/* Layout: a working desk — header band with the class name and countdown, tabbed panes below,
   the exam answer sheet drawn as a real A–D bubble grid. Ink-blue pen on lightly blue-tinted paper,
   pencil-yellow for the one highlight. */
:root{
  --paper:#f5f7fb; --card:#ffffff; --ink:#15213d; --muted:#5b6785; --line:#dbe1ee;
  --pen:#2346b8; --pen-soft:#e5ebfb; --pencil:#f2c230; --pencil-ink:#4a3a00;
  --good:#1d7a4c; --good-bg:#e2f4ea; --warn:#9a6200; --warn-bg:#fdf1d6; --bad:#b3261e; --bad-bg:#fbe4e2;
  --f-display:"Bricolage Grotesque", "Segoe UI", system-ui, sans-serif;
  --f-body:"Source Sans 3", "Segoe UI", system-ui, sans-serif;
  --f-mono:"JetBrains Mono", ui-monospace, Consolas, monospace;
  color-scheme:light;
}
@media (prefers-color-scheme: dark){:root{
  --paper:#0f1424; --card:#171e33; --ink:#e6eaf5; --muted:#9aa5c2; --line:#2a3452;
  --pen:#8aa6ff; --pen-soft:#1f2a4d; --pencil:#f2c230; --pencil-ink:#2a2000;
  --good:#5fd197; --good-bg:#14301f; --warn:#f0b54a; --warn-bg:#33270e; --bad:#ff8a80; --bad-bg:#3a1714;
  color-scheme:dark }}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{margin:0;background:var(--paper);color:var(--ink);font-family:var(--f-body);font-size:16px;line-height:1.5}
[hidden]{display:none!important}
img{max-width:100%}
h1,h2,h3{font-family:var(--f-display);text-wrap:balance;margin:0;line-height:1.15}
h1{font-size:1.6rem;font-weight:800}
h2{font-size:1.25rem;font-weight:800}
h3{font-size:1.02rem;font-weight:600}
p{margin:0}
.minw0{min-width:0}
.wrap{max-width:1080px;margin:0 auto;padding-left:max(16px, env(safe-area-inset-left, 0px));padding-right:max(16px, env(safe-area-inset-right, 0px))}
header.band{background:var(--card);border-bottom:1px solid var(--line)}
header .wrap{padding-block:18px 0;display:grid;gap:14px}
.top{display:flex;flex-wrap:wrap;gap:12px 20px;align-items:center;justify-content:space-between}
.brand{display:flex;gap:12px;align-items:center;min-width:0}
.mark{width:40px;height:40px;flex:none}
.sub{color:var(--muted);font-size:.92rem}
.countdown{display:flex;align-items:baseline;gap:8px;background:var(--pencil);color:var(--pencil-ink);border-radius:8px;padding:6px 12px;font-weight:700}
.countdown b{font-family:var(--f-mono);font-size:1.3rem}
nav.tabs{display:flex;gap:4px;overflow-x:auto}
nav.tabs button{border:0;background:none;font:inherit;font-weight:600;color:var(--muted);padding:10px 14px;border-bottom:3px solid transparent;cursor:pointer;white-space:nowrap}
nav.tabs button[aria-selected="true"]{color:var(--ink);border-bottom-color:var(--pen)}
main .wrap{padding-block:24px 48px;display:grid;gap:24px}
.stack{display:grid;gap:24px}
.grid{display:grid;gap:16px}
.cols-4{grid-template-columns:repeat(auto-fit,minmax(170px,1fr))}
.cols-2{grid-template-columns:repeat(auto-fit,minmax(min(100%,420px),1fr))}
.panel{background:var(--card);border:1px solid var(--line);border-radius:10px;padding:18px;display:grid;gap:14px;min-width:0}
.stat{display:grid;gap:2px;align-content:start}
.stat .k{font-size:.78rem;letter-spacing:.06em;text-transform:uppercase;color:var(--muted);font-weight:700}
.stat .v{font-family:var(--f-mono);font-size:1.7rem;font-weight:700;font-variant-numeric:tabular-nums}
.stat .n{font-size:.88rem;color:var(--muted)}
.row{display:flex;flex-wrap:wrap;gap:10px;align-items:center}
.between{justify-content:space-between}
.start{justify-self:start}
.end{align-self:end}
.btn{font:inherit;font-weight:700;border-radius:8px;padding:9px 16px;border:1px solid var(--pen);background:var(--pen);color:var(--card);cursor:pointer;text-decoration:none;display:inline-block}
.btn.ghost{background:transparent;color:var(--pen)}
.btn.danger{background:transparent;border-color:var(--bad);color:var(--bad)}
.btn.small{padding:5px 11px;font-size:.88rem}
.btn.link{border:0;background:none;color:var(--pen);padding:4px 6px}
.btn:disabled{opacity:.5;cursor:not-allowed}
.btn:focus-visible,nav.tabs button:focus-visible,input:focus-visible,select:focus-visible,textarea:focus-visible,.bubble input:focus-visible+span{outline:3px solid var(--pencil);outline-offset:2px}
label.f{display:grid;gap:4px;font-weight:600;font-size:.92rem;min-width:0}
input[type=text],input[type=password],input[type=number],input[type=date],select,textarea{font:inherit;font-weight:400;color:var(--ink);background:var(--paper);border:1px solid var(--line);border-radius:8px;padding:8px 10px;width:100%}
textarea{min-height:140px;font-family:var(--f-mono);font-size:.9rem}
input[type=file]{font:inherit;max-width:100%}
.form-grid{display:grid;gap:12px;grid-template-columns:repeat(auto-fit,minmax(180px,1fr))}
.chip{display:inline-block;font-size:.8rem;font-weight:700;padding:2px 9px;border-radius:999px;white-space:nowrap}
.chip.good{background:var(--good-bg);color:var(--good)}
.chip.warn{background:var(--warn-bg);color:var(--warn)}
.chip.bad{background:var(--bad-bg);color:var(--bad)}
.chip.neutral{background:var(--pen-soft);color:var(--pen)}
.table-wrap{overflow-x:auto}
table{width:100%;border-collapse:collapse;font-variant-numeric:tabular-nums}
th{font-size:.76rem;letter-spacing:.06em;text-transform:uppercase;color:var(--muted);text-align:left;padding:8px 10px;border-bottom:1px solid var(--line);white-space:nowrap}
td{padding:10px;border-bottom:1px solid var(--line);vertical-align:middle}
tr.click{cursor:pointer}
tr.click:hover td{background:var(--pen-soft)}
tr.me td{background:var(--pen-soft)}
.rank{font-family:var(--f-mono);font-weight:700;width:42px;text-align:center}
.rank.top{color:var(--pencil-ink);background:var(--pencil);border-radius:6px}
.num{font-family:var(--f-mono)}
.exam{border:1px solid var(--line);border-radius:10px;padding:14px 16px;display:grid;gap:8px;background:var(--card)}
.exam .meta{color:var(--muted);font-size:.9rem}
.sheet{display:grid;grid-template-columns:repeat(auto-fill,minmax(190px,1fr));gap:6px 18px}
.q{display:flex;align-items:center;gap:8px;padding:3px 0}
.q .qn{font-family:var(--f-mono);font-weight:700;width:30px;text-align:right;color:var(--muted)}
.bubble{position:relative;cursor:pointer}
.bubble input{position:absolute;opacity:0;width:1px;height:1px}
.bubble span{display:grid;place-items:center;width:28px;height:28px;border-radius:50%;border:1.5px solid var(--muted);font-family:var(--f-mono);font-size:.78rem;font-weight:700;color:var(--muted)}
.bubble input:checked+span{background:var(--pen);border-color:var(--pen);color:var(--card)}
.bubble.right input:checked+span{border-color:var(--good);background:var(--good-bg);color:var(--good)}
.bubble.wrong input:checked+span{border-color:var(--bad);background:var(--bad-bg);color:var(--bad)}
.stat .chip,.stat .btn{justify-self:start}
.empty{border:1.5px dashed var(--line);border-radius:10px;padding:22px;color:var(--muted);display:grid;gap:6px}
.empty strong{color:var(--ink)}
.notice{background:var(--warn-bg);color:var(--warn);border-radius:8px;padding:10px 14px;font-weight:600}
.error{background:var(--bad-bg);color:var(--bad);border-radius:8px;padding:10px 14px;font-weight:600}
.toast{position:fixed;left:50%;transform:translateX(-50%);bottom:calc(20px + env(safe-area-inset-bottom, 0px));background:var(--ink);color:var(--paper);padding:10px 18px;border-radius:8px;font-weight:600;z-index:20;max-width:calc(100% - 32px)}
.bars text,.spark text{fill:var(--muted);font-family:var(--f-mono);font-size:10px}
.bars{width:100%;max-width:440px;height:auto}
.detail{background:var(--paper);border-radius:8px;padding:14px;display:grid;gap:10px}
.mini{display:flex;flex-wrap:wrap;gap:6px}
.mini span{font-size:.85rem;background:var(--card);border:1px solid var(--line);border-radius:6px;padding:2px 8px}
.confirm{display:flex;flex-wrap:wrap;gap:8px;align-items:center;background:var(--bad-bg);color:var(--bad);border-radius:8px;padding:8px 12px;font-weight:600}
.auth{max-width:420px;margin:8vh auto 0;display:grid;gap:18px}
.auth .brand h1{font-size:1.4rem}
.key{font-family:var(--f-mono);letter-spacing:.12em;word-break:break-all}
.slips{display:grid;gap:12px;grid-template-columns:repeat(auto-fill,minmax(230px,1fr))}
.slip{border:1.5px dashed var(--muted);border-radius:8px;padding:12px;display:grid;gap:2px;break-inside:avoid}
.slip .pw{font-family:var(--f-mono);font-size:1.15rem;font-weight:700}
.badge{display:inline-grid;place-items:center;min-width:20px;height:20px;padding:0 6px;margin-left:6px;border-radius:999px;background:var(--pencil);color:var(--pencil-ink);font-family:var(--f-mono);font-size:.75rem;font-weight:700}
.announce{background:var(--pen-soft);border:1px solid var(--pen);border-radius:10px;padding:16px 18px;display:grid;gap:8px;min-width:0}
.announce .k{font-size:.78rem;letter-spacing:.06em;text-transform:uppercase;color:var(--pen);font-weight:700}
.body{white-space:pre-wrap;overflow-wrap:anywhere;max-width:70ch}
.exam.pinned{border-color:var(--pen)}
textarea.prose{font-family:var(--f-body);font-size:1rem}
label.check{display:flex;gap:8px;align-items:center;font-weight:600;padding-bottom:8px}
label.check input{width:18px;height:18px}
.grow{flex:1 1 200px;min-width:0}
/* exam: question sheet beside the answer sheet */
.exam-split{display:grid;grid-template-columns:minmax(0,1.4fr) minmax(280px,1fr);gap:20px;align-items:start}
.paper{min-width:0;border:1px solid var(--line);border-radius:8px;overflow:hidden;background:var(--paper)}
.paper .empty{border:0}
.paper-frame{display:block;width:100%;height:78vh;min-height:420px;border:0;background:#fff}
.paper-img{display:block;width:100%;height:auto}
.answers{display:grid;gap:12px;min-width:0;position:sticky;top:12px;max-height:calc(100vh - 24px);overflow:auto;padding-right:4px}
.answers .sheet{grid-template-columns:repeat(auto-fill,minmax(180px,1fr))}
@media (max-width:820px){.exam-split{grid-template-columns:1fr}.answers{position:static;max-height:none;overflow:visible}.paper-frame{height:65vh}}
/* study plan */
.plan{display:grid;gap:8px}
.plan-row{display:grid;grid-template-columns:minmax(90px,140px) 1fr auto;gap:10px;align-items:center}
.plan-name{font-weight:600;font-size:.92rem}
.plan-num{font-size:.85rem;color:var(--muted);white-space:nowrap}
.meter{display:block;height:10px;border-radius:999px;background:var(--pen-soft);overflow:hidden}
.meter .fill{display:block;height:100%;background:var(--pen);border-radius:999px}
.meter .fill.done{background:var(--good)}
.plan-edit{display:grid;gap:10px;grid-template-columns:repeat(auto-fill,minmax(150px,1fr));margin-block:10px}
details summary{cursor:pointer;font-weight:700;color:var(--pen)}
/* attendance */
.seg{display:inline-flex;flex-wrap:wrap;gap:4px}
.seg-opt{position:relative;cursor:pointer}
.seg-opt input{position:absolute;opacity:0;width:1px;height:1px}
.seg-opt span{display:inline-block;padding:4px 10px;border:1px solid var(--line);border-radius:6px;font-size:.85rem;font-weight:600;color:var(--muted)}
.seg-opt input:focus-visible+span{outline:3px solid var(--pencil);outline-offset:1px}
.seg-opt.present input:checked+span{background:var(--good-bg);border-color:var(--good);color:var(--good)}
.seg-opt.late input:checked+span{background:var(--warn-bg);border-color:var(--warn);color:var(--warn)}
.seg-opt.absent input:checked+span{background:var(--bad-bg);border-color:var(--bad);color:var(--bad)}
.seg-opt.excused input:checked+span{background:var(--pen-soft);border-color:var(--pen);color:var(--pen)}
.tabs-seg{gap:6px}
.seg-btn{font:inherit;font-weight:600;border:1px solid var(--line);background:var(--card);color:var(--muted);border-radius:8px;padding:7px 14px;cursor:pointer}
.seg-btn[aria-selected="true"]{background:var(--pen);border-color:var(--pen);color:var(--card)}
.seg-btn:focus-visible{outline:3px solid var(--pencil);outline-offset:2px}
select{width:auto;max-width:100%}
label.f select,.form-grid select{width:100%}
/* parents and activity */
fieldset.kids{border:1px solid var(--line);border-radius:8px;padding:10px 12px;display:grid;gap:8px;min-width:0;margin:0}
fieldset.kids legend{font-weight:600;font-size:.92rem;padding:0 4px}
.kid-list{display:grid;grid-template-columns:repeat(auto-fill,minmax(200px,1fr));gap:2px 12px;max-height:220px;overflow:auto}
.kid-list label.check{padding-bottom:0;font-weight:400}
ol.log{list-style:none;margin:0;padding:0;display:grid}
ol.log li{display:flex;flex-wrap:wrap;gap:6px 10px;align-items:baseline;padding:8px 0;border-bottom:1px solid var(--line);overflow-wrap:anywhere}
.log-time{color:var(--muted);font-size:.85rem;min-width:110px}
/* profile and avatars */
.avatar{display:inline-grid;place-items:center;flex:none;border-radius:50%;object-fit:cover;background:var(--pen-soft);color:var(--pen);font-weight:700;border:1px solid var(--line)}
.profile-btn{display:inline-flex;align-items:center;gap:8px;padding-block:3px}
.file-btn{position:relative;overflow:hidden;cursor:pointer}
.file-btn input{position:absolute;inset:0;opacity:0;cursor:pointer}
.file-btn:focus-within{outline:3px solid var(--pencil);outline-offset:2px}
.person-cell{display:flex;align-items:center;gap:8px}
.stack>.auth{margin:0;max-width:none}
/* teacher: my classes */
.class-cards{display:grid;gap:12px;grid-template-columns:repeat(auto-fill,minmax(min(100%,260px),1fr))}
.class-card{border:1px solid var(--line);border-radius:8px;padding:12px 14px;display:grid;gap:6px;align-content:start}
.class-card.open{grid-column:1/-1;border-color:var(--pen)}
.student-list{margin:0;padding-left:22px;columns:2 220px}
/* timed exams */
.exam-clock{display:flex;align-items:baseline;justify-content:space-between;gap:10px;position:sticky;top:0;z-index:2;background:var(--pen);color:var(--card);border-radius:8px;padding:8px 12px}
.exam-clock .sub{color:inherit;opacity:.85}
.exam-clock b{font-family:var(--f-mono);font-size:1.5rem;font-variant-numeric:tabular-nums}
.exam-clock:has(b.low){background:var(--bad)}
.start-confirm{background:var(--warn-bg);color:var(--ink)}
/* images on daily reports */
.f-label{font-weight:600;font-size:.92rem}
.report-images{display:grid;gap:10px;grid-template-columns:repeat(auto-fill,minmax(150px,1fr))}
.report-images figure{margin:0;display:grid;gap:4px;justify-items:start}
.report-images img{width:100%;height:130px;object-fit:cover;border-radius:8px;border:1px solid var(--line);background:var(--paper)}
/* download format dialog */
.dl-overlay{position:fixed;inset:0;z-index:50;background:rgb(15 20 36 / .45);display:grid;place-items:center;padding:16px}
.dl-box{background:var(--card);color:var(--ink);border-radius:12px;padding:20px 22px;display:grid;gap:12px;width:min(100%,420px);box-shadow:0 12px 40px rgb(0 0 0 / .25)}
.dl-box h2{font-size:1.1rem}
.dl-options{display:flex;flex-wrap:wrap;gap:8px}
.dl-options .btn{flex:1 1 100px}
/* announcement images */
.ann-image{display:block;max-width:560px}
.ann-image img{display:block;width:100%;height:auto;max-height:420px;object-fit:contain;border-radius:8px;border:1px solid var(--line);background:var(--paper)}
.ann-preview{max-width:200px;max-height:140px;border-radius:6px;border:1px solid var(--line)}
/* daily report */
.panel.daily{border-left:4px solid var(--line)}
.panel.daily.done{border-left-color:var(--good)}
.panel.daily.partial{border-left-color:var(--warn)}
.panel.daily.missing{border-left-color:var(--bad)}
.search-wide{min-width:min(100%,260px);flex:1 1 220px;max-width:360px}
/* exams written out as questions: teacher's check list */
.qedit-list{display:grid;gap:12px}
.qedit{display:grid;gap:8px;padding:12px;border:1px solid var(--line);border-radius:10px;background:var(--paper)}
.qedit textarea{width:100%;resize:vertical;min-height:0;font-family:var(--f-body);font-size:1rem}
.qedit-choice{display:flex;align-items:center;gap:10px}
.qedit-choice input[type=text]{flex:1;min-width:0}
details.paste{border:1px dashed var(--line);border-radius:10px;padding:10px 12px}
details.paste summary{cursor:pointer;font-weight:600}
details.paste[open]{display:grid;gap:8px}
details.paste textarea{width:100%;font-family:var(--f-body)}
/* students: one question at a time */
.qnav{display:flex;flex-wrap:wrap;gap:6px}
.qnav-btn{min-width:34px;height:34px;padding:0 6px;border-radius:8px;border:1.5px solid var(--line);background:var(--card);color:var(--muted);font-family:var(--f-mono);font-size:.8rem;font-weight:700;cursor:pointer}
.qnav-btn.done{background:var(--pen-soft);border-color:var(--pen);color:var(--pen)}
.qnav-btn.right{background:var(--good-bg);border-color:var(--good);color:var(--good)}
.qnav-btn.wrong{background:var(--bad-bg);border-color:var(--bad);color:var(--bad)}
.qnav-btn.current{outline:3px solid var(--pencil);outline-offset:1px}
.qcard{display:grid;gap:12px;padding:18px;border:1px solid var(--line);border-radius:12px;background:var(--card)}
.qcount{margin:0;color:var(--muted);font-size:.85rem;font-weight:600;text-transform:uppercase;letter-spacing:.04em}
.qtext{margin:0;font-size:1.12rem;line-height:1.5;white-space:pre-line}
.choices{display:grid;gap:8px}
.choice{position:relative;display:flex;align-items:flex-start;gap:12px;padding:12px 14px;border:1.5px solid var(--line);border-radius:10px;cursor:pointer;background:var(--card)}
.choice input{position:absolute;opacity:0;width:1px;height:1px}
.choice-letter{flex:none;display:grid;place-items:center;width:28px;height:28px;border-radius:50%;border:1.5px solid var(--muted);font-family:var(--f-mono);font-size:.78rem;font-weight:700;color:var(--muted)}
.choice-text{padding-top:3px;line-height:1.4}
.choice:hover{border-color:var(--pen)}
.choice:has(input:checked){border-color:var(--pen);background:var(--pen-soft)}
.choice input:checked~.choice-letter{background:var(--pen);border-color:var(--pen);color:var(--card)}
.choice:has(input:focus-visible){outline:3px solid var(--pencil);outline-offset:2px}
.choice.right:has(input:checked){border-color:var(--good);background:var(--good-bg)}
.choice.right input:checked~.choice-letter{background:var(--good);border-color:var(--good)}
.choice.wrong:has(input:checked){border-color:var(--bad);background:var(--bad-bg)}
.choice.wrong input:checked~.choice-letter{background:var(--bad);border-color:var(--bad)}
.choice:has(input:disabled){cursor:default}
.qsteps{display:flex;justify-content:space-between;gap:10px}
.qsteps .btn{min-width:120px}
.qfooter{display:grid;gap:8px}
.tone-good{color:var(--good)}.tone-warn{color:var(--warn)}.tone-bad{color:var(--bad)}.tone-neutral{color:var(--pen)}
@media (prefers-reduced-motion: no-preference){.btn,.bubble span{transition:background .15s, color .15s}}
@media print{
  header.band,.toast,.no-print,.tabs-seg,.btn,.seg-btn{display:none!important}
  .panel{break-inside:avoid;border-color:#bbb}
  .table-wrap{overflow:visible}
  .answers{position:static;max-height:none;overflow:visible}
  body{background:#fff;color:#000}
  main .wrap{padding:0}
  .print-area{border:0;padding:0}
}