:root{
  /* ink & paper */
  --ink:#1E2420; --ink-soft:#57625C; --ink-faint:#95998D;
  --bg:#F2F3EA; --panel:#FFFFFF; --line:#E2E6D8;
  --grid-line:#DEE3D2;

  /* red-pen ink — the primary / brand colour, drawn from a teacher's grading pen */
  --indigo:#B23328; --indigo-deep:#8A2620; --indigo-glow:#F5E1DD;
  /* chalk jade — completion, correctness, "done" */
  --teal:#1F7A5C; --teal-glow:#DFEFE6;
  /* rust — needs attention / flagged, kept distinct from the brand red */
  --coral:#C1652E; --coral-glow:#F8E6D3;
  /* ochre — pending / scheduled */
  --amber:#AD7A1D; --amber-glow:#F5EBD6;

  --radius-lg:18px; --radius-md:12px; --radius-sm:8px;
  --shadow:0 1px 2px rgba(24,28,22,.05), 0 10px 26px rgba(24,28,22,.08);

  --font-display:'Fraunces',ui-serif,Georgia,serif;
  --font-body:'Be Vietnam Pro',sans-serif;
  --font-mono:'JetBrains Mono',ui-monospace,monospace;
}
*{box-sizing:border-box;}
body{
  margin:0;font-family:var(--font-body);background:var(--bg);color:var(--ink);
  background-image:
    linear-gradient(var(--grid-line) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid-line) 1px, transparent 1px);
  background-size:27px 27px;
}
h1,h2,h3,.disp{font-family:var(--font-display);}
button{font-family:inherit;cursor:pointer;}
a{font-family:inherit;}
.screen{display:none;}
.screen.active{display:block;}
.screen.center-screen.active{display:flex;}

:focus-visible{outline:2px solid var(--indigo);outline-offset:2px;}

@media (prefers-reduced-motion: reduce){
  *,*::before,*::after{transition:none !important;animation:none !important;}
}

.brandmark{display:flex;align-items:center;gap:11px;}
.brandmark .dot{
  width:36px;height:36px;border-radius:50%;flex-shrink:0;
  background:var(--panel);border:1.5px solid var(--indigo);color:var(--indigo-deep);
  display:flex;align-items:center;justify-content:center;
  font-family:var(--font-display);font-weight:700;font-style:italic;font-size:16px;
  position:relative;transform:rotate(-9deg);
}
.brandmark .dot::after{
  content:"";position:absolute;inset:3px;border-radius:50%;
  border:1px dashed var(--indigo);opacity:.45;
}
.brandmark span{font-family:var(--font-display);font-weight:600;font-size:20px;letter-spacing:-.01em;color:var(--ink);}

.center-screen{
  min-height:100vh;display:flex;flex-direction:column;align-items:center;justify-content:center;
  padding:40px 20px;position:relative;overflow:hidden;
}
.center-screen .brandmark{margin-bottom:44px;}
.cs-title{
  font-family:var(--font-display);font-size:36px;font-weight:600;letter-spacing:-.01em;
  text-align:center;max-width:580px;line-height:1.28;margin:0 0 12px;color:var(--ink);
}
.cs-title em{font-style:italic;font-weight:600;color:var(--indigo-deep);}
.cs-sub{color:var(--ink-soft);font-size:15px;text-align:center;max-width:440px;margin:0 0 40px;line-height:1.6;}

@media (min-width:760px){
  .center-screen::before{
    content:"";position:absolute;left:64px;top:0;bottom:0;width:1px;background:var(--indigo);opacity:.28;z-index:0;
  }
  .center-screen::after{
    content:"";position:absolute;left:0;top:0;bottom:0;width:64px;
    background:linear-gradient(90deg, rgba(178,51,40,.05), transparent);z-index:0;
  }
  .center-screen > *{position:relative;z-index:1;}
}

.role-grid{display:flex;gap:22px;flex-wrap:wrap;justify-content:center;}
.role-card{
  width:270px;background:var(--panel);border:1px solid var(--line);
  border-radius:var(--radius-lg);border-top-right-radius:6px;
  padding:30px 24px;box-shadow:var(--shadow);
  transition:transform .2s ease, box-shadow .2s ease;text-align:left;position:relative;
}
.role-card::after{
  content:"";position:absolute;top:0;right:0;width:0;height:0;
  border-style:solid;border-width:0 18px 18px 0;
  border-color:transparent var(--bg) transparent transparent;
  filter:drop-shadow(-1px 1px 1px rgba(24,28,22,.14));
}
.role-card:hover{transform:translateY(-4px);box-shadow:0 4px 8px rgba(24,28,22,.07), 0 18px 34px rgba(24,28,22,.12);}
.role-icon{width:50px;height:50px;border-radius:14px;display:flex;align-items:center;justify-content:center;font-size:22px;margin-bottom:18px;}
.role-card h3{font-size:19px;margin:0 0 8px;font-weight:600;}
.role-card p{color:var(--ink-soft);font-size:13.5px;line-height:1.6;margin:0 0 18px;}
.role-cta{display:inline-flex;align-items:center;gap:6px;font-weight:700;font-size:13.5px;color:var(--indigo-deep);}

.auth-card{
  width:380px;background:var(--panel);border:1px solid var(--line);
  border-radius:var(--radius-lg);border-top-right-radius:6px;
  box-shadow:var(--shadow);padding:32px 30px;position:relative;
}
.auth-card::after{
  content:"";position:absolute;top:0;right:0;width:0;height:0;
  border-style:solid;border-width:0 18px 18px 0;
  border-color:transparent var(--bg) transparent transparent;
  filter:drop-shadow(-1px 1px 1px rgba(24,28,22,.14));
}
.auth-tabs{display:flex;gap:4px;background:var(--line);padding:4px;border-radius:11px;margin-bottom:22px;}
.auth-tabs .tab-btn{flex:1;text-align:center;}
.back-link{display:inline-flex;align-items:center;gap:6px;font-size:13px;font-weight:700;color:var(--ink-soft);background:none;border:none;margin-bottom:18px;}
.back-link:hover{color:var(--ink);}
.auth-submit{width:100%;justify-content:center;margin-top:6px;}
.auth-foot{text-align:center;font-size:12.5px;color:var(--ink-faint);margin-top:16px;line-height:1.6;}
.auth-foot a{color:var(--indigo-deep);font-weight:700;text-decoration:none;}
.auth-foot a:hover{text-decoration:underline;}
.reg-success{font-size:12.5px;font-weight:700;color:var(--teal);margin-top:14px;text-align:center;}

.topnav{
  position:sticky;top:0;z-index:20;background:var(--ink);color:#fff;padding:0 32px;
  border-bottom:3px solid;border-image:linear-gradient(90deg,var(--indigo),var(--teal)) 1;
}
.topnav-row{display:flex;align-items:center;justify-content:space-between;height:64px;}
.avatar-row{display:flex;align-items:center;gap:10px;}
.avatar{width:32px;height:32px;border-radius:50%;background:var(--indigo);display:flex;align-items:center;justify-content:center;font-size:12.5px;font-weight:700;color:#fff;flex-shrink:0;font-family:var(--font-display);}
.avatar-row .who b{display:block;font-size:13px;color:#fff;line-height:1.3;font-weight:600;}
.avatar-row .who small{color:#b7bcae;font-size:11.5px;}
.logout-btn{border:none;background:rgba(255,255,255,.08);color:#fff;font-size:12px;font-weight:700;padding:7px 12px;border-radius:8px;margin-left:12px;}
.logout-btn:hover{background:rgba(255,255,255,.16);}
.section-nav{display:flex;gap:6px;padding:0 0 14px;border-top:1px solid rgba(255,255,255,.08);padding-top:12px;flex-wrap:wrap;overflow-x:auto;}
.nav-item{display:flex;align-items:center;gap:8px;padding:9px 16px;border-radius:999px;color:#b7bcae;font-size:13.5px;font-weight:600;background:none;border:none;white-space:nowrap;}
.nav-item:hover{background:rgba(255,255,255,.07);color:#fff;}
.nav-item.active{background:rgba(255,255,255,.14);color:#fff;box-shadow:inset 0 -2px 0 var(--indigo);}

.main{padding:32px 40px 60px;max-width:1280px;margin:0 auto;}
.topbar{display:flex;justify-content:space-between;align-items:flex-start;margin-bottom:28px;flex-wrap:wrap;gap:14px;}
.topbar h1{font-size:25px;margin:0 0 4px;letter-spacing:-.01em;font-weight:600;}
.topbar p{color:var(--ink-soft);font-size:14px;margin:0;}
.pill-btn{background:var(--indigo);color:#fff;border:none;padding:10px 18px;border-radius:999px;font-weight:700;font-size:13.5px;display:inline-flex;align-items:center;gap:8px;}
.pill-btn.ghost{background:var(--panel);color:var(--ink);border:1px solid var(--line);}
.pill-btn:hover{opacity:.92;}

.grid{display:grid;gap:18px;}
.g4{grid-template-columns:repeat(4,1fr);}
.g3{grid-template-columns:repeat(3,1fr);}
.g2{grid-template-columns:repeat(2,1fr);}
.g13{grid-template-columns:1fr 340px;}
.card{background:var(--panel);border:1px solid var(--line);border-radius:var(--radius-lg);padding:22px 24px;box-shadow:var(--shadow);}
.card h3{font-size:15.5px;margin:0 0 4px;letter-spacing:-.01em;font-weight:600;}
.card .hint{color:var(--ink-faint);font-size:12.5px;margin:0 0 16px;}
.metric-label{color:var(--ink-soft);font-size:12.5px;font-weight:600;text-transform:uppercase;letter-spacing:.04em;}
.metric-val{font-size:28px;font-weight:700;font-family:var(--font-display);margin:6px 0 2px;letter-spacing:-.01em;}
.metric-delta{font-size:12.5px;font-weight:700;}
.up{color:var(--teal);} .down{color:var(--coral);}

.badge{display:inline-flex;align-items:center;gap:5px;padding:4px 10px;border-radius:999px;font-size:11.5px;font-weight:700;}
.b-indigo{background:var(--indigo-glow);color:var(--indigo-deep);}
.b-teal{background:var(--teal-glow);color:#155943;}
.b-coral{background:var(--coral-glow);color:#8f4419;}
.b-amber{background:var(--amber-glow);color:#7a5713;}

.progress-track{height:8px;border-radius:999px;background:var(--line);overflow:hidden;}
.progress-fill{height:100%;border-radius:999px;background:var(--teal);}

.streak-row{display:flex;gap:8px;margin-top:6px;}
.streak-day{flex:1;text-align:center;}
.streak-day .lbl{font-size:11px;color:var(--ink-faint);margin-bottom:6px;font-weight:700;}
.streak-dot{width:100%;aspect-ratio:1;border-radius:10px;background:var(--line);display:flex;align-items:center;justify-content:center;font-size:13px;}
.streak-dot.done{background:var(--teal);color:#fff;}
.streak-dot.today{background:var(--indigo);color:#fff;box-shadow:0 0 0 3px var(--indigo-glow);}

.lesson-row{display:flex;align-items:center;gap:14px;padding:13px 0;border-bottom:1px solid var(--line);}
.lesson-row:last-child{border-bottom:none;}
.lrow-ic{width:36px;height:36px;border-radius:10px;flex-shrink:0;display:flex;align-items:center;justify-content:center;font-size:16px;}
.lesson-row .body{flex:1;min-width:0;}
.lesson-row .body b{font-size:13.5px;display:block;font-weight:600;}
.lesson-row .body span{font-size:12px;color:var(--ink-faint);}

table{width:100%;border-collapse:collapse;font-size:13.5px;}
th{text-align:left;color:var(--ink-faint);font-size:11.5px;text-transform:uppercase;letter-spacing:.04em;font-weight:700;padding:0 10px 10px;border-bottom:1px solid var(--line);}
td{padding:12px 10px;border-bottom:1px solid var(--line);vertical-align:middle;}
tr.flag td{background:var(--coral-glow);}
tr.rowlink:hover td{background:#f5f6ee;cursor:pointer;}
.name-cell{display:flex;align-items:center;gap:10px;}
.mini-avatar{width:30px;height:30px;border-radius:50%;background:var(--indigo-glow);color:var(--indigo-deep);display:flex;align-items:center;justify-content:center;font-weight:700;font-size:12px;flex-shrink:0;font-family:var(--font-display);}
.mono{font-family:var(--font-mono);font-size:12px;background:#f5f6ee;padding:2px 6px;border-radius:5px;letter-spacing:-.01em;}

.tabs{display:flex;gap:4px;background:var(--line);padding:4px;border-radius:11px;width:fit-content;margin-bottom:20px;}
.tab-btn{border:none;background:none;padding:8px 16px;border-radius:8px;font-size:13px;font-weight:700;color:var(--ink-soft);}
.tab-btn.active{background:#fff;color:var(--ink);box-shadow:0 1px 2px rgba(0,0,0,.06);}

.form-row{margin-bottom:14px;}
.form-row label{display:block;font-size:12.5px;font-weight:700;color:var(--ink-soft);margin-bottom:6px;}
.form-row input,.form-row select,.form-row textarea{width:100%;padding:10px 12px;border:1px solid var(--line);border-radius:var(--radius-sm);font-size:13.5px;font-family:inherit;background:#fbfbf7;color:var(--ink);}
.form-row input:focus,.form-row select:focus,.form-row textarea:focus{border-color:var(--indigo);}
.dropzone{border:1.5px dashed var(--line);border-radius:var(--radius-md);padding:28px;text-align:center;color:var(--ink-soft);font-size:13px;background:#fbfbf7;}

.chat-list{display:flex;flex-direction:column;gap:2px;}
.chat-item{display:flex;align-items:center;gap:12px;padding:12px 10px;border-radius:var(--radius-sm);border:none;background:none;width:100%;text-align:left;}
.chat-item:hover{background:#f5f6ee;}
.chat-item.active{background:var(--indigo-glow);}
.chat-item .who b{display:block;font-size:13.5px;font-weight:600;}
.chat-item .who span{font-size:12px;color:var(--ink-faint);}
.chat-bubble{max-width:75%;padding:10px 14px;border-radius:14px;font-size:13.5px;margin-bottom:10px;line-height:1.5;}
.chat-in{background:var(--panel);border:1px solid var(--line);border-bottom-left-radius:4px;}
.chat-out{background:var(--ink);color:#fff;margin-left:auto;border-bottom-right-radius:4px;}
.chat-input-row{display:flex;gap:8px;margin-top:14px;}
.chat-input-row input{flex:1;}

.class-chip{padding:9px 16px;border-radius:999px;border:1px solid var(--line);background:#fff;font-size:13px;font-weight:700;color:var(--ink-soft);}
.class-chip.active{background:var(--indigo);border-color:var(--indigo);color:#fff;}

.stat-bar-row{display:flex;align-items:center;gap:12px;margin-bottom:14px;}
.stat-bar-row .lbl{width:150px;font-size:13px;font-weight:600;flex-shrink:0;}
.stat-bar-track{flex:1;height:10px;border-radius:999px;background:var(--line);overflow:hidden;}
.stat-bar-fill{height:100%;border-radius:999px;background:var(--coral);}
.stat-bar-row .pct{width:40px;text-align:right;font-size:12.5px;font-weight:700;color:var(--coral);}

.qcard{border:1px solid var(--line);border-radius:var(--radius-md);padding:16px;margin-bottom:12px;}
.qcard .qhead{display:flex;justify-content:space-between;align-items:center;margin-bottom:8px;}
.remove-q{border:none;background:none;color:var(--ink-faint);font-size:16px;}
.remove-q:hover{color:var(--coral);}

.locked{opacity:.55;}
.hidden{display:none !important;}
::-webkit-scrollbar{width:8px;height:8px;}
::-webkit-scrollbar-thumb{background:#cfd4c1;border-radius:4px;}

@media (max-width:860px){
  .g4{grid-template-columns:repeat(2,1fr);}
  .g3{grid-template-columns:repeat(2,1fr);}
  .g13{grid-template-columns:1fr;}
  .main{padding:24px 18px 48px;}
  .topnav{padding:0 18px;}
}
@media (max-width:560px){
  .g4{grid-template-columns:1fr 1fr;}
  .g2{grid-template-columns:1fr;}
  .role-grid{gap:16px;}
  .role-card{width:100%;max-width:340px;}
  .auth-card{width:100%;max-width:340px;padding:26px 22px;}
  .cs-title{font-size:27px;}
  .topbar{flex-direction:column;}
}