/* ============================================================
 * 学习频道（课程商城）样式
 * 布局参考中公教育首页：考试项目导航 → 主推位 + 数据条 → 课程筛选 → 卡片网格 → 热门榜
 * ============================================================ */
.st-wrap{max-width:1180px;margin:0 auto;padding:16px 14px 40px}
.st-hero{background:linear-gradient(120deg,#fff1e8 0%,#ffe4d4 42%,#ffd9c2 100%);border-radius:16px;padding:22px 24px;display:grid;grid-template-columns:1.45fr .85fr;gap:20px;align-items:center}
.st-hero-left h1{margin:0 0 8px;font-size:26px;line-height:1.35;color:#3a2b23}
.st-hero-left h1 em{font-style:normal;color:#ff6b35}
.st-hero-left p{margin:0 0 14px;color:#8a6a58;font-size:13.5px;line-height:1.8}
.st-hero-tags{display:flex;flex-wrap:wrap;gap:8px;margin-bottom:14px}
.st-hero-tags span{background:rgba(255,255,255,.75);border:1px solid #ffd6c0;color:#d0603a;font-size:12.5px;border-radius:20px;padding:3px 12px}
.st-hero-search{display:flex;gap:8px;max-width:460px}
.st-hero-search input{flex:1;height:40px;border:1px solid #ffcdb4;border-radius:10px;padding:0 14px;font-size:14px;background:#fff;outline:0}
.st-hero-search input:focus{border-color:#ff6b35;box-shadow:0 0 0 3px rgba(255,107,53,.12)}
.st-hero-search button{height:40px;padding:0 20px;border:0;border-radius:10px;background:#ff6b35;color:#fff;font-size:14px;cursor:pointer}
.st-hero-search button:hover{background:#f25a24}
.st-hero-stats{display:grid;grid-template-columns:repeat(3,1fr);gap:10px}
.st-hero-stats .it{background:rgba(255,255,255,.82);border-radius:12px;padding:12px 10px;text-align:center}
.st-hero-stats .it b{display:block;font-size:20px;color:#ff6b35;line-height:1.5}
.st-hero-stats .it span{color:#8a6a58;font-size:12px}

/* 考试项目导航 */
.st-nav{margin:16px 0;background:#fff;border:1px solid #f0f2f6;border-radius:14px;padding:8px;display:flex;gap:6px;overflow-x:auto;scrollbar-width:none}
.st-nav::-webkit-scrollbar{display:none}
.st-nav a{flex:0 0 auto;display:flex;align-items:center;gap:6px;padding:9px 16px;border-radius:10px;font-size:14px;color:#4b5563;text-decoration:none;white-space:nowrap}
.st-nav a i{font-style:normal;font-size:16px}
.st-nav a:hover{background:#fff6f1;color:#ff6b35}
.st-nav a.on{background:#ff6b35;color:#fff;font-weight:600}
.st-nav a .n{font-size:11.5px;opacity:.7}

/* 主推 + 热门榜 */
.st-top{display:grid;grid-template-columns:1fr 320px;gap:14px;margin-bottom:16px}
.st-sec{background:#fff;border:1px solid #f0f2f6;border-radius:14px;overflow:hidden}
.st-sec-head{display:flex;align-items:center;justify-content:space-between;padding:12px 16px;border-bottom:1px solid #f4f6fa}
.st-sec-head h3{margin:0;font-size:15px;color:#2f3439;display:flex;align-items:center;gap:8px}
.st-sec-head h3:before{content:'';width:4px;height:15px;border-radius:2px;background:#ff6b35}
.st-sec-head a{font-size:12.5px;color:#8a919f;text-decoration:none}
.st-sec-head a:hover{color:#ff6b35}
.st-sec-body{padding:14px 16px}
.st-rec{display:grid;grid-template-columns:repeat(2,1fr);gap:12px}
.st-rec .rc{display:flex;gap:10px;border:1px solid #f0f2f6;border-radius:12px;padding:10px;text-decoration:none;transition:.15s}
.st-rec .rc:hover{border-color:#ffd0b8;box-shadow:0 6px 16px rgba(255,107,53,.1);transform:translateY(-2px)}
.st-rec .rc img{width:96px;height:62px;border-radius:8px;object-fit:cover;background:#f4f6fa;flex:0 0 auto}
.st-rec .rc .m{min-width:0;display:flex;flex-direction:column;justify-content:center}
.st-rec .rc .m b{font-size:13.5px;color:#2f3439;line-height:1.5;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden}
.st-rec .rc .m .p{margin-top:6px;color:#ff6b35;font-weight:600;font-size:14px}
.st-rec .rc .m .p s{color:#b9bfc9;font-weight:400;font-size:12px;margin-left:5px}

.st-rank{display:flex;flex-direction:column;gap:2px}
.st-rank a{display:flex;align-items:center;gap:10px;padding:8px 6px;border-radius:8px;text-decoration:none;color:#4b5563;font-size:13.5px}
.st-rank a:hover{background:#fff6f1}
.st-rank a .no{flex:0 0 20px;height:20px;line-height:20px;text-align:center;border-radius:5px;background:#f2f4f8;color:#8a919f;font-size:11.5px}
.st-rank a:nth-child(1) .no{background:#ff6b35;color:#fff}
.st-rank a:nth-child(2) .no{background:#ffa06b;color:#fff}
.st-rank a:nth-child(3) .no{background:#ffc9a8;color:#fff}
.st-rank a .t{flex:1;min-width:0;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.st-rank a .h{color:#a6adb9;font-size:12px}

/* 筛选条 */
.st-filter{display:flex;flex-wrap:wrap;gap:10px;align-items:center;margin-bottom:14px;background:#fff;border:1px solid #f0f2f6;border-radius:14px;padding:10px 14px}
.st-filter .fs{display:flex;gap:4px;background:#f6f8fb;border-radius:9px;padding:3px}
.st-filter .fs a{padding:6px 14px;border-radius:7px;font-size:13px;color:#5b6472;text-decoration:none}
.st-filter .fs a.on{background:#fff;color:#ff6b35;font-weight:600;box-shadow:0 1px 4px rgba(20,30,50,.08)}
.st-filter .sp{flex:1}
.st-filter .cnt{color:#8a919f;font-size:12.5px}

/* 课程卡片 */
.st-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:14px}
.st-card{background:#fff;border:1px solid #f0f2f6;border-radius:14px;overflow:hidden;display:flex;flex-direction:column;text-decoration:none;transition:.16s}
.st-card:hover{transform:translateY(-3px);box-shadow:0 12px 26px rgba(30,40,60,.1);border-color:#ffd9c2}
.st-card-media{position:relative;aspect-ratio:16/9;background:#f4f6fa}
.st-card-media img{width:100%;height:100%;object-fit:cover;display:block}
.st-card-media .ph{width:100%;height:100%;display:flex;align-items:center;justify-content:center;font-size:26px;color:#cbd3de}
.st-card-badge{position:absolute;top:8px;left:8px;background:rgba(255,107,53,.95);color:#fff;font-size:11.5px;border-radius:5px;padding:2px 7px}
.st-card-badge.free{background:rgba(26,156,74,.95)}
.st-card-body{padding:10px 12px 12px;display:flex;flex-direction:column;flex:1}
.st-card-body h4{margin:0 0 6px;font-size:14px;color:#2f3439;line-height:1.45;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden}
.st-card-body .sub{color:#8a919f;font-size:12px;line-height:1.5;display:-webkit-box;-webkit-line-clamp:1;-webkit-box-orient:vertical;overflow:hidden;min-height:18px}
.st-card-body .tch{color:#6b7480;font-size:12px;margin-top:7px;display:flex;align-items:center;gap:5px}
.st-card-body .tch i{font-style:normal;width:18px;height:18px;border-radius:50%;background:#fff1e8;color:#ff6b35;font-size:11px;display:flex;align-items:center;justify-content:center}
.st-card-foot{margin-top:auto;padding-top:9px;display:flex;align-items:flex-end;justify-content:space-between}
.st-card-price{color:#ff6b35;font-weight:700;font-size:16px;line-height:1.2}
.st-card-price.free-price{color:#1a9c4a}
.st-card-price small{font-size:12px;font-weight:400}
.st-card-price s{color:#b9bfc9;font-weight:400;font-size:12px;margin-left:4px}
.st-card-num{color:#a6adb9;font-size:12px}
.st-empty{grid-column:1/-1;text-align:center;color:#8a919f;padding:48px 0;font-size:13.5px}
.st-pager{display:flex;justify-content:center;margin-top:22px}
.st-pager ul{display:flex;gap:6px;list-style:none;padding:0;margin:0}
.st-pager li a,.st-pager li span{display:block;min-width:34px;height:34px;line-height:34px;text-align:center;border:1px solid #eef0f4;border-radius:9px;color:#5b6472;font-size:13px;text-decoration:none;background:#fff;padding:0 8px}
.st-pager li.active span{background:#ff6b35;border-color:#ff6b35;color:#fff}
.st-pager li a:hover{border-color:#ffd0b8;color:#ff6b35}

/* 底部说明 */
.st-tips{margin-top:20px;background:#fff;border:1px solid #f0f2f6;border-radius:14px;padding:14px 16px;color:#8a919f;font-size:12.5px;line-height:2}
.st-tips b{color:#5b6472}

/* ---------------- 课程详情 ---------------- */
.st-detail{display:grid;grid-template-columns:1fr 320px;gap:16px;align-items:start}
.st-crumb{max-width:1180px;margin:14px auto 0;padding:0 14px;color:#8a919f;font-size:12.5px}
.st-crumb a{color:#8a919f;text-decoration:none}
.st-crumb a:hover{color:#ff6b35}
.st-crumb em{font-style:normal;color:#5b6472}
.st-chead{background:#fff;border:1px solid #f0f2f6;border-radius:16px;padding:18px;display:grid;grid-template-columns:300px 1fr;gap:18px}
.st-chead-cover{aspect-ratio:16/9;border-radius:12px;overflow:hidden;background:#f4f6fa;position:relative}
.st-chead-cover img{width:100%;height:100%;object-fit:cover;display:block}
.st-chead-cover .ph{width:100%;height:100%;display:flex;align-items:center;justify-content:center;font-size:34px;color:#cbd3de}
.st-chead-info h1{margin:0 0 8px;font-size:21px;line-height:1.4;color:#2f3439}
.st-chead-info .sub{color:#8a919f;font-size:13px;line-height:1.7;margin:0 0 10px}
.st-chip{display:inline-flex;align-items:center;gap:5px;background:#fff6f1;color:#e2542a;border-radius:6px;padding:2px 9px;font-size:12px;margin:0 6px 6px 0}
.st-chip.gray{background:#f4f6fa;color:#6b7480}
.st-chead-data{display:flex;flex-wrap:wrap;gap:16px;color:#8a919f;font-size:12.5px;margin:10px 0 12px}
.st-chead-data b{color:#2f3439;font-size:13.5px}
.st-buybar{display:flex;align-items:center;gap:12px;flex-wrap:wrap;border-top:1px dashed #eef0f4;padding-top:12px}
.st-price-big{color:#ff6b35;font-weight:700;font-size:24px;line-height:1.1}
.st-price-big.free{color:#1a9c4a}
.st-price-big s{color:#b9bfc9;font-weight:400;font-size:13px;margin-left:6px}
.st-btn{display:inline-block;padding:10px 26px;border-radius:10px;background:#ff6b35;color:#fff;font-size:14.5px;text-decoration:none;border:0;cursor:pointer}
.st-btn:hover{background:#f25a24}
.st-btn.ghost{background:#fff6f1;color:#e2542a}
.st-btn.ghost:hover{background:#ffe8dc}
.st-btn.green{background:#22a95b}
.st-btn.green:hover{background:#1c9250}
.st-btn.earn{background:linear-gradient(135deg,#ffb020,#ff8f00);color:#fff}
.st-btn.earn:hover{background:linear-gradient(135deg,#ffa414,#ef8300)}
.st-btn[disabled],.st-btn.disabled{background:#eceff4;color:#a6adb9;cursor:not-allowed}
.st-progress{margin-top:10px;display:flex;align-items:center;gap:10px;font-size:12.5px;color:#8a919f}
.st-progress .bar{flex:1;height:8px;border-radius:6px;background:#f2f4f8;overflow:hidden;max-width:280px}
.st-progress .bar i{display:block;height:100%;background:linear-gradient(90deg,#ff9a5b,#ff6b35)}

/* 目录 */
.st-lessons{background:#fff;border:1px solid #f0f2f6;border-radius:16px;overflow:hidden;margin-top:16px}
.st-tabs{display:flex;gap:4px;padding:10px 14px 0;border-bottom:1px solid #f4f6fa}
.st-tabs button{background:0;border:0;padding:10px 16px;font-size:14px;color:#6b7480;cursor:pointer;border-bottom:2px solid transparent}
.st-tabs button.on{color:#ff6b35;font-weight:600;border-bottom-color:#ff6b35}
.st-tab-pane{padding:16px}
.st-lgroup{margin-bottom:16px}
.st-lgroup h4{margin:0 0 8px;font-size:14px;color:#2f3439;display:flex;align-items:center;gap:8px}
.st-lgroup h4:before{content:'';width:3px;height:14px;border-radius:2px;background:#ffb28a}
.st-lrow{display:flex;align-items:center;gap:12px;padding:10px 12px;border:1px solid #f4f6fa;border-radius:10px;margin-bottom:6px}
.st-lrow:hover{border-color:#ffd9c2;background:#fffaf7}
.st-lrow .no{flex:0 0 26px;height:26px;line-height:26px;text-align:center;border-radius:7px;background:#f6f8fb;color:#8a919f;font-size:12px}
.st-lrow .tt{flex:1;min-width:0;font-size:13.5px;color:#3f4650;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.st-lrow .du{color:#a6adb9;font-size:12.5px}
.st-lrow .act{flex:0 0 auto}
.st-lrow .act a,.st-lrow .act span{display:inline-block;padding:5px 14px;border-radius:8px;font-size:12.5px;text-decoration:none;background:#fff6f1;color:#e2542a;cursor:pointer}
.st-lrow .act span.lock{background:#f4f6fa;color:#a6adb9;cursor:not-allowed}
.st-lrow .act a.try{background:#e9f8ee;color:#1a9c4a}
.st-ldone{color:#22a95b;font-size:12.5px;flex:0 0 auto}
.st-intro{color:#4b5563;font-size:14px;line-height:2}
.st-intro img{max-width:100%;height:auto;border-radius:8px}
.st-intro h2,.st-intro h3{margin:16px 0 8px;font-size:16px;color:#2f3439}

/* 侧栏 */
.st-side-card{background:#fff;border:1px solid #f0f2f6;border-radius:14px;padding:14px;margin-bottom:14px}
.st-side-card h4{margin:0 0 10px;font-size:14px;color:#2f3439;display:flex;align-items:center;gap:8px}
.st-side-card h4:before{content:'';width:3px;height:13px;border-radius:2px;background:#ff6b35}
.st-tch-card{display:flex;align-items:center;gap:12px}
.st-tch-card .av{width:52px;height:52px;border-radius:50%;background:#fff1e8;color:#ff6b35;display:flex;align-items:center;justify-content:center;font-size:20px;overflow:hidden;flex:0 0 auto}
.st-tch-card .av img{width:100%;height:100%;object-fit:cover}
.st-tch-card .m b{display:block;font-size:14px;color:#2f3439}
.st-tch-card .m span{color:#8a919f;font-size:12.5px}
.st-rel a{display:flex;gap:10px;padding:8px 0;text-decoration:none;border-bottom:1px dashed #f4f6fa}
.st-rel a:last-child{border-bottom:0}
.st-rel a img{width:84px;height:54px;border-radius:8px;object-fit:cover;background:#f4f6fa;flex:0 0 auto}
.st-rel a .m{min-width:0}
.st-rel a .m b{display:block;font-size:13px;color:#3f4650;line-height:1.5;display:-webkit-box;-webkit-box-lines:2;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden}
.st-rel a .m .p{color:#ff6b35;font-size:13px;font-weight:600;margin-top:4px}

/* 播放器弹层 */
.st-player{position:fixed;inset:0;background:rgba(12,16,24,.82);z-index:300;display:flex;align-items:center;justify-content:center;padding:20px}
.st-player[hidden]{display:none}
.st-player .box{width:min(960px,94vw);background:#0e1117;border-radius:14px;overflow:hidden;box-shadow:0 24px 60px rgba(0,0,0,.5);position:relative}
.st-player .hd{display:flex;align-items:center;justify-content:space-between;padding:12px 16px;color:#e6e9ef;font-size:14px}
.st-player .hd button{background:0;border:0;color:#a9b1bd;font-size:22px;cursor:pointer;line-height:1}
.st-player .ft{padding:10px 16px;color:#8b93a1;font-size:12.5px;display:flex;justify-content:space-between;gap:10px;flex-wrap:wrap}
.st-player .ft a{color:#ff9a5b;text-decoration:none}
.st-player iframe{margin:0 16px;width:calc(100% - 32px)}
.st-player .ft a{margin-left:12px}
/* 加密音视频：取流 + 本地解密时的进度层 */
.st-loading{position:absolute;inset:0;display:flex;align-items:center;justify-content:center;background:rgba(10,13,19,.9);z-index:6}
.st-loading[hidden]{display:none}
.st-loading-box{width:min(300px,74%);text-align:center;color:#c8cfda;font-size:13px}
.st-loading-title{margin-bottom:12px;letter-spacing:.5px}
.st-loading-bar{height:6px;background:#232833;border-radius:99px;overflow:hidden}
.st-loading-bar i{display:block;height:100%;width:0;background:linear-gradient(90deg,#ff9a5b,#ff7a3d);border-radius:99px;transition:width .18s ease}
.st-loading-num{margin-top:8px;font-size:12px;color:#8a93a2}

/* ============================================================
 * 加密播放器（视频 = MSE 分片流 + xgplayer 自定义控件；
 *            音频 = Web Audio 自绘控件条）
 * 不使用浏览器原生控件，所以没有下载按钮 / 画中画 / 视频另存为入口。
 * ============================================================ */
.ep-host{display:block}
.ep-video{position:relative;width:100%;height:340px;margin:0 auto;background:#000}
.ep-video video{background:#000;object-fit:contain}
.ep-video .xgplayer{height:100%;font-size:13px}
.ep-video,.ep-audio{-webkit-user-select:none;user-select:none;-webkit-touch-callout:none;-webkit-tap-highlight-color:transparent}

/* ---- 音频：Web Audio 播放，页面上没有 media 元素 ---- */
.ep-audio{margin:24px 20px 30px;padding:16px 16px 13px;border:1px solid #232833;border-radius:12px;background:linear-gradient(180deg,#1a1f2a,#131720)}
.ep-a-head{display:flex;align-items:center;gap:10px;margin-bottom:15px}
.ep-a-ico{flex:0 0 38px;height:38px;border-radius:50%;background:linear-gradient(135deg,#ff9a5b,#ff7a3d);color:#241404;font-size:18px;display:flex;align-items:center;justify-content:center}
.ep-a-title{flex:1;min-width:0;color:#e6e9ef;font-size:13.5px;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.ep-a-tag{flex:0 0 auto;font-size:11px;color:#ffb27f;border:1px solid #4a3324;background:#2a1f18;border-radius:99px;padding:2px 9px}
.ep-a-bar{display:flex;align-items:center;gap:10px}
.ep-a-btn{background:#232833;border:1px solid #2e3542;color:#d6dbe4;border-radius:7px;cursor:pointer;font-size:13px;line-height:1;padding:7px 10px;min-width:36px}
.ep-a-btn:hover{background:#2e3542}
.ep-a-btn:disabled{opacity:.45;cursor:not-allowed}
.ep-a-time{color:#8f98a8;font-size:12px;font-variant-numeric:tabular-nums;min-width:44px;text-align:center}
.ep-a-track{position:relative;flex:1;height:6px;border-radius:99px;background:#232833;cursor:pointer;touch-action:none}
.ep-a-load{position:absolute;left:0;top:0;bottom:0;width:0;border-radius:99px;background:#333b4a}
.ep-a-fill{position:absolute;left:0;top:0;bottom:0;width:0;border-radius:99px;background:linear-gradient(90deg,#ff9a5b,#ff7a3d)}
.ep-a-dot{position:absolute;top:50%;left:0;width:12px;height:12px;margin:-6px 0 0 -6px;border-radius:50%;background:#fff;box-shadow:0 1px 5px rgba(0,0,0,.55)}
.ep-a-range{width:74px;accent-color:#ff7a3d;background:0;cursor:pointer}
.ep-a-hint{margin-top:11px;color:#7d8697;font-size:12px;text-align:center}
.ep-a-hint[hidden]{display:none}
@media (max-width:600px){
  .ep-video{height:240px}
  .ep-audio{margin:16px 12px 22px;padding:13px 12px 11px}
  .ep-a-range{display:none}
  .ep-a-time{min-width:38px}
}
/* 目录里的媒体类型小徽标 */
.st-lmedia{display:inline-block;font-size:11px;color:#a6adb9;background:#f6f8fb;border-radius:4px;padding:1px 6px;margin-left:6px}

/* 支付弹层 */
.st-modal{position:fixed;inset:0;background:rgba(18,22,32,.45);z-index:320;display:flex;align-items:center;justify-content:center}
.st-modal[hidden]{display:none}
.st-modal .box{background:#fff;border-radius:14px;width:360px;max-width:90vw;padding:20px}
.st-modal h4{margin:0 0 10px;font-size:15px;color:#2f3439}
.st-modal p{margin:0 0 12px;color:#6b7480;font-size:13px;line-height:1.7}
.st-modal input{width:100%;height:40px;border:1px solid #e3e7ee;border-radius:9px;padding:0 12px;font-size:14px;box-sizing:border-box}
.st-modal .foot{display:flex;gap:10px;margin-top:16px}
.st-modal .foot button{flex:1;height:40px;border:0;border-radius:9px;font-size:14px;cursor:pointer}
.st-modal .foot .ok{background:#ff6b35;color:#fff}
.st-modal .foot .no{background:#f2f4f8;color:#5b6472}
.st-toast{position:fixed;left:50%;top:70px;transform:translateX(-50%);background:rgba(28,32,42,.9);color:#fff;font-size:13px;padding:9px 18px;border-radius:20px;z-index:400}

/* ---------------- 响应式 ---------------- */
@media (max-width:1000px){
  .st-hero{grid-template-columns:1fr}
  .st-top{grid-template-columns:1fr}
  .st-grid{grid-template-columns:repeat(3,1fr)}
  .st-detail{grid-template-columns:1fr}
}
@media (max-width:760px){
  .st-grid{grid-template-columns:repeat(2,1fr)}
  .st-rec{grid-template-columns:1fr}
  .st-chead{grid-template-columns:1fr}
  .st-hero-left h1{font-size:21px}
  .st-wrap{padding:12px 10px 32px}
}
@media (max-width:430px){
  .st-grid{grid-template-columns:1fr}
  .st-lrow .du{display:none}
}

/* ============ 资料下载 ============ */
.st-frow{display:flex;align-items:center;gap:12px;padding:11px 12px;border:1px solid #f4f6fa;border-radius:10px;margin-bottom:6px}
.st-frow:hover{border-color:#ffd9c2;background:#fffaf7}
.st-frow .icon{flex:0 0 34px;height:34px;display:flex;align-items:center;justify-content:center;font-size:20px;background:#f6f8fb;border-radius:9px}
.st-frow .m{flex:1;min-width:0}
.st-frow .m b{display:block;font-size:13.5px;color:#3f4650;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.st-frow .m span{font-size:12px;color:#a6adb9}
.st-frow .ftag{display:inline-block;font-style:normal;background:#eef4ff;color:#3a5a8c;border-radius:4px;padding:1px 6px;font-size:11px;margin-right:6px}
.st-frow .act{flex:0 0 auto}
.st-frow .act a,.st-frow .act span{display:inline-block;padding:6px 14px;border-radius:8px;font-size:12.5px;text-decoration:none;background:#fff6f1;color:#e2542a;cursor:pointer}
.st-frow .act a.dl{background:#fff1e8;color:#e2542a;font-weight:600}
.st-frow .act a.gray{background:#f4f6fa;color:#6b7480}
.st-frow .act span.lock{background:#f4f6fa;color:#a6adb9;cursor:not-allowed}
.st-filetip{margin-top:10px;padding:9px 12px;background:#fff8ef;border:1px solid #ffe3bd;border-radius:8px;font-size:12.5px;color:#9a6b1f}

/* ============ 在线练习 ============ */
.st-quizhead{display:flex;align-items:center;justify-content:space-between;padding:10px 12px;background:#f6f8fb;border-radius:10px;margin-bottom:12px;font-size:13px;color:#6b7480}
.st-quizhead b{color:#ff6b35}
.st-quizreset{background:#fff;border:1px solid #e3e7ee;border-radius:8px;padding:5px 14px;font-size:12.5px;color:#6b7480;cursor:pointer}
.st-quizreset:hover{color:#ff6b35;border-color:#ffd9c2}
.st-qrow{border:1px solid #f4f6fa;border-radius:12px;padding:14px;margin-bottom:10px}
.st-qrow .qt{display:flex;align-items:flex-start;gap:8px;margin-bottom:10px}
.st-qrow .qt .no{flex:0 0 24px;height:24px;line-height:24px;text-align:center;border-radius:7px;background:#f6f8fb;color:#8a919f;font-size:12px}
.st-qrow .qt .badge{flex:0 0 auto;font-size:11px;border-radius:4px;padding:2px 7px;margin-top:2px}
.st-qrow .qt .badge.t1{background:#fff1e8;color:#e2542a}
.st-qrow .qt .badge.t2{background:#eef4ff;color:#3a5a8c}
.st-qrow .qt .badge.t3{background:#e9f8ee;color:#1a9c4a}
.st-qrow .qt .tt{flex:1;font-size:13.5px;color:#3f4650;line-height:1.7}
.st-qrow .opts{display:flex;flex-wrap:wrap;gap:8px}
.st-qrow .opts button{border:1px solid #e9edf3;background:#fafbfd;border-radius:9px;padding:8px 14px;font-size:13px;color:#4b5563;cursor:pointer;text-align:left;line-height:1.6}
.st-qrow .opts button b{color:#8a919f;margin-right:6px;font-weight:600}
.st-qrow .opts button:hover{border-color:#ffd9c2;background:#fffaf7}
.st-qrow .opts button.pick{border-color:#ff6b35;background:#fff3ec;color:#e2542a}
.st-qrow .opts button.pick b{color:#ff6b35}
.st-qrow .opts button.right{border-color:#9fdcb4;background:#eaf9f0;color:#1a7c42;cursor:default}
.st-qrow .opts button.right b{color:#1a9c4a}
.st-qrow .opts button.wrong{border-color:#f3b6b6;background:#fdeeee;color:#c0392b;cursor:default}
.st-qrow .opts button:disabled{cursor:default}
.st-qrow .verdict{margin-top:10px;font-size:13px;font-weight:600;border-radius:8px;padding:7px 11px}
.st-qrow .verdict.ok{background:#eaf9f0;color:#1a7c42}
.st-qrow .verdict.bad{background:#fdeeee;color:#c0392b}
.st-qrow .qfoot{margin-top:10px;display:flex;align-items:flex-start;gap:10px}
.st-qrow .qfoot .js-submit-q{border:0;background:linear-gradient(135deg,#ff8a4d,#ff6b35);color:#fff;border-radius:8px;padding:7px 18px;font-size:12.5px;cursor:pointer}
.st-qrow .qfoot .js-submit-q:disabled{background:#e9edf3;color:#a6adb9;cursor:not-allowed}
.st-qrow .qfoot .analysis{flex:1;font-size:12.5px;color:#8a919f;background:#f6f8fb;border-radius:8px;padding:7px 11px;line-height:1.7}
.st-quizdone{margin-top:6px;padding:12px 14px;background:#fff8ef;border:1px solid #ffe3bd;border-radius:10px;font-size:13.5px;color:#9a6b1f}
.st-quizdone b{color:#e2542a}
/* hidden 属性优先级兜底（避免被 display:flex 覆盖） */
.st-quizhead[hidden],.st-quizdone[hidden],.st-quizreset[hidden],.st-qrow .verdict[hidden],.st-qrow .qfoot .analysis[hidden]{display:none !important}

@media (max-width:600px){
  .st-frow .m span{display:block;margin-top:2px}
  .st-qrow .opts{flex-direction:column}
  .st-qrow .opts button{width:100%}
}

/* ---- 文档阅读器（pdf.js 画布渲染） ---- */
.st-doc{background:#0e1117}
.st-doc-bar{display:flex;align-items:center;gap:8px;padding:9px 14px;background:#161a22;border-bottom:1px solid #232833;color:#a9b1bd;font-size:12.5px;flex-wrap:wrap}
.st-doc-bar button{background:#232833;border:1px solid #2e3542;color:#d6dbe4;font-size:12.5px;padding:5px 12px;border-radius:6px;cursor:pointer;line-height:1.4}
.st-doc-bar button:hover{background:#2e3542}
.st-doc-bar button.on{background:#2f4a7a;border-color:#3f63a0;color:#e8effc}
.st-doc-bar #docPrev,.st-doc-bar #docNext{font-size:16px;padding:2px 12px;line-height:1.3;font-weight:600}
.st-doc-no b{color:#ff9a5b;font-weight:600}
.st-doc-bar input{width:64px;background:#0e1117;border:1px solid #2e3542;color:#e6e9ef;font-size:12.5px;padding:5px 8px;border-radius:6px;text-align:center}
.st-doc-bar input[hidden]{display:none}
.st-doc-sep{flex:0 0 1px;align-self:stretch;margin:0 2px;background:#2a303c}
.st-doc-zoom{min-width:44px;text-align:center;color:#8f98a8;font-variant-numeric:tabular-nums}
.st-doc-tip{margin-left:auto;color:#6b7382;font-size:11.5px}
.st-doc-body{max-height:min(72vh,760px);overflow:auto;background:#3a3f4b;padding:14px;text-align:center;position:relative;-webkit-user-select:none;user-select:none;-webkit-touch-callout:none}
.st-doc-body[hidden]{display:none}
/* 连续滚动模式：每页一个占位容器，滚近才渲染、滚远即卸载 */
.st-doc-page{position:relative;margin:0 auto 16px;background:#fff;border-radius:4px;box-shadow:0 3px 14px rgba(0,0,0,.35);overflow:hidden;text-align:left}
.st-doc-page:last-child{margin-bottom:2px}
.st-doc-page canvas{display:block}
.st-doc-canvas{display:block;background:#fff}
.st-doc-loading{text-align:center;color:#9aa2b1;padding:70px 0;font-size:13px}
.st-doc-fail{text-align:center;color:#d0d6e0;padding:60px 16px;font-size:13.5px;line-height:2}
.st-doc-fail span{color:#8f98a8;font-size:12.5px}
@media (max-width:600px){
  .st-doc-tip{display:none}
  .st-doc-bar{padding:8px 10px;gap:6px}
  .st-doc-bar input{width:52px}
  .st-doc-bar button{padding:5px 9px}
}