/* ============================================================
   次元惜·音乐 官网样式 · 大厂亮色系
   原则：白底浅灰、单一品牌主色、克制极简、无渐变装饰
   背景：3D 立体粒子（canvas，见 script.js）
   ============================================================ */

:root {
  /* 品牌色（主色仅 1 个，辅色 ≤ 2） */
  --brand: #E5486F;        /* 品牌玫粉（主按钮，白字可读） */
  --brand-deep: #C93A5E;   /* 悬停加深 */
  --purple: #8B6FE8;       /* 辅助紫 */
  --blue: #4C8DFF;         /* 点缀蓝 */
  --pink-soft: #FF8FA3;    /* 品牌浅粉（点缀） */

  /* 背景（纯色浅灰白） */
  --bg: #F7F8FA;
  --bg-soft: #F0F1F4;
  --card: #FFFFFF;

  /* 边框与文字灰阶 */
  --border: #E5E7EB;
  --border-strong: #D1D5DB;
  --text: #111827;
  --text-2: #4B5563;
  --text-3: #6B7280;
  --text-4: #9CA3AF;

  /* 尺寸与圆角（克制：卡片 12，最大 16） */
  --radius-sm: 8px;
  --radius: 12px;
  --radius-lg: 16px;

  /* 字体（无衬线大厂风） */
  --font-body: 'Manrope', -apple-system, 'PingFang SC', 'HarmonyOS Sans SC', 'Microsoft YaHei', sans-serif;
  --font-mono: 'JetBrains Mono', 'SF Mono', Consolas, monospace;

  /* 阴影（单层浅阴影） */
  --shadow-sm: 0 1px 2px rgba(17, 24, 39, 0.05);
  --shadow: 0 4px 16px rgba(17, 24, 39, 0.07);
  --shadow-lg: 0 8px 30px rgba(17, 24, 39, 0.10);
}

/* ====== Reset ====== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
  font-family: var(--font-body);
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}
a { color: inherit; text-decoration: none; }
img { display: block; max-width: 100%; }
button { font: inherit; cursor: pointer; border: none; background: none; color: inherit; }

/* ====== 3D 粒子背景层（canvas 由 script.js 绘制） ====== */
.bg3d {
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
}

/* ====== 导航栏 ====== */
.nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  transition: background 0.3s, box-shadow 0.3s;
}
.nav.scrolled {
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: saturate(180%) blur(16px);
  -webkit-backdrop-filter: saturate(180%) blur(16px);
  border-bottom: 1px solid var(--border);
}
.nav__inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 14px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}
.nav__brand { display: flex; align-items: center; gap: 10px; }
.nav__logo { width: 36px; height: 36px; border-radius: var(--radius-sm); }
.nav__name {
  font-weight: 700;
  font-size: 18px;
  letter-spacing: 0.2px;
  color: var(--text);
}
.nav__dot { color: var(--brand); margin: 0 2px; }
.nav__links { display: flex; gap: 32px; }
.nav__links a {
  font-size: 15px;
  font-weight: 500;
  color: var(--text-2);
  position: relative;
  transition: color 0.2s;
}
.nav__links a::after {
  content: '';
  position: absolute;
  left: 0; bottom: -6px;
  width: 0; height: 2px;
  background: var(--brand);
  border-radius: 1px;
  transition: width 0.25s ease;
}
.nav__links a:hover { color: var(--text); }
.nav__links a:hover::after { width: 100%; }
.nav__cta {
  padding: 9px 22px;
  background: var(--brand);
  color: #fff;
  border-radius: var(--radius-sm);
  font-size: 14px;
  font-weight: 600;
  transition: background 0.2s;
}
.nav__cta:hover { background: var(--brand-deep); }
.nav__burger {
  display: none;
  flex-direction: column;
  gap: 5px;
  padding: 8px;
}
.nav__burger span {
  width: 22px; height: 2px;
  background: var(--text);
  border-radius: 1px;
  transition: transform 0.3s, opacity 0.3s;
}
.nav__burger.active span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav__burger.active span:nth-child(2) { opacity: 0; }
.nav__burger.active span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }
.nav__mobile {
  display: none;
  flex-direction: column;
  padding: 0 24px 16px;
  gap: 8px;
  background: rgba(255, 255, 255, 0.98);
  border-bottom: 1px solid var(--border);
}
.nav__mobile.active { display: flex; }
.nav__mobile a {
  padding: 12px 0;
  font-size: 16px;
  color: var(--text-2);
  border-bottom: 1px solid var(--border);
}

/* ====== 通用按钮（圆角克制 8px，主按钮纯色） ====== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 13px 28px;
  border-radius: var(--radius-sm);
  font-size: 15px;
  font-weight: 600;
  transition: background 0.2s, border-color 0.2s, transform 0.15s;
  cursor: pointer;
}
.btn--primary {
  background: var(--brand);
  color: #fff;
}
.btn--primary:hover { background: var(--brand-deep); }
.btn--primary:active { transform: scale(0.98); }
.btn--ghost {
  background: var(--card);
  color: var(--text);
  border: 1px solid var(--border-strong);
}
.btn--ghost:hover { border-color: var(--brand); color: var(--brand); }
.btn--large { padding: 15px 36px; font-size: 16px; }

/* ====== 区块通用 ====== */
section { padding: 100px 24px; position: relative; z-index: 1; }
.section__head { max-width: 1200px; margin: 0 auto 64px; }
.section__head--center { text-align: center; }
.section__tag {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 3px;
  color: var(--brand);
  padding: 5px 12px;
  background: rgba(229, 72, 111, 0.07);
  border-radius: var(--radius-sm);
  margin-bottom: 20px;
  font-weight: 500;
}
.section__title {
  font-size: clamp(30px, 4.5vw, 46px);
  font-weight: 800;
  line-height: 1.25;
  letter-spacing: -0.5px;
  color: var(--text);
}
.section__title em {
  font-style: normal;
  color: var(--brand);
}
.section__lead {
  margin-top: 20px;
  font-size: 16px;
  color: var(--text-3);
  line-height: 1.8;
}

/* ====== Hero 英雄区 ====== */
.hero {
  min-height: 100vh;
  padding: 140px 24px 80px;
  display: flex;
  align-items: center;
  position: relative;
  z-index: 1;
}

.hero__content {
  max-width: 1200px;
  margin: 0 auto;
  width: 100%;
  position: relative;
  z-index: 2;
}
.hero__badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 7px 16px;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  font-size: 13px;
  font-weight: 500;
  color: var(--text-2);
  margin-bottom: 28px;
  box-shadow: var(--shadow-sm);
}
.pulse-dot {
  width: 8px; height: 8px;
  background: var(--brand);
  border-radius: 50%;
  box-shadow: 0 0 0 0 rgba(229, 72, 111, 0.5);
  animation: pulse 2s infinite;
}
@keyframes pulse {
  0% { box-shadow: 0 0 0 0 rgba(229, 72, 111, 0.5); }
  70% { box-shadow: 0 0 0 10px rgba(229, 72, 111, 0); }
  100% { box-shadow: 0 0 0 0 rgba(229, 72, 111, 0); }
}
.hero__title {
  font-size: clamp(40px, 6.5vw, 72px);
  font-weight: 800;
  line-height: 1.12;
  letter-spacing: -1px;
  margin-bottom: 26px;
  color: var(--text);
}
.hero__title-line { display: block; }
.hero__title-line--accent { color: var(--brand); }
.hero__desc {
  font-size: 17px;
  color: var(--text-3);
  line-height: 1.9;
  margin-bottom: 40px;
  max-width: 560px;
}
.hero__actions { display: flex; gap: 16px; flex-wrap: wrap; margin-bottom: 64px; }

/* 频谱律动（纯色淡粉，克制装饰） */
.hero__spectrum {
  display: flex;
  align-items: flex-end;
  gap: 6px;
  height: 72px;
  max-width: 360px;
}
.hero__spectrum span {
  flex: 1;
  height: var(--h);
  background: var(--pink-soft);
  border-radius: 3px 3px 1px 1px;
  opacity: 0.45;
  animation: spectrum 1.6s ease-in-out infinite;
  animation-delay: var(--d, 0s);
}
.hero__spectrum span:nth-child(1) { --d: 0s; }
.hero__spectrum span:nth-child(2) { --d: 0.1s; }
.hero__spectrum span:nth-child(3) { --d: 0.2s; }
.hero__spectrum span:nth-child(4) { --d: 0.3s; }
.hero__spectrum span:nth-child(5) { --d: 0.4s; }
.hero__spectrum span:nth-child(6) { --d: 0.5s; }
.hero__spectrum span:nth-child(7) { --d: 0.6s; }
.hero__spectrum span:nth-child(8) { --d: 0.7s; }
.hero__spectrum span:nth-child(9) { --d: 0.8s; }
.hero__spectrum span:nth-child(10) { --d: 0.9s; }
.hero__spectrum span:nth-child(11) { --d: 1.0s; }
.hero__spectrum span:nth-child(12) { --d: 1.1s; }
.hero__spectrum span:nth-child(13) { --d: 1.2s; }
.hero__spectrum span:nth-child(14) { --d: 1.3s; }
.hero__spectrum span:nth-child(15) { --d: 0.05s; }
@keyframes spectrum {
  0%, 100% { transform: scaleY(1); }
  50% { transform: scaleY(1.5); }
}

/* 浮动唱片（黑胶点缀，阴影轻量） */
.hero__vinyl {
  position: absolute;
  right: 4%;
  top: 50%;
  transform: translateY(-50%);
  z-index: 1;
}
.vinyl {
  width: 320px;
  height: 320px;
  border-radius: 50%;
  background: radial-gradient(circle at 50% 50%,
    #17181C 0%, #23242B 30%, #17181C 45%, #23242B 60%, #17181C 75%, #0D0E12 100%);
  position: relative;
  box-shadow: 0 16px 48px rgba(17, 24, 39, 0.22);
  animation: spin 20s linear infinite;
}
.vinyl::before {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: 50%;
  background: repeating-radial-gradient(circle at 50% 50%,
    transparent 0, transparent 3px, rgba(255,255,255,0.03) 3px, rgba(255,255,255,0.03) 4px);
}
.vinyl__center {
  position: absolute;
  top: 50%; left: 50%;
  transform: translate(-50%, -50%);
  width: 104px; height: 104px;
  border-radius: 50%;
  box-shadow: 0 0 0 4px #17181C;
}
@keyframes spin { to { transform: rotate(360deg); } }

.hero__scroll {
  position: absolute;
  bottom: 32px; left: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
  font-size: 12px;
  letter-spacing: 2px;
  color: var(--text-4);
}
.hero__scroll-line {
  width: 1px; height: 40px;
  background: linear-gradient(180deg, var(--text-4), transparent);
  position: relative;
  overflow: hidden;
}
.hero__scroll-line::after {
  content: '';
  position: absolute;
  top: -40px; left: 0;
  width: 100%; height: 40px;
  background: var(--brand);
  animation: scroll-down 2s ease-in-out infinite;
}
@keyframes scroll-down {
  to { transform: translateY(80px); }
}

/* ====== 数据统计 ====== */
.stats { padding: 40px 24px 60px; }
.stats__inner {
  max-width: 1100px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
  padding: 44px 48px;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
}
.stat { text-align: center; }
.stat__num {
  font-size: clamp(34px, 4.5vw, 52px);
  font-weight: 800;
  color: var(--brand);
  line-height: 1;
  font-variant-numeric: tabular-nums;
}
.stat__label {
  margin-top: 10px;
  font-size: 14px;
  color: var(--text-3);
  letter-spacing: 1px;
}

/* ====== 功能展示 ====== */
.features__grid {
  max-width: 1200px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}
.card {
  padding: 32px 28px;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  position: relative;
  overflow: hidden;
  transition: transform 0.25s cubic-bezier(0.25, 0.1, 0.25, 1), box-shadow 0.25s, border-color 0.25s;
}
.card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow);
  border-color: var(--border-strong);
}
.card__icon {
  width: 52px; height: 52px;
  border-radius: var(--radius);
  display: grid;
  place-items: center;
  margin-bottom: 20px;
  background: color-mix(in srgb, var(--accent) 10%, #FFFFFF);
  color: var(--accent);
}
.card__icon svg { width: 26px; height: 26px; }
.card h3 {
  font-size: 19px;
  font-weight: 700;
  margin-bottom: 10px;
  color: var(--text);
}
.card p {
  font-size: 14.5px;
  color: var(--text-3);
  line-height: 1.7;
}

/* ====== 母带音质区 ====== */
.audio {
  background: var(--bg-soft);
  overflow: hidden;
}
.audio__bg-text {
  position: absolute;
  top: 8%;
  left: 50%;
  transform: translateX(-50%);
  font-size: clamp(110px, 20vw, 260px);
  font-weight: 800;
  color: transparent;
  -webkit-text-stroke: 1px rgba(17, 24, 39, 0.05);
  white-space: nowrap;
  pointer-events: none;
  letter-spacing: -4px;
}
.audio__tiers {
  max-width: 1000px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 14px;
  position: relative;
  z-index: 2;
}
.tier {
  display: flex;
  align-items: stretch;
  gap: 24px;
  padding: 26px 32px;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  position: relative;
  overflow: hidden;
  transition: transform 0.25s cubic-bezier(0.25, 0.1, 0.25, 1), box-shadow 0.25s;
}
.tier::before {
  content: '';
  position: absolute;
  left: 0; top: 0; bottom: 0;
  width: 4px;
  background: var(--g2);
}
.tier:hover {
  transform: translateX(6px);
  box-shadow: var(--shadow);
}
.tier__rank {
  font-size: 40px;
  font-weight: 800;
  line-height: 1;
  color: var(--g2);
  min-width: 56px;
  display: flex;
  align-items: center;
  font-variant-numeric: tabular-nums;
}
.tier__body { flex: 1; }
.tier__name {
  font-size: 21px;
  font-weight: 700;
  margin-bottom: 6px;
  color: var(--text);
}
.tier__sub {
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.5px;
  color: var(--g2);
  margin-bottom: 12px;
}
.tier__desc {
  font-size: 14.5px;
  color: var(--text-3);
  line-height: 1.75;
}

/* 技术参数 */
.audio__tech {
  max-width: 1000px;
  margin: 52px auto 0;
  padding: 34px;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  display: flex;
  align-items: center;
  justify-content: space-around;
  flex-wrap: wrap;
  gap: 24px;
}
.tech__item { text-align: center; }
.tech__value {
  font-family: var(--font-mono);
  font-size: 21px;
  font-weight: 600;
  color: var(--brand);
  margin-bottom: 6px;
}
.tech__key {
  font-size: 13px;
  color: var(--text-3);
  letter-spacing: 0.5px;
}
.tech__divider {
  width: 1px;
  height: 40px;
  background: var(--border);
}

/* ====== 下载区 ====== */
.download {
  position: relative;
  overflow: hidden;
}
.download__card {
  max-width: 560px;
  margin: 0 auto;
  padding: 44px;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow);
  text-align: center;
  position: relative;
  z-index: 2;
}
.download__info {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 16px;
  margin-bottom: 30px;
}
.download__logo {
  width: 68px; height: 68px;
  border-radius: var(--radius);
  box-shadow: var(--shadow-sm);
}
.download__name {
  font-size: 23px;
  font-weight: 700;
  text-align: left;
  color: var(--text);
}
.download__ver {
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--text-4);
  margin-top: 4px;
  text-align: left;
}
.download__meta {
  display: flex;
  justify-content: center;
  gap: 36px;
  margin-bottom: 30px;
  flex-wrap: wrap;
}
.download__meta-item { display: flex; flex-direction: column; gap: 4px; }
.download__meta-key {
  font-size: 12px;
  color: var(--text-4);
  letter-spacing: 1px;
}
.download__meta-val {
  font-size: 15px;
  font-weight: 600;
  color: var(--text);
}
/* 下载按钮组：普通版 + 极简版并排，小屏自动换行 */
.download__btns {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 14px;
  flex-wrap: wrap;
}
/* 极简版版本信息小字 */
.download__lowmeta {
  margin-top: 16px;
  font-size: 13px;
  color: var(--text-4);
}
.download__hint {
  margin-top: 18px;
  font-size: 13px;
  color: var(--text-4);
}

/* ====== FAQ ====== */
.faq__list {
  max-width: 800px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 12px;
}
.faq__item {
  padding: 20px 26px;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  transition: border-color 0.2s;
  cursor: pointer;
}
.faq__item[open] {
  border-color: var(--brand);
}
.faq__item summary {
  font-size: 16px;
  font-weight: 600;
  list-style: none;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
  color: var(--text);
}
.faq__item summary::-webkit-details-marker { display: none; }
.faq__item summary::after {
  content: '+';
  font-size: 22px;
  font-weight: 400;
  color: var(--brand);
  transition: transform 0.25s;
}
.faq__item[open] summary::after { transform: rotate(45deg); }
.faq__item p {
  margin-top: 12px;
  font-size: 14.5px;
  color: var(--text-3);
  line-height: 1.8;
}

/* ====== 页脚 ====== */
.footer {
  padding: 56px 24px 40px;
  background: var(--card);
  border-top: 1px solid var(--border);
}
.footer__inner {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 32px;
}
.footer__brand { display: flex; align-items: center; gap: 12px; }
.footer__logo { width: 44px; height: 44px; border-radius: var(--radius); }
.footer__name { font-size: 17px; font-weight: 700; }
.footer__slogan { font-size: 13px; color: var(--text-4); margin-top: 2px; }
.footer__links { display: flex; gap: 28px; }
.footer__links a {
  font-size: 14px;
  color: var(--text-3);
  transition: color 0.2s;
}
.footer__links a:hover { color: var(--brand); }
.footer__copy { text-align: right; }
.footer__copy p { font-size: 13px; color: var(--text-4); }
.footer__note { margin-top: 4px; font-size: 12px; }

/* ====== 滚动渐入动画 ====== */
.reveal {
  opacity: 0;
  transform: translateY(32px);
  transition: opacity 0.6s cubic-bezier(0.25, 0.1, 0.25, 1), transform 0.6s cubic-bezier(0.25, 0.1, 0.25, 1);
}
.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ====== 响应式 ====== */
@media (max-width: 900px) {
  .nav__links, .nav__cta { display: none; }
  .nav__burger { display: flex; }
  .features__grid { grid-template-columns: repeat(2, 1fr); }
  .stats__inner { grid-template-columns: repeat(2, 1fr); }
  .hero__vinyl { display: none; }
  .tier { flex-direction: column; gap: 12px; }
  .tier__rank { font-size: 34px; }
}
@media (max-width: 600px) {
  section { padding: 70px 20px; }
  .hero { min-height: auto; padding: 120px 20px 60px; }
  .features__grid { grid-template-columns: 1fr; }
  .stats__inner { grid-template-columns: repeat(2, 1fr); padding: 30px 24px; gap: 20px; }
  .audio__tech { flex-direction: column; gap: 20px; }
  .tech__divider { display: none; }
  .download__card { padding: 32px 22px; }
  .footer__inner { flex-direction: column; text-align: center; }
  .footer__copy { text-align: center; }
  .hero__desc br { display: none; }
}

/* ====== 减少动画偏好 ====== */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
  .reveal { opacity: 1; transform: none; }
  .bg3d { display: none; }
}