/* 课爱 classai —— 浅灰蓝底 + 大圆角卡片 + 黑色胶囊导航 + 荧光黄绿点缀 */
:root{
  --bg:#EEF1F5; --card:#F7F8FA; --white:#FFFFFF; --ink:#111214; --ink2:#3A3D44; --sub:#5C616C; --mute:#8A8F99;
  --line:#E1E4EA; --line2:#D8DCE3; --chip:#E6E9EE;
  --lime:#D7F24A; --lime-d:#A9C41F; --dark:#1A1B1E; --dark2:#1C1D21; --dark3:#26272C; --dark4:#2E3036; --dline:#3A3C42; --dsub:#9A9EA8; --dtext:#F2F3F5;
  --steel:#5D7890; --steel-l:#DCE5EC;
  --red:#E5484D; --red-d:#A3262B; --red-soft:#FDEBEC; --green-d:#2F5A1E; --green-soft:#DCEBD3; --amber-soft:#FFF4D6; --amber-d:#7A5410;
  --orange:#F2672E; --blue:#2F7BEA; --green:#12A57A; --purple:#7C5CE0;
  --fl:"Urbanist","Helvetica Neue",Arial,system-ui,sans-serif;
  --f:"Urbanist","Noto Sans SC","PingFang SC","Hiragino Sans GB","Microsoft YaHei",system-ui,sans-serif;
  --r-xl:32px; --r-l:28px; --r-m:20px;
}
*{box-sizing:border-box}
html,body{margin:0}
body{background:var(--bg);color:var(--ink);font-family:var(--f);font-size:16px;line-height:1.6;-webkit-font-smoothing:antialiased;min-height:100vh;display:flex;flex-direction:column}
a{color:inherit;text-decoration:none}
button{font-family:inherit}
:focus-visible{outline:3px solid var(--steel);outline-offset:2px}
.skip{position:absolute;left:-999px;top:8px;background:var(--ink);color:#fff;padding:8px 14px;border-radius:999px;z-index:50}
.skip:focus{left:12px}
main{flex:1;width:100%;max-width:1280px;margin:0 auto;padding:8px 32px 64px;outline:none}
.en{font-family:var(--fl);color:var(--mute);font-weight:500;letter-spacing:0;margin-left:.35em}
.num{font-family:var(--fl);font-variant-numeric:tabular-nums}

/* ---------- 顶部 ---------- */
.top{display:flex;align-items:center;justify-content:space-between;gap:16px;flex-wrap:wrap;padding:20px 32px;max-width:1344px;width:100%;margin:0 auto}
.brand{display:flex;align-items:center;gap:12px}
.brand svg{flex:none}
.brand-name{display:flex;align-items:baseline;gap:8px;font-size:23px;font-weight:700;letter-spacing:-.01em}
.brand-name small{font-size:15px;font-weight:600;color:var(--sub);letter-spacing:0}
.capsule{display:flex;align-items:center;gap:4px;padding:6px;border-radius:999px;background:var(--dark)}
.capsule a{display:flex;align-items:center;gap:8px;height:44px;padding:0 18px;border-radius:999px;color:#C9CCD3;font-size:15px;white-space:nowrap;transition:background .15s,color .15s}
.capsule a:hover{color:#fff;background:var(--dark4)}
.capsule a.on{background:var(--lime);color:var(--ink);font-weight:600}
.capsule a.on::before{content:"";width:6px;height:6px;border-radius:50%;background:var(--ink)}
.capsule .cap-n{font-family:var(--fl);font-size:12px;font-weight:700;min-width:20px;height:20px;padding:0 6px;border-radius:999px;background:var(--red);color:#fff;display:grid;place-items:center}
.tools{display:flex;align-items:center;gap:10px}
.seg{display:flex;padding:4px;border-radius:999px;background:var(--white);border:1px solid var(--line)}
.seg button{height:36px;padding:0 14px;border-radius:999px;border:0;background:transparent;color:var(--sub);font-size:14px;font-weight:600;cursor:pointer}
.seg button[aria-pressed=true],.seg button.on{background:var(--ink);color:#fff}
.seg button:disabled{color:#B5BAC3;cursor:not-allowed}

/* ---------- 通用 ---------- */
.card{background:var(--card);border-radius:var(--r-xl);padding:28px}
.card.white{background:var(--white)}
.card.dark{background:var(--dark2);color:var(--dtext)}
.card.steel{background:var(--steel);color:#fff}
.rbtn{width:48px;height:48px;flex:none;border-radius:50%;border:1px solid var(--line);background:var(--white);color:var(--ink);cursor:pointer;display:inline-flex;align-items:center;justify-content:center;transition:background .15s}
.rbtn:hover{background:var(--chip)}
.rbtn.lg{width:56px;height:56px}
.rbtn.sm{width:40px;height:40px}
.rbtn.on-dark{background:transparent;border-color:rgba(255,255,255,.35);color:#fff}
.rbtn.on-dark:hover{background:rgba(255,255,255,.12)}
.rbtn:disabled{opacity:.35;cursor:default}
.pill-btn{height:52px;padding:0 24px;border-radius:999px;border:1px solid transparent;font-size:15px;font-weight:700;cursor:pointer;display:inline-flex;align-items:center;justify-content:center;gap:10px;white-space:nowrap;transition:filter .15s,transform .1s,background .15s;text-decoration:none}
.pill-btn:active{transform:scale(.97)}
.pill-btn:disabled{opacity:.45;cursor:default}
.pill-btn.lime{background:var(--lime);color:var(--ink)}
.pill-btn.lime:hover{filter:brightness(.96)}
.pill-btn.dark{background:var(--ink);color:#fff}
.pill-btn.dark:hover{background:#2A2C31}
.pill-btn.ghost{background:transparent;border-color:var(--line2);color:var(--ink);font-weight:500}
.pill-btn.ghost:hover{background:var(--chip)}
.pill-btn.white{background:#fff;color:var(--ink)}
.pill-btn.lg{height:60px;padding:0 28px;font-size:16px}
.pill-btn.sm{height:42px;padding:0 18px;font-size:14px}
.chip{display:inline-flex;align-items:center;gap:6px;font-size:13px;padding:6px 12px;border-radius:999px;background:var(--chip);color:var(--ink2);white-space:nowrap}
.chip.lime{background:var(--lime);color:var(--ink);font-weight:600}
.chip.dark{background:var(--ink);color:#fff;font-weight:700}
.chip.red{background:var(--red-soft);color:var(--red-d)}
.chip.line{background:transparent;border:1px solid var(--line);color:var(--mute)}
.chip.ondark{background:transparent;border:1px solid var(--dline);color:#C9CCD3}
.chip.green{background:var(--green-soft);color:var(--green-d)}
.link{font:inherit;font-weight:700;color:var(--ink);background:none;border:0;padding:0 2px;cursor:pointer;text-decoration:underline;text-decoration-color:var(--lime-d);text-decoration-thickness:2px;text-underline-offset:3px}
.muted{color:var(--sub)}
.sec-title{display:flex;justify-content:space-between;align-items:baseline;gap:12px;flex-wrap:wrap;margin:36px 0 14px}
.sec-title h2{margin:0;font-size:26px;font-weight:500;letter-spacing:-.01em}
.sec-title .en{font-size:18px;margin-left:6px}
.sec-title p{margin:0;font-size:14px;color:var(--sub)}

/* 页头 */
.phead{display:flex;justify-content:space-between;align-items:flex-end;gap:20px;flex-wrap:wrap;margin:12px 0 22px}
.phead-l{display:flex;align-items:center;gap:20px;min-width:0}
.phead .eyebrow{font-size:15px;color:var(--sub)}
.phead h1{margin:2px 0 0;font-size:60px;font-weight:500;letter-spacing:-.02em;line-height:1.08}
.phead h1 .en{font-size:28px;margin-left:8px}
.phead-r{display:flex;gap:10px;flex-wrap:wrap}

/* ---------- 学习总览 ---------- */
.insights{display:grid;grid-template-columns:repeat(auto-fit,minmax(320px,1fr));gap:16px}
.insight{display:flex;gap:16px;align-items:flex-start;padding:22px 24px;border-radius:var(--r-l);background:var(--card)}
.insight.good{background:linear-gradient(135deg,#DCEBD3,#C9E2BE)}
.insight .ic{width:44px;height:44px;flex:none;border-radius:50%;display:flex;align-items:center;justify-content:center;background:rgba(255,255,255,.65)}
.insight.warn .ic{background:var(--red-soft)}
.insight b{display:block;font-size:16px}
.insight.good b{color:#22401A}
.insight p{margin:2px 0 0;font-size:14px;color:var(--sub)}
.insight.good p{color:#3E5C33}
.kpis{display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:16px;margin-top:16px}
.kpi{display:flex;flex-direction:column;gap:16px}
.kpi-h{display:flex;justify-content:space-between;align-items:center;gap:8px;font-size:15px;color:var(--sub)}
.card.dark .kpi-h{color:var(--dsub)}
.big{font-family:var(--fl);font-size:56px;font-weight:600;letter-spacing:-.02em;line-height:1}
.big small{font-size:24px;color:var(--mute);font-weight:500}
.card.dark .big small{color:var(--dsub)}
.segbar{display:flex;gap:4px;height:40px}
.segbar span{border-radius:12px;min-width:4px}
.segbar .m{background:var(--lime)}
.segbar .l{background:#EEF1F5 repeating-linear-gradient(135deg,#C9D96A 0 3px,transparent 3px 8px)}
.segbar .t{background:var(--line)}
.legend{display:flex;gap:16px;flex-wrap:wrap;font-size:13px;color:var(--sub)}
.legend i{display:inline-block;width:10px;height:10px;border-radius:3px;margin-right:6px;vertical-align:-1px}
.gauge{width:100%;max-width:250px;align-self:center;height:auto}
.kpi-foot{display:flex;justify-content:space-between;gap:8px;font-size:13px;color:var(--sub)}
.kpi-foot b{color:var(--ink);font-family:var(--fl)}
.daily{display:flex;flex-wrap:wrap;align-items:center;gap:20px 24px;margin-top:16px;padding:26px 28px}
.daily-t{flex:1 1 420px;display:flex;flex-direction:column;gap:6px;min-width:0}
.daily-t span{font-size:14px;color:var(--steel-l)}
.daily-t p{margin:0;font-size:21px;font-weight:500;line-height:1.55}
.daily-r{display:flex;gap:10px;align-items:center;flex-wrap:wrap}
.daily .chip{background:rgba(255,255,255,.16);color:#fff}
.topics{display:grid;grid-template-columns:repeat(auto-fill,minmax(300px,1fr));gap:16px}
.topic{display:flex;align-items:center;gap:16px;padding:20px;border-radius:var(--r-l);background:var(--card);transition:transform .15s,background .15s}
.topic:hover{background:#fff;transform:translateY(-2px)}
.topic svg{flex:none}
.topic-t{flex:1;min-width:0;display:flex;flex-direction:column;gap:2px}
.topic-t b{font-size:17px;font-weight:500}
.topic-t .en{font-size:14px}
.topic-t small{font-size:13px;color:var(--sub)}
.ask{position:relative;z-index:8;width:min(720px,100%);margin:44px auto 0;display:flex;flex-direction:column;align-items:center;gap:10px}
.ask-sug{display:flex;gap:8px;flex-wrap:wrap;justify-content:center}
.ask-sug button{font:inherit;font-size:13px;padding:8px 14px;border-radius:999px;background:rgba(255,255,255,.9);border:1px solid var(--line);cursor:pointer;color:var(--ink)}
.ask-sug button:hover{background:#fff}
.ask-bar{position:relative;display:flex;align-items:center;gap:12px;width:100%;height:64px;padding:0 8px 0 24px;border-radius:999px;background:var(--dark);box-shadow:0 18px 40px rgba(17,18,20,.22)}
.ask-bar input{flex:1;min-width:0;border:0;background:transparent;color:var(--dtext);font:inherit;font-size:15px;outline:none}
.ask-bar input::placeholder{color:var(--dsub)}
.ask-go{width:48px;height:48px;flex:none;border-radius:50%;border:0;background:var(--lime);display:flex;align-items:center;justify-content:center;cursor:pointer}
.ask-res{position:absolute;left:0;right:0;bottom:74px;background:#fff;border-radius:24px;box-shadow:0 18px 40px rgba(17,18,20,.18);padding:8px;max-height:360px;overflow:auto}
.ask-res:empty{display:none}
.ask-res a{display:flex;gap:12px;align-items:center;padding:10px 14px;border-radius:16px}
.ask-res a:hover,.ask-res a.on{background:var(--bg)}
.ask-res .chip{flex:none}
.ask-res span{min-width:0;overflow:hidden;text-overflow:ellipsis;white-space:nowrap;font-size:14px}
.ask-res .none{padding:12px 14px;color:var(--sub);font-size:14px}

/* ---------- 题库 ---------- */
.filters{display:flex;gap:10px;flex-wrap:wrap;align-items:center;margin-bottom:18px}
.filters .chips{display:flex;gap:8px;flex-wrap:wrap}
.fbtn{font:inherit;font-size:14px;height:40px;display:inline-flex;align-items:center;padding:0 16px;border-radius:999px;border:1px solid var(--line);background:#fff;color:var(--ink2);cursor:pointer;white-space:nowrap}
.fbtn:hover{background:var(--chip)}
.fbtn.on{background:var(--ink);border-color:var(--ink);color:#fff}
.qgrid{display:grid;grid-template-columns:repeat(auto-fill,minmax(300px,1fr));gap:16px}
.qitem{display:flex;flex-direction:column;gap:12px;padding:22px;border-radius:var(--r-l);background:var(--card);transition:transform .15s,background .15s}
.qitem:hover{background:#fff;transform:translateY(-2px)}
.qitem-h{display:flex;justify-content:space-between;align-items:center;gap:8px}
.qitem-h .l{display:flex;gap:8px;align-items:center}
.qitem b{font-size:18px;font-weight:600}
.qitem p{margin:0;font-size:14px;color:var(--sub);display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden}
.st{flex:none;font-size:12px;padding:5px 10px;border-radius:999px;border:1px solid var(--line);color:var(--mute);white-space:nowrap}
.st.mastered{background:var(--lime);border-color:var(--lime);color:var(--ink);font-weight:600}
.st.correct,.st.learned{background:var(--chip);border-color:var(--chip);color:var(--ink2)}
.st.wrong{background:var(--red-soft);border-color:var(--red-soft);color:var(--red-d)}
.empty{padding:48px 28px;text-align:center;border-radius:var(--r-xl);background:var(--card);color:var(--sub)}
.empty b{display:block;font-size:20px;color:var(--ink);margin-bottom:6px;font-weight:600}
.empty .pill-btn{margin-top:16px}

/* ---------- 题目页 ---------- */
.crumb{font-size:14px;color:var(--sub)}
.qrow{display:flex;flex-wrap:wrap;gap:20px}
.qcard{flex:2 1 600px;min-width:0;display:flex;flex-direction:column;gap:22px}
.qcard-h{display:flex;justify-content:space-between;align-items:center;gap:12px;flex-wrap:wrap}
.qcard-h .l{display:flex;align-items:center;gap:10px;font-size:14px;color:var(--sub)}
.q-text{margin:0;font-size:20px;line-height:1.85}
.q-text b{font-weight:700}
.fig{display:flex;justify-content:center;background:#fff;border-radius:var(--r-m);padding:14px}
.fig-svg{width:100%;max-width:360px;height:auto;max-height:320px}
.ans-row{display:flex;flex-wrap:wrap;gap:12px 14px;align-items:center}
.ans{display:flex;align-items:center;gap:10px;flex-wrap:wrap}
.ans-label{font-size:15px;color:var(--sub)}
.ans-input{width:140px;height:60px;padding:0 20px;border-radius:999px;border:2px solid var(--line2);background:#fff;color:var(--ink);font-family:"Urbanist","Noto Sans SC",sans-serif;font-size:26px;font-weight:600;outline:none;transition:border-color .15s}
.ans-input:focus{border-color:var(--ink)}
.ans-input.bad{border-color:var(--red)}
.ans-input.ok{border-color:var(--lime-d)}
.ans-pi{font-size:22px;font-weight:700;font-style:italic}
.ans-unit{font-size:16px;color:var(--sub)}
.btns{display:flex;gap:10px;flex-wrap:wrap;align-items:center}
.fb{display:flex;align-items:flex-start;gap:12px;padding:14px 18px;border-radius:var(--r-m);font-size:15px;line-height:1.7}
.fb:empty{display:none}
.fb svg{flex:none;margin-top:3px}
.fb.bad{background:var(--red-soft);color:var(--red-d)}
.fb.good{background:var(--green-soft);color:#22401A}
.fb.hint{background:var(--amber-soft);color:var(--amber-d)}
.fb.warn{background:var(--chip);color:var(--ink2)}
.unit{flex:1 1 340px;min-width:0;display:flex;flex-direction:column;gap:20px}
.unit-h{display:flex;justify-content:space-between;align-items:flex-start;gap:12px}
.unit-h .muted{font-size:15px}
.unit-qs{display:flex;align-items:flex-end;gap:8px;margin-top:auto;overflow-x:auto;padding-bottom:2px}
.unit-q{flex:1 0 64px;height:92px;border-radius:var(--r-m);background:var(--chip);padding:12px 14px;display:flex;flex-direction:column;justify-content:space-between;transition:background .15s}
.unit-q:hover{background:#DCE0E6}
.unit-q b{font-family:var(--fl);font-size:15px;font-weight:700}
.unit-q span{font-size:12px;color:var(--sub)}
.unit-q.m span{color:#4F8A2E}
.unit-q.cur{height:120px;border-radius:var(--r-m) var(--r-m) 6px 6px;background:var(--lime)}
.unit-q.cur span{color:var(--ink);font-weight:600}

/* 讲解区 */
.ex-sec{margin-top:40px;background:var(--dark2);border-radius:40px;padding:0 28px 28px;color:var(--dtext)}
.ex-top{display:flex;justify-content:space-between;align-items:flex-start;gap:16px;flex-wrap:wrap}
.ex-top h2{margin:0;font-size:22px;font-weight:500}
.ex-top .l{padding-top:26px}
.ex-top .l span{font-size:14px;color:var(--dsub)}
.ex-tabs{display:flex;gap:8px;padding:12px 14px;border-radius:0 0 32px 32px;background:var(--bg)}
.ex-tabs button{height:46px;padding:0 20px;border-radius:999px;border:1px solid var(--line2);background:#fff;color:var(--ink);font-size:15px;cursor:pointer;display:inline-flex;align-items:center;gap:8px}
.ex-tabs button[aria-selected=true]{background:var(--lime);border-color:var(--lime);font-weight:600}
.ex-tabs button:disabled{background:transparent;color:var(--mute);border-color:var(--line);cursor:not-allowed}
.ex-tabs small{font-size:11px;padding:2px 7px;border-radius:999px;background:var(--chip);color:var(--sub)}
.ex-top .r{padding-top:26px;display:flex;gap:8px}
.ex-body{margin-top:22px}
.ex{display:flex;flex-wrap:wrap;gap:18px;align-items:flex-start}
.ex-steps{flex:1 1 260px;min-width:0;margin:0;padding:0;list-style:none;display:flex;flex-direction:column;gap:10px}
.ex-step{width:100%;display:flex;align-items:center;gap:14px;padding:11px 14px 11px 11px;border-radius:24px;border:0;background:var(--dark3);color:var(--dtext);text-align:left;cursor:pointer;font-size:15px;transition:background .15s}
.ex-step:hover{background:#303137}
.ex-step.now{background:var(--steel)}
.ex-dot{width:42px;height:42px;flex:none;border-radius:50%;display:flex;align-items:center;justify-content:center;font-family:var(--fl);font-size:15px;font-weight:700;background:var(--dline);color:#C9CCD3}
.ex-step.seen .ex-dot{background:var(--lime);color:var(--ink)}
.ex-step.now .ex-dot{background:#fff;color:var(--ink)}
.ex-step-t{flex:1;min-width:0;line-height:1.4}
.ex-tag{flex:none;font-size:12px;padding:4px 10px;border-radius:999px;color:var(--dsub);border:1px solid var(--dline)}
.ex-tag:empty{display:none}
.ex-step.now .ex-tag{background:#fff;border-color:#fff;color:var(--ink)}
.ex-panel{flex:2.6 1 560px;min-width:0;background:var(--steel);border-radius:30px;padding:20px;display:flex;flex-direction:column;gap:14px}
.ex-head{display:flex;justify-content:space-between;align-items:baseline;gap:12px;color:#fff;font-size:17px;font-weight:600}
.ex-count{font-family:var(--fl);font-size:15px;color:var(--steel-l);font-weight:600}
.stage-wrap{background:#FFFEFB;border-radius:22px;overflow:hidden}
.stage{display:block;width:100%;height:auto}
.stage text,.fig-svg text,.vfig text{font-family:"Urbanist","Noto Sans SC",sans-serif}
.ex-say{display:flex;align-items:flex-end;gap:16px;flex-wrap:wrap;padding:16px 16px 16px 22px;border-radius:24px;background:rgba(17,18,20,.28);color:#fff}
.ex-say .say{flex:1 1 300px;font-size:16.5px;line-height:1.8;min-height:58px}
.ex-btns{display:flex;gap:8px;margin-left:auto}
.ex-opts{display:flex;justify-content:space-between;align-items:center;gap:12px;flex-wrap:wrap;font-size:14px;color:var(--steel-l)}
.ex-auto{display:flex;align-items:center;gap:8px;cursor:pointer}
.ex-auto input{width:18px;height:18px;accent-color:var(--lime)}
.ex-speed{display:flex;gap:4px;padding:3px;border-radius:999px;background:rgba(17,18,20,.22)}
.ex-speed button{height:32px;padding:0 12px;border-radius:999px;border:0;background:transparent;color:#fff;font-family:var(--fl);font-size:13px;font-weight:600;cursor:pointer}
.ex-speed button.on{background:#fff;color:var(--ink)}
.say b{font-weight:700}
.say .c-orange{color:#FFC59E}.say .c-blue{color:#BFDCFF}.say .c-green{color:#B6F0CF}.say .c-red{color:#FFB4B6}.say .c-purple{color:#D9CCFF}
.say .rule{margin-top:10px;padding:10px 14px;border-radius:14px;background:rgba(255,255,255,.12);border-left:4px solid var(--lime);font-size:15px}
.ex-cover{position:relative;border-radius:22px;overflow:hidden;background:#15161A;aspect-ratio:2/1;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:16px;text-align:center;padding:24px}
.ex-cover p{margin:0;color:var(--steel-l);font-size:15px;max-width:420px}
.ex-cover .pill-btn{height:60px}
.ex-lock{padding:22px;border-radius:24px;background:var(--dark3);color:var(--dsub);font-size:15px}
.c-orange{color:var(--orange)}.c-blue{color:var(--blue)}.c-green{color:var(--green)}.c-red{color:var(--red)}.c-purple{color:var(--purple)}
.rule{margin-top:10px;padding:10px 14px;border-radius:14px;background:#fff;border-left:4px solid var(--lime-d);font-size:15px}
.frac{display:inline-flex;flex-direction:column;align-items:center;vertical-align:middle;font-size:.8em;line-height:1.2;margin:0 3px}
.frac i{font-style:normal}
.frac i:first-child{border-bottom:1.5px solid currentColor;padding:0 3px}

/* 举一反三 */
.pr-note{margin-bottom:14px}
.loading{display:flex;gap:16px;align-items:center;padding:22px 24px;border-radius:var(--r-l);background:var(--card);color:var(--sub);font-size:14px}
.loading b{display:block;color:var(--ink);font-size:16px}
.spinner{width:34px;height:34px;flex:none;border-radius:50%;border:4px solid var(--line);border-top-color:var(--ink);animation:spin 1s linear infinite}
@keyframes spin{to{transform:rotate(360deg)}}
.vqs{display:grid;gap:16px}
.vq{display:flex;flex-direction:column;gap:14px;padding:24px;border-radius:var(--r-l);background:var(--card)}
.vq.done{background:#F2F4F7}
.vq-h{display:flex;align-items:center;gap:10px;flex-wrap:wrap}
.vq-text{font-size:17px;line-height:1.8;white-space:pre-wrap}
.vq .ans-input{width:120px;height:52px;font-size:22px}
.vq .fig{padding:10px}
.vfig{width:100%;max-width:300px;height:auto;max-height:240px}
.sol{margin:6px 0 0;padding-left:22px}
.sol li{margin:2px 0}
.sum{display:flex;flex-direction:column;align-items:center;gap:8px;text-align:center;padding:28px;border-radius:var(--r-xl);background:var(--card);margin-top:16px}
.sum.good{background:linear-gradient(135deg,#DCEBD3,#C9E2BE)}
.sum .big{font-size:52px}
.sum-msg{font-size:17px}
.pr-start{display:flex;align-items:center;justify-content:space-between;gap:16px;flex-wrap:wrap;padding:24px 28px;border-radius:var(--r-xl);background:var(--card)}
.pr-start p{margin:0;color:var(--sub);font-size:15px}
.next-row{display:flex;justify-content:flex-end;margin-top:24px}

/* ---------- 错题本 ---------- */
.mlist{display:grid;gap:14px}
.mitem{display:flex;gap:18px;align-items:flex-start;padding:22px 24px;border-radius:var(--r-l);background:var(--card);flex-wrap:wrap}
.mitem-t{flex:1 1 360px;min-width:0;display:flex;flex-direction:column;gap:8px}
.mitem-t .h{display:flex;gap:8px;flex-wrap:wrap;align-items:center;font-size:13px;color:var(--sub)}
.mitem-t p{margin:0;font-size:16px;line-height:1.75}
.mitem-r{display:flex;gap:8px;align-items:center;flex-wrap:wrap}
.mitem .redo{flex-basis:100%;display:flex;flex-direction:column;gap:12px}

/* ---------- 学习报告 ---------- */
.rgrid{display:grid;grid-template-columns:repeat(auto-fit,minmax(380px,1fr));gap:16px}
.rgrid .wide{grid-column:1/-1}
.bars{width:100%;height:auto;max-height:300px;display:block}
.tbars{display:grid;gap:12px}
.tbar{display:grid;grid-template-columns:minmax(120px,180px) 1fr 52px;gap:14px;align-items:center;font-size:14px}
.tbar .tr{height:14px;border-radius:999px;background:var(--line);overflow:hidden}
.tbar .tr i{display:block;height:100%;border-radius:999px;background:var(--lime-d)}
.tbar .num{text-align:right;font-weight:600}
.feed{display:grid;grid-template-columns:minmax(0,1fr);gap:8px;font-size:14px}
.feed div{display:flex;gap:12px;align-items:center;padding:10px 14px;border-radius:16px;background:#fff}
.feed time{flex:none;width:88px;color:var(--mute);font-family:var(--fl)}
.feed span{min-width:0;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.soon{display:flex;gap:16px;align-items:center;flex-wrap:wrap}
.soon p{margin:0;flex:1 1 300px;font-size:15px;color:var(--steel-l)}

.site-foot{max-width:1280px;width:100%;margin:0 auto;padding:8px 32px 36px;font-size:13px;color:var(--mute);display:flex;justify-content:space-between;gap:12px;flex-wrap:wrap}

/* ---------- 平板 / 手机 ---------- */
@media (max-width:1100px){
  .top{padding:16px 24px}
  main{padding:8px 24px 56px}
  .capsule{order:3;width:100%;justify-content:space-between;overflow-x:auto}
  .capsule a{flex:1;justify-content:center;padding:0 12px}
  .phead h1{font-size:48px}
}
@media (max-width:640px){
  .rgrid{grid-template-columns:minmax(0,1fr)}
  .kpis{grid-template-columns:minmax(0,1fr)}
  .top{padding:12px 16px}
  main{padding:4px 16px 48px}
  .brand-name small{display:none}
  .capsule a{font-size:14px;padding:0 8px}
  .capsule a.on::before{display:none}
  .phead h1{font-size:36px}
  .phead h1 .en{display:block;margin:4px 0 0;font-size:20px}
  .card{padding:22px}
  .q-text{font-size:17.5px}
  .ex-sec{padding:0 14px 16px;border-radius:28px}
  .ex-tabs button{padding:0 14px;font-size:14px}
  .ex-panel{padding:12px;border-radius:22px}
  .ex-say{padding:14px}
  .big{font-size:44px}
  .tbar{grid-template-columns:110px 1fr 44px}
  .site-foot{padding:8px 16px 28px}
}
@media (prefers-reduced-motion:reduce){*{transition:none!important;animation-duration:.01s!important}}

/* ---------- 账号 ---------- */
.who{display:flex;align-items:center;gap:10px;height:48px;padding:0 16px 0 5px;border-radius:999px;background:#fff;border:1px solid var(--line)}
.who:hover{background:var(--chip)}
.who-n{font-size:14px;font-weight:600;max-width:120px;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.ava{width:38px;height:38px;flex:none;border-radius:50%;display:inline-flex;align-items:center;justify-content:center;font-size:16px;font-weight:700;color:var(--ink)}
.ava.lg{width:52px;height:52px;font-size:20px}
.pill-btn.danger{background:var(--red-soft);color:var(--red-d)}
.pill-btn.danger:hover{background:#FAD7D9}
.auth{display:flex;flex-wrap:wrap;gap:20px;margin-top:12px;align-items:stretch}
.auth-side{flex:1 1 340px;display:flex;flex-direction:column;gap:14px;padding:36px}
.auth-side h1{margin:0;font-size:40px;font-weight:500;letter-spacing:-.02em;line-height:1.15}
.auth-side ul{margin:0;padding-left:20px;display:grid;gap:8px;font-size:16px;color:#EEF3F7}
.auth-side .small{margin-top:auto;font-size:13px;color:var(--steel-l)}
.auth-card{flex:1.2 1 400px;display:flex;flex-direction:column;gap:22px;padding:36px}
.auth-tabs{align-self:flex-start}
.auth-tabs a{height:40px;padding:0 20px;border-radius:999px;display:flex;align-items:center;font-size:15px;font-weight:600;color:var(--sub)}
.auth-tabs a.on{background:var(--ink);color:#fff}
.form{display:flex;flex-direction:column;gap:16px}
.form .pill-btn{align-self:flex-start}
.field{display:flex;flex-direction:column;gap:6px;min-width:0;flex:1}
.field span{font-size:14px;color:var(--sub);display:flex;gap:8px;align-items:baseline}
.field small{font-size:12px;color:var(--mute)}
.field-row{display:flex;gap:14px;flex-wrap:wrap}
.field-row .field:last-child{flex:0 0 130px}
.tx{height:52px;padding:0 18px;border-radius:16px;border:1.5px solid var(--line2);background:#fff;color:var(--ink);font:inherit;font-size:16px;outline:none;min-width:0;transition:border-color .15s}
.tx:focus{border-color:var(--ink)}
select.tx{padding-right:10px}
.note{margin:0;font-size:13px;color:var(--sub)}
.kids{display:grid;grid-template-columns:repeat(auto-fill,minmax(340px,1fr));gap:14px}
.kid{display:flex;align-items:center;gap:14px;flex-wrap:wrap;padding:18px 20px;border-radius:var(--r-l);background:var(--card);border:2px solid transparent}
.kid.on{border-color:var(--lime-d);background:#fff}
.kid-t{flex:1;min-width:0;display:flex;flex-direction:column}
.kid-t b{font-size:18px;font-weight:600}
.kid-t span{font-size:13px;color:var(--sub)}
.kid .tx{flex:1 1 140px;height:44px}
.kid select.tx{flex:0 0 96px}
.kid.add{border:2px dashed var(--line2);background:transparent}
.sync::before{content:"";display:inline-block;width:8px;height:8px;border-radius:50%;margin-right:8px;background:var(--mute);vertical-align:1px}
.sync.synced::before{background:var(--lime-d)}
.sync.syncing::before{background:var(--steel)}
.sync.offline::before{background:var(--red)}
@media (max-width:640px){.who-n{display:none}.who{padding:0 5px}.auth-side,.auth-card{padding:24px}.auth-side h1{font-size:30px}}

/* 举一反三：出题中的占位和淡入 */
.sk{display:grid;gap:10px;padding:4px 0 6px}
.sk i{display:block;height:14px;border-radius:8px;background:linear-gradient(90deg,#E6E9EE 0%,#F2F4F7 50%,#E6E9EE 100%);background-size:200% 100%;animation:sk 1.2s linear infinite}
@keyframes sk{to{background-position:-200% 0}}
.vq.in{animation:vqin .35s ease-out}
@keyframes vqin{from{opacity:.4;transform:translateY(6px)}to{opacity:1;transform:none}}
.vq-badge{margin-left:auto}
.dotpulse{display:inline-block;width:8px;height:8px;border-radius:50%;background:var(--steel);margin-right:6px;animation:dp 1s ease-in-out infinite}
@keyframes dp{50%{opacity:.25}}