:root{
  --blue:#3b82f6; --green:#10b981; --orange:#f59e0b; --red:#ef4444;
  --purple:#8b5cf6; --pink:#ec4899; --teal:#06b6d4;
  --ink:#1f2937; --ink2:#4b5563; --muted:#6b7280;
  --line:#e5e7eb; --bg:#f1f5f9; --card:#ffffff;
  --shadow:0 6px 20px rgba(15,23,42,.08);
}
*{box-sizing:border-box}
body{
  margin:0; font-family:"Microsoft YaHei","PingFang SC","Helvetica Neue",Arial,sans-serif;
  background:linear-gradient(160deg,#eef6ff 0%,#f3f0ff 45%,#eafaf3 100%);
  color:var(--ink); min-height:100vh;
}
.hidden{display:none !important}
.wrap{max-width:1080px;margin:0 auto;padding:18px 16px 60px}

/* ---------- 顶栏 ---------- */
.topbar{
  background:#fff;border-bottom:1px solid var(--line);
  padding:10px 18px;display:flex;align-items:center;gap:14px;flex-wrap:wrap;
  box-shadow:0 2px 10px rgba(15,23,42,.05);position:sticky;top:0;z-index:20;
}
.brand{display:flex;align-items:center;gap:10px}
.logo{font-size:30px}
.topbar h1{margin:0;font-size:19px;letter-spacing:.5px}
.topbar p{margin:2px 0 0;font-size:12px;color:var(--muted)}
.nav{display:flex;gap:6px;margin-left:auto;flex-wrap:wrap}
.nav-btn{
  border:1px solid var(--line);background:#f8fafc;color:var(--ink2);
  padding:7px 14px;border-radius:20px;cursor:pointer;font-size:14px;transition:.2s;
}
.nav-btn:hover{background:#eef2ff;color:var(--blue)}
.nav-btn.active{background:var(--blue);color:#fff;border-color:var(--blue)}
.userbox{display:flex;align-items:center;gap:8px}
.chip{background:#eef2ff;color:var(--blue);padding:5px 12px;border-radius:14px;font-size:13px;font-weight:700}
.chip.score{background:#ecfdf5;color:var(--green)}
.mini-btn{border:1px solid var(--line);background:#fff;border-radius:50%;width:32px;height:32px;cursor:pointer;font-size:15px}

/* ---------- 通用卡片 ---------- */
.card{background:var(--card);border-radius:16px;padding:20px;box-shadow:var(--shadow);margin-bottom:16px}
.page-title{font-size:20px;margin:6px 0 14px}
.muted{color:var(--muted);font-size:13px}
.tip{font-size:12px;color:var(--muted);margin-top:10px}
.row{display:flex;gap:10px;align-items:center;flex-wrap:wrap}
.row.center{justify-content:center}
input[type=text],input[type=password]{
  border:1px solid var(--line);border-radius:10px;padding:10px 12px;font-size:14px;
  min-width:160px;flex:1;outline:none;background:#fff;color:var(--ink);
}
input:focus{border-color:var(--blue);box-shadow:0 0 0 3px rgba(59,130,246,.12)}
.wrap-row{gap:8px}
.codebox{
  width:100%;border:1px solid var(--line);border-radius:10px;padding:10px 12px;
  font-size:12px;font-family:Consolas,Monaco,monospace;line-height:1.6;
  resize:vertical;outline:none;background:#f9fafb;color:var(--ink2);margin-top:10px;
  word-break:break-all;box-sizing:border-box;
}
.codebox:focus{border-color:var(--blue);box-shadow:0 0 0 3px rgba(59,130,246,.12)}
.tag{display:inline-block;font-size:11px;padding:2px 7px;border-radius:8px;white-space:nowrap;line-height:1.5}
.tag.local{background:#eef2ff;color:#4f46e5}
.tag.import{background:#ecfdf5;color:#059669}
.tag.merge{background:#fff7ed;color:#c2410c}
.tag.server{background:#e0f2fe;color:#0369a1}
.tag.cloud{background:#f5f3ff;color:#7c3aed}

/* ---------- 实时状态条 ---------- */
.livebar,.srvbar{
  display:flex;align-items:center;gap:8px;flex-wrap:wrap;
  background:#ecfdf5;border:1px solid #a7f3d0;color:#065f46;
  padding:8px 14px;border-radius:10px;font-size:13px;margin-bottom:12px;
}
.srvbar{background:#eff6ff;border-color:#bfdbfe;color:#1e40af;margin-bottom:12px}
.dot{
  width:9px;height:9px;border-radius:50%;background:#10b981;flex:none;
  box-shadow:0 0 0 0 rgba(16,185,129,.6);animation:pulse 1.8s infinite;
}
.srvbar .dot{background:#3b82f6;box-shadow:0 0 0 0 rgba(59,130,246,.6)}
@keyframes pulse{
  0%{box-shadow:0 0 0 0 rgba(16,185,129,.55)}
  70%{box-shadow:0 0 0 8px rgba(16,185,129,0)}
  100%{box-shadow:0 0 0 0 rgba(16,185,129,0)}
}

/* ---------- 局域网面板 ---------- */
.lan-card{padding:18px}
.langrid{display:flex;gap:24px;align-items:flex-start;flex-wrap:wrap}
.qrbox{
  flex:none;text-align:center;background:#fff;border:1px solid var(--line);
  border-radius:14px;padding:14px;box-shadow:var(--shadow);
}
.qrbox canvas{display:block;width:220px;height:220px;image-rendering:pixelated}
.qrbox p{margin:8px 0 0;font-size:12px}
.laninfo{flex:1;min-width:280px}
.lanurl{
  background:#f8fafc;border:1px dashed var(--line);border-radius:10px;
  padding:12px 14px;font-size:15px;margin-bottom:12px;word-break:break-all;
}
.lanurl b{color:var(--blue);font-size:17px}
.steps{margin:12px 0 0;padding-left:20px;font-size:13px;color:var(--ink2);line-height:1.9}
.steps li{margin-bottom:2px}
.ck{display:flex;align-items:center;gap:5px;font-size:13px;color:var(--ink2);cursor:pointer}
.livetitle{align-items:center}

/* ---------- 云班面板 ---------- */
#cloudSetup input{flex:1;min-width:240px}
#cloudMsg{margin:10px 0 0;font-size:13px;line-height:1.7}
#cloudMsg:not(:empty){background:#f8fafc;border-left:3px solid var(--blue);padding:8px 12px;border-radius:6px}
.shareurl{
  flex:1;min-width:240px;background:#f8fafc;border:1px dashed var(--line);
  border-radius:10px;padding:11px 14px;font-size:13px;color:var(--blue);word-break:break-all;
}
.qrrow{display:flex;gap:20px;align-items:flex-start;flex-wrap:wrap;margin-top:14px}
.qrrow canvas{
  flex:none;width:200px;height:200px;background:#fff;border:1px solid var(--line);
  border-radius:14px;padding:10px;box-shadow:var(--shadow);image-rendering:pixelated;
}
.qrtip{flex:1;min-width:240px}
.qrtip .row{gap:8px;flex-wrap:wrap}
.lan-head{display:flex;justify-content:space-between;align-items:center;gap:12px;flex-wrap:wrap;margin-bottom:8px}
.grow{flex:1}
.lan-card h3,.card h3{margin:0 0 6px;font-size:16px}

@media (max-width:640px){
  .langrid{flex-direction:column;align-items:center}
  .laninfo{min-width:0;width:100%}
}
.btn{
  border:1px solid var(--line);background:#fff;color:var(--ink2);
  padding:10px 18px;border-radius:10px;cursor:pointer;font-size:14px;transition:.15s;
}
.btn:hover{background:#f1f5f9;transform:translateY(-1px)}
.btn.primary{background:var(--blue);color:#fff;border-color:var(--blue)}
.btn.primary:hover{background:#2563eb}
.btn.ghost{background:#f8fafc}
.btn.danger{background:#fef2f2;color:var(--red);border-color:#fecaca}
.btn.next{width:100%;margin-top:14px}
.back{margin-bottom:10px}

/* ---------- 登录 ---------- */
.login-card{max-width:760px;margin:10px auto}
.namelist{display:flex;gap:8px;flex-wrap:wrap;margin-top:14px}
.namepill{background:#f1f5f9;border:1px dashed var(--line);border-radius:18px;padding:5px 14px;cursor:pointer;font-size:13px}
.namepill:hover{background:#e0e7ff;border-color:var(--blue);color:var(--blue)}

/* ---------- 统计条 ---------- */
.statbar{display:grid;grid-template-columns:repeat(4,1fr);gap:12px;margin-bottom:16px}
.stat{background:#fff;border-radius:14px;padding:14px;text-align:center;box-shadow:var(--shadow)}
.stat b{display:block;font-size:24px;color:var(--blue)}
.stat span{font-size:12px;color:var(--muted)}
@media(max-width:600px){.statbar{grid-template-columns:repeat(2,1fr)}}

/* ---------- 选册 / 单元 / 课 ---------- */
.booklist{display:grid;grid-template-columns:repeat(auto-fill,minmax(240px,1fr));gap:14px}
.book{
  background:#fff;border-radius:16px;padding:18px;box-shadow:var(--shadow);cursor:pointer;
  border-top:5px solid var(--blue);transition:.2s;
}
.book:nth-child(2){border-top-color:var(--green)}
.book:nth-child(3){border-top-color:var(--orange)}
.book:nth-child(4){border-top-color:var(--purple)}
.book:hover{transform:translateY(-3px);box-shadow:0 10px 24px rgba(15,23,42,.12)}
.book h3{margin:0 0 4px;font-size:17px}
.book .sub{font-size:12px;color:var(--muted)}
.book .pg{margin-top:10px;font-size:12px;color:var(--muted)}
.book .pb{height:8px;background:#f1f5f9;border-radius:6px;overflow:hidden;margin-top:6px}
.book .pb i{display:block;height:100%;background:linear-gradient(90deg,var(--teal),var(--green))}
.unitlist{display:grid;gap:12px}
.unit{
  background:#fff;border-radius:14px;padding:16px;box-shadow:var(--shadow);cursor:pointer;
  display:flex;align-items:center;gap:12px;transition:.2s;border-left:6px solid var(--teal)
}
.unit:hover{transform:translateX(4px)}
.unit .uicon{font-size:26px}
.unit .uname{font-size:16px;font-weight:700}
.unit .uinfo{font-size:12px;color:var(--muted)}
.lessonlist{display:grid;grid-template-columns:repeat(auto-fill,minmax(210px,1fr));gap:12px}
.lesson{
  background:#fff;border-radius:12px;padding:14px;box-shadow:var(--shadow);cursor:pointer;
  display:flex;flex-direction:column;gap:8px;transition:.2s;border:1px solid transparent
}
.lesson:hover{border-color:var(--blue);transform:translateY(-2px)}
.lesson .ltitle{font-size:14px;font-weight:700;line-height:1.4}
.lesson .lmeta{font-size:12px;color:var(--muted);display:flex;justify-content:space-between;align-items:center}
.lstar{color:#fbbf24;letter-spacing:1px}
.lbadge{background:#ecfdf5;color:var(--green);font-size:11px;padding:2px 8px;border-radius:10px}

/* ---------- 答题 ---------- */
.quiz-head{display:flex;align-items:center;gap:12px;margin-bottom:8px}
.qtitle{font-size:16px;font-weight:700;flex:1;text-align:center}
.qmeta{display:flex;gap:10px;font-size:13px;color:var(--muted)}
.progress{height:8px;background:#e5e7eb;border-radius:6px;overflow:hidden;margin-bottom:16px}
.progress .bar{height:100%;width:0;background:linear-gradient(90deg,var(--blue),var(--purple));transition:width .35s}
.qcard{max-width:820px;margin:0 auto}
.qtypeline{display:flex;align-items:center;gap:10px;margin-bottom:12px;flex-wrap:wrap}
.qtype{display:inline-block;background:#eef2ff;color:var(--blue);font-size:12px;padding:3px 10px;border-radius:12px}
.qdots{display:flex;gap:5px;margin-left:auto;flex-wrap:wrap}
.qdots i{
  width:23px;height:23px;line-height:21px;text-align:center;border-radius:50%;
  background:#f1f5f9;color:var(--muted);font-size:11px;font-style:normal;
  border:1px solid var(--line);transition:.2s;
}
.qdots i.cur{background:var(--blue);color:#fff;border-color:var(--blue);transform:scale(1.12)}
.qdots i.ok{background:var(--green);color:#fff;border-color:var(--green)}
.qdots i.no{background:var(--red);color:#fff;border-color:var(--red)}
.qctx{
  background:#fffbeb;border:1px dashed #fcd34d;border-radius:12px;
  padding:12px 14px;margin-bottom:14px;font-size:14px;line-height:1.8;color:#78350f;
}
.qctx b{display:block;margin-bottom:4px;color:#b45309;font-size:13px}
.qtext{font-size:18px;line-height:1.7;margin-bottom:18px;font-weight:600}
.options{display:grid;gap:10px}
.opt{
  border:2px solid var(--line);border-radius:12px;padding:13px 16px;cursor:pointer;
  background:#fff;font-size:15px;text-align:left;transition:.15s;display:flex;gap:10px;align-items:flex-start;
}
.opt:hover{border-color:var(--blue);background:#f8fafc}
.opt .k{font-weight:800;color:var(--blue);min-width:22px}
.opt.right{border-color:var(--green);background:#ecfdf5}
.opt.right .k{color:var(--green)}
.opt.wrong{border-color:var(--red);background:#fef2f2}
.opt.wrong .k{color:var(--red)}
.opt:disabled{cursor:default}

/* ---------- 选词填空 ---------- */
.slot{
  display:inline-block;min-width:76px;padding:1px 12px;margin:0 4px;
  border-bottom:2px solid var(--blue);background:#eff6ff;border-radius:8px;
  color:var(--blue);font-weight:700;text-align:center;cursor:pointer;transition:.15s;
}
.slot:hover{background:#dbeafe}
.slot.filled{background:#dbeafe}
.slot.ok{background:#ecfdf5;border-color:var(--green);color:var(--green)}
.slot.bad{background:#fef2f2;border-color:var(--red);color:var(--red)}
.wordbank{
  display:flex;flex-wrap:wrap;gap:8px;padding:14px;
  background:#f8fafc;border:1px dashed #cbd5e1;border-radius:12px;
}
.wordbank:empty::before{content:"（词库）";color:var(--muted);font-size:13px}
.word{
  border:2px solid var(--line);background:#fff;border-radius:20px;
  padding:7px 16px;cursor:pointer;font-size:15px;transition:.15s;color:var(--ink);
}
.word:hover{border-color:var(--blue);color:var(--blue);background:#f8fafc}
.word.used{opacity:.32;cursor:default;border-style:dashed}
.word.used:hover{border-color:var(--line);color:var(--ink);background:#fff}

/* ---------- 实验步骤排序 ---------- */
.orderbox{gap:8px}
.step{
  border:2px solid var(--line);border-radius:12px;padding:12px 14px;cursor:pointer;
  background:#fff;font-size:15px;text-align:left;transition:.15s;display:flex;gap:10px;align-items:flex-start;line-height:1.6;
}
.step:hover{border-color:var(--blue);background:#f8fafc}
.step .no{min-width:26px;color:var(--blue);font-weight:800;font-size:16px}
.step.picked{background:#eff6ff;border-color:var(--blue)}
.step.right{background:#ecfdf5;border-color:var(--green)}
.step.right .no{color:var(--green)}
.step.bad{background:#fef2f2;border-color:var(--red)}
.step.bad .no{color:var(--red)}
.feedback{margin-top:16px;padding:14px;border-radius:12px;background:#f8fafc;border-left:5px solid var(--muted);font-size:14px;line-height:1.7}
.feedback.ok{background:#ecfdf5;border-left-color:var(--green)}
.feedback.no{background:#fef2f2;border-left-color:var(--red)}
.feedback .ftitle{font-weight:800;margin-bottom:4px}
.feedback .fexp{color:var(--ink2)}
.pop{animation:pop .35s}
@keyframes pop{0%{transform:scale(1)}40%{transform:scale(1.04)}100%{transform:scale(1)}}

/* ---------- 结算 ---------- */
.result-card{max-width:720px;margin:20px auto;text-align:center}
.res-emoji{font-size:56px}
.stars{font-size:30px;letter-spacing:6px;color:#fbbf24;margin:6px 0 12px}
.res-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:12px;margin:16px 0}
.res-grid div{background:#f8fafc;border-radius:12px;padding:12px}
.res-grid b{display:block;font-size:22px;color:var(--blue)}
.res-grid span{font-size:12px;color:var(--muted)}
.res-badges{display:flex;gap:10px;justify-content:center;flex-wrap:wrap;margin-bottom:12px}
.newbadge{background:linear-gradient(135deg,#fef3c7,#fde68a);border:1px solid #fcd34d;color:#92400e;padding:8px 14px;border-radius:14px;font-size:13px;font-weight:700;animation:pop .5s}
.res-wrong{text-align:left;background:#fffbeb;border:1px solid #fde68a;border-radius:12px;padding:12px;font-size:13px;margin-bottom:14px}
.res-wrong b{color:#92400e}
.res-wrong li{margin:4px 0}

/* ---------- 排行榜 ---------- */
.podium{display:grid;grid-template-columns:repeat(3,1fr);gap:12px;margin:16px 0}
.pd{background:linear-gradient(160deg,#fff,#f8fafc);border-radius:14px;padding:16px;text-align:center;border:2px solid var(--line)}
.pd.p1{border-color:#fbbf24;background:linear-gradient(160deg,#fffbeb,#fef3c7)}
.pd.p2{border-color:#cbd5e1}
.pd.p3{border-color:#f59e0b}
.pd .medal{font-size:34px}
.pd .pname{font-weight:800;font-size:15px;margin-top:4px}
.pd .pscore{color:var(--blue);font-weight:800}
.table{width:100%;border-collapse:collapse;font-size:14px}
.table th,.table td{padding:10px 8px;text-align:center;border-bottom:1px solid var(--line)}
.table th{background:#f8fafc;color:var(--ink2);font-size:13px}
.table tr.me{background:#eff6ff}
.table td.name{font-weight:700}

/* ---------- 徽章墙 ---------- */
.badgewall{display:grid;grid-template-columns:repeat(auto-fill,minmax(150px,1fr));gap:14px;margin-bottom:18px}
.bg{background:#fff;border-radius:16px;padding:16px;text-align:center;box-shadow:var(--shadow);opacity:.42;filter:grayscale(1)}
.bg.on{opacity:1;filter:none;border:2px solid #fcd34d;background:linear-gradient(160deg,#fff,#fffbeb)}
.bg .bi{font-size:34px}
.bg .bn{font-weight:800;font-size:13px;margin-top:6px}
.bg .bd{font-size:11px;color:var(--muted);margin-top:4px;line-height:1.4}
.cert-card .row{margin:10px 0}
.certbox{margin-top:14px;text-align:center}
#certCanvas{max-width:100%;border-radius:12px;box-shadow:var(--shadow)}

/* ---------- 教师端 ---------- */
.wrap-row{gap:8px}

/* ---------- 提示 & 页脚 ---------- */
.toast{
  position:fixed;left:50%;bottom:40px;transform:translateX(-50%);
  background:rgba(17,24,39,.92);color:#fff;padding:12px 22px;border-radius:12px;
  font-size:14px;z-index:99;animation:pop .3s;
}
.toast.good{background:linear-gradient(135deg,#10b981,#059669)}
/* 云端连不上时的醒目提示框（部分宽带会拦数据库域名） */
.offline{
  background:#fff5f5;border:1px solid #ffcaca;border-left:5px solid #e5484d;
  border-radius:12px;padding:13px 16px;margin:12px 0;font-size:13.5px;line-height:1.85;color:#4b1d1d;
}
.offline b{color:#c62828}
.foot{text-align:center;color:var(--muted);font-size:12px;padding:20px}
/* 教师模式入口：低调藏在页脚，避免分散学生注意力 */
.teach-entry{text-align:center;padding:0 0 26px}
.teach-link{
  background:none;border:0;color:#c7cede;font-size:12px;cursor:pointer;
  padding:2px 6px;border-radius:6px;font-family:inherit;
}
.teach-link:hover{color:var(--blue);background:#f1f5f9}
.teach-entry b{color:var(--muted);font-weight:600;font-size:12px}
/* 密码弹窗 */
.mask{position:fixed;inset:0;background:rgba(15,23,42,.45);display:flex;align-items:center;justify-content:center;z-index:120}
.mask-box{background:#fff;border-radius:16px;padding:24px;max-width:360px;width:88%;box-shadow:0 20px 50px rgba(0,0,0,.2)}
.mask-box h3{margin:0 0 6px;font-size:18px}
.mask-box .tip{min-height:18px;color:var(--red)}
/* 单元复习卡片：和普通课文区别开，放在一课的最后 */
.lesson.review{background:linear-gradient(135deg,#fffbeb,#fef3c7);border-color:#fcd34d}
.lesson.review .ltitle{color:#b45309;font-weight:700}
.lesson.review .lbadge{background:#fde68a;color:#92400e}
.row.end{display:flex;justify-content:flex-end;gap:8px;margin-top:12px}
.stale{background:linear-gradient(135deg,#fef2f2,#fee2e2);border:1px solid #fca5a5;color:#b91c1c;padding:10px 14px;border-radius:10px;margin:10px 0;display:flex;align-items:center;gap:10px;flex-wrap:wrap;font-size:14px;line-height:1.6}
.stale .mini-btn{flex:none}
.advrow{border:1px dashed var(--line,#e5e7eb);border-radius:10px;padding:10px 12px;margin-top:10px}
.advrow summary{cursor:pointer;color:var(--muted);font-size:13px;user-select:none}
.advrow summary::marker{color:var(--muted)}
.mt2{margin-top:10px}

/* ---------- 年级横条（四、五年级分开） ---------- */
.gradebar{
  display:flex;align-items:center;gap:10px;flex-wrap:wrap;
  background:linear-gradient(135deg,#eff6ff,#e0e7ff);border:1px solid #c7d2fe;
  border-radius:12px;padding:10px 14px;margin-bottom:14px;font-size:14px;
}
.gradebar.warn{background:linear-gradient(135deg,#fffbeb,#fef3c7);border-color:#fcd34d;color:#92400e}
.gradebar .gchip{font-weight:700;color:#1d4ed8}
.gradebar.warn .gchip{color:#b45309}
.gradebar .gmuted{color:var(--muted);font-size:12px}
.gradebar .gbtn{margin-left:auto}
@media(max-width:600px){.gradebar .gbtn{margin-left:0}}
select.gradesel{
  border:1px solid var(--line);background:#fff;color:var(--ink2);border-radius:10px;
  padding:10px 14px;font-size:14px;font-family:inherit;cursor:pointer;max-width:100%;
}