/* 酷狗音乐官网 - 单页落地页样式
   移动优先，min-width 断点向后增强：576 / 768 / 992 / 1200 */

/* ---------- 设计变量 ---------- */
:root {
  --brand: #6D28D9;
  --brand-dark: #5B21B6;
  --brand-soft: rgba(109, 40, 217, 0.08);
  --ink: #09090B;
  --text: #1F2937;
  --muted: #6B7280;
  --bg: #FFFFFF;
  --surface: #F7F6F3;
  --accent: #F59E0B;
  --success: #10B981;
  --border: #E7E5E4;

  --space-1: 4px;
  --space-2: 8px;
  --space-3: 16px;
  --space-4: 24px;
  --space-5: 32px;
  --space-6: 48px;

  --radius-pill: 9999px;
  --radius-card: 16px;
  --radius-sm: 12px;
  --radius-icon: 8px;

  --shadow-card: 0 1px 3px rgba(0, 0, 0, .08), 0 8px 24px rgba(0, 0, 0, .04);
  --shadow-hover: 0 2px 6px rgba(0, 0, 0, .10), 0 14px 32px rgba(0, 0, 0, .08);

  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
               "Hiragino Sans GB", "Microsoft YaHei", Roboto, Helvetica, Arial, sans-serif;

  --header-h: 64px;
  --container: 1200px;
}

/* ---------- 基础 ---------- */
*, *::before, *::after { box-sizing: border-box; }

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

body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.6;
  color: var(--text);
  background: var(--bg);
  font-weight: 400;
}

h1, h2, h3 {
  color: var(--ink);
  margin: 0 0 var(--space-3);
  font-weight: 700;
  letter-spacing: -.01em;
}

h1 { font-size: 30px; line-height: 1.2; }
h2 { font-size: 24px; line-height: 1.25; }
h3 { font-size: 18px; line-height: 1.4; font-weight: 600; }

p { margin: 0 0 var(--space-3); }

a { color: var(--brand); text-decoration: none; }
a:hover { color: var(--brand-dark); }

img { max-width: 100%; height: auto; }

ul { margin: 0; padding: 0; list-style: none; }

:focus-visible { outline: 2px solid var(--brand); outline-offset: 3px; border-radius: 4px; }

.sr-only {
  position: absolute; width: 1px; height: 1px;
  padding: 0; margin: -1px; overflow: hidden;
  clip: rect(0 0 0 0); white-space: nowrap; border: 0;
}

.container {
  width: 100%;
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 20px;
}

/* ---------- 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  min-height: 48px;
  padding: 0 var(--space-4);
  border: 1px solid transparent;
  border-radius: var(--radius-pill);
  font-size: 16px;
  font-weight: 700;
  line-height: 1;
  cursor: pointer;
  transition: transform .2s ease, background-color .2s ease, box-shadow .2s ease, color .2s ease;
}

.btn-sm { min-height: 40px; padding: 0 var(--space-3); font-size: 15px; }

.btn-primary { background: var(--brand); color: #fff; box-shadow: var(--shadow-card); }
.btn-primary:hover { background: var(--brand-dark); color: #fff; transform: translateY(-2px); box-shadow: var(--shadow-hover); }

.btn-ghost { background: transparent; color: var(--brand); border-color: var(--brand); }
.btn-ghost:hover { background: var(--brand-soft); color: var(--brand-dark); transform: translateY(-2px); }

.btn-outline { background: transparent; color: var(--brand); border-color: var(--border); }
.btn-outline:hover { border-color: var(--brand); background: var(--brand-soft); color: var(--brand-dark); transform: translateY(-2px); }

.btn-light { background: #fff; color: var(--brand); }
.btn-light:hover { background: #fff; color: var(--brand-dark); transform: translateY(-2px); box-shadow: var(--shadow-hover); }

.btn-outline-light { background: transparent; color: #fff; border-color: rgba(255, 255, 255, .6); }
.btn-outline-light:hover { background: rgba(255, 255, 255, .16); color: #fff; transform: translateY(-2px); }

/* ---------- 顶部导航 ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(255, 255, 255, .92);
  border-bottom: 1px solid transparent;
  transition: background-color .2s ease, border-color .2s ease, box-shadow .2s ease;
}

.site-header.is-scrolled {
  background: rgba(255, 255, 255, .78);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom-color: var(--border);
  box-shadow: 0 1px 3px rgba(0, 0, 0, .05);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3);
  min-height: var(--header-h);
}

.brand { display: inline-flex; align-items: center; gap: var(--space-2); color: var(--ink); }
.brand-mark { display: inline-flex; border-radius: var(--radius-icon); overflow: hidden; }
.brand-name { font-weight: 700; font-size: 17px; color: var(--ink); }

.nav-toggle {
  display: inline-flex;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 44px; height: 44px;
  padding: 0 10px;
  background: transparent;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  cursor: pointer;
}
.nav-toggle-bar { display: block; height: 2px; background: var(--ink); border-radius: 2px; transition: transform .2s ease, opacity .2s ease; }
.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(2) { opacity: 0; }
.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

.nav {
  position: fixed;
  inset: var(--header-h) 0 auto 0;
  display: none;
  flex-direction: column;
  gap: var(--space-4);
  padding: var(--space-4) 20px var(--space-5);
  background: #fff;
  border-bottom: 1px solid var(--border);
  box-shadow: var(--shadow-card);
}
.nav.is-open { display: flex; }

.nav-list { display: flex; flex-direction: column; gap: var(--space-1); }
.nav-list a {
  display: block;
  padding: var(--space-3) var(--space-2);
  color: var(--text);
  font-weight: 500;
  border-radius: var(--radius-icon);
}
.nav-list a:hover, .nav-list a.is-active { background: var(--brand-soft); color: var(--brand); }

.nav-cta { display: flex; align-items: center; gap: var(--space-3); }
.nav-login { color: var(--muted); font-weight: 500; }
.nav-login:hover { color: var(--brand); }

/* ---------- Hero ---------- */
.hero { position: relative; overflow: hidden; padding: var(--space-6) 0; }
.hero-bg { position: absolute; inset: 0; background: linear-gradient(180deg, #F4F1FE 0%, #FBF9FF 55%, #fff 100%); }
.blob { position: absolute; border-radius: 50%; filter: blur(52px); opacity: .5; }
.blob-1 { width: 260px; height: 260px; top: -60px; right: -60px; background: rgba(109, 40, 217, .30); }
.blob-2 { width: 200px; height: 200px; bottom: 20px; left: -70px; background: rgba(245, 158, 11, .22); }
.blob-3 { width: 180px; height: 180px; top: 45%; right: 12%; background: rgba(16, 185, 129, .16); }

.hero-inner { position: relative; display: flex; flex-direction: column; gap: var(--space-5); }

.hero-badges { display: flex; flex-wrap: wrap; gap: var(--space-2); margin: 0 0 var(--space-3); }
.tag {
  display: inline-block;
  padding: 4px 12px;
  border-radius: var(--radius-pill);
  font-size: 13px;
  font-weight: 500;
}
.tag-brand { background: var(--brand-soft); color: var(--brand); }
.tag-accent { background: rgba(245, 158, 11, .14); color: #92400E; }

.hero-sub { font-size: 16px; color: var(--text); max-width: 640px; }

.hero-actions { display: flex; flex-wrap: wrap; gap: var(--space-3); margin: 0 0 var(--space-4); }
.hero-meta { font-size: 13px; color: var(--muted); margin: 0; }

.hero-visual { display: flex; justify-content: center; }

.player-card {
  width: 100%;
  max-width: 380px;
  padding: var(--space-4);
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius-card);
  box-shadow: var(--shadow-card);
}

.player-cover {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  height: 180px;
  border-radius: var(--radius-sm);
  background: linear-gradient(135deg, var(--brand) 0%, #8B5CF6 60%, #F59E0B 140%);
}
.player-cover-ring {
  position: absolute;
  width: 128px; height: 128px;
  border: 1px solid rgba(255, 255, 255, .35);
  border-radius: 50%;
}
.player-cover-disc {
  width: 88px; height: 88px;
  border-radius: 50%;
  background: radial-gradient(circle at 50% 50%, rgba(255, 255, 255, .95) 0 12%, rgba(255, 255, 255, .35) 13% 100%);
}

.player-info { padding-top: var(--space-3); }
.player-title { font-weight: 600; color: var(--ink); margin: 0 0 var(--space-1); }
.player-artist { font-size: 13px; color: var(--muted); margin: 0 0 var(--space-3); }

.player-bar { height: 4px; background: #EFEDEA; border-radius: 4px; overflow: hidden; }
.player-bar-fill { display: block; width: 38%; height: 100%; background: var(--brand); }
.player-times { display: flex; justify-content: space-between; font-size: 12px; color: var(--muted); margin: var(--space-2) 0 var(--space-3); }

.player-list { display: grid; gap: var(--space-2); font-size: 14px; color: var(--text); }
.player-list li { display: flex; align-items: center; gap: var(--space-2); }
.dot { width: 6px; height: 6px; border-radius: 50%; background: var(--accent); flex: none; }

/* ---------- 通用区块 ---------- */
.section { padding: 48px 0; }
.section-surface { background: var(--surface); }

.section-head { max-width: 720px; margin-bottom: var(--space-5); }
.section-title { font-size: 24px; }
.section-sub { color: var(--muted); margin: 0; }

/* ---------- 信任条 ---------- */
.trust-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: var(--space-3); }
.trust-item {
  padding: var(--space-4) var(--space-3);
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius-card);
  box-shadow: var(--shadow-card);
  transition: transform .2s ease, box-shadow .2s ease;
}
.trust-item:hover { transform: translateY(-3px); box-shadow: var(--shadow-hover); }
.trust-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 40px; height: 40px;
  margin-bottom: var(--space-3);
  border-radius: var(--radius-icon);
  background: var(--brand-soft);
  color: var(--brand);
}
.trust-num { font-size: 18px; font-weight: 700; color: var(--ink); margin: 0 0 var(--space-1); }
.trust-num .unit { display: block; font-size: 13px; font-weight: 500; color: var(--muted); margin-top: 2px; }
.trust-desc { font-size: 14px; color: var(--muted); margin: 0; }

/* ---------- 核心功能 ---------- */
.feature-row { display: grid; gap: var(--space-5); align-items: center; padding: var(--space-4) 0; }
.feature-text p { color: var(--text); }
.feature-media { margin: 0; }
.feature-media img {
  display: block;
  width: 100%;
  border: 1px solid var(--border);
  border-radius: var(--radius-card);
  box-shadow: var(--shadow-card);
  background: #fff;
}
.chip-list { display: flex; flex-wrap: wrap; gap: var(--space-2); }
.chip {
  display: inline-block;
  padding: 5px 12px;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius-pill);
  font-size: 13px;
  color: var(--text);
}

/* ---------- 场景矩阵 ---------- */
.scene-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: var(--space-3); }
.scene-card {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  padding: var(--space-4) var(--space-3);
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius-card);
  box-shadow: var(--shadow-card);
  transition: transform .2s ease, box-shadow .2s ease;
}
.scene-card:hover { transform: translateY(-3px); box-shadow: var(--shadow-hover); }
.scene-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px; height: 36px;
  border-radius: var(--radius-icon);
  background: var(--brand-soft);
  color: var(--brand);
}
.scene-card h3 { margin: var(--space-1) 0 0; font-size: 18px; }
.scene-card p { font-size: 14px; color: var(--muted); margin: 0 0 var(--space-2); }
.scene-link { font-weight: 600; margin-top: auto; }

.playlist-strip { margin-top: var(--space-5); }
.playlist-tag { display: inline-block; margin-bottom: var(--space-3); font-size: 13px; color: var(--muted); }
.playlist-scroll { display: flex; gap: var(--space-3); overflow-x: auto; padding-bottom: var(--space-2); -webkit-overflow-scrolling: touch; }
.playlist-item {
  flex: none;
  width: 148px;
  padding: var(--space-3);
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
}
.playlist-item p { font-size: 14px; font-weight: 500; margin: var(--space-2) 0 2px; }
.playlist-count { font-size: 12px; color: var(--muted); }
.playlist-cover {
  display: block;
  height: 96px;
  border-radius: var(--radius-icon);
  background: linear-gradient(135deg, #EDE9FE, #FDE68A);
}

/* ---------- AI 区块 ---------- */
.ai-inner { display: grid; gap: var(--space-5); align-items: center; }
.ai-points { display: grid; gap: var(--space-2); }
.ai-points li { position: relative; padding-left: var(--space-4); font-size: 15px; color: var(--text); }
.ai-points li::before {
  content: "";
  position: absolute;
  left: 0; top: 10px;
  width: 8px; height: 8px;
  border-radius: 50%;
  background: var(--success);
}

.ai-chat {
  padding: var(--space-4);
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius-card);
  box-shadow: var(--shadow-card);
}
.ai-bubble {
  display: inline-block;
  max-width: 100%;
  padding: 10px 14px;
  border-radius: var(--radius-sm);
  font-size: 14px;
  margin: 0 0 var(--space-2);
}
.ai-bubble-user { background: var(--brand); color: #fff; border-top-left-radius: 4px; }
.ai-bubble-bot { background: var(--surface); color: var(--text); border-top-left-radius: 4px; }
.ai-tags { display: flex; flex-wrap: wrap; gap: var(--space-2); margin: var(--space-3) 0; }
.ai-songs { display: grid; gap: var(--space-2); }
.ai-songs li {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-2) var(--space-3);
  background: var(--surface);
  border-radius: var(--radius-icon);
  font-size: 14px;
}
.ai-song-index { color: var(--muted); font-variant-numeric: tabular-nums; }
.ai-song-name { flex: 1; color: var(--text); }
.ai-song-tag { font-size: 12px; color: var(--brand); background: var(--brand-soft); padding: 2px 8px; border-radius: var(--radius-pill); }

/* ---------- 多端下载 ---------- */
.download-inner { text-align: center; }
.download-inner .section-sub { max-width: 560px; margin: 0 auto var(--space-5); }
.platform-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: var(--space-3); max-width: 720px; margin: 0 auto var(--space-5); }
.platform-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-4) var(--space-2);
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius-card);
}
.platform-icon { color: var(--brand); }
.platform-name { font-weight: 600; font-size: 15px; color: var(--ink); }

.download-actions { display: flex; flex-wrap: wrap; gap: var(--space-3); justify-content: center; }

/* ---------- 数据背书 ---------- */
.stat-grid { display: grid; gap: var(--space-3); margin-bottom: var(--space-5); }
.stat-item { padding: var(--space-4); background: var(--surface); border-radius: var(--radius-card); text-align: center; }
.stat-num { font-size: 22px; font-weight: 700; color: var(--brand); margin: 0 0 var(--space-1); }
.stat-label { font-size: 13px; color: var(--muted); margin: 0; }

.review-grid { display: grid; gap: var(--space-3); margin-bottom: var(--space-5); }
.review-card { padding: var(--space-4); background: #fff; border: 1px solid var(--border); border-radius: var(--radius-card); box-shadow: var(--shadow-card); }
.review-head { display: flex; align-items: center; gap: var(--space-3); margin-bottom: var(--space-3); }
.review-avatar {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  flex: none;
  width: 44px; height: 44px;
  border-radius: 50%;
  background: linear-gradient(135deg, #DDD6FE, #A78BFA);
  color: #3B0764;
  font-size: 17px;
  font-weight: 600;
}
.review-avatar-b { background: linear-gradient(135deg, #FDE68A, #F59E0B); color: #7C2D12; }
.review-avatar-c { background: linear-gradient(135deg, #A7F3D0, #10B981); color: #064E3B; }
.review-who { min-width: 0; }
.review-name { font-weight: 600; color: var(--ink); margin: 0 0 2px; }
.review-tag { font-size: 12px; color: var(--muted); margin: 0; }
.review-quote { font-size: 15px; color: var(--text); margin: 0 0 var(--space-3); }
.review-stars { color: var(--accent); margin: 0; letter-spacing: 2px; }

/* ---------- FAQ ---------- */
.faq-grid { display: grid; gap: var(--space-3); align-items: start; }
.faq-item {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius-card);
  padding: var(--space-3) var(--space-4);
}
.faq-item[open] { border-color: var(--brand); }
.faq-item summary {
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3);
  min-height: 32px;
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-q { font-size: 17px; font-weight: 600; color: var(--ink); line-height: 1.4; margin: 0; }
.faq-item summary::after {
  content: "+";
  flex: none;
  color: var(--brand);
  font-size: 20px;
  line-height: 1;
  transition: transform .2s ease;
}
.faq-item[open] summary::after { transform: rotate(45deg); }
.faq-a { margin: var(--space-3) 0 0; font-size: 15px; color: var(--text); }

/* ---------- 底部 CTA ---------- */
.cta-band {
  padding: 48px 0;
  background: linear-gradient(120deg, var(--brand) 0%, #7C3AED 55%, #4C1D95 100%);
  color: #fff;
}
.cta-inner { text-align: center; }
.cta-band .section-title { color: #fff; }
.cta-band .section-sub { color: rgba(255, 255, 255, .82); margin-bottom: var(--space-4); }
.cta-actions { display: flex; flex-wrap: wrap; gap: var(--space-3); justify-content: center; }

/* ---------- 页脚 ---------- */
.site-footer { background: #fff; border-top: 1px solid var(--border); padding: var(--space-6) 0 var(--space-4); }
.footer-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: var(--space-4); }
.footer-col h3 { font-size: 15px; margin: 0 0 var(--space-2); }
.footer-col ul { display: grid; gap: var(--space-2); }
.footer-col a { color: var(--muted); font-size: 14px; }
.footer-col a:hover { color: var(--brand); }
.social-list a { display: inline-flex; align-items: center; gap: var(--space-2); }
.social-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 28px; height: 28px;
  border-radius: var(--radius-icon);
  background: var(--surface);
  color: var(--text);
  font-size: 12px;
}

.footer-bottom {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  margin-top: var(--space-5);
  padding-top: var(--space-4);
  border-top: 1px solid var(--border);
}
.footer-bottom p { margin: 0; font-size: 13px; color: var(--muted); }
.footer-legal { display: flex; flex-wrap: wrap; gap: var(--space-2); font-size: 13px; color: var(--muted); }
.footer-legal a { color: var(--muted); }
.footer-legal a:hover { color: var(--brand); }

/* ---------- 内页 ---------- */
.page-hero { padding: var(--space-5) 0 var(--space-4); background: linear-gradient(180deg, #F4F1FE, #fff); }
.page-body { padding: var(--space-5) 0 var(--space-6); }
.page-body h2 { font-size: 20px; margin-top: var(--space-5); }
.page-body ul { list-style: disc; padding-left: 22px; color: var(--text); }
.page-body ul li { margin-bottom: var(--space-2); }
.page-body .container { max-width: 860px; }
.breadcrumb { font-size: 13px; color: var(--muted); margin: 0 0 var(--space-2); }
.breadcrumb a { color: var(--muted); }

/* ---------- 响应式增强（移动优先，向上叠加） ---------- */
@media (min-width: 576px) {
  h1 { font-size: 34px; }
  h2, .section-title { font-size: 28px; }
  .section { padding: 64px 0; }
  .section-head { margin-bottom: var(--space-6); }
  .stat-grid, .review-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (min-width: 768px) {
  h1 { font-size: 40px; }
  h2, .section-title { font-size: 30px; }

  .nav-toggle { display: none; }
  .nav {
    position: static;
    display: flex;
    flex-direction: row;
    align-items: center;
    gap: var(--space-5);
    padding: 0;
    background: transparent;
    border: 0;
    box-shadow: none;
  }
  .nav-list { flex-direction: row; gap: var(--space-1); }
  .nav-list a { padding: var(--space-2) var(--space-3); }

  .hero { padding: 72px 0; }
  .hero-inner { flex-direction: row; align-items: center; }
  .hero-copy { flex: 1 1 56%; }
  .hero-visual { flex: 1 1 44%; justify-content: flex-end; }

  .feature-row { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: var(--space-6); }
  .feature-row-reverse .feature-text { order: 2; }
  .feature-row-reverse .feature-media { order: 1; }

  .ai-inner { grid-template-columns: 1fr 1fr; gap: var(--space-6); }
  .trust-grid { grid-template-columns: repeat(4, minmax(0, 1fr)); }
  .scene-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .faq-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .platform-grid { grid-template-columns: repeat(4, minmax(0, 1fr)); }
  .footer-grid { grid-template-columns: repeat(4, minmax(0, 1fr)); }
  .footer-bottom { flex-direction: row; align-items: center; justify-content: space-between; }
}

@media (min-width: 992px) {
  h1 { font-size: 50px; }
  h2, .section-title { font-size: 34px; }
  .section { padding: 96px 0; }
  .hero { padding: 96px 0; }
  .cta-band { padding: 80px 0; }
  .scene-grid { grid-template-columns: repeat(4, minmax(0, 1fr)); }
  .stat-grid { grid-template-columns: repeat(3, minmax(0, 1fr)); }
  .review-grid { grid-template-columns: repeat(3, minmax(0, 1fr)); }
  .faq-grid { grid-template-columns: repeat(3, minmax(0, 1fr)); }
}

@media (min-width: 1200px) {
  .container { padding: 0 24px; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition: none !important; animation: none !important; }
}