { order: 2; }
.kicker { color: var(--accent); font-size: 14px; font-weight: 600; }
.feature h2 { margin-top: 12px; font-size: clamp(30px, 3.8vw, 44px); line-height: 1.12; }
.lang-zh .feature h2, .lang-ja .feature h2 { line-height: 1.3; }
.feature .body { margin-top: 18px; max-width: 32em; color: var(--muted); font-size: 17px; line-height: 1.7; }
.feature-media { display: flex; justify-content: center; }
.feature-media .device { width: 300px; }
.feature-media .device-tablet { width: 100%; max-width: 470px; }
.feature-media.pair { position: relative; min-height: 640px; }
.feature-media.pair .device { position: absolute; left: 6%; top: 0; width: 280px; z-index: 2; }
.feature-media.pair .second { position: absolute; right: 6%; top: 70px; --w: 250px; transform: rotate(4deg); z-index: 1; }

/* --- 价格 --- */
.pricing, .faq { max-width: 880px; margin: 0 auto; padding: clamp(88px, 11vw, 140px) var(--gutter) 0; }
.pricing h2, .faq h2, .cta h2 { font-size: clamp(30px, 3.8vw, 44px); line-height: 1.15; text-align: center; }
.section-lead { margin-top: 14px; text-align: center; color: var(--muted); font-size: 17px; }
.plans { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; margin-top: 40px; }
.plan { padding: 26px 26px 22px; border-radius: 20px; background: var(--surface); border: 1px solid var(--line); }
.plan h3 { display: flex; align-items: center; gap: 8px; font-size: 17px; }
.pro-tag {
  padding: 1px 7px 0; border: 1px solid var(--muted); border-radius: 6px;
  font-size: 10px; font-weight: 700; letter-spacing: 0.14em; line-height: 16px;
}
.price { margin-top: 14px; color: var(--muted); font-size: 15px; }
.price span { color: var(--text); font-size: 40px; font-weight: 750; letter-spacing: -0.02em; }
.price-alt { margin-top: 4px; color: var(--muted); font-size: 14px; }
.plan ul { margin: 20px 0 0; padding: 0; list-style: none; border-top: 1px solid var(--line); }
.plan li { display: flex; gap: 10px; padding: 11px 0 0; color: var(--text); font-size: 15px; line-height: 1.5; }
.tick { flex: none; width: 16px; height: 16px; margin-top: 3px; color: var(--dim); }
.plan.pro .tick { color: var(--accent); }
.fine { margin-top: 18px; color: var(--dim); font-size: 12.5px; line-height: 1.6; text-align: center; }

/* --- 常见问题:和 App 设置页一样的分组列表;答案直接展开(Google 只给看得见的文字做直达链接) --- */
.faq h2 { margin-bottom: 32px; }
.faq-list { margin: 0; border-radius: 16px; background: var(--surface); border: 1px solid var(--line); overflow: hidden; }
.faq-list > div { padding: 18px 20px 20px; }
.faq-list > div + div { border-top: 1px solid var(--line); }
.faq-list dt { font-size: 16px; font-weight: 600; }
.faq-list dd { margin: 6px 0 0; color: var(--muted); font-size: 15px; line-height: 1.7; }

/* --- 收尾 --- */
.cta { display: flex; flex-direction: column; align-items: center; text-align: center; max-width: var(--maxw); margin: 0 auto; padding: clamp(96px, 12vw, 150px) var(--gutter) 24px; }
.cta > img { border-radius: 17px; margin-bottom: 26px; box-shadow: 0 16px 40px rgba(249, 115, 22, 0.16); }
.cta p { margin-top: 12px; color: var(--muted); font-size: 17px; }
.cta .download { justify-content: center; }

.foot {
  display: flex; flex-wrap: wrap; align-items: center; gap: 16px 32px;
  max-width: var(--maxw); margin: 72px auto 0; padding: 28px var(--gutter) 40px;
  border-top: 1px solid var(--line); color: var(--dim); font-size: 13px;
}
.foot a { color: var(--muted); text-decoration: none; }
.foot a:hover { color: var(--text); }
.foot-links, .foot-lang { display: flex; flex-wrap: wrap; gap: 8px 20px; }
.foot-lang span { color: var(--text); }
.copy { width: 100%; }
.copy.tm { margin-top: -8px; font-size: 11.5px; line-height: 1.6; }

.notfound { display: flex; flex-direction: column; align-items: center; gap: 14px; padding: 18vh var(--gutter) 0; text-align: center; }
.notfound img { border-radius: 17px; margin-bottom: 8px; }
.notfound h1 { font-size: 56px; }
.notfound p { color: var(--muted); }

/* --- 窄屏 --- */
@media (max-width: 860px) {
  .top-nav { display: none; }
  .lang-switch { margin-left: auto; }
  .top { gap: 12px; }
  .hero { grid-template-columns: 1fr; gap: 8px; padding-top: 40px; }
  .hero::before { right: -30%; top: 40%; width: 120%; height: 60%; }
  .lead { font-size: 17px; }
  .hero-media { margin-top: 24px; }
  .hero-devices { height: 510px; }
  .hero-devices .front { left: 0; width: 240px; }
  .hero-devices .back { right: -36px; top: 46px; --w: 214px; }
  .decode-chord { font-size: 26px; }
  .feature, .feature.flip { grid-template-columns: 1fr; }
  .feature.flip .feature-text { order: 0; }
  .feature-media .device { width: 260px; }
  .feature-media .device-tablet { width: 100%; }
  .feature-media.pair { min-height: 520px; }
  .feature-media.pair .device { left: 2%; width: 228px; }
  .feature-media.pair .second { right: 2%; --w: 206px; }
  .plans { grid-template-columns: 1fr; }
}
@media (max-width: 380px) {
  .hero-devices { height: 470px; }
  .hero-devices .front { width: 222px; }
  .hero-devices .back { --w: 196px; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .decode-slide, .decode-dots i { transition: none; }
}