/* ============================================================
   幼师音乐律动资源站 · style.css
   设计规范：莫兰迪低饱和 —— 低饱和高级灰 / 柔和过渡 / 克制装饰 / 大量留白
   配色与字体严格遵循给定规范，定义为一组 CSS 变量贯穿全站
   ============================================================ */

:root{
  /* ---- 规范配色 ---- */
  --c-primary:#497097;      /* 主色 */
  --c-secondary:#6062a9;    /* 辅助色 */
  --c-accent:#b94646;       /* 强调色 CTA/高亮 */
  --bg:#f8fafb;             /* 页面背景 */
  --card:#ffffff;           /* 卡片/表面 */
  --text:#1b242c;           /* 正文 */
  --text-muted:#5c6b7a;     /* 次要文字 */
  --border:#dbe0e6;         /* 描边 */

  /* ---- 派生（基于规范色值的克制过渡） ---- */
  --primary-soft:rgba(73,112,151,.10);
  --primary-soft-2:rgba(73,112,151,.06);
  --secondary-soft:rgba(96,98,169,.10);
  --accent-soft:rgba(185,70,70,.09);
  --ink-soft:rgba(27,36,44,.04);

  /* ---- 字体 ---- */
  --serif:'Noto Serif SC','Songti SC',Georgia,'Times New Roman',serif;
  --sans:system-ui,-apple-system,'PingFang SC','Microsoft YaHei','Segoe UI',sans-serif;

  /* ---- 圆角 / 阴影 / 过渡 ---- */
  --radius:14px;
  --radius-sm:10px;
  --shadow-soft:0 1px 2px rgba(27,36,44,.04),0 10px 28px rgba(27,36,44,.06);
  --shadow-lift:0 2px 6px rgba(27,36,44,.06),0 18px 44px rgba(27,36,44,.10);
  --ring:0 0 0 3px rgba(73,112,151,.16);
  --ease:cubic-bezier(.22,.61,.36,1);
}

/* ---------------- Reset / 基础 ---------------- */
*,*::before,*::after{box-sizing:border-box}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}
body{
  margin:0;
  font-family:var(--sans);
  color:var(--text);
  background:var(--bg);
  line-height:1.75;
  font-size:15.5px;
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
}
/* 极淡噪点叠加，克制装饰 */
body::before{
  content:"";
  position:fixed;inset:0;z-index:0;pointer-events:none;
  opacity:.035;
  background-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='120' height='120'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.9' numOctaves='2' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
}
body::after{
  content:"";
  position:fixed;inset:0;z-index:0;pointer-events:none;
  background:
    radial-gradient(1100px 460px at 82% -6%, rgba(73,112,151,.06), transparent 62%),
    radial-gradient(900px 420px at 6% 4%, rgba(96,98,169,.05), transparent 60%);
}
.wrap{position:relative;z-index:1}
h1,h2,h3,h4{font-family:var(--serif);font-weight:600;color:var(--text);margin:0 0 .55em;line-height:1.35;letter-spacing:.02em}
p{margin:0 0 1em}
a{color:var(--c-primary);text-decoration:none;transition:color .25s var(--ease)}
a:hover{color:var(--c-secondary)}
img{max-width:100%;display:block}
ul{margin:0;padding:0;list-style:none}
figure{margin:0}
button{font-family:inherit;cursor:pointer}
::selection{background:var(--primary-soft);color:var(--c-primary)}

/* ---------------- 布局容器 ---------------- */
.container{max-width:1180px;margin:0 auto;padding:0 28px}
.section{padding:72px 0}
.section-head{max-width:640px;margin-bottom:42px}
.section-head.center{margin-left:auto;margin-right:auto;text-align:center}
.eyebrow{
  display:inline-flex;align-items:center;gap:10px;
  font-size:12.5px;letter-spacing:.22em;text-transform:uppercase;
  color:var(--c-primary);font-weight:600;margin-bottom:14px;
}
.eyebrow::before{content:"";width:26px;height:1px;background:var(--c-primary);opacity:.55}
.section-head.center .eyebrow::before,.section-head.center .eyebrow::after{content:"";width:26px;height:1px;background:var(--c-primary);opacity:.55}
.section-head.center .eyebrow::before{margin-left:-10px}
.section-title{font-size:clamp(26px,3.4vw,34px);margin-bottom:12px}
.section-sub{color:var(--text-muted);font-size:15.5px;margin:0}

/* ---------------- 顶部导航 ---------------- */
.site-header{
  position:sticky;top:0;z-index:50;
  background:rgba(248,250,251,.86);
  -webkit-backdrop-filter:blur(12px);backdrop-filter:blur(12px);
  border-bottom:1px solid var(--border);
  transition:box-shadow .3s var(--ease);
}
.site-header.scrolled{box-shadow:0 6px 24px rgba(27,36,44,.05)}
.nav{display:flex;align-items:center;gap:28px;height:70px}
.brand{display:flex;align-items:center;gap:12px;margin-right:auto;color:var(--text)}
.brand-mark{
  width:40px;height:40px;border-radius:12px;
  background:var(--c-primary);color:#fff;
  display:grid;place-items:center;
  font-family:var(--serif);font-size:21px;font-weight:700;
  box-shadow:0 6px 16px rgba(73,112,151,.28);
  flex:none;
}
.brand-name{font-family:var(--serif);font-size:19px;font-weight:700;letter-spacing:.05em}
.brand-tag{display:block;font-family:var(--sans);font-size:10.5px;color:var(--text-muted);letter-spacing:.18em;font-weight:400;margin-top:-2px}
.nav-links{display:flex;align-items:center;gap:6px}
.nav-links a{
  position:relative;color:var(--text-muted);
  padding:9px 14px;border-radius:var(--radius-sm);
  font-size:14.5px;font-weight:500;transition:color .25s var(--ease),background .25s var(--ease);
}
.nav-links a:hover{color:var(--c-primary);background:var(--primary-soft-2)}
.nav-links a.active{color:var(--c-primary)}
.nav-links a.active::after{
  content:"";position:absolute;left:14px;right:14px;bottom:3px;height:2px;border-radius:2px;
  background:var(--c-primary);
}
.nav-cta{
  background:var(--c-accent);color:#fff!important;
  padding:9px 18px;border-radius:var(--radius-sm);
  font-weight:600;box-shadow:0 6px 16px rgba(185,70,70,.22);
}
.nav-cta:hover{background:#a63c3c!important;color:#fff!important}
.nav-burger{display:none;background:none;border:0;width:40px;height:40px;border-radius:10px;color:var(--text);font-size:22px;align-items:center;justify-content:center}
.nav-burger:hover{background:var(--primary-soft-2)}

/* ---------------- Hero ---------------- */
.hero{padding:96px 0 64px;border-bottom:1px solid var(--border);background:
  radial-gradient(900px 320px at 88% -10%, rgba(73,112,151,.08), transparent 60%),
  radial-gradient(700px 300px at 4% 0%, rgba(96,98,169,.06), transparent 55%);
}
.hero-inner{max-width:760px}
.hero-eyebrow{font-size:12.5px;letter-spacing:.24em;text-transform:uppercase;color:var(--c-secondary);font-weight:600;margin-bottom:20px;display:flex;align-items:center;gap:10px}
.hero-eyebrow::before{content:"";width:30px;height:1px;background:var(--c-secondary);opacity:.6}
.hero h1{font-size:clamp(32px,5vw,48px);line-height:1.28;margin-bottom:20px;letter-spacing:.03em}
.hero h1 .thin{font-weight:400;color:var(--c-primary)}
.hero p{color:var(--text-muted);font-size:17px;max-width:600px;margin-bottom:34px}
.hero-actions{display:flex;gap:14px;flex-wrap:wrap;align-items:center}
.hero-note{margin-top:22px;font-size:13px;color:var(--text-muted);display:flex;align-items:center;gap:8px}
.hero-note .dot{width:6px;height:6px;border-radius:50%;background:var(--c-primary);display:inline-block}

/* ---------------- 按钮 ---------------- */
.btn{
  display:inline-flex;align-items:center;gap:9px;justify-content:center;
  border-radius:var(--radius-sm);border:1px solid transparent;
  font-size:14.5px;font-weight:600;line-height:1;
  padding:13px 22px;transition:transform .2s var(--ease),box-shadow .25s var(--ease),background .25s var(--ease),color .25s var(--ease),border-color .25s var(--ease);
}
.btn:hover{transform:translateY(-1px)}
.btn:active{transform:translateY(0) scale(.99)}
.btn-primary{background:var(--c-primary);color:#fff;box-shadow:0 8px 20px rgba(73,112,151,.26)}
.btn-primary:hover{background:#3d6085;color:#fff;box-shadow:0 12px 26px rgba(73,112,151,.32)}
.btn-accent{background:var(--c-accent);color:#fff;box-shadow:0 8px 20px rgba(185,70,70,.24)}
.btn-accent:hover{background:#a63c3c;color:#fff;box-shadow:0 12px 26px rgba(185,70,70,.3)}
.btn-ghost{background:transparent;color:var(--c-primary);border-color:var(--c-primary);opacity:.9}
.btn-ghost:hover{background:var(--primary-soft);border-color:var(--c-primary);color:var(--c-primary)}
.btn-soft{background:var(--primary-soft);color:var(--c-primary);border-color:transparent}
.btn-soft:hover{background:rgba(73,112,151,.16);color:var(--c-primary)}
.btn-sm{padding:9px 14px;font-size:13px;border-radius:9px}
.btn-block{width:100%}
.btn[disabled]{opacity:.5;pointer-events:none}

/* ---------------- 统计条 ---------------- */
.stats{display:grid;grid-template-columns:repeat(4,1fr);gap:1px;background:var(--border);border:1px solid var(--border);border-radius:var(--radius);overflow:hidden;box-shadow:var(--shadow-soft)}
.stat{background:var(--card);padding:28px 20px;text-align:center}
.stat b{display:block;font-family:var(--serif);font-size:30px;font-weight:700;color:var(--c-primary);line-height:1.1;margin-bottom:6px}
.stat b em{font-style:normal;font-size:16px;margin-left:2px;color:var(--c-primary);opacity:.8}
.stat span{font-size:13px;color:var(--text-muted);letter-spacing:.08em}

/* ---------------- 筛选区 ---------------- */
.filter-bar{
  background:var(--card);border:1px solid var(--border);border-radius:var(--radius);
  padding:22px 24px;box-shadow:var(--shadow-soft);margin-bottom:34px;
  display:flex;flex-direction:column;gap:18px;
}
.filter-row{display:flex;align-items:center;gap:14px;flex-wrap:wrap}
.filter-label{font-size:12.5px;color:var(--text-muted);letter-spacing:.14em;flex:none;min-width:44px}
.chips{display:flex;gap:9px;flex-wrap:wrap}
.chip{
  border:1px solid var(--border);background:var(--bg);color:var(--text-muted);
  padding:7px 15px;border-radius:999px;font-size:13.5px;font-weight:500;
  transition:all .22s var(--ease);
}
.chip:hover{border-color:var(--c-primary);color:var(--c-primary)}
.chip.on{background:var(--c-primary);border-color:var(--c-primary);color:#fff;box-shadow:0 6px 14px rgba(73,112,151,.24)}
.search-box{position:relative;flex:1;min-width:220px;max-width:360px;margin-left:auto}
.search-box svg{position:absolute;left:13px;top:50%;transform:translateY(-50%);color:var(--text-muted);pointer-events:none}
.search-box input{
  width:100%;padding:10px 14px 10px 38px;border:1px solid var(--border);border-radius:999px;
  background:var(--bg);color:var(--text);font-family:inherit;font-size:14px;outline:none;
  transition:border-color .25s var(--ease),box-shadow .25s var(--ease),background .25s var(--ease);
}
.search-box input::placeholder{color:var(--text-muted);opacity:.75}
.search-box input:focus{border-color:var(--c-primary);box-shadow:var(--ring);background:var(--card)}

/* ---------------- 活动卡片 ---------------- */
.card-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:26px}
.activity-card{
  background:var(--card);border:1px solid var(--border);border-radius:var(--radius);
  overflow:hidden;box-shadow:var(--shadow-soft);display:flex;flex-direction:column;
  transition:transform .32s var(--ease),box-shadow .32s var(--ease),border-color .32s var(--ease);
  position:relative;
}
.activity-card:hover{transform:translateY(-5px);box-shadow:var(--shadow-lift);border-color:#c9d2dc}
.card-cover{position:relative;height:172px;display:grid;place-items:center;overflow:hidden;border-bottom:1px solid var(--border)}
.card-cover::before{content:"";position:absolute;inset:0;background:
  radial-gradient(420px 160px at 20% 0%, var(--cover-a), transparent 60%),
  radial-gradient(360px 150px at 85% 100%, var(--cover-b), transparent 60%),
  var(--cover-bg);
  transition:transform .5s var(--ease);}
.activity-card:hover .card-cover::before{transform:scale(1.06)}
.card-cover .cover-glyph{position:relative;z-index:1;width:74px;height:74px;border-radius:50%;background:rgba(255,255,255,.86);border:1px solid var(--border);display:grid;place-items:center;font-size:32px;box-shadow:0 10px 24px rgba(27,36,44,.10)}
.card-badge{
  position:absolute;top:14px;left:14px;z-index:2;
  background:rgba(255,255,255,.92);border:1px solid var(--border);
  color:var(--c-primary);font-size:12px;font-weight:600;letter-spacing:.06em;
  padding:4px 10px;border-radius:999px;
}
.card-body{padding:22px 24px 24px;display:flex;flex-direction:column;flex:1}
.card-meta{display:flex;gap:8px;flex-wrap:wrap;margin-bottom:12px}
.tag{
  display:inline-flex;align-items:center;gap:5px;
  font-size:12px;font-weight:600;padding:4px 10px;border-radius:8px;letter-spacing:.03em;
}
.tag-age{background:var(--primary-soft);color:var(--c-primary)}
.tag-theme{background:var(--secondary-soft);color:var(--c-secondary)}
.tag-diff{background:var(--accent-soft);color:var(--c-accent)}
.card-title{font-size:20px;margin-bottom:8px;line-height:1.4}
.card-title a{color:var(--text)}
.card-title a:hover{color:var(--c-primary)}
.card-desc{color:var(--text-muted);font-size:13.5px;margin-bottom:18px;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden}
.card-foot{margin-top:auto;display:flex;align-items:center;justify-content:space-between;border-top:1px solid var(--border);padding-top:14px}
.card-foot .mini{font-size:12.5px;color:var(--text-muted);display:inline-flex;align-items:center;gap:6px}
.card-link{font-size:13.5px;font-weight:600;color:var(--c-primary);display:inline-flex;align-items:center;gap:5px}
.card-link:hover{color:var(--c-secondary)}
.card-link svg{transition:transform .25s var(--ease)}
.card-link:hover svg{transform:translateX(3px)}

.empty-state{grid-column:1/-1;text-align:center;padding:60px 20px;color:var(--text-muted);background:var(--card);border:1px dashed var(--border);border-radius:var(--radius)}
.empty-state b{display:block;font-family:var(--serif);font-size:22px;color:var(--text);margin-bottom:8px}

/* ---------------- 面包屑 / 详情页 ---------------- */
.crumbs{display:flex;align-items:center;gap:8px;font-size:13px;color:var(--text-muted);padding:26px 0 8px;flex-wrap:wrap}
.crumbs a{color:var(--text-muted)}
.crumbs a:hover{color:var(--c-primary)}
.crumbs .sep{opacity:.5}
.crumbs .now{color:var(--text);font-weight:500}

.detail-hero{background:var(--card);border:1px solid var(--border);border-radius:var(--radius);box-shadow:var(--shadow-soft);padding:44px 46px;position:relative;overflow:hidden;margin-bottom:40px}
.detail-hero::before{content:"";position:absolute;left:0;top:0;bottom:0;width:4px;background:linear-gradient(var(--c-primary),var(--c-secondary))}
.detail-kicker{font-size:12.5px;letter-spacing:.2em;text-transform:uppercase;color:var(--c-secondary);font-weight:600;margin-bottom:14px}
.detail-title{font-size:clamp(26px,3.6vw,36px);line-height:1.35;margin-bottom:14px}
.detail-sub{color:var(--text-muted);font-size:15.5px;max-width:640px;margin-bottom:24px}
.detail-meta{display:flex;gap:12px;flex-wrap:wrap}
.meta-item{display:inline-flex;align-items:center;gap:8px;background:var(--bg);border:1px solid var(--border);border-radius:10px;padding:8px 14px;font-size:13px;color:var(--text-muted)}
.meta-item b{color:var(--text);font-weight:600}
.meta-item svg{color:var(--c-primary);flex:none}

.detail-layout{display:grid;grid-template-columns:minmax(0,1fr) 340px;gap:34px;align-items:start}
.detail-main{display:flex;flex-direction:column;gap:34px}
.detail-side{display:flex;flex-direction:column;gap:24px;position:sticky;top:96px}

/* ---------------- 视频 ---------------- */
.video-block{background:var(--card);border:1px solid var(--border);border-radius:var(--radius);overflow:hidden;box-shadow:var(--shadow-soft)}
.video-cover{
  position:relative;aspect-ratio:16/9;background:linear-gradient(135deg,#3c5a76,#4a6f93 55%,#6062a9);
  display:grid;place-items:center;cursor:pointer;overflow:hidden;
}
.video-cover::before{content:"";position:absolute;inset:0;background:radial-gradient(600px 240px at 70% 20%, rgba(255,255,255,.16), transparent 55%),radial-gradient(500px 220px at 15% 90%, rgba(96,98,169,.4), transparent 60%);}
.video-cover .vc-text{position:relative;z-index:1;text-align:center;color:#fff;padding:0 24px}
.video-cover .vc-glyph{font-size:44px;margin-bottom:10px;line-height:1}
.video-cover h3{color:#fff;font-size:22px;margin-bottom:6px}
.video-cover p{color:rgba(255,255,255,.82);font-size:13.5px;margin:0}
.play-btn{
  width:66px;height:66px;border-radius:50%;border:0;background:rgba(255,255,255,.94);
  color:var(--c-primary);font-size:22px;display:grid;place-items:center;margin:0 auto 14px;
  box-shadow:0 12px 28px rgba(0,0,0,.22);transition:transform .25s var(--ease),box-shadow .25s var(--ease);
}
.play-btn:hover{transform:scale(1.08);box-shadow:0 16px 34px rgba(0,0,0,.28)}
.video-frame-wrap{position:relative;aspect-ratio:16/9;background:#000}
.video-frame-wrap iframe{position:absolute;inset:0;width:100%;height:100%;border:0}
.video-caption{padding:13px 20px;font-size:12.5px;color:var(--text-muted);border-top:1px solid var(--border);display:flex;justify-content:space-between;gap:12px;flex-wrap:wrap}

/* ---------------- 区块卡片 ---------------- */
.panel{background:var(--card);border:1px solid var(--border);border-radius:var(--radius);box-shadow:var(--shadow-soft);padding:32px 34px}
.panel-head{display:flex;align-items:center;gap:14px;margin-bottom:24px}
.panel-index{
  width:40px;height:40px;flex:none;border-radius:12px;background:var(--primary-soft);
  color:var(--c-primary);display:grid;place-items:center;font-family:var(--serif);font-size:18px;font-weight:700;
}
.panel-title{font-size:20px;margin:0}
.panel-head .sub{color:var(--text-muted);font-size:13px;margin-left:auto;text-align:right}

/* 动作分解 */
.steps{display:flex;flex-direction:column;gap:0;counter-reset:step}
.step{display:flex;gap:20px;padding:20px 0;border-bottom:1px dashed var(--border);transition:background .25s var(--ease)}
.step:last-child{border-bottom:0}
.step:hover{background:var(--primary-soft-2);border-radius:var(--radius-sm);padding-left:12px;padding-right:12px}
.step-num{
  width:42px;height:42px;flex:none;border-radius:12px;border:1px solid var(--border);
  display:grid;place-items:center;font-family:var(--serif);font-weight:700;font-size:18px;color:var(--c-primary);
  background:var(--card);box-shadow:0 4px 10px rgba(27,36,44,.05);
}
.step h4{font-size:16.5px;margin:0 0 5px}
.step p{color:var(--text-muted);font-size:14px;margin:0}
.step-pose{font-size:26px;line-height:1;margin-right:2px}

/* 歌词 */
.lyrics-box{background:var(--bg);border:1px solid var(--border);border-radius:var(--radius-sm);padding:22px 24px}
.lyrics-box .verse{font-family:var(--serif);font-size:15.5px;line-height:2.1;color:var(--text);white-space:pre-line}
.lyrics-box .verse+.verse{margin-top:14px;padding-top:14px;border-top:1px solid var(--border)}
.lyrics-box .lyr-label{display:inline-block;font-size:11px;letter-spacing:.2em;color:var(--text-muted);margin-bottom:6px}

/* 音频试听 */
.track{display:flex;align-items:center;gap:14px;padding:14px 16px;border:1px solid var(--border);border-radius:var(--radius-sm);background:var(--card);margin-bottom:12px;transition:border-color .25s var(--ease),box-shadow .25s var(--ease)}
.track:last-child{margin-bottom:0}
.track:hover{border-color:#c9d2dc;box-shadow:var(--shadow-soft)}
.track-playing{border-color:var(--c-primary);box-shadow:0 0 0 3px var(--primary-soft)}
.track-btn{
  width:46px;height:46px;flex:none;border-radius:50%;border:1px solid var(--c-primary);
  background:var(--primary-soft);color:var(--c-primary);font-size:16px;
  display:grid;place-items:center;transition:all .22s var(--ease);
}
.track-btn:hover{background:var(--c-primary);color:#fff;box-shadow:0 6px 14px rgba(73,112,151,.3)}
.track-btn.playing{background:var(--c-primary);color:#fff}
.track-info{flex:1;min-width:0}
.track-info b{display:block;font-size:14.5px;font-weight:600;color:var(--text);white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.track-info span{font-size:12.5px;color:var(--text-muted)}
.track-bar{display:flex;align-items:center;gap:10px;margin-top:8px}
.track-bar .eq{display:flex;gap:3px;align-items:flex-end;height:16px}
.track-bar .eq i{width:3px;background:var(--c-primary);border-radius:2px;height:4px;transition:height .2s var(--ease)}
.track-bar .eq i.on{animation:eq .8s ease-in-out infinite}
.track-bar .eq i.on:nth-child(2){animation-delay:.12s}
.track-bar .eq i.on:nth-child(3){animation-delay:.24s}
.track-bar .eq i.on:nth-child(4){animation-delay:.36s}
@keyframes eq{0%,100%{height:4px}50%{height:15px}}
.track-time{font-size:12px;color:var(--text-muted);font-variant-numeric:tabular-nums}

/* 教学建议 / 材料清单 */
.tips{display:grid;grid-template-columns:1fr 1fr;gap:14px}
.tip{background:var(--bg);border:1px solid var(--border);border-radius:var(--radius-sm);padding:16px 18px;display:flex;gap:12px}
.tip .t-ico{flex:none;width:30px;height:30px;border-radius:9px;background:var(--secondary-soft);color:var(--c-secondary);display:grid;place-items:center;font-size:15px}
.tip p{margin:0;font-size:13.5px;color:var(--text-muted)}
.tip b{color:var(--text);display:block;font-size:13.5px;margin-bottom:2px}

.material-list{border:1px solid var(--border);border-radius:var(--radius-sm);overflow:hidden}
.material-list li{display:flex;align-items:center;gap:14px;padding:14px 18px;border-bottom:1px solid var(--border);background:var(--card)}
.material-list li:last-child{border-bottom:0}
.material-list .m-ico{width:38px;height:38px;flex:none;border-radius:10px;background:var(--primary-soft);color:var(--c-primary);display:grid;place-items:center;font-size:17px}
.material-list .m-info{flex:1;min-width:0}
.material-list .m-info b{display:block;font-size:14px;font-weight:600}
.material-list .m-info span{font-size:12px;color:var(--text-muted)}
.material-list .dl-link{font-size:12.5px;font-weight:600;color:var(--c-accent);white-space:nowrap;display:inline-flex;align-items:center;gap:4px}
.material-list .dl-link:hover{color:#a63c3c}

/* 侧栏 */
.side-card{background:var(--card);border:1px solid var(--border);border-radius:var(--radius);box-shadow:var(--shadow-soft);padding:26px 26px}
.side-card h3{font-size:17px;margin-bottom:18px;display:flex;align-items:center;gap:10px}
.side-card h3::before{content:"";width:3px;height:18px;border-radius:2px;background:linear-gradient(var(--c-primary),var(--c-secondary))}
.side-info{display:flex;flex-direction:column;gap:0}
.side-info li{display:flex;justify-content:space-between;padding:11px 0;border-bottom:1px dashed var(--border);font-size:14px}
.side-info li:last-child{border-bottom:0}
.side-info .k{color:var(--text-muted)}
.side-info .v{font-weight:600;color:var(--text)}
.diff-dots{display:inline-flex;gap:4px;align-items:center}
.diff-dots i{width:8px;height:8px;border-radius:50%;background:var(--border)}
.diff-dots i.fill{background:var(--c-accent)}

.related{display:flex;flex-direction:column;gap:10px}
.related a{display:flex;align-items:center;gap:12px;background:var(--bg);border:1px solid var(--border);border-radius:var(--radius-sm);padding:12px 14px;transition:all .22s var(--ease)}
.related a:hover{border-color:var(--c-primary);background:var(--primary-soft-2)}
.related .r-g{width:44px;height:44px;flex:none;border-radius:10px;display:grid;place-items:center;font-size:21px;background:var(--card);border:1px solid var(--border)}
.related b{display:block;font-size:13.5px;color:var(--text);font-weight:600}
.related span{font-size:11.5px;color:var(--text-muted)}

/* ---------------- 教师交流区 ---------------- */
.discussion{background:var(--card);border:1px solid var(--border);border-radius:var(--radius);box-shadow:var(--shadow-soft);padding:34px 36px}
.disc-head{display:flex;align-items:flex-end;gap:16px;margin-bottom:24px;flex-wrap:wrap}
.disc-head .eyebrow{margin-bottom:6px}
.disc-head .count{font-size:13px;color:var(--text-muted);margin-left:auto;background:var(--bg);border:1px solid var(--border);padding:5px 12px;border-radius:999px}
.comment{display:flex;gap:16px;padding:22px 0;border-bottom:1px solid var(--border)}
.comment:last-of-type{border-bottom:0}
.avatar{
  width:44px;height:44px;flex:none;border-radius:50%;display:grid;place-items:center;
  font-family:var(--serif);font-size:17px;color:#fff;font-weight:600;
}
.comment-main{flex:1;min-width:0}
.comment-top{display:flex;align-items:center;gap:12px;flex-wrap:wrap;margin-bottom:6px}
.comment-name{font-size:14px;font-weight:600}
.comment-role{font-size:12px;color:var(--c-secondary);background:var(--secondary-soft);padding:2px 9px;border-radius:999px}
.comment-time{font-size:12px;color:var(--text-muted)}
.comment p{font-size:14px;color:var(--text);margin:0;line-height:1.8}
.comment .like{margin-top:10px;font-size:12px;color:var(--text-muted);display:inline-flex;align-items:center;gap:5px;background:none;border:0;padding:4px 10px;border-radius:8px;transition:color .2s var(--ease)}
.comment .like:hover{color:var(--c-accent)}
.comment .like.on{color:var(--c-accent)}

.comment-form{margin-top:26px;background:var(--bg);border:1px solid var(--border);border-radius:var(--radius-sm);padding:22px}
.comment-form h4{font-size:15px;margin-bottom:14px}
.form-row{display:grid;grid-template-columns:1fr 1fr;gap:12px;margin-bottom:12px}
.form-row input,.comment-form textarea{
  width:100%;border:1px solid var(--border);border-radius:var(--radius-sm);background:var(--card);
  padding:11px 14px;font-family:inherit;font-size:14px;color:var(--text);outline:none;transition:border-color .22s var(--ease),box-shadow .22s var(--ease);
}
.comment-form textarea{min-height:92px;resize:vertical;margin-bottom:12px}
.form-row input:focus,.comment-form textarea:focus{border-color:var(--c-primary);box-shadow:var(--ring)}
.form-foot{display:flex;align-items:center;justify-content:space-between;gap:12px;flex-wrap:wrap}
.form-hint{font-size:12px;color:var(--text-muted)}

/* ---------------- 下载页 ---------------- */
.dl-intro{background:var(--card);border:1px solid var(--border);border-radius:var(--radius);box-shadow:var(--shadow-soft);padding:38px 42px;margin-bottom:44px;display:grid;grid-template-columns:1fr auto;gap:28px;align-items:center}
.dl-intro h2{font-size:26px;margin-bottom:10px}
.dl-intro p{color:var(--text-muted);margin:0;max-width:520px;font-size:14.5px}
.pack-group{margin-bottom:44px}
.pack-group-head{display:flex;align-items:center;gap:16px;margin-bottom:22px}
.pack-age{
  width:52px;height:52px;flex:none;border-radius:var(--radius-sm);
  background:var(--c-primary);color:#fff;display:grid;place-items:center;
  font-family:var(--serif);font-weight:700;font-size:22px;box-shadow:0 8px 18px rgba(73,112,151,.28);
}
.pack-group-head h3{font-size:22px;margin:0}
.pack-group-head p{margin:2px 0 0;color:var(--text-muted);font-size:13px}
.pack-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:22px}
.pack-card{background:var(--card);border:1px solid var(--border);border-radius:var(--radius);box-shadow:var(--shadow-soft);padding:24px;display:flex;flex-direction:column;transition:transform .3s var(--ease),box-shadow .3s var(--ease)}
.pack-card:hover{transform:translateY(-4px);box-shadow:var(--shadow-lift)}
.pack-card .pc-ico{width:52px;height:52px;border-radius:14px;background:var(--secondary-soft);color:var(--c-secondary);display:grid;place-items:center;font-size:24px;margin-bottom:16px}
.pack-card h4{font-size:17px;margin-bottom:6px}
.pack-card .pc-desc{color:var(--text-muted);font-size:13px;margin-bottom:14px;flex:1}
.pack-files{border-top:1px dashed var(--border);padding-top:14px;margin-bottom:16px;display:flex;flex-direction:column;gap:8px}
.pack-files li{display:flex;align-items:center;gap:8px;font-size:13px;color:var(--text-muted)}
.pack-files li svg{color:var(--c-primary);flex:none}
.pack-foot{display:flex;align-items:center;justify-content:space-between;gap:10px}
.pack-size{font-size:12px;color:var(--text-muted)}
.note-card{display:flex;gap:16px;background:var(--accent-soft);border:1px solid rgba(185,70,70,.24);border-radius:var(--radius);padding:22px 26px;margin-bottom:44px}
.note-card .n-ico{flex:none;width:40px;height:40px;border-radius:12px;background:var(--c-accent);color:#fff;display:grid;place-items:center;font-size:19px}
.note-card b{display:block;margin-bottom:4px;color:var(--c-accent);font-size:15px}
.note-card p{margin:0;color:var(--text-muted);font-size:13.5px}
.faq{background:var(--card);border:1px solid var(--border);border-radius:var(--radius);box-shadow:var(--shadow-soft);padding:30px 34px}
.faq-item{border-bottom:1px solid var(--border)}
.faq-item:last-child{border-bottom:0}
.faq-q{width:100%;text-align:left;background:none;border:0;padding:18px 0;font-family:var(--serif);font-size:16px;font-weight:600;color:var(--text);display:flex;align-items:center;gap:12px;transition:color .22s var(--ease)}
.faq-q:hover{color:var(--c-primary)}
.faq-q .fi{width:26px;height:26px;flex:none;border-radius:8px;border:1px solid var(--border);display:grid;place-items:center;font-size:14px;color:var(--c-primary);transition:all .25s var(--ease)}
.faq-item.open .fi{background:var(--c-primary);color:#fff;transform:rotate(45deg)}
.faq-a{max-height:0;overflow:hidden;transition:max-height .35s var(--ease)}
.faq-a p{margin:0;padding:0 0 20px;color:var(--text-muted);font-size:14px;max-width:720px}

/* ---------------- 页脚 ---------------- */
.site-footer{background:#2b3440;color:#b9c4d0;margin-top:72px}
.footer-inner{display:grid;grid-template-columns:1.4fr 1fr 1fr;gap:40px;padding:54px 0 40px}
.footer-brand{display:flex;align-items:center;gap:12px;margin-bottom:16px}
.footer-brand .brand-mark{background:rgba(255,255,255,.12);box-shadow:none;color:#fff}
.footer-brand b{color:#fff;font-family:var(--serif);font-size:18px;letter-spacing:.05em}
.footer-about{font-size:13.5px;line-height:1.9;max-width:340px;margin:0}
.footer-col h4{color:#fff;font-size:15px;margin-bottom:16px;font-weight:600}
.footer-col ul{display:flex;flex-direction:column;gap:10px}
.footer-col a{color:#b9c4d0;font-size:13.5px;transition:color .22s var(--ease)}
.footer-col a:hover{color:#fff}
.footer-bottom{border-top:1px solid rgba(255,255,255,.1);padding:20px 0;font-size:12.5px;color:#8b98a6;display:flex;justify-content:space-between;gap:12px;flex-wrap:wrap}

/* ---------------- 浮动回到顶部 ---------------- */
.to-top{
  position:fixed;right:26px;bottom:26px;z-index:40;width:46px;height:46px;border-radius:50%;
  border:1px solid var(--border);background:var(--card);color:var(--c-primary);font-size:18px;
  box-shadow:var(--shadow-soft);display:grid;place-items:center;opacity:0;pointer-events:none;
  transform:translateY(10px);transition:all .3s var(--ease);
}
.to-top.show{opacity:1;pointer-events:auto;transform:none}
.to-top:hover{background:var(--c-primary);color:#fff}

/* ---------------- 弹窗（下载） ---------------- */
.modal-mask{position:fixed;inset:0;z-index:80;background:rgba(27,36,44,.4);display:grid;place-items:center;padding:20px;opacity:0;pointer-events:none;transition:opacity .28s var(--ease)}
.modal-mask.open{opacity:1;pointer-events:auto}
.modal{
  background:var(--card);border-radius:var(--radius);box-shadow:var(--shadow-lift);max-width:460px;width:100%;
  padding:34px 34px 30px;transform:translateY(16px) scale(.98);transition:transform .3s var(--ease);
}
.modal-mask.open .modal{transform:none}
.modal .m-ico{width:56px;height:56px;border-radius:16px;background:var(--accent-soft);color:var(--c-accent);display:grid;place-items:center;font-size:26px;margin-bottom:18px}
.modal h3{font-size:21px;margin-bottom:10px}
.modal p{color:var(--text-muted);font-size:14px;margin-bottom:18px}
.modal .fileline{display:flex;align-items:center;gap:8px;font-size:13.5px;color:var(--text);padding:8px 12px;background:var(--bg);border-radius:9px;margin-bottom:7px}
.modal .fileline svg{color:var(--c-primary)}
.modal-actions{display:flex;gap:10px;margin-top:22px}

/* ---------------- 动画 ---------------- */
.reveal{opacity:0;transform:translateY(22px);transition:opacity .7s var(--ease),transform .7s var(--ease)}
.reveal.in{opacity:1;transform:none}
.reveal-d1{transition-delay:.06s}
.reveal-d2{transition-delay:.12s}
.reveal-d3{transition-delay:.18s}

@keyframes fadeUp{from{opacity:0;transform:translateY(14px)}to{opacity:1;transform:none}}
.fade-in{animation:fadeUp .6s var(--ease) both}

@media (prefers-reduced-motion:reduce){
  *{animation:none!important;transition:none!important}
  .reveal{opacity:1;transform:none}
}

/* ---------------- 响应式 ---------------- */
@media (max-width:980px){
  .card-grid,.pack-grid{grid-template-columns:repeat(2,1fr)}
  .detail-layout{grid-template-columns:1fr}
  .detail-side{position:static;order:-1}
  .stats{grid-template-columns:repeat(2,1fr)}
}
@media (max-width:720px){
  .container{padding:0 18px}
  .section{padding:52px 0}
  .hero{padding:64px 0 48px}
  .nav-links{
    position:fixed;top:70px;left:0;right:0;background:var(--bg);
    flex-direction:column;align-items:stretch;padding:14px 18px 20px;gap:4px;
    border-bottom:1px solid var(--border);box-shadow:var(--shadow-soft);
    display:none;
  }
  .nav-links.open{display:flex}
  .nav-links a{padding:13px 14px}
  .nav-links a.active::after{left:14px;bottom:8px;right:auto;width:26px}
  .nav-cta{margin-top:8px;text-align:center}
  .nav-burger{display:inline-flex}
  .nav .nav-cta{display:none}
  .card-grid,.pack-grid{grid-template-columns:1fr}
  .detail-hero{padding:30px 26px}
  .panel{padding:24px 20px}
  .tips{grid-template-columns:1fr}
  .footer-inner{grid-template-columns:1fr;gap:28px;padding:40px 0 30px}
  .dl-intro{grid-template-columns:1fr;padding:28px 24px}
  .form-row{grid-template-columns:1fr}
  .discussion{padding:24px 20px}
  .stats{grid-template-columns:repeat(2,1fr)}
  .stat b{font-size:24px}
}