:root{
  --bg:#f4f7fb; --card:#ffffff; --ink:#1f2937; --ink2:#374151; --muted:#6b7280;
  --line:#e5e9f0; --line2:#eef2f7;
  --brand:#2563eb; --brand-d:#1d4ed8; --brand-soft:#eef4ff;
  --ok:#16a34a; --ok-soft:#e9f9ef; --err:#e11d48; --err-soft:#fff1f3;
  --warn:#d97706; --warn-soft:#fff7ed;
  --r:14px; --sh:0 1px 2px rgba(16,24,40,.04),0 6px 18px rgba(16,24,40,.06);
}
*{box-sizing:border-box}
html,body{margin:0;padding:0}
body{
  background:var(--bg); color:var(--ink);
  font:15px/1.7 "PingFang SC","Microsoft YaHei","Source Han Sans SC",-apple-system,"Segoe UI",Roboto,sans-serif;
  -webkit-font-smoothing:antialiased;
}
a{color:inherit;text-decoration:none}
.wrap{max-width:1080px;margin:0 auto;padding:0 16px}

/* ---------- 顶栏 ---------- */
.topbar{position:sticky;top:0;z-index:50;background:rgba(255,255,255,.92);backdrop-filter:blur(8px);border-bottom:1px solid var(--line)}
.topbar-in{display:flex;align-items:center;gap:18px;height:60px}
.brand{display:flex;align-items:center;gap:10px;cursor:pointer;flex:none}
.brand-badge{width:34px;height:34px;border-radius:10px;background:linear-gradient(135deg,#3b82f6,#2563eb);color:#fff;display:grid;place-items:center;font-size:13px;font-weight:700;letter-spacing:1px}
.brand-txt{font-weight:700;font-size:16px;display:flex;flex-direction:column;line-height:1.2}
.brand-txt em{font-style:normal;font-weight:400;font-size:11px;color:var(--muted);margin-top:2px}
.nav{display:flex;gap:4px;margin-left:auto;flex-wrap:wrap}
.nav a{padding:7px 13px;border-radius:9px;font-size:14px;color:var(--ink2);position:relative}
.nav a:hover{background:var(--line2)}
.nav a.on{background:var(--brand-soft);color:var(--brand);font-weight:600}
.dot{position:absolute;top:3px;right:3px;min-width:16px;height:16px;padding:0 4px;border-radius:9px;background:var(--err);color:#fff;font-size:10px;line-height:16px;text-align:center;display:none}
.dot.show{display:block}

/* ---------- 通用 ---------- */
.card{background:var(--card);border:1px solid var(--line);border-radius:var(--r);box-shadow:var(--sh)}
.pad{padding:18px}
.sec-t{font-size:20px;margin:26px 0 14px;font-weight:700}
.muted{color:var(--muted);font-size:13.5px}
.center{text-align:center;margin:18px 0;display:flex;gap:12px;justify-content:center;flex-wrap:wrap}
.btn{border:1px solid var(--line);background:#fff;color:var(--ink2);padding:10px 18px;border-radius:10px;font-size:14px;cursor:pointer;font-family:inherit;transition:.15s;text-align:center}
.btn:hover{border-color:#c9d4e5;background:#fbfcfe}
.btn.primary{background:var(--brand);border-color:var(--brand);color:#fff;font-weight:600}
.btn.primary:hover{background:var(--brand-d)}
.btn.ghost{background:transparent;color:var(--muted)}
.btn.sm{padding:6px 12px;font-size:13px;border-radius:8px}
.btn:disabled{opacity:.5;cursor:not-allowed}
.tag{display:inline-block;padding:2px 10px;border-radius:999px;font-size:12px;background:var(--line2);color:var(--muted);border:1px solid transparent}
.tag.gray{background:#f3f5f9;color:var(--muted)}
.tag.blue{background:var(--brand-soft);color:var(--brand)}
.tag[style*="--c"]{color:#fff;border:none}
.empty{text-align:center;padding:54px 20px;color:var(--muted);font-size:15px}
select,input[type=text]{font-family:inherit;font-size:14px;padding:9px 12px;border:1px solid var(--line);border-radius:9px;background:#fff;color:var(--ink)}
select{cursor:pointer}
select:focus,input:focus{outline:2px solid var(--brand-soft);border-color:var(--brand)}

/* ---------- 首页 ---------- */
.hero{background:linear-gradient(135deg,#eef4ff,#f6fbff 60%,#fff);border:1px solid var(--line);border-radius:18px;padding:26px;margin-top:22px}
.hero h1{margin:0 0 8px;font-size:23px}
.hero p{margin:0;color:var(--muted);font-size:14px;max-width:720px}
.hero-stat{display:grid;grid-template-columns:repeat(4,1fr);gap:12px;margin:22px 0 8px}
.hero-stat div{background:#fff;border:1px solid var(--line);border-radius:12px;padding:14px;text-align:center}
.hero-stat b{display:block;font-size:24px;line-height:1.3;color:var(--brand)}
.hero-stat span{font-size:12px;color:var(--muted)}
.hero-acts{display:flex;gap:12px;flex-wrap:wrap}
.subj-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(220px,1fr));gap:14px}
.subj-card{background:#fff;border:1px solid var(--line);border-radius:14px;padding:18px;display:flex;flex-direction:column;gap:6px;transition:.16s;border-top:4px solid var(--c,#2563eb)}
.subj-card:hover{transform:translateY(-3px);box-shadow:0 10px 26px rgba(16,24,40,.10)}
.subj-ico{width:42px;height:42px;border-radius:11px;display:grid;place-items:center;color:#fff;font-size:18px;font-weight:700;background:var(--c,#2563eb)}
.subj-name{font-size:17px;font-weight:700}
.subj-meta{font-size:12.5px;color:var(--muted)}
.subj-wrong{font-size:12.5px;color:var(--err);margin-top:auto}

/* ---------- 选择流程 ---------- */
.crumbs{font-size:13.5px;color:var(--muted);margin:8px 0 16px;display:flex;align-items:center;gap:6px;flex-wrap:wrap}
.crumbs a{color:var(--brand)}
.pick-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(150px,1fr));gap:12px}
.pick{display:flex;align-items:center;gap:10px;background:#fff;border:1px solid var(--line);border-radius:12px;padding:16px;cursor:pointer;font-size:15px;font-weight:600;transition:.15s;border-left:4px solid var(--c,#2563eb)}
.pick:hover{background:var(--brand-soft);transform:translateY(-2px)}
.pick-ico{width:34px;height:34px;border-radius:9px;display:grid;place-items:center;background:var(--c,#2563eb);color:#fff;font-size:14px}
.pick-list{display:flex;flex-direction:column;gap:10px}
.pick-row{display:flex;align-items:center;justify-content:space-between;background:#fff;border:1px solid var(--line);border-radius:12px;padding:15px 18px;cursor:pointer;font-size:15px;text-align:left;font-family:inherit;transition:.15s}
.pick-row:hover{background:var(--brand-soft);border-color:#bcd0f7}
.pick-row .muted{font-size:12.5px}

/* ---------- 设置面板 ---------- */
.setup{background:#fff;border:1px solid var(--line);border-radius:14px;padding:22px;max-width:480px;margin:10px auto}
.setup h3{margin:0 0 16px;font-size:17px}
.field{margin-bottom:16px;display:flex;flex-direction:column;gap:6px}
.field label{font-size:13px;color:var(--muted)}
.field.inline{flex-direction:row;align-items:center;gap:10px}
.field.inline label{width:48px;flex:none}

/* ---------- 刷题引擎 ---------- */
.practice{max-width:760px;margin:18px auto}
.p-bar{margin-bottom:16px}
.p-prog{height:8px;background:var(--line2);border-radius:99px;overflow:hidden;position:relative}
.p-prog span{position:absolute;left:0;top:0;height:100%;border-radius:99px;transition:width .3s}
.p-prog span:first-child{background:var(--line)}
.p-prog span:last-child{background:var(--brand)}
.p-info{display:flex;justify-content:space-between;font-size:12.5px;color:var(--muted);margin-top:7px}
.q-card{background:#fff;border:1px solid var(--line);border-radius:16px;padding:24px;box-shadow:var(--sh)}
.q-card.wrong{border-color:#fca5a5}
.q-card.right{border-color:#86efac}
.q-top{display:flex;align-items:center;gap:8px;flex-wrap:wrap;margin-bottom:16px}
.q-stem{font-size:17px;line-height:1.9;margin:0 0 18px;white-space:pre-wrap;font-weight:500}
.q-body{display:flex;flex-direction:column;gap:11px}
.opt{display:flex;gap:12px;align-items:flex-start;border:1.5px solid var(--line);border-radius:12px;padding:13px 15px;cursor:pointer;transition:.14s;background:#fff}
.opt:hover{border-color:#b9caea;background:#fafcff}
.opt-l{width:26px;height:26px;flex:none;border-radius:50%;border:1.5px solid #cbd5e1;display:grid;place-items:center;font-size:12.5px;font-weight:700;color:var(--muted)}
.opt-t{line-height:1.6;padding-top:2px}
.opt.corr{border-color:var(--ok);background:var(--ok-soft)}
.opt.corr .opt-l{background:var(--ok);border-color:var(--ok);color:#fff}
.opt.mine:not(.corr){border-color:var(--err);background:var(--err-soft)}
.opt.mine:not(.corr) .opt-l{background:var(--err);border-color:var(--err);color:#fff}
.hint{font-size:12.5px;color:var(--muted);margin-top:2px}
.fill-box{display:flex;gap:10px;align-items:center}
.fill-box .ans,.ans{width:100%;font-size:15px;padding:13px;border:1.5px solid var(--line);border-radius:11px;font-family:inherit}
.ans:focus{outline:2px solid var(--brand-soft);border-color:var(--brand)}
.p-acts{display:flex;gap:12px;margin-top:18px;flex-wrap:wrap}

/* ---------- 讲解 ---------- */
.explain{margin-top:18px;border:1px solid var(--line);border-radius:14px;overflow:hidden;background:#fff}
.ex-head{padding:12px 16px;font-weight:700;font-size:14.5px}
.ex-head.ok{background:var(--ok-soft);color:var(--ok)}
.ex-head.bad{background:var(--err-soft);color:var(--err)}
.ex-sec{padding:14px 16px;border-top:1px solid var(--line2)}
.ex-sec b{font-size:13px;color:var(--ink2);display:block;margin-bottom:8px}
.ex-sec p{margin:0;font-size:14.2px;line-height:1.8}
.ex-sec ol{margin:0;padding-left:20px}
.ex-sec ol li{font-size:14.2px;line-height:1.8;margin-bottom:5px}
.ex-sec.tip b{color:var(--warn)}
.kp-card{margin:0 16px 16px;border:1px dashed #c7d2e8;background:#f8fafc;border-radius:11px;padding:14px 16px}
.kp-h{font-size:14px;font-weight:700;margin-bottom:8px;color:var(--brand)}
.kp-sec{margin-bottom:10px}
.kp-sec:last-child{margin-bottom:0}
.kp-sec b{font-size:12.5px;color:var(--muted);display:block;margin-bottom:5px}
.kp-sec ul{margin:0;padding-left:18px}
.kp-sec li{font-size:13.6px;line-height:1.7}

/* ---------- 结果页 ---------- */
.summary{background:#fff;border:1px solid var(--line);border-radius:16px;padding:30px;text-align:center;max-width:620px;margin:24px auto}
.summary h2{margin:0 0 18px}
.sum-stat{display:grid;grid-template-columns:repeat(4,1fr);gap:12px;margin-bottom:18px}
.sum-stat div{background:var(--line2);border-radius:12px;padding:14px}
.sum-stat b{display:block;font-size:22px}
.sum-stat span{font-size:12px;color:var(--muted)}

/* ---------- 错题本 ---------- */
.wrong-bar{display:flex;gap:10px;align-items:center;flex-wrap:wrap;background:#fff;border:1px solid var(--line);border-radius:12px;padding:13px 16px;margin-bottom:16px}
.wrong-list{display:flex;flex-direction:column;gap:12px}
.wrong-item{display:flex;gap:14px;align-items:center;background:#fff;border:1px solid var(--line);border-radius:14px;padding:15px 18px;flex-wrap:wrap}
.wi-main{flex:1;min-width:240px}
.wi-top{display:flex;gap:7px;flex-wrap:wrap;margin-bottom:7px}
.wi-stem{font-size:14.5px;line-height:1.6;margin-bottom:9px}
.wi-mast{display:flex;align-items:center;gap:8px;font-size:12px;color:var(--muted)}
.mast-bar{flex:1;max-width:200px;height:7px;background:var(--line2);border-radius:99px;overflow:hidden}
.mast-bar span{display:block;height:100%;background:linear-gradient(90deg,#fca5a5,#fbbf24,#86efac);border-radius:99px}
.wi-acts{display:flex;gap:8px;flex-wrap:wrap}

/* ---------- 举一反三 ---------- */
.variant-section{background:#fff;border:1px solid var(--line);border-radius:14px;padding:18px 20px;margin-bottom:16px}
.variant-section h3{margin:0 0 14px;font-size:16px}
.chip-row{display:flex;gap:9px;flex-wrap:wrap;margin-bottom:14px}
.chip{border:1px solid var(--line);background:#fff;border-radius:999px;padding:8px 14px;font-size:13px;cursor:pointer;transition:.15s}
.chip:hover{background:var(--brand-soft);border-color:#bcd0f7;color:var(--brand)}

/* ---------- 学习报告 ---------- */
.rep-overview{display:grid;grid-template-columns:repeat(4,1fr);gap:12px;margin:8px 0 20px}
.rep-card{background:#fff;border:1px solid var(--line);border-radius:12px;padding:16px;text-align:center}
.rep-card b{display:block;font-size:24px;color:var(--brand)}
.rep-card span{font-size:12px;color:var(--muted)}
.rep-t{font-size:16px;margin:22px 0 12px}
.bar-list{display:flex;flex-direction:column;gap:10px;background:#fff;border:1px solid var(--line);border-radius:12px;padding:16px}
.bar-row{display:flex;align-items:center;gap:10px;font-size:13.5px}
.bar-name{width:150px;flex:none;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.bar-track{flex:1;height:14px;background:var(--line2);border-radius:6px;overflow:hidden}
.bar-track span{display:block;height:100%;border-radius:6px;transition:width .4s}
.bar-val{width:48px;flex:none;text-align:right;color:var(--muted)}
.bar-w{width:42px;flex:none;text-align:right;color:var(--err);font-size:12px}
.log-list{background:#fff;border:1px solid var(--line);border-radius:12px;padding:8px 16px}
.log-row{display:flex;gap:12px;padding:10px 0;border-bottom:1px solid var(--line2);font-size:13.5px;align-items:center}
.log-row:last-child{border-bottom:none}
.log-row span:nth-child(1){color:var(--muted);width:80px}
.log-row span:nth-child(2){font-weight:600;width:90px}

/* ---------- 弹窗 ---------- */
.overlay{position:fixed;inset:0;background:rgba(15,23,42,.45);display:grid;place-items:center;z-index:80;padding:18px}
.modal{background:#fff;border-radius:16px;width:min(680px,96vw);max-height:88vh;display:flex;flex-direction:column;overflow:hidden;box-shadow:0 20px 60px rgba(0,0,0,.3)}
.modal-h{display:flex;align-items:center;padding:15px 18px;border-bottom:1px solid var(--line);font-weight:700;font-size:16px}
.modal-h .x{margin-left:auto;border:none;background:var(--line2);width:30px;height:30px;border-radius:8px;font-size:18px;cursor:pointer;color:var(--muted)}
.modal-b{padding:18px;overflow:auto}
.modal-f{padding:13px 18px;border-top:1px solid var(--line);display:flex;gap:10px;justify-content:flex-end}
.q-stem.big{font-size:16.5px;line-height:1.85;margin:0 0 16px;white-space:pre-wrap;font-weight:500}
.q-body-static{display:flex;flex-direction:column;gap:10px;margin-bottom:16px}
.q-body-static .opt{cursor:default}
.q-body-static .opt.corr{border-color:var(--ok);background:var(--ok-soft)}
.q-body-static .opt.corr .opt-l{background:var(--ok);border-color:var(--ok);color:#fff}
.rk{margin-left:auto;font-size:12px;color:var(--ok);font-weight:700}
.fill-ans{font-size:15px;color:var(--ok);font-weight:600;padding:12px 14px;background:var(--ok-soft);border-radius:10px}

.toast{position:fixed;left:50%;bottom:38px;transform:translate(-50%,20px);background:#1f2937;color:#fff;padding:10px 20px;border-radius:10px;font-size:14px;opacity:0;pointer-events:none;transition:.25s;z-index:99}
.toast.show{opacity:1;transform:translate(-50%,0)}
.foot{padding:26px 16px 40px;text-align:center;color:#9aa4b2;font-size:12px}

/* 云端同步区 */
.cloud-area{display:flex;align-items:center;gap:8px;margin-left:10px}
.cloud-user{font-size:13px;color:var(--ink2);max-width:120px;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.cloud-btn{margin:0}
.tabs{display:flex;gap:8px;margin-bottom:14px}
.tab{border:1px solid var(--line);background:#fff;color:var(--muted);padding:7px 16px;border-radius:9px;font-size:14px;cursor:pointer;font-family:inherit}
.tab.on{background:var(--brand-soft);color:var(--brand);font-weight:600;border-color:var(--brand)}
.c-msg{min-height:18px;font-size:13px;color:var(--muted);margin-top:4px}
.c-msg.bad{color:#e8604c}
.small{font-size:12px}

@media(max-width:820px){
  .hero-stat,.rep-overview,.sum-stat{grid-template-columns:repeat(2,1fr)}
  .topbar-in{height:auto;padding:10px 0;flex-wrap:wrap}
  .nav{width:100%;margin-left:0;overflow-x:auto}
}
@media(max-width:560px){
  .hero{padding:20px}
  .q-card{padding:16px}
  .bar-name{width:96px}
  .log-row span:nth-child(2){width:70px}
}