:root{--navy:#1f3a5f;--blue:#2f6fed;--blue-dark:#1e56c9;--bg:#f6f8fc;--card:#fff;--ink:#1b2430;--muted:#6b7785;--line:#e5e9f0;--ok:#0a7d3c;--err:#c0392b;--radius:14px}
*{box-sizing:border-box;margin:0;padding:0}
html,body{font-family:'Segoe UI','Heebo',Arial,sans-serif;background:var(--bg);color:var(--ink);line-height:1.6}
a{color:var(--blue);text-decoration:none}a:hover{text-decoration:underline}
.top{background:var(--navy);color:#fff;display:flex;align-items:center;justify-content:space-between;padding:12px 22px;flex-wrap:wrap;gap:10px}
.top .brand{color:#fff;font-weight:800;font-size:22px;letter-spacing:.5px}
.top nav{display:flex;align-items:center;gap:16px}
.top nav a{color:#dfe8f7}.top nav a:hover{color:#fff}
.top .who{color:#9fb4d6;font-size:14px}
.btn-sm{background:var(--blue);color:#fff!important;padding:6px 14px;border-radius:999px;font-size:14px}
.linkbtn{background:none;border:none;color:#dfe8f7;cursor:pointer;font:inherit}
.inline{display:inline}
main{max-width:1000px;margin:0 auto;padding:28px 20px}
h1{font-size:34px;margin-bottom:10px;color:var(--navy)}h2{font-size:26px;margin:6px 0 16px;color:var(--navy)}
h3{font-size:19px;margin:22px 0 10px;color:var(--navy)}
.hero{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:40px 32px;text-align:center;margin-bottom:22px}
.hero p{color:var(--muted);font-size:18px;max-width:640px;margin:0 auto 22px}
.cta{display:flex;gap:12px;justify-content:center;flex-wrap:wrap}
.btn{display:inline-block;background:var(--blue);color:#fff!important;padding:12px 26px;border-radius:999px;font-weight:700;border:none;cursor:pointer;font-size:15px}
.btn:hover{background:var(--blue-dark);text-decoration:none}
.btn.ghost{background:transparent;color:var(--blue)!important;border:2px solid var(--blue)}
.btn.ghost:hover{background:var(--blue);color:#fff!important}
.cards{display:grid;grid-template-columns:repeat(3,1fr);gap:16px}
.card{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:24px}
.card h3{margin-top:0}.card p{color:var(--muted)}
.form{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:22px;max-width:460px;display:flex;flex-direction:column;gap:12px}
.form.grid{max-width:none;display:grid;grid-template-columns:1fr 1fr;gap:14px}
.form.grid .wide,.form.grid button{grid-column:1/-1}
label{display:flex;flex-direction:column;gap:6px;font-size:14px;color:var(--muted);font-weight:600}
input,select,textarea{padding:10px 12px;border:1px solid var(--line);border-radius:10px;font:inherit;background:#fff;color:var(--ink)}
textarea{resize:vertical;min-height:90px}
input:focus,select:focus,textarea:focus{outline:2px solid var(--blue);border-color:var(--blue)}
.muted{color:var(--muted);font-size:14px}
.flash{padding:12px 16px;border-radius:10px;margin-bottom:18px;font-weight:600}
.flash.ok{background:#e5f6ec;color:var(--ok);border:1px solid #b7e2c7}
.flash.err{background:#fdecea;color:var(--err);border:1px solid #f5c6c0}
.chips{display:flex;gap:8px;flex-wrap:wrap;margin:6px 0 16px}
.chip{display:inline-flex;align-items:center;gap:6px;padding:7px 14px;border:1px solid var(--line);border-radius:999px;background:var(--card);color:var(--ink);font-weight:600;font-size:14px}
.chip:hover{border-color:var(--blue);color:var(--blue);text-decoration:none}
.chip.active{background:var(--blue);color:#fff;border-color:var(--blue)}
.chip.active .badge{background:rgba(255,255,255,.25);color:#fff}
.statrow{display:flex;gap:12px;flex-wrap:wrap;margin:6px 0 12px}
.stat{display:inline-flex;flex-direction:column;background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:16px 26px;margin-bottom:10px}
.stat span{color:var(--muted);font-size:13px}.stat strong{font-size:28px;color:var(--navy)}
.stat.neg strong{color:var(--err)}
.tbl{width:100%;border-collapse:collapse;background:var(--card);border:1px solid var(--line);border-radius:var(--radius);overflow:hidden;margin:8px 0 20px}
.tbl th,.tbl td{padding:11px 14px;text-align:right;border-bottom:1px solid var(--line);font-size:14px}
.tbl th{background:#eef2f9;color:var(--navy);font-weight:700}
.tbl tr:last-child td{border-bottom:none}
.cols{display:grid;grid-template-columns:1fr 1fr;gap:18px;align-items:start}
.row-actions{display:flex;gap:12px}
.linkbtn.go{color:var(--ok);font-weight:700}.linkbtn.del{color:var(--err)}
.linkbtn.go:hover,.linkbtn.del:hover{text-decoration:underline}
.top .linkbtn{color:#dfe8f7}
.list{list-style:none;background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:14px 20px}
.list li{padding:8px 0;border-bottom:1px solid var(--line)}.list li:last-child{border:none}
.prose{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:26px}
.prose h2{margin:0 0 12px}.prose h3{margin:20px 0 8px}
.prose ul{margin:8px 0 8px 20px;padding-inline-start:20px}.prose li{margin:4px 0}
.prose table{width:100%;border-collapse:collapse;margin:12px 0}
.prose th,.prose td{border:1px solid var(--line);padding:8px 10px;text-align:left;font-size:14px}
.prose th{background:#eef2f9;color:var(--navy)}
.prose .src{margin-top:20px;padding-top:12px;border-top:1px dashed var(--line);font-size:13px}
footer{max-width:1000px;margin:20px auto;padding:16px 20px;color:var(--muted);font-size:12px;text-align:center}
/* content library */
.cgrid{display:grid;grid-template-columns:repeat(auto-fill,minmax(220px,1fr));gap:14px;margin:6px 0 22px}
.ccard{display:block;background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:16px 18px;color:var(--ink)}
.ccard:hover{text-decoration:none;box-shadow:0 8px 22px rgba(31,58,95,.10);transform:translateY(-2px);transition:.15s}
.ccard h4{color:var(--navy);margin-bottom:8px;font-size:16px}
.badge{display:inline-block;background:#eaf0fd;color:var(--blue);font-size:12px;font-weight:700;padding:3px 10px;border-radius:999px}
.badge.page{background:#eef7ee;color:var(--ok)}
/* quiz runner */
.quiz{background:transparent;border:none;padding:0;max-width:none;display:block}
.q{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:18px 20px;margin-bottom:14px}
.q.good{border-color:#b7e2c7;background:#f4fbf6}.q.bad{border-color:#f5c6c0;background:#fdf5f4}
.q-text{font-size:17px;margin-bottom:12px;color:var(--ink)}
.q-body{display:flex;flex-direction:column;gap:8px}
.opt{display:flex;align-items:center;gap:10px;background:#fff;border:1px solid var(--line);border-radius:10px;padding:10px 12px;cursor:pointer;font-weight:500;color:var(--ink)}
.opt:hover{border-color:var(--blue)}
.opt input{width:auto}
.ans{max-width:220px}
.q-fb{margin-top:12px;padding-top:10px;border-top:1px dashed var(--line);font-size:15px}
.q-fb .ok{color:var(--ok)}.q-fb .no{color:var(--err)}
.q-fb .exp{color:var(--muted);margin-top:6px;line-height:1.6}
.quiz-result{background:var(--navy);color:#fff;border-radius:var(--radius);padding:18px 22px;margin-top:12px;text-align:center}
.quiz-result h3{color:#fff;margin:0}
/* teacher sub-nav */
.subnav{display:flex;gap:6px;flex-wrap:wrap;margin:0 0 18px;border-bottom:2px solid var(--line);padding-bottom:0}
.subnav-link{padding:9px 18px;border-radius:10px 10px 0 0;color:var(--muted);font-weight:700;border:2px solid transparent;border-bottom:none;margin-bottom:-2px}
.subnav-link:hover{color:var(--blue);text-decoration:none}
.subnav-link.active{color:var(--navy);background:var(--card);border-color:var(--line)}
.inline-form{display:flex;gap:10px;align-items:flex-end;flex-wrap:wrap;margin:10px 0}
.inline-form select,.inline-form input{min-width:180px}
details.edit{display:inline}details.edit>summary{list-style:none;cursor:pointer;color:var(--blue);font-weight:700}
details.edit .form{margin-top:10px}
/* Gantt chart */
.gantt{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:14px 16px;overflow-x:auto}
.gantt-head .gantt-track{height:26px}
.gantt-row{display:flex;align-items:center;gap:12px;min-height:38px;border-bottom:1px solid var(--line)}
.gantt-row:last-child{border-bottom:none}
.gantt-label{flex:0 0 200px;width:200px;font-size:14px;font-weight:600;color:var(--navy);white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.gantt-track{position:relative;flex:1;height:30px;min-width:420px;background:linear-gradient(90deg,transparent,transparent);border-radius:8px}
.gantt-scale{height:26px}
.gantt-tick{position:absolute;top:0;bottom:0;border-right:1px dashed var(--line)}
.gantt-tick span{position:absolute;top:2px;right:4px;font-size:11px;color:var(--muted);white-space:nowrap}
.gantt-bar{position:absolute;top:5px;height:20px;border:2px solid var(--blue);border-radius:6px;background:#fff;overflow:hidden;display:flex;align-items:center;min-width:12px}
.gantt-fill{position:absolute;top:0;bottom:0;right:0;opacity:.28}
.gantt-btxt{position:relative;font-size:11px;font-weight:700;color:var(--ink);padding:0 6px;z-index:1}
.gantt-nodate{position:absolute;top:6px;right:8px;font-size:12px;color:var(--muted)}
.gantt-legend{display:flex;gap:16px;margin:10px 2px;flex-wrap:wrap}
.gantt-leg{display:inline-flex;align-items:center;gap:6px;font-size:13px;color:var(--muted)}
.gantt-leg i{width:14px;height:14px;border-radius:3px;display:inline-block}
@media(max-width:760px){.cards,.cols,.form.grid{grid-template-columns:1fr}.gantt-label{flex-basis:120px;width:120px}}
/* exam prep */
.qcard{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:16px 18px;margin-bottom:12px}
.qcard b{color:var(--navy)}
.qcard.ok{border-inline-start:4px solid var(--ok)}
.qcard.bad{border-inline-start:4px solid var(--err)}
.opts{margin:10px 0 0;display:flex;flex-direction:column;gap:8px}
.opt{display:flex;align-items:center;gap:10px;border:1px solid var(--line);border-radius:10px;padding:10px 12px;cursor:pointer}
.opt:hover{border-color:var(--blue)}
.opt input{width:auto;margin:0}
ol.opts{list-style:none}
ol.opts li{border:1px solid var(--line);border-radius:10px;padding:8px 12px}
ol.opts li.ok{border-color:var(--ok);background:#e9f7ef;color:var(--ok);font-weight:700}
.numin{margin-top:10px;max-width:240px;padding:10px 12px;border:1px solid var(--line);border-radius:10px;font:inherit;width:100%}
.examform .btn{margin-top:8px}
/* dictation game */
.dict-bar{display:flex;gap:10px;flex-wrap:wrap;align-items:center;background:var(--navy);color:#fff;border-radius:12px;padding:10px 16px;margin-bottom:16px;font-weight:700;font-size:14px}
.dict-bar .dict-prog{color:#cfe0f0;font-weight:500}
.dict-bar .dict-score{margin-inline-start:auto;color:#8fe3b0}
.dict-bar .dict-timer{background:rgba(255,255,255,.14);padding:3px 12px;border-radius:999px;font-variant-numeric:tabular-nums}
.dict-q{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:26px 22px;min-height:230px;text-align:center}
.dict-fb{min-height:28px;text-align:center;font-weight:800;margin-top:12px;font-size:17px}
.dict-fb.ok{color:var(--ok)}.dict-fb.bad{color:var(--err)}
.d-prompt{color:var(--muted);font-size:15px;margin-bottom:8px}
.d-he{font-size:30px;font-weight:900;color:var(--navy);margin-bottom:18px}
.d-en{font-size:34px;font-weight:900;color:var(--blue);margin-bottom:20px;letter-spacing:1px}
/* stage 1 */
.d1-ans{display:flex;gap:7px;justify-content:center;flex-wrap:wrap;margin:6px 0 20px;min-height:52px;align-items:center}
.d1-slot{width:42px;height:50px;border-bottom:3px solid var(--blue);display:inline-flex;align-items:center;justify-content:center;font-size:26px;font-weight:800;color:var(--navy);text-transform:lowercase;cursor:pointer}
.d1-slot.filled{background:#eef4ff;border-radius:8px 8px 0 0}
.d1-space{width:22px}
.d1-pool{display:flex;gap:9px;justify-content:center;flex-wrap:wrap;margin-bottom:14px}
.d1-tile{width:48px;height:52px;border:2px solid var(--line);background:#fff;border-radius:12px;font-size:26px;font-weight:800;color:var(--navy);cursor:pointer;text-transform:lowercase;box-shadow:0 3px 0 #e2e8f2;transition:transform .08s}
.d1-tile:hover{border-color:var(--blue);transform:translateY(-2px)}
.d1-tile.used{opacity:0;pointer-events:none}
/* stage 2 */
.d2-opts{display:grid;grid-template-columns:1fr 1fr;gap:12px;max-width:560px;margin:0 auto}
.d2-opt{padding:16px;border:2px solid var(--line);background:#fff;border-radius:12px;font-size:19px;font-weight:700;color:var(--navy);cursor:pointer}
.d2-opt:hover{border-color:var(--blue)}
.d2-opt.ok{border-color:var(--ok);background:#e9f7ef;color:var(--ok)}
.d2-opt.bad{border-color:var(--err);background:#fdecea;color:var(--err)}
/* stage 3 cannon */
.d3-field{position:relative;display:flex;gap:16px;justify-content:center;flex-wrap:wrap;align-items:center;min-height:150px;margin:10px 0}
.d3-target{padding:16px 22px;border:none;border-radius:50%/40%;font-size:20px;font-weight:800;color:#fff;cursor:crosshair;animation:bob 2.2s ease-in-out infinite;box-shadow:0 6px 14px rgba(15,25,40,.18)}
.d3-target.t0{background:#2f6fed}.d3-target.t1{background:#e8731c}.d3-target.t2{background:#0a7d3c}.d3-target.t3{background:#8b46d6}
.d3-target:nth-child(2){animation-delay:.3s}.d3-target:nth-child(3){animation-delay:.6s}.d3-target:nth-child(4){animation-delay:.9s}
.d3-target.hit{transform:scale(1.25);transition:transform .2s}
.d3-target.boom{animation:none;background:#fbae02!important;transform:scale(1.4)}
.d3-target.miss{animation:none;opacity:.35;filter:grayscale(1)}
.d3-cannon{font-size:46px;margin-top:6px;transform:rotate(0deg)}
@keyframes bob{0%,100%{transform:translateY(0)}50%{transform:translateY(-10px)}}
/* done */
.dict-done .dict-done-emoji{font-size:64px}
.dict-done h2{color:var(--navy);margin:6px 0}
/* staged math exam */
.mx-text{font-size:22px;font-weight:800;color:var(--navy);margin:4px auto 20px;max-width:640px;line-height:1.5}
.mx-numrow{display:flex;gap:10px;justify-content:center;align-items:center;flex-wrap:wrap}
.mx-numrow .numin{max-width:200px;margin:0;text-align:center;font-size:20px}
.mx-intro{padding:16px}
.mx-intro-ic{font-size:52px}
.mx-intro h3{color:var(--navy);margin:6px 0}
.mx-expl{display:block;font-weight:500;color:var(--muted);font-size:14px;margin-top:6px}
.card-box{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:18px 20px;margin-top:16px}
.card-box h3{margin:0 0 10px;color:var(--navy)}
.card-box ul{margin:0;padding-inline-start:20px}.card-box li{margin-bottom:5px}
.subj-switch{display:flex;gap:10px;flex-wrap:wrap}
.subj-chip{display:inline-flex;align-items:center;gap:7px;border:2px solid var(--line);border-radius:999px;padding:9px 16px;font-weight:700;color:var(--navy);background:#fff}
.subj-chip:hover{border-color:var(--blue);text-decoration:none}
.subj-chip.on{background:var(--navy);color:#fff;border-color:var(--navy)}
.subjbar{background:#16304f;display:flex;gap:4px;justify-content:center;flex-wrap:wrap;padding:7px 10px}
.subj-link{color:#cfe0f0;font-size:13px;font-weight:600;padding:4px 11px;border-radius:999px;white-space:nowrap}
.subj-link:hover{background:rgba(255,255,255,.14);color:#fff;text-decoration:none}
.subj-link.on{background:var(--blue);color:#fff}
.foot-subj{display:flex;gap:6px;justify-content:center;flex-wrap:wrap;margin-bottom:10px}
.foot-subj .subj-link{color:var(--navy);border:1px solid var(--line)}
.foot-subj .subj-link:hover{background:var(--bg);color:var(--navy)}
.foot-subj .subj-link.on{background:var(--navy);color:#fff;border-color:var(--navy)}
@media(max-width:620px){.d2-opts{grid-template-columns:1fr}.d-en{font-size:28px}.d1-tile,.d1-slot{width:40px}.mx-text{font-size:19px}}