:root {
  --bg: #0e1116; --panel: #161b22; --border: #262d37;
  --text: #e6e9ee; --dim: #7d8590; --accent: #58a6ff;
  --good: #3fb950; --warn: #d29922; --bad: #f85149;
}
* { box-sizing: border-box; margin: 0; }
body {
  background: var(--bg); color: var(--text);
  font: 15px/1.5 -apple-system, "SF Pro Text", "Segoe UI", Roboto, sans-serif;
  min-height: 100vh; display: flex; flex-direction: column;
}
header {
  display: flex; align-items: center; gap: 10px;
  padding: 12px 18px; border-bottom: 1px solid var(--border);
}
.brand { font-weight: 600; }
.dim { color: var(--dim); }
.spacer { flex: 1; }
.chip {
  background: var(--panel); border: 1px solid var(--border); border-radius: 8px;
  padding: 3px 10px; font-variant-numeric: tabular-nums; white-space: nowrap;
}
.chip.forecast { color: var(--dim); }
button.ghost {
  background: none; border: 1px solid var(--border); border-radius: 8px;
  color: var(--text); padding: 4px 12px; cursor: pointer; font: inherit;
}
button.ghost:hover { border-color: var(--accent); }
button.ghost.danger { color: var(--bad); }
main { flex: 1; display: flex; flex-direction: column; align-items: center; padding: 18px; gap: 14px; }
.next-unlock { color: var(--dim); min-height: 1.5em; text-align: center; }
.next-unlock b { color: var(--text); }
.next-unlock .stalled { color: var(--warn); }
.lesson {
  font: 26px/2 "SF Mono", ui-monospace, Menlo, Consolas, monospace;
  letter-spacing: 0.06em; max-width: 900px; min-height: 4.2em;
  outline: none; cursor: text; user-select: none; text-align: left;
}
.lesson span { border-radius: 4px; padding: 0 1px; }
.lesson .done { color: var(--dim); }
.lesson .miss { color: var(--bad); }
.lesson .cur { background: #1f6feb55; box-shadow: 0 2px 0 var(--accent); }
.lesson .cur-miss { background: #f8514933; box-shadow: 0 2px 0 var(--bad); }
.lesson .sp { position: relative; }
.lesson .sp::after {
  content: '·'; position: absolute; left: 50%; transform: translateX(-50%);
  color: #484f58; opacity: 0;
}
.lesson .sp.cur::after, .lesson .sp.cur-miss::after { opacity: 1; }
.drill-banner {
  background: #d2992218; border: 1px solid var(--warn); color: var(--warn);
  border-radius: 8px; padding: 6px 14px; font-weight: 600;
}
#boardWrap { width: min(860px, 96vw); }
#board { width: 100%; height: auto; display: block; }
.results {
  background: var(--panel); border: 1px solid var(--border); border-radius: 12px;
  padding: 16px 24px; text-align: center; min-width: 320px;
}
.results .big { font-size: 34px; font-weight: 700; font-variant-numeric: tabular-nums; }
.results .delta-up { color: var(--good); }
.results .delta-down { color: var(--bad); }
.results .hint { color: var(--dim); margin-top: 6px; }
dialog {
  background: var(--panel); color: var(--text); border: 1px solid var(--border);
  border-radius: 12px; padding: 20px; max-width: min(560px, 92vw); max-height: 84vh; overflow: auto;
}
dialog::backdrop { background: #000a; }
dialog h2 { font-size: 17px; margin-bottom: 12px; }
dialog form { margin-top: 14px; text-align: right; }
.setrow { display: flex; align-items: center; gap: 12px; margin: 10px 0; justify-content: space-between; }
.setrow label { color: var(--dim); flex: 1; }
table.lstats { border-collapse: collapse; width: 100%; font-variant-numeric: tabular-nums; }
table.lstats td, table.lstats th { padding: 3px 8px; text-align: right; border-bottom: 1px solid var(--border); }
table.lstats th { color: var(--dim); font-weight: 500; }
table.lstats td:first-child, table.lstats th:first-child { text-align: left; font-weight: 600; }
.weak { color: var(--warn); }
.ok { color: var(--good); }
@media (max-width: 700px) {
  .lesson { font-size: 20px; }
  header { flex-wrap: wrap; }
}
#drillCtl { margin-top: -6px; }
#drillCtl .ghost { color: var(--dim); font-size: 13px; }

.tabs { display:flex; gap:6px; margin-bottom:10px; }
.tab { background:none; border:1px solid #30363d; color:#7d8590; border-radius:6px; padding:3px 12px; cursor:pointer; font-size:13px; }
.tab.active { color:#e6e9ee; border-color:#58a6ff; }
.acctform { display:flex; gap:6px; flex-wrap:wrap; align-items:center; }
.acctform input { background:#0d1117; border:1px solid #30363d; color:#e6e9ee; border-radius:6px; padding:5px 8px; font-size:13px; width:130px; }
#acctMsg { display:block; font-size:12px; margin-top:4px; }
.sep { border:none; border-top:1px solid #21262d; margin:12px 0; }
.ok { color:#3fb950; } .weak { color:#f0883e; }

.chart { display:block; width:100%; height:auto; background:#0d1117; border:1px solid #21262d; border-radius:8px; margin:4px 0 10px; }
.clab { fill:#7d8590; font-size:9px; }
.chartrow { display:flex; justify-content:space-between; align-items:center; margin-top:12px; font-size:13px; color:#7d8590; flex-wrap:wrap; row-gap:6px; }
.chartrow label { display:flex; align-items:center; gap:6px; flex:1 1 auto; min-width:0; white-space:nowrap; }
.chartrow label select { flex:1 1 auto; min-width:0; }
.chartrow > select.rangepick { flex-shrink:0; }
.rangepick, #letterPick { background:#0d1117; border:1px solid #30363d; color:#e6e9ee; border-radius:6px; padding:2px 6px; font-size:12px; }

/* settings polish */
.setrow label .sub, .acctinfo .sub { display: block; font-size: 12px; color: var(--dim); font-weight: 400; margin-top: 2px; }
.acctinfo { flex: 1; font-size: 14px; min-width: 0; }
button.ghost { white-space: nowrap; }
.dictctl { display: flex; gap: 8px; align-items: center; flex-shrink: 0; }
dialog select { background: #0d1117; border: 1px solid var(--border); color: var(--text); border-radius: 6px; padding: 5px 8px; font-size: 13px; width: 140px; flex-shrink: 0; }
dialog input[type=range] { accent-color: var(--accent); width: 200px; flex-shrink: 0; }
@media (max-width: 560px) { dialog input[type=range] { width: 140px; } }
@media (max-width: 560px) {
  .dictrow { flex-wrap: wrap; row-gap: 6px; }
  .dictrow .dictctl { margin-left: 0; max-width: 100%; flex-wrap: wrap; flex-shrink: 1; min-width: 0; }
  .chartrow { flex-wrap: wrap; row-gap: 6px; }
  .chartrow label { flex: 1 1 100%; display: flex; gap: 6px; align-items: center; }
  .chartrow label select { flex: 1; min-width: 0; }
}

.keylegend { display:flex; flex-wrap:wrap; gap:2px 6px; margin:-2px 0 8px; font-size:11px; color:#c9d1d9; }
.kl { cursor:pointer; padding:1px 6px; border-radius:6px; white-space:nowrap; }
.kl:hover { background:#21262d; }
.kl i { display:inline-block; width:8px; height:8px; border-radius:2px; margin-right:4px; }
.kl b { font-weight:600; font-variant-numeric:tabular-nums; }
svg.chart path[data-k] { transition: opacity .12s; }