:root {
  --bg: #f1f5f9;
  --card: #ffffff;
  --text: #0f172a;
  --muted: #64748b;
  --accent: #2563eb;
  --accent-soft: #dbeafe;
  --pink: #db2777;
  --good: #16a34a;
  --warn-bg: #fef3c7;
  --warn: #92400e;
  --err-bg: #fee2e2;
  --err: #991b1b;
  --border: #e2e8f0;
  --radius: 12px;
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.5;
}

header {
  background: linear-gradient(135deg, #1e3a8a, #2563eb);
  color: white;
  padding: 24px 24px 0;
}
header h1 { margin: 0; font-size: 1.8rem; }
.subtitle { margin: 4px 0 16px; opacity: 0.9; }

.tabs { display: flex; gap: 4px; flex-wrap: wrap; }
.tab {
  background: transparent;
  color: rgba(255, 255, 255, 0.85);
  border: none;
  padding: 10px 16px;
  font-size: 0.95rem;
  border-radius: 10px 10px 0 0;
  cursor: pointer;
}
.tab:hover { background: rgba(255, 255, 255, 0.12); }
.tab.active { background: var(--bg); color: var(--accent); font-weight: 600; }

main { max-width: 1000px; margin: 0 auto; padding: 20px; }
.panel { display: none; }
.panel.active { display: block; }

.card {
  background: var(--card);
  border-radius: var(--radius);
  padding: 20px;
  margin-bottom: 16px;
  box-shadow: 0 1px 3px rgba(15, 23, 42, 0.08);
}
.card h2 { margin-top: 0; font-size: 1.2rem; }
.card h3 { font-size: 0.95rem; color: var(--muted); margin: 16px 0 4px; }
.card.error { background: var(--err-bg); color: var(--err); }

label { display: block; font-size: 0.9rem; color: var(--muted); }
label.inline { display: inline-flex; align-items: center; gap: 6px; }

textarea, input[type="number"], input[type="text"], select {
  width: 100%;
  font: inherit;
  color: var(--text);
  padding: 8px 10px;
  border: 1px solid var(--border);
  border-radius: 8px;
  margin-top: 4px;
  background: white;
}
label.inline select { width: auto; margin-top: 0; }
textarea { font-family: ui-monospace, Menlo, monospace; resize: vertical; }
textarea:focus, input:focus, select:focus { outline: 2px solid var(--accent-soft); border-color: var(--accent); }

.row { display: flex; flex-wrap: wrap; gap: 16px; align-items: center; margin-top: 12px; }

.toggle { border: 1px solid var(--border); border-radius: 8px; padding: 6px 12px; margin: 0; display: flex; gap: 14px; }
.toggle legend { font-size: 0.8rem; color: var(--muted); padding: 0 4px; }
.toggle label { display: inline-flex; gap: 6px; align-items: center; color: var(--text); cursor: pointer; }

.file-btn, button.secondary {
  display: inline-block;
  background: var(--accent-soft);
  color: var(--accent);
  border: none;
  padding: 8px 14px;
  border-radius: 8px;
  font: inherit;
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
}
.file-btn:hover, button.secondary:hover { background: #bfdbfe; }
button.link { background: none; border: none; color: var(--err); cursor: pointer; padding: 4px 0; font: inherit; font-size: 0.85rem; }
button.link-tab { background: none; border: none; color: var(--accent); cursor: pointer; padding: 0; font: inherit; font-weight: 600; text-decoration: underline; }
.mn-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(min(420px, 100%), 1fr)); gap: 16px; }
.mn-grid .card { margin-bottom: 0; scroll-margin-top: 16px; transition: box-shadow 0.3s; }
.mn-card.flash { box-shadow: 0 0 0 3px var(--accent); }
.mn-letters { display: flex; flex-wrap: wrap; gap: 8px; margin: 8px 0 12px; }
.mn-letter { display: flex; flex-direction: column; align-items: center; background: var(--accent-soft); border-radius: 8px; padding: 6px 10px; min-width: 64px; }
.mn-letter b { font-size: 1.05rem; color: #1e3a8a; }
.mn-letter b::first-letter { font-size: 1.3rem; color: var(--accent); }
.mn-letter small { color: var(--muted); font-size: 0.78rem; text-align: center; }
.chip.static { cursor: inherit; display: inline-block; margin: 2px 0; }
.chip.static:hover { border-color: var(--border); color: inherit; }
.mn-match { border: 1px solid var(--border); border-radius: 8px; padding: 10px 12px; margin-top: 10px; }
.mn-match.best { border-color: var(--accent); background: var(--accent-soft); }
.mn-formula { font-family: ui-monospace, Menlo, monospace; margin-top: 4px; }
.mn-cheat-table td { text-align: left; }
.mn-cheat-table a { color: var(--accent); }
#mn-question { margin-top: 4px; }
.stem-plot td:first-child { text-align: right; font-weight: 700; font-family: ui-monospace, Menlo, monospace; }
.stem-plot td.leaf { text-align: left; font-family: ui-monospace, Menlo, monospace; letter-spacing: 0.12em; }

.chips { display: inline-flex; gap: 6px; align-items: center; font-size: 0.85rem; color: var(--muted); flex-wrap: wrap; }
.chip { border: 1px solid var(--border); background: white; border-radius: 999px; padding: 4px 10px; cursor: pointer; font: inherit; font-size: 0.85rem; }
.chip:hover { border-color: var(--accent); color: var(--accent); }

.stats-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(170px, 1fr)); gap: 12px; margin-bottom: 8px; }
.stat { background: var(--card); border-radius: var(--radius); padding: 14px 16px; box-shadow: 0 1px 3px rgba(15, 23, 42, 0.08); }
.stat-label { font-size: 0.8rem; color: var(--muted); text-transform: uppercase; letter-spacing: 0.03em; }
.stat-value { font-size: 1.6rem; font-weight: 700; color: var(--accent); font-variant-numeric: tabular-nums; }
.stat-symbol { font-size: 0.85rem; color: var(--muted); }

.hint { color: var(--muted); font-size: 0.88rem; }
.warning { background: var(--warn-bg); color: var(--warn); padding: 8px 12px; border-radius: 8px; font-size: 0.9rem; }
.note { background: var(--warn-bg); color: var(--warn); padding: 8px 12px; border-radius: 8px; }
.formula { font-family: ui-monospace, Menlo, monospace; background: var(--accent-soft); color: #1e3a8a; padding: 8px 12px; border-radius: 8px; display: inline-block; }
.answer { font-size: 1.05rem; }
.answer.big { font-size: 2.4rem; font-weight: 700; color: var(--pink); margin: 0 0 8px; }

.steps li { margin-bottom: 8px; }
table { border-collapse: collapse; margin: 8px 0; font-variant-numeric: tabular-nums; }
th, td { border: 1px solid var(--border); padding: 4px 12px; text-align: right; }
th { background: #f8fafc; }
.guide td, .guide th { text-align: left; }
tfoot td { background: #f8fafc; }

.grid2 { display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); gap: 16px; margin: 12px 0; }
.grid2.tight { gap: 8px; margin: 8px 0 0; grid-template-columns: 1fr 1fr; }
.grid3 { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 12px; margin: 12px 0; }
.cv-group { border: 1px solid var(--border); border-radius: 10px; padding: 12px; display: flex; flex-direction: column; gap: 8px; }

.chart { width: 100%; height: auto; display: block; }

.classes-input input { width: 110px; margin-top: 0; }
.classes-input td, .classes-input th { text-align: left; }
.classes-input .cls-num { color: var(--muted); }
.build { display: inline-flex; gap: 6px; align-items: center; font-size: 0.9rem; color: var(--muted); }
.build input { margin-top: 0; }
.table-scroll { overflow-x: auto; }
.q-table { width: 100%; }
.q-table th { text-align: left; white-space: nowrap; }
.q-table td { text-align: center; }
.q-label { display: block; font-size: 0.72rem; color: var(--muted); }
.inline-answer { color: var(--pink); }
mark { background: #fce7f3; color: var(--pink); font-weight: 700; padding: 0 3px; border-radius: 4px; }
tr.hl td { background: #fce7f3; font-weight: 700; }
td.computed { font-variant-numeric: tabular-nums; color: var(--muted); min-width: 140px; }
.freq-table { width: 100%; }
.freq-table td:first-child, .freq-table td:nth-child(2) { text-align: left; }

.tips-switch { display: inline-flex; gap: 6px; align-items: center; color: rgba(255, 255, 255, 0.9); font-size: 0.85rem; margin-bottom: 12px; cursor: pointer; }

[data-tip] { cursor: help; }
input[data-tip], select[data-tip], textarea[data-tip], button[data-tip], label[data-tip] input, label[data-tip] select, label[data-tip] textarea { cursor: auto; }
button[data-tip], label.file-btn[data-tip], label[data-tip] input[type="radio"] { cursor: pointer; }
.stat[data-tip]:hover, .steps li[data-tip]:hover, tr[data-tip]:hover, td[data-tip]:hover, th[data-tip]:hover { background: #eff6ff; }
.chart [data-tip]:hover { filter: brightness(0.92); }
body.tips-off [data-tip] { cursor: auto; }
body.tips-off .stat[data-tip]:hover, body.tips-off .steps li[data-tip]:hover, body.tips-off tr[data-tip]:hover,
body.tips-off td[data-tip]:hover, body.tips-off th[data-tip]:hover { background: inherit; }

.tooltip {
  position: fixed;
  z-index: 1000;
  max-width: 320px;
  background: #0f172a;
  color: #e2e8f0;
  padding: 10px 12px;
  border-radius: 10px;
  font-size: 0.85rem;
  line-height: 1.45;
  box-shadow: 0 8px 24px rgba(15, 23, 42, 0.3);
  pointer-events: none;
}
.tooltip .tt-title { font-weight: 700; color: white; margin-bottom: 4px; }
.tooltip ol, .tooltip ul { margin: 4px 0; padding-left: 18px; }
.tooltip li { margin: 1px 0; }
.tooltip .f {
  font-family: ui-monospace, Menlo, monospace;
  background: rgba(255, 255, 255, 0.08);
  border-radius: 6px;
  padding: 4px 8px;
  margin: 6px 0;
  color: #bfdbfe;
}
.tooltip .tt-calc {
  margin-top: 8px;
  padding-top: 8px;
  border-top: 1px solid rgba(255, 255, 255, 0.15);
  font-family: ui-monospace, Menlo, monospace;
  color: #fbcfe8;
  font-size: 0.8rem;
  word-break: break-word;
}
.tooltip .tt-calc span { display: block; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif; color: #94a3b8; font-size: 0.75rem; margin-bottom: 2px; }
code { background: #f1f5f9; padding: 1px 5px; border-radius: 4px; }