:root {
  --bg: #0e1013;
  --panel: #14171c;
  --panel2: #191d23;
  --border: #262b33;
  --border2: #333a45;
  --text: #d6dae0;
  --dim: #8b93a0;
  --dimmer: #5c6472;
  --accent: #7aa2f7;
  --good: #7dc98f;
  --bad: #e06c75;
  --warn: #d8a657;
  --mono: ui-monospace, 'Cascadia Code', 'JetBrains Mono', Menlo, monospace;
}
* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; background: var(--bg); color: var(--text);
  font: 15px/1.6 system-ui, -apple-system, 'Segoe UI', sans-serif; }
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

.wrap { max-width: 980px; margin: 0 auto; padding: 0 clamp(12px, 3vw, 28px) 80px; }
@media (min-width: 1500px) { .wrap { max-width: 1160px; } }

/* ---- terminal dock (right side on wide screens, bottom sheet on narrow) ---- */
.termdock { position: fixed; z-index: 50; background: #0b0d10; border-left: 1px solid var(--border2);
  display: flex; flex-direction: column; top: 0; right: 0; bottom: 0; width: min(44vw, 860px); }
.termdock .termbar { display: flex; align-items: center; gap: 10px; padding: 8px 12px;
  border-bottom: 1px solid var(--border); font-size: 12.5px; letter-spacing: .05em; color: var(--dim); }
.termdock #termhost { flex: 1; min-height: 0; padding: 6px 4px 6px 10px; }
.termdock #termhost .xterm { height: 100%; }
button.mini { padding: 2px 10px; font-size: 12px; }
body.term-open .wrap { margin-right: calc(min(44vw, 860px) + 24px); margin-left: 24px; max-width: none; }
@media (max-width: 1200px) {
  .termdock { top: auto; left: 0; right: 0; height: 45vh; border-left: 0; border-top: 1px solid var(--border2); }
  body.term-open .wrap { margin-right: auto; margin-left: auto; padding-bottom: 48vh; }
}

/* ---- read-aloud ---- */
.ttsbar { display: flex; align-items: center; gap: 8px; flex-wrap: wrap; margin-bottom: 14px; }
.ttsbar .mutest { margin-left: 4px; }
.reading { background: rgba(122,162,247,.10) !important; outline: 1px solid rgba(122,162,247,.35);
  border-radius: 6px; }

/* ---- live-update toast ---- */
.toast { position: fixed; left: 18px; bottom: 18px; z-index: 60; background: var(--panel);
  border: 1px solid var(--accent); border-radius: 9px; padding: 10px 16px; cursor: pointer;
  font-size: 13.5px; color: var(--text); box-shadow: 0 4px 18px rgba(0,0,0,.5); }
.toast:hover { background: var(--panel2); }
header.top { display: flex; align-items: center; gap: 14px; padding: 14px 0; border-bottom: 1px solid var(--border);
  margin-bottom: 22px; flex-wrap: wrap; }
header.top .brand { font-weight: 600; letter-spacing: .04em; }
header.top .brand span { color: var(--dim); font-weight: 400; }
header.top nav { display: flex; gap: 4px; flex-wrap: wrap; }
header.top nav a { color: var(--dim); padding: 4px 10px; border: 1px solid transparent; border-radius: 6px; }
header.top nav a.active { color: var(--text); border-color: var(--border2); background: var(--panel); }
header.top nav a:hover { text-decoration: none; color: var(--text); }
.spacer { flex: 1; }
.lvlchip { font-family: var(--mono); font-size: 13px; color: var(--dim); border: 1px solid var(--border2);
  border-radius: 6px; padding: 3px 10px; background: var(--panel); }
.lvlchip b { color: var(--accent); font-weight: 600; }

.panel { background: var(--panel); border: 1px solid var(--border); border-radius: 10px; padding: 18px 20px; margin-bottom: 14px; }
.panel h2 { margin: 0 0 10px; font-size: 15px; font-weight: 600; letter-spacing: .03em; color: var(--dim);
  text-transform: uppercase; }
.grid2 { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 14px; }

.xpbar { height: 8px; background: var(--panel2); border: 1px solid var(--border); border-radius: 5px; overflow: hidden; margin: 8px 0 4px; }
.xpbar > div { height: 100%; background: var(--accent); opacity: .85; }
.muted { color: var(--dim); font-size: 13px; }
.mutest { color: var(--dimmer); font-size: 12.5px; }

.itemrow { display: flex; align-items: center; gap: 10px; padding: 8px 10px; border: 1px solid var(--border);
  border-radius: 8px; margin: 6px 0; background: var(--panel2); }
.itemrow:hover { border-color: var(--border2); }
.itemrow .tick { font-family: var(--mono); width: 18px; color: var(--dimmer); }
.itemrow .tick.done { color: var(--good); }
.itemrow .kind { font-size: 11.5px; color: var(--dimmer); border: 1px solid var(--border2); border-radius: 4px;
  padding: 0 6px; text-transform: uppercase; letter-spacing: .05em; }
.itemrow .xp { margin-left: auto; font-family: var(--mono); font-size: 12.5px; color: var(--dimmer); }

.arc { border: 1px solid var(--border); border-radius: 10px; margin-bottom: 12px; background: var(--panel); overflow: hidden; }
.arc > .archead { display: flex; gap: 12px; align-items: baseline; padding: 12px 16px; cursor: pointer; }
.arc > .archead:hover { background: var(--panel2); }
.arc .lvls { font-family: var(--mono); font-size: 12.5px; color: var(--dimmer); min-width: 84px; }
.arc .arcprog { margin-left: auto; font-family: var(--mono); font-size: 12.5px; color: var(--dim); }
.arc .arcbody { padding: 4px 16px 14px; border-top: 1px solid var(--border); }
.arc.locked .archead { cursor: default; }
.arc.locked .archead, .arc.locked .lvls { color: var(--dimmer); }

button, .btn { background: var(--panel2); border: 1px solid var(--border2); color: var(--text); border-radius: 7px;
  padding: 7px 16px; font: inherit; font-size: 14px; cursor: pointer; }
button:hover, .btn:hover { border-color: var(--accent); }
button.primary { border-color: var(--accent); color: var(--accent); }
button:disabled { opacity: .45; cursor: default; }
input[type=text], input[type=password], textarea, select { background: var(--panel2); border: 1px solid var(--border2);
  color: var(--text); border-radius: 7px; padding: 8px 12px; font: inherit; width: 100%; }
textarea { font-family: var(--mono); font-size: 13.5px; min-height: 110px; resize: vertical; }
input:focus, textarea:focus, select:focus { outline: none; border-color: var(--accent); }

.md { line-height: 1.7; }
.md h1, .md h2, .md h3 { line-height: 1.3; margin: 1.4em 0 .5em; }
.md h1 { font-size: 22px; } .md h2 { font-size: 18px; } .md h3 { font-size: 15.5px; }
.md pre { background: #0b0d10; border: 1px solid var(--border); border-radius: 8px; padding: 12px 14px;
  overflow-x: auto; font-size: 13px; }
.md code { font-family: var(--mono); font-size: .92em; background: #0b0d10; border: 1px solid var(--border);
  border-radius: 4px; padding: 1px 5px; }
.md pre code { border: 0; padding: 0; background: none; }
.md blockquote { border-left: 3px solid var(--border2); margin: 1em 0; padding: 2px 16px; color: var(--dim); }
.md table { border-collapse: collapse; } .md th, .md td { border: 1px solid var(--border2); padding: 5px 10px; }
.md img { max-width: 100%; }

.q { border: 1px solid var(--border); border-radius: 10px; padding: 14px 16px; margin: 12px 0; background: var(--panel2); }
.q .qhead { display: flex; gap: 10px; align-items: baseline; margin-bottom: 6px; }
.q .qpts { margin-left: auto; font-family: var(--mono); font-size: 12px; color: var(--dimmer); white-space: nowrap; }
.q label.opt { display: flex; gap: 10px; align-items: baseline; padding: 6px 10px; border: 1px solid var(--border);
  border-radius: 7px; margin: 5px 0; cursor: pointer; }
.q label.opt:hover { border-color: var(--border2); }
.q label.opt.unsure { border-style: dashed; color: var(--dim); margin-top: 10px; }
.q label.opt.unsure:has(input:checked) { border-color: var(--warn); color: var(--warn); }
.q.correct { border-color: rgba(125,201,143,.5); }
.q.wrong { border-color: rgba(224,108,117,.5); }
.verdict { font-family: var(--mono); font-size: 13px; margin-top: 8px; }
.verdict.ok { color: var(--good); } .verdict.no { color: var(--bad); } .verdict.pend { color: var(--warn); }

.labout { background: #0b0d10; border: 1px solid var(--border); border-radius: 8px; padding: 12px 14px;
  font-family: var(--mono); font-size: 13px; white-space: pre-wrap; overflow-x: auto; }
.pass { color: var(--good); } .fail { color: var(--bad); }

.msg { border: 1px solid var(--border); border-radius: 10px; padding: 12px 16px; margin: 10px 0; background: var(--panel2); }
.msg.tutor { border-left: 3px solid var(--accent); }
.msg.student { border-left: 3px solid var(--border2); }
.msg .who { font-size: 12px; color: var(--dimmer); text-transform: uppercase; letter-spacing: .05em; margin-bottom: 4px; }

.login { max-width: 360px; margin: 18vh auto 0; }
.login h1 { font-size: 18px; font-weight: 600; letter-spacing: .04em; }
.err { color: var(--bad); font-size: 13.5px; margin-top: 8px; }

table.tx { width: 100%; border-collapse: collapse; font-size: 13.5px; }
table.tx td { padding: 6px 8px; border-bottom: 1px solid var(--border); }
table.tx td.r { text-align: right; font-family: var(--mono); color: var(--dim); white-space: nowrap; }

@media (max-width: 640px) {
  header.top { gap: 8px; }
  .panel { padding: 14px; }
}