:root {
  --bg: #0f1419;
  --panel: #1a222c;
  --panel-2: #222d3a;
  --line: #2e3b4a;
  --text: #e6edf3;
  --muted: #9fb0c0;
  --accent: #6ea8fe;
  --concept: #7c5cff;
  --case: #e8793a;
  --statute: #2bb673;
  --again: #e5484d;
  --hard: #d99a2b;
  --good: #2bb673;
  --easy: #3b82f6;
  --radius: 14px;
}

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

/* Topbar */
.topbar {
  display: flex; align-items: center; justify-content: space-between;
  gap: 12px; padding: 8px 18px;
  background: linear-gradient(180deg, #16202b, #11181f);
  border-bottom: 1px solid var(--line);
  flex-wrap: wrap;
}
.brand { display: flex; align-items: center; gap: 9px; }
.logo { font-size: 20px; }
.brand h1 { font-size: 15px; margin: 0; }
.tagline { margin: 0; font-size: 11px; color: var(--muted); }
.tabs { display: flex; gap: 6px; }
.tab {
  background: transparent; border: 1px solid transparent; color: var(--muted);
  padding: 6px 13px; border-radius: 10px; cursor: pointer; font-size: 13px;
}
.tab:hover { color: var(--text); background: var(--panel); }
.tab.active { color: var(--text); background: var(--panel-2); border-color: var(--line); }

main { max-width: 820px; margin: 0 auto; padding: 12px 18px 60px; }

/* Filter bar */
.filterbar {
  display: flex; gap: 16px; align-items: center; flex-wrap: wrap;
  margin-bottom: 18px;
}
.filterbar label { font-size: 12px; color: var(--muted); display: flex; flex-direction: column; gap: 4px; }
.filterbar select {
  background: var(--panel); color: var(--text); border: 1px solid var(--line);
  border-radius: 8px; padding: 7px 10px; font-size: 14px; min-width: 140px;
}
.counts { margin-left: auto; font-size: 13px; color: var(--muted); }
.counts b { color: var(--text); }

/* Views */
.view { display: none; }
.view.active { display: block; }
.hidden { display: none !important; }

/* Card */
.cardwrap { display: flex; flex-direction: column; align-items: center; }
.card {
  width: 100%; background: var(--panel); border: 1px solid var(--line);
  border-radius: var(--radius); padding: 28px 26px; min-height: 240px;
  box-shadow: 0 8px 30px rgba(0,0,0,.25);
}
.card-meta { display: flex; gap: 8px; margin-bottom: 18px; flex-wrap: wrap; }
.badge {
  font-size: 11px; text-transform: uppercase; letter-spacing: .6px;
  padding: 3px 9px; border-radius: 20px; font-weight: 600; color: #fff;
}
.badge.subtle { background: var(--panel-2); color: var(--muted); font-weight: 500; }
.badge.concept, .badge.elements { background: var(--concept); }
.badge.case { background: var(--case); }
.badge.statute { background: var(--statute); }

.card-front { font-size: 21px; font-weight: 600; white-space: pre-wrap; }
.card-back {
  margin-top: 20px; padding-top: 18px; border-top: 1px dashed var(--line);
  font-size: 16px; white-space: pre-wrap; color: #d7e2ee;
}
.card-tags { margin-top: 18px; display: flex; gap: 6px; flex-wrap: wrap; }
.card-tags span { font-size: 11px; color: var(--muted); background: var(--panel-2); padding: 2px 8px; border-radius: 6px; }

/* Actions */
.actions { width: 100%; margin-top: 18px; }
.btn {
  background: var(--panel-2); color: var(--text); border: 1px solid var(--line);
  padding: 11px 18px; border-radius: 10px; cursor: pointer; font-size: 14px;
  transition: filter .12s, transform .05s;
}
.btn:hover { filter: brightness(1.15); }
.btn:active { transform: translateY(1px); }
.btn.primary { background: var(--accent); border-color: var(--accent); color: #0b1620; font-weight: 600; }
.btn.wide { width: 100%; padding: 14px; font-size: 15px; }
.grade-row { display: grid; grid-template-columns: repeat(4, 1fr); gap: 10px; }
.btn.grade { display: flex; flex-direction: column; gap: 3px; align-items: center; color: #fff; border: none; padding: 12px 6px; }
.btn.grade small { font-size: 11px; opacity: .85; }
.btn.grade.again { background: var(--again); }
.btn.grade.hard { background: var(--hard); }
.btn.grade.good { background: var(--good); }
.btn.grade.easy { background: var(--easy); }
.hint { text-align: center; color: var(--muted); font-size: 12px; margin-top: 14px; }

.empty { text-align: center; padding: 60px 20px; color: var(--muted); }
.empty h2 { color: var(--text); }

/* Browse */
.browse-head { display: flex; gap: 10px; margin-bottom: 14px; }
#search { flex: 1; background: var(--panel); border: 1px solid var(--line); color: var(--text); border-radius: 10px; padding: 10px 14px; font-size: 14px; }
.browse-list { display: flex; flex-direction: column; gap: 8px; }
.row {
  background: var(--panel); border: 1px solid var(--line); border-radius: 10px;
  padding: 12px 14px; display: flex; gap: 12px; align-items: flex-start;
}
.row .row-main { flex: 1; min-width: 0; }
.row .row-front { font-weight: 600; }
.row .row-back { color: var(--muted); font-size: 13px; margin-top: 3px; }
.row .row-sched { font-size: 11px; color: var(--muted); margin-top: 6px; }
.row-actions { display: flex; gap: 6px; }
.icon-btn { background: none; border: 1px solid var(--line); color: var(--muted); border-radius: 8px; padding: 5px 9px; cursor: pointer; font-size: 12px; }
.icon-btn:hover { color: var(--text); }

/* Panels */
.panel { background: var(--panel); border: 1px solid var(--line); border-radius: var(--radius); padding: 20px; margin-bottom: 16px; }
.panel h2 { margin-top: 0; font-size: 17px; }
.panel p { color: var(--muted); font-size: 14px; }
code { background: var(--panel-2); padding: 1px 6px; border-radius: 5px; font-size: 13px; }
.data-tools { display: flex; gap: 8px; flex-wrap: wrap; margin: 14px 0; }
textarea#json-area {
  width: 100%; min-height: 260px; background: #0c1116; color: #cbd5e1;
  border: 1px solid var(--line); border-radius: 10px; padding: 14px;
  font-family: "SF Mono", Consolas, monospace; font-size: 13px; resize: vertical;
}
.msg { min-height: 20px; font-size: 13px; }
.msg.ok { color: var(--good); }
.msg.err { color: var(--again); }
.schema { margin-top: 14px; }
.schema summary { cursor: pointer; color: var(--accent); }
.schema pre { background: #0c1116; border: 1px solid var(--line); border-radius: 10px; padding: 14px; overflow-x: auto; font-size: 12px; color: #cbd5e1; }
.danger { margin-top: 20px; display: flex; gap: 10px; }
.ghost-danger { background: transparent; border-color: var(--again); color: var(--again); }
.ghost-danger:hover { background: rgba(229,72,77,.12); }

/* Stats */
.stat-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(130px, 1fr)); gap: 12px; margin-bottom: 16px; }
.stat {
  background: var(--panel); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 18px; text-align: center;
}
.stat .num { font-size: 28px; font-weight: 700; }
.stat .lbl { font-size: 12px; color: var(--muted); text-transform: uppercase; letter-spacing: .5px; }
.mbar { display: flex; align-items: center; gap: 10px; margin: 8px 0; font-size: 13px; }
.mbar .mname { width: 140px; color: var(--muted); }
.mbar .track { flex: 1; height: 8px; background: var(--panel-2); border-radius: 6px; overflow: hidden; }
.mbar .fill { height: 100%; background: var(--good); }

/* Modal */
.modal { position: fixed; inset: 0; background: rgba(0,0,0,.6); display: flex; align-items: center; justify-content: center; padding: 20px; z-index: 50; }
.modal-box { background: var(--panel); border: 1px solid var(--line); border-radius: var(--radius); padding: 22px; width: 100%; max-width: 480px; }
.modal-box h2 { margin-top: 0; }
.modal-box label { display: flex; flex-direction: column; gap: 4px; font-size: 13px; color: var(--muted); margin-bottom: 12px; }
.modal-box input, .modal-box textarea, .modal-box select {
  background: #0c1116; color: var(--text); border: 1px solid var(--line);
  border-radius: 8px; padding: 9px 11px; font-size: 14px; font-family: inherit;
}
.modal-actions { display: flex; justify-content: flex-end; gap: 10px; margin-top: 8px; }

/* Topic multi-select */
.filterbar { margin-bottom: 12px; }
.topic-select { position: relative; flex: 0 0 auto; }
.topic-toggle {
  display: inline-flex; align-items: center; gap: 10px; cursor: pointer;
  background: var(--panel); border: 1px solid var(--line); color: var(--text);
  border-radius: 10px; padding: 8px 13px; font-size: 14px; font-weight: 600;
  white-space: nowrap;
}
.topic-toggle:hover { border-color: var(--accent); }
.topic-toggle .caret { color: var(--muted); font-size: 12px; }
.topic-toggle[aria-expanded="true"] .caret { transform: rotate(180deg); }
.topic-panel {
  position: absolute; top: calc(100% + 6px); left: 0; z-index: 30;
  width: min(560px, 92vw); max-height: 60vh; overflow-y: auto;
  background: var(--panel); border: 1px solid var(--line); border-radius: 12px;
  padding: 14px; box-shadow: 0 14px 40px rgba(0,0,0,.45);
}
.topic-head { display: flex; align-items: center; gap: 10px; font-size: 12px; color: var(--muted); margin-bottom: 10px; }
.topic-head .mini { background: var(--panel); border: 1px solid var(--line); color: var(--muted); border-radius: 6px; padding: 2px 10px; font-size: 12px; cursor: pointer; }
.topic-head .mini:hover { color: var(--text); }
.topic-chips { display: flex; flex-wrap: wrap; gap: 6px; }
.chip {
  display: inline-flex; align-items: center; gap: 6px; cursor: pointer;
  background: var(--panel); border: 1px solid var(--line); color: var(--muted);
  padding: 6px 11px; border-radius: 999px; font-size: 13px; user-select: none;
}
.chip input { display: none; }
.chip.on { background: var(--accent); border-color: var(--accent); color: #0b1620; font-weight: 600; }
.chip .cnum { font-size: 11px; opacity: .75; }
.filter-row { display: flex; gap: 10px; align-items: center; flex-wrap: wrap; }
.filter-row select { background: var(--panel); color: var(--text); border: 1px solid var(--line); border-radius: 10px; padding: 8px 10px; font-size: 14px; min-width: 0; flex: 1 1 140px; }

/* Stats below the card */
.card-foot { width: 100%; margin-top: 14px; display: flex; flex-direction: column; gap: 6px; }
.card-foot .progress-strip { margin: 0; }
.card-foot .counts { margin: 0; text-align: center; }

/* Answer sections (Facts / Principle) */
.ans-block { margin-top: 16px; }
.ans-block:first-child { margin-top: 20px; padding-top: 18px; border-top: 1px dashed var(--line); }
.ans-label { font-size: 11px; text-transform: uppercase; letter-spacing: .6px; color: var(--accent); font-weight: 700; margin-bottom: 4px; }
.ans-text { font-size: 15.5px; white-space: pre-wrap; color: #dbe6f1; }
.ans-case { font-size: 20px; font-weight: 700; }
.ans-cite { color: var(--muted); font-weight: 500; font-size: 15px; }
.progress-strip { display: flex; align-items: center; gap: 12px; margin-bottom: 16px; }
.progress-strip .track { flex: 1; height: 10px; background: var(--panel-2); border-radius: 6px; overflow: hidden; }
.progress-strip .fill { height: 100%; width: 0; background: linear-gradient(90deg, var(--good), #3bdb78); transition: width .25s; }
.progress-strip span { font-size: 12px; color: var(--muted); white-space: nowrap; }

/* Card notes + citation */
.card-notes { margin-top: 14px; font-size: 14px; color: var(--muted); white-space: pre-wrap; }
.card-cite { margin-top: 10px; font-size: 13px; color: var(--accent); font-style: italic; }
.card-dir { }
.card { cursor: pointer; }

/* Two-button grade row */
.grade-row { display: grid; grid-template-columns: repeat(2, 1fr); gap: 12px; }
.btn.grade.know { background: var(--good); }
.btn.grade.again { background: var(--again); }
.show-btn small, .btn small { opacity: .75; font-size: 11px; }

.btn.ghost { background: transparent; border-color: var(--accent); color: var(--accent); padding: 4px 10px; }
.btn.ghost:hover { background: rgba(110,168,254,.12); }

/* Direction badge tint */
.badge.rev { background: #475569; color: #e2e8f0; }

/* Modal grid + checkbox */
.modal-grid { display: grid; grid-template-columns: 1fr 120px; gap: 12px; }
.modal-box label.check { flex-direction: row; align-items: center; gap: 8px; color: var(--text); }
.modal-box label.check input { width: auto; }

@media (max-width: 560px) {
  .card-front { font-size: 18px; }
  .counts { width: 100%; margin-left: 0; }
  .modal-grid { grid-template-columns: 1fr; }
}

/* Tablet / iPad: larger type + touch targets, keep flashcard above the fold */
@media (min-width: 640px) and (max-width: 1180px) {
  main { max-width: 720px; padding: 10px 22px 60px; }
  .filterbar { margin-bottom: 10px; }
  .topic-toggle { font-size: 15px; padding: 10px 16px; min-height: 44px; }
  .topic-panel { width: min(640px, 92vw); padding: 16px; }
  .topic-head .mini { font-size: 14px; padding: 6px 14px; min-height: 36px; }
  .chip { font-size: 15px; padding: 9px 15px; }
  .chip .cnum { font-size: 13px; }
  .filter-row select { font-size: 15px; padding: 10px 12px; min-height: 44px; }
  .tab { font-size: 14px; padding: 7px 14px; }
  .card { padding: 22px 26px; min-height: 180px; }
  .card-front { font-size: 24px; }
  .card-back, .ans-text { font-size: 18px; }
  .ans-case { font-size: 23px; }
  .btn { font-size: 16px; padding: 13px 20px; }
  .btn.wide { padding: 15px; font-size: 17px; }
  .btn.grade { min-height: 50px; font-size: 17px; }
}

.src-link { color: #4f8cff; text-decoration: none; font-weight: 600; }
.src-link:hover { text-decoration: underline; }
.coverage-summary { margin: 0; font-size: 12px; color: var(--muted); }