:root{
  --bg:#f4f6fb; --surface:#ffffff; --ink:#16202e; --muted:#64748b; --line:#e6eaf1;
  --accent:#3b5bdb; --accent-ink:#fff; --accent-soft:#eef2ff;
  --ok:#188038; --warn:#b8860b; --err:#d93025; --shadow:0 1px 2px rgba(16,32,46,.06),0 4px 16px rgba(16,32,46,.05);
  --radius:12px;
}
*{box-sizing:border-box}
html,body{margin:0}
body{
  font-family:"Noto Sans Bengali","Hind Siliguri",-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Arial,sans-serif;
  background:var(--bg); color:var(--ink); font-size:14px; line-height:1.5;
}
a{color:var(--accent); text-decoration:none}
a:hover{text-decoration:underline}

/* layout */
.layout{display:grid; grid-template-columns:236px 1fr; min-height:100vh}
.sidebar{background:#0f172a; color:#cbd5e1; padding:20px 14px; position:sticky; top:0; height:100vh}
.brand{display:flex; align-items:center; gap:10px; font-weight:700; color:#fff; font-size:16px; padding:6px 8px 18px}
.brand .logo{width:30px;height:30px;border-radius:8px;background:linear-gradient(135deg,#3b5bdb,#7048e8);display:grid;place-items:center;color:#fff;font-weight:800}
.nav a{display:flex;align-items:center;gap:10px;color:#cbd5e1;padding:10px 12px;border-radius:9px;margin:2px 0;font-weight:500}
.nav a:hover{background:#1e293b;text-decoration:none;color:#fff}
.nav a.active{background:var(--accent);color:#fff}
.nav .ico{width:18px;text-align:center;opacity:.9}
.sidebar .foot{position:absolute;bottom:16px;left:14px;right:14px;font-size:12px;color:#64748b}
.sidebar .foot a{color:#94a3b8}

.main{display:flex;flex-direction:column;min-width:0}
.topbar{display:flex;align-items:center;justify-content:space-between;padding:16px 28px;border-bottom:1px solid var(--line);background:var(--surface)}
.topbar h1{font-size:18px;margin:0}
.topbar .user{color:var(--muted);font-size:13px}
.content{padding:24px 28px;max-width:1200px;width:100%}

/* cards */
.cards{display:grid;grid-template-columns:repeat(auto-fit,minmax(170px,1fr));gap:16px;margin-bottom:24px}
.card{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);padding:18px;box-shadow:var(--shadow)}
.card .k{color:var(--muted);font-size:12px;text-transform:uppercase;letter-spacing:.04em}
.card .v{font-size:28px;font-weight:700;margin-top:6px}
.card .v.warn{color:var(--warn)}

.panel{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);box-shadow:var(--shadow);margin-bottom:24px;overflow:hidden}
.panel h2{font-size:14px;margin:0;padding:14px 18px;border-bottom:1px solid var(--line);display:flex;justify-content:space-between;align-items:center}
.panel .body{padding:18px}

/* table */
table{width:100%;border-collapse:collapse}
th,td{text-align:left;padding:11px 14px;border-bottom:1px solid var(--line);vertical-align:top}
th{font-size:12px;color:var(--muted);text-transform:uppercase;letter-spacing:.03em;font-weight:600}
tbody tr:hover{background:#fafbff}
td.qtext{max-width:460px}
.muted{color:var(--muted)}
.mono{font-variant-numeric:tabular-nums}

/* badges & chips */
.badge{display:inline-block;padding:2px 9px;border-radius:999px;font-size:12px;font-weight:600;line-height:1.6}
.badge.mcq{background:#e7f0ff;color:#1c4ed8}
.badge.descriptive{background:#fdeede;color:#9a5b00}
.badge.short{background:#e9f9ee;color:#127a35}
.b-status{font-weight:600;font-size:12px}
.b-status.draft{color:var(--muted)} .b-status.needs_review{color:var(--warn)} .b-status.published{color:var(--ok)}
.b-status.pending{color:var(--muted)} .b-status.processing{color:var(--warn)} .b-status.done{color:var(--ok)} .b-status.failed{color:var(--err)} .b-status.cancelled{color:var(--muted)}
.chip{display:inline-block;background:var(--accent-soft);color:#3a4cc0;border-radius:7px;padding:2px 8px;font-size:12px;margin:2px 4px 2px 0}
.chip.cat{background:#f1f5f9;color:#475569}

/* forms */
.field{margin-bottom:16px}
.field label{display:block;font-weight:600;margin-bottom:6px}
.field .help{color:var(--muted);font-size:12px;margin-top:4px}

/* LaTeX snippet bar, glued to the top of the field it types into (matheditor.js) */
.mathbar{display:flex;flex-wrap:wrap;align-items:center;gap:2px;padding:5px 6px;
  border:1px solid var(--line);border-bottom:0;border-radius:9px 9px 0 0;background:#f8fafc}
.mathbar + textarea{border-top-left-radius:0;border-top-right-radius:0}
.mathbar-key{min-width:26px;height:26px;padding:0 7px;border:1px solid transparent;
  border-radius:6px;background:transparent;color:var(--ink);font:inherit;font-size:13px;
  line-height:1;cursor:pointer}
.mathbar-key:hover{background:#fff;border-color:var(--line)}
.mathbar-key:active{background:var(--accent-soft);border-color:var(--accent)}
.mathbar-sep{width:1px;height:16px;margin:0 4px;background:var(--line)}
.mathbar-note{color:var(--muted);font-size:12px;margin-left:6px}
/* the Unicode symbol pad, folded away behind the bar's Ω key */
.mathbar-pad{flex-basis:100%;display:flex;flex-wrap:wrap;align-items:center;gap:2px;
  margin-top:5px;padding-top:5px;border-top:1px solid var(--line)}
.mathbar-pad[hidden]{display:none}   /* a class beats the browser's own [hidden] rule */
.mathbar-sym{min-width:28px;font-size:15px}
/* what MathJax makes of the field, under the field */
.mathprev{margin-top:6px;padding:6px 10px;border:1px dashed var(--line);border-radius:9px;
  background:#f8fafc}
.mathprev-h{display:flex;flex-wrap:wrap;align-items:baseline;gap:8px;margin-bottom:3px;
  font-size:11px;letter-spacing:.04em;text-transform:uppercase;color:var(--muted)}
.mathprev-hint{text-transform:none;letter-spacing:0;opacity:.9}
/* the same line, when the field holds a LaTeX command with no \( \) around it */
.mathprev-warn{color:var(--warn);opacity:1;font-weight:600}
.mathprev-body{white-space:pre-wrap;line-height:1.7;overflow-x:auto}
.mathprev-empty{color:var(--muted)}
input[type=text],input[type=number],input[type=password],select,input[type=file]{
  width:100%;padding:10px 12px;border:1px solid var(--line);border-radius:9px;background:#fff;font:inherit;color:var(--ink)
}
input:focus,select:focus{outline:none;border-color:var(--accent);box-shadow:0 0 0 3px var(--accent-soft)}
.row2{display:grid;grid-template-columns:1fr 1fr;gap:16px}
.errornote{color:var(--err);font-size:12px;margin-top:4px}

.btn{display:inline-flex;align-items:center;gap:8px;background:var(--accent);color:var(--accent-ink);border:0;border-radius:9px;padding:10px 18px;font:inherit;font-weight:600;cursor:pointer}
.btn:hover{filter:brightness(1.05);text-decoration:none}
.btn.ghost{background:#fff;color:var(--ink);border:1px solid var(--line)}
.btn.sm{padding:6px 12px;font-size:13px}
.btn.xs{padding:2px 7px;font-size:11px;border-radius:6px}
.btn.danger{color:#b91c1c;border-color:#fca5a5}
.btn.danger:hover{background:#fee2e2}
.hidden{display:none!important}
.msg-banner{border-radius:6px;padding:8px 14px;margin-bottom:12px;background:#f1f5f9;color:var(--ink)}
.msg-banner.success{background:#d4edda;color:#155724}

/* subject-index toolbar + create forms */
.toolbar{display:flex;align-items:center;gap:8px;margin-bottom:14px;flex-wrap:wrap}
.toolbar .spacer{flex:1}
.create-form{display:flex;align-items:flex-end;gap:10px;flex-wrap:wrap;padding:12px 14px;margin-bottom:14px;background:#f8faff;border:1px solid var(--line);border-radius:8px}
.create-form .cf-field{display:flex;flex-direction:column;gap:3px}
.create-form .cf-field label{font-size:12px;color:var(--muted)}
.create-form .cf-field .req{color:#b91c1c}
.create-form .cf-actions{display:flex;gap:6px}

/* tree node action icons (appear on hover) */
.iconbtn{border:0;background:transparent;cursor:pointer;color:var(--muted);font-size:13px;line-height:1;padding:3px 6px;border-radius:6px}
.iconbtn:hover{background:#eef2ff;color:var(--ink)}
.iconbtn.danger:hover{background:#fee2e2;color:#b91c1c}
.iconbtn.ok:hover{background:#dcfce7;color:#15803d}
.rename-input{flex:none;font:inherit;padding:3px 8px;border:1px solid var(--accent);border-radius:6px}
/* inline node editors: rename and add-sub-category */
.node-edit,.addsub-box{display:inline-flex;gap:6px;align-items:center}
.node-edit{flex:1}
.addsub-box{margin:2px 0 2px 32px}
.node-edit .iconbtn,.addsub-box .iconbtn{font-size:14px}
/* "all N matching are selected" banner above the bulk-move table */
.move-all{display:flex;align-items:center;gap:8px;margin-bottom:10px;padding:6px 10px;
  background:#f8fafc;border:1px solid var(--line);border-radius:6px}
.move-all[hidden]{display:none}
.tnode-actions{display:none;gap:4px;align-items:center}
.tnode:hover .tnode-actions{display:inline-flex}
.rename-form{display:flex;align-items:center;gap:8px;padding:4px 8px 6px 32px;flex-wrap:wrap}

/* filter bar */
.filters{display:flex;flex-wrap:wrap;gap:10px;align-items:end;margin-bottom:18px}
.filters .field{margin:0}
.filters input[type=text]{min-width:240px}
.filters select{min-width:150px}

.pagination{display:flex;gap:6px;align-items:center;margin-top:16px;flex-wrap:wrap}
.pagination a,.pagination span{padding:6px 11px;border:1px solid var(--line);border-radius:8px;background:#fff}
.pagination .current{background:var(--accent);color:#fff;border-color:var(--accent)}

.log{background:#0f172a;color:#cbd5e1;border-radius:9px;padding:14px;font-family:ui-monospace,Menlo,Consolas,monospace;font-size:12.5px;white-space:pre-wrap;max-height:340px;overflow:auto}
.progress{height:10px;background:var(--line);border-radius:99px;overflow:hidden}
.progress>span{display:block;height:100%;background:var(--accent);transition:width .4s}
.empty{padding:40px;text-align:center;color:var(--muted)}
.messages{margin-bottom:16px}
.messages .msg{background:#e9f9ee;border:1px solid #b7e3c4;color:#127a35;padding:10px 14px;border-radius:9px}

/* subject index tree */
.tree, .tree ul{list-style:none;margin:0;padding:0}
.tree ul{margin-left:18px;border-left:1px solid var(--line);padding-left:12px}
.tree li{margin:1px 0}
.tnode{display:flex;align-items:center;gap:8px;padding:6px 8px;border-radius:8px}
.tnode:hover{background:#fafbff}
.tnode .toggle{width:16px;cursor:pointer;color:var(--muted);user-select:none;text-align:center}
.tnode .toggle.leaf{visibility:hidden}
.tnode a{flex:1;color:var(--ink);font-weight:500}
.tnode a:hover{color:var(--accent)}
.tnode .cnt{color:var(--muted);font-size:12px;background:#f1f5f9;border-radius:999px;padding:1px 9px;min-width:26px;text-align:center}
.tree li.collapsed > ul{display:none}
.tnode .gname{flex:1;font-weight:600;color:var(--ink)}

/* tabs (index page) */
.tabs{display:flex;gap:4px;padding:10px 18px 0;border-bottom:1px solid var(--line)}
.tabs .tab{background:none;border:0;border-bottom:2px solid transparent;padding:10px 16px;margin-bottom:-1px;font:inherit;font-weight:600;color:var(--muted);cursor:pointer}
.tabs .tab:hover{color:var(--ink)}
.tabs .tab.active{color:var(--accent);border-bottom-color:var(--accent)}
.crumb{color:var(--muted);font-size:13px;margin-bottom:14px}
.crumb a{color:var(--muted)} .crumb b{color:var(--ink)}

/* question editor */
.opt-row{display:flex;align-items:center;gap:10px;margin-bottom:8px}
.opt-row .letter{width:30px;height:30px;flex:none;display:grid;place-items:center;border-radius:8px;background:#f1f5f9;font-weight:700}
.opt-row input[type=text]{flex:1}
.opt-row .correct{display:flex;align-items:center;gap:6px;white-space:nowrap;color:var(--muted);font-size:13px}
.opt-row .correct input{width:18px;height:18px}
.opt-row .rm{cursor:pointer;color:var(--err);border:0;background:none;font-size:18px;line-height:1}
.opt-row input[type=radio]:checked ~ .lbl,.opt-row.is-correct .letter{background:#d6f3df;color:#127a35}
.tagbox{border:1px solid var(--line);border-radius:10px;padding:10px;background:#fff}
.tagbox .chips{display:flex;flex-wrap:wrap;gap:6px;margin-bottom:10px;min-height:8px}
.tagbox .chip{display:inline-flex;align-items:center;gap:6px}
.tagbox .chip .x{cursor:pointer;font-weight:700;opacity:.6}
.tagbox .chip .x:hover{opacity:1;color:var(--err)}
.tagbox .addrow{display:flex;gap:8px;flex-wrap:wrap}
.tagbox select{flex:1;min-width:200px}
.formgrid{display:grid;grid-template-columns:repeat(auto-fit,minmax(150px,1fr));gap:16px}
.sticky-actions{position:sticky;bottom:0;background:var(--surface);border-top:1px solid var(--line);padding:14px 0;margin-top:8px;display:flex;gap:10px}

/* login */
.login-wrap{min-height:100vh;display:grid;place-items:center;background:linear-gradient(135deg,#eef2ff,#f4f6fb)}
.login-card{background:#fff;border:1px solid var(--line);border-radius:16px;box-shadow:var(--shadow);padding:32px;width:360px}
.login-card .brand{justify-content:center;color:var(--ink);padding-bottom:8px}
.login-card p.sub{text-align:center;color:var(--muted);margin:0 0 20px}

/* ===================================================================
   Responsive
   The sidebar is the only structural element that cannot survive a
   phone: below 860px it becomes an off-canvas drawer toggled from the
   topbar. Everything else just needs room to wrap.
   =================================================================== */

/* wraps a wide table so IT scrolls sideways, not the whole page. Stays on at every width:
   between 860 and 1024px the sidebar still costs 236px, and the 9-column question list
   overflows there too. */
.tablewrap{overflow-x:auto}
.tablewrap table{min-width:600px}

/* hamburger + drawer scrim: only ever visible on narrow screens.
   Chrome is a .btn.ghost — this only adds the square icon shape. */
.navtoggle{display:none;width:36px;height:36px;padding:0;flex:none;font-size:17px;margin-right:12px}
.navtoggle:hover{background:var(--accent-soft)}
.scrim{display:none;position:fixed;inset:0;background:rgba(15,23,42,.45);z-index:55}

@media (max-width:860px){
  /* off-canvas drawer */
  .layout{grid-template-columns:1fr}
  /* height:auto is load-bearing: the base rule's height:100vh would otherwise win over
     bottom:0 and push .sidebar .foot below the visible viewport while the URL bar shows */
  .sidebar{position:fixed;top:0;bottom:0;left:0;height:auto;width:250px;z-index:60;
    transform:translateX(-100%);transition:transform .22s ease;overflow-y:auto}
  body.nav-open .sidebar{transform:none}
  body.nav-open .scrim{display:block}
  body.nav-open{overflow:hidden}
  .navtoggle{display:inline-flex;justify-content:center}

  .topbar{padding:8px 14px;gap:10px;flex-wrap:wrap}
  .topbar h1{font-size:16px;flex:1;min-width:0}
  .topbar .user{display:flex;gap:8px;flex-wrap:wrap;align-items:center}
  .content{padding:16px 14px}

  /* stacks: one column everywhere a two-up grid was assumed */
  .row2{grid-template-columns:1fr}
  .cards{grid-template-columns:repeat(auto-fit,minmax(140px,1fr));gap:12px;margin-bottom:18px}
  .card{padding:14px}
  .card .v{font-size:22px}
  .panel{margin-bottom:16px}
  .panel .body{padding:14px}
  .panel h2{padding:12px 14px;gap:8px;flex-wrap:wrap}

  /* filter bar: full-width controls beat a squeezed inline row */
  .filters .field{flex:1 1 100%}
  .filters input[type=text],.filters select{min-width:0;width:100%}
  .filters .btn{flex:1 1 auto}

  /* templates pin a few control widths inline (width:280px etc.) — cap them all */
  input,select,textarea{max-width:100%}
  th,td{padding:9px 10px}

  /* touch targets */
  .btn.xs{padding:5px 9px;font-size:12px}
  .pagination a,.pagination span{padding:9px 13px}

  /* subject tree: shallower indents so deep paths still fit */
  .tree ul{margin-left:8px;padding-left:8px}
  .tnode{gap:6px;padding:8px 4px}
  .addsub-box,.rename-form{margin-left:0;padding-left:8px}
  .tnode-actions{display:inline-flex}   /* no hover on touch — always show */

  .create-form{flex-direction:column;align-items:stretch}
  .create-form .cf-field{width:100%}
  .create-form .cf-actions{justify-content:flex-end}

  .formgrid{grid-template-columns:1fr}
  .sticky-actions{flex-wrap:wrap;padding:12px 0}
  .sticky-actions .btn{flex:1 1 auto;justify-content:center}

  .opt-row{flex-wrap:wrap}
  .opt-row > input[type=text]{flex:1 1 100%;order:3}   /* editor page nests its own in .opt-main */
  .opt-row .opt-main{min-width:0}
  .opt-row .correct{white-space:normal}
  .tagbox select{min-width:0}
  .tagbox .addrow{flex-direction:column;align-items:stretch}

  .tabs{overflow-x:auto;padding:8px 12px 0}
  .tabs .tab{white-space:nowrap;padding:9px 12px}

  .login-card{width:100%;max-width:360px;margin:0 16px;padding:24px}
}

@media (max-width:520px){
  .cards{grid-template-columns:1fr 1fr}
  .content{padding:14px 12px}
  .topbar .user .btn.sm{padding:7px 10px;font-size:12px}
}