/* Designz usage page (usage.html) */
:root {
  --paper: #f4f1ea;
  --paper2: #ebe6da;
  --card: #fbf9f4;
  --ink: #151515;
  --ink2: #4a463f;
  --mute: #7b766b;
  --line: #ddd6c8;
  --red: #ff4a1c;
  /* chart series, in fixed order */
  --s1: #2a78d6;
  --s2: #eb6834;
  --s3: #1baf7a;
  --serif: 'Fraunces', Georgia, serif;
  --sans: 'Instrument Sans', 'Helvetica Neue', Arial, sans-serif;
  --mono: 'JetBrains Mono', ui-monospace, monospace;
}
* { box-sizing: border-box; }
[hidden] { display: none !important; }
html, body { margin: 0; }
body { background: var(--paper); color: var(--ink); font: 15px/1.5 var(--sans); -webkit-font-smoothing: antialiased; }
button { font: inherit; color: inherit; cursor: pointer; }

.u-top { position: sticky; top: 0; z-index: 5; display: flex; align-items: center; justify-content: space-between; gap: 16px; flex-wrap: wrap; padding: 14px 32px; background: rgba(244, 241, 234, 0.92); backdrop-filter: blur(8px); border-bottom: 1px solid var(--line); }
.wordmark { font: 700 26px/1 var(--serif); letter-spacing: -0.04em; color: var(--ink); text-decoration: none; }
.wordmark span { color: var(--red); }
.u-controls { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; }
.seg { display: inline-flex; padding: 3px; border-radius: 999px; background: var(--paper2); border: 1px solid var(--line); }
.seg button { border: 0; background: none; padding: 6px 14px; border-radius: 999px; font-weight: 600; font-size: 13px; color: var(--ink2); }
.seg button.on { background: var(--card); color: var(--ink); box-shadow: 0 1px 2px rgba(0, 0, 0, 0.12); }
.btn { height: 36px; padding: 0 16px; border-radius: 999px; border: 1px solid var(--ink); background: none; font-weight: 600; font-size: 13px; }
.btn:hover { background: var(--card); }
.btn.dark { background: var(--ink); color: var(--paper); }
.btn.dark:hover { background: #000; }

.u-main { max-width: 1240px; margin: 0 auto; padding: 32px 32px 64px; }
.u-head h1 { font: 700 44px/1.05 var(--serif); letter-spacing: -0.03em; margin: 0 0 8px; }
.u-head p { margin: 0 0 28px; color: var(--ink2); max-width: 820px; }

.tiles { display: grid; grid-template-columns: repeat(6, minmax(0, 1fr)); gap: 12px; margin-bottom: 18px; }
.tile { background: var(--card); border: 1px solid var(--line); border-radius: 16px; padding: 16px 16px 14px; display: flex; flex-direction: column; gap: 4px; min-width: 0; }
.tile span { font-size: 13px; font-weight: 600; color: var(--ink2); }
.tile b { font: 500 34px/1.1 var(--mono); letter-spacing: -0.04em; }
.tile small { font-size: 12px; color: var(--mute); line-height: 1.4; }
.chg { font: 500 11px var(--mono); padding: 1px 6px; border-radius: 999px; white-space: nowrap; }
.chg.up { color: #0b6b3a; background: #e1f2e7; }
.chg.down { color: #a3261b; background: #fbe4e0; }
.chg.flat { color: var(--ink2); background: var(--paper2); }

.grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 16px; }
.card { background: var(--card); border: 1px solid var(--line); border-radius: 18px; padding: 20px 22px; min-width: 0; break-inside: avoid; }
.card.wide { grid-column: 1 / -1; }
.card h2 { font: 600 20px/1.2 var(--serif); letter-spacing: -0.01em; margin: 0 0 4px; }
.note { margin: 0 0 12px; font-size: 13px; color: var(--mute); }
.legend { display: flex; flex-wrap: wrap; gap: 14px; margin: -4px 0 8px; font-size: 12px; color: var(--ink2); }
.legend span, .tip .row span { display: inline-flex; align-items: center; gap: 6px; }
.legend i, .tip i { width: 10px; height: 10px; border-radius: 3px; display: inline-block; }
.chart { width: 100%; }
.chart svg { display: block; width: 100%; height: auto; overflow: visible; }
svg .grid { stroke: var(--line); stroke-width: 1; stroke-dasharray: 2 3; }
svg .base { stroke: #c9c1b0; stroke-width: 1; }
svg .ax { font: 11px var(--mono); fill: var(--mute); }
svg .cross { stroke: var(--ink2); stroke-width: 1; opacity: 0; pointer-events: none; }
svg .bar { transition: opacity 0.1s; }
svg .bar.dim { opacity: 0.45; }

.hb { display: flex; flex-direction: column; gap: 8px; }
.hb-row { display: grid; grid-template-columns: minmax(110px, 38%) 1fr; gap: 12px; align-items: center; padding: 2px 0; }
.hb-row:hover .hb-label { color: var(--ink); }
.hb-label { font-size: 13px; color: var(--ink2); overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.hb-label em { font-style: normal; font: 11px var(--mono); color: var(--mute); }
.hb-bars { display: flex; flex-direction: column; gap: 3px; }
.hb-line { display: flex; align-items: center; gap: 8px; }
.hb-bar { display: block; height: 10px; min-width: 2px; border-radius: 0 4px 4px 0; }
.hb-line b { font: 500 12px var(--mono); color: var(--ink2); }
.empty { color: var(--mute); font-size: 13px; margin: 8px 0; }

.tscroll { overflow-x: auto; }
.cohorts table { border-collapse: separate; border-spacing: 3px; width: 100%; font-size: 13px; }
.cohorts th { font-weight: 600; color: var(--ink2); text-align: left; padding: 4px 8px; white-space: nowrap; font-size: 12px; }
.cohorts td { padding: 8px; border-radius: 6px; white-space: nowrap; }
.cohorts .num { text-align: right; font-family: var(--mono); }
.cohorts .heat { background: color-mix(in srgb, var(--s1) calc(var(--p) * 100%), #eef3fb); color: var(--ink); }
.cohorts .heat.hi { color: #fff; }
.cohorts .zero { color: var(--mute); }

.foot { margin: 28px 0 0; font-size: 12px; color: var(--mute); max-width: 760px; }

.tip { position: fixed; z-index: 50; pointer-events: none; background: var(--ink); color: var(--paper); border-radius: 10px; padding: 8px 10px; font-size: 12px; min-width: 150px; box-shadow: 0 8px 24px rgba(0, 0, 0, 0.2); }
.tip .th { font-weight: 600; margin-bottom: 4px; }
.tip .row { display: flex; justify-content: space-between; gap: 16px; }
.tip .row b { font: 500 12px var(--mono); }
.tip .tot { border-top: 1px solid rgba(255, 255, 255, 0.2); margin-top: 4px; padding-top: 4px; }

@media (max-width: 1100px) { .tiles { grid-template-columns: repeat(3, minmax(0, 1fr)); } }
@media (max-width: 760px) {
  .u-top { padding: 12px 16px; }
  .u-main { padding: 20px 16px 48px; }
  .u-head h1 { font-size: 34px; }
  .tiles { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .grid { grid-template-columns: 1fr; }
  .tile b { font-size: 26px; }
}

/* Print or save as PDF: a clean, investor-ready sheet. */
@media print {
  @page { margin: 14mm; }
  body { background: #fff; }
  .u-top { position: static; background: none; border: 0; padding: 0 0 8px; backdrop-filter: none; }
  .u-controls, .tip { display: none !important; }
  .u-main { padding: 0; max-width: none; }
  .tile, .card { border-color: #ddd; background: #fff; }
  .card, .tile { break-inside: avoid; }
  * { -webkit-print-color-adjust: exact; print-color-adjust: exact; }
}

/* Teacher beta tab (js/beta-admin.js) */
.u-tabs { margin: 0 0 14px; }
.u-tabs em { font-style: normal; font: 600 11px var(--mono); background: var(--red); color: #fff; border-radius: 999px; padding: 1px 6px; margin-left: 4px; }
.u-tabs em:empty { display: none; }
body.bz-on .u-controls { display: none; }
.bz-tiles { grid-template-columns: repeat(4, minmax(0, 1fr)); }
.bz-bar { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; margin: 4px 0 14px; }
.bz-bar .grow, .bz-fb .grow { flex: 1; }
.bz-bar a.btn { display: inline-flex; align-items: center; text-decoration: none; color: var(--ink); }
.bz-note { color: var(--ink2); font-size: 14px; margin: 0 0 14px; }
.bz-empty { padding: 30px 0; text-align: center; font-size: 15px; }
#bzList { display: grid; gap: 14px; }
.bz-card header, .bz-fb header { display: flex; align-items: flex-start; justify-content: space-between; gap: 12px; margin-bottom: 10px; }
.bz-card header a, .bz-fb header a { color: var(--ink2); font-size: 14px; }
.bz-status { font: 600 12px var(--sans); padding: 4px 10px; border-radius: 999px; background: var(--paper2); color: var(--ink2); white-space: nowrap; }
.bz-status.new { background: #fff1d6; color: #7a4b00; }
.bz-status.approved { background: #e1f2e7; color: #0b6b3a; }
.bz-status.declined { background: #fbe4e0; color: #a3261b; }
.bz-facts { display: flex; flex-wrap: wrap; gap: 8px 24px; margin: 0 0 12px; }
.bz-facts dt { font-size: 12px; color: var(--mute); }
.bz-facts dd { margin: 0; font-weight: 600; font-size: 14px; }
.bz-use { margin: 0 0 12px; white-space: pre-wrap; background: var(--paper); border-radius: 12px; padding: 12px 14px; font-size: 14px; }
.bz-note-field { display: grid; gap: 4px; font-size: 12px; color: var(--mute); margin-bottom: 12px; }
.bz-note-field input, .bz-invite input { font: 14px var(--sans); padding: 8px 10px; border-radius: 10px; border: 1px solid var(--line); background: #fff; color: var(--ink); }
.bz-invite { display: flex; align-items: flex-end; gap: 10px; flex-wrap: wrap; margin-bottom: 12px; padding: 12px; border-radius: 12px; background: #eef7f1; }
.bz-invite label { display: grid; gap: 4px; font-size: 12px; color: var(--ink2); flex: 1 1 320px; }
.bz-invite a.btn { display: inline-flex; align-items: center; text-decoration: none; }
.bz-joined { font-size: 13px; color: var(--ink2); align-self: center; }
.bz-actions { display: flex; gap: 8px; }
.bz-actions:empty { display: none; }
.bz-fb header { align-items: center; flex-wrap: wrap; font-size: 14px; }
.bz-fb small { color: var(--mute); }
.bz-kind { font: 600 12px var(--sans); padding: 3px 10px; border-radius: 999px; background: var(--paper2); }
.bz-kind.bug { background: #fbe4e0; color: #a3261b; }
.bz-kind.idea { background: #e6efff; color: #1f4fae; }
.bz-kind.liked { background: #e1f2e7; color: #0b6b3a; }
.bz-shot { display: block; max-width: 100%; max-height: 460px; cursor: zoom-in; border-radius: 10px; border: 1px solid var(--line); }
@media (max-width: 760px) { .bz-tiles { grid-template-columns: repeat(2, minmax(0, 1fr)); } }
.bz-connect { padding: 26px; display: grid; gap: 12px; max-width: 680px; justify-items: start; }
.bz-connect h2 { margin: 0; }
.bz-connect p { margin: 0; }
.bz-connect .btn { text-decoration: none; }