:root {
  --bg: #1e1e22;
  --panel: #2a2a30;
  --text: #e8e6e3;
  --muted: #9a98a3;
  --accent: #6fb3ff;
  --good: #5fc97a;
  --bad: #e0625f;
  --border: #3c3c44;
}

* { box-sizing: border-box; }

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

.layout { display: flex; min-height: 100vh; }

#sidebar {
  width: 280px;
  flex-shrink: 0;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  padding: 1rem;
  background: var(--panel);
  border-right: 1px solid var(--border);
  height: 100vh;
  position: sticky;
  top: 0;
  overflow-y: auto;
}

#sidebar h1 {
  font-size: 1.1rem;
  margin: 0;
}

#main-nav { display: flex; flex-direction: column; gap: 0.25rem; flex-shrink: 0; }
.sidebar-actions { display: flex; flex-direction: column; gap: 0.25rem; margin-top: auto; flex-shrink: 0; }

.browse-tree {
  flex: 1;
  overflow-y: auto;
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
  padding: 0.5rem 0;
  font-size: 0.85rem;
}

.tree-chapter > .tree-chapter-head {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.35rem 0.4rem;
  cursor: pointer;
  border-radius: 4px;
  font-weight: 600;
}
.tree-chapter > .tree-chapter-head:hover { background: var(--bg); }
.tree-chapter > .tree-chapter-head .twist { color: var(--muted); width: 0.9em; display: inline-block; }

.tree-gp-list { list-style: none; margin: 0; padding: 0; display: none; }
.tree-chapter.open > .tree-gp-list { display: block; }

.tree-gp {
  padding: 0.3rem 0.4rem 0.3rem 1.6rem;
  cursor: pointer;
  border-radius: 4px;
  color: var(--muted);
  line-height: 1.3;
}
.tree-gp:hover { background: var(--bg); color: var(--text); }
.tree-gp.active { background: var(--accent); color: #111; }
.tree-gp .section { font-size: 0.75rem; margin-right: 0.3rem; }

nav button, .iconbtn {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--text);
  padding: 0.5rem 0.8rem;
  border-radius: 6px;
  cursor: pointer;
  font-size: 0.9rem;
  text-align: left;
  width: 100%;
}

nav button.active { background: var(--accent); color: #111; border-color: var(--accent); }
nav button:hover, .iconbtn:hover { border-color: var(--accent); }

main { flex: 1; padding: 1rem 1.25rem; max-width: 900px; }

@media (max-width: 700px) {
  .layout { flex-direction: column; }
  #sidebar {
    width: auto;
    height: auto;
    max-height: 70vh;
    position: static;
    border-right: none;
    border-bottom: 1px solid var(--border);
  }
  #sidebar > h1 { flex-shrink: 0; }
  #main-nav { flex-direction: row; flex-wrap: wrap; flex-shrink: 0; }
  nav button { width: auto; }
  .sidebar-actions { flex-direction: row; margin-top: 0; }
  main { margin: 0 auto; }
}

.view { display: none; }
.view.active { display: block; }

.card {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 1rem;
  margin-bottom: 0.75rem;
}

.chapter-list, .gp-list { list-style: none; padding: 0; margin: 0; }
.chapter-list li, .gp-list li {
  padding: 0.6rem 0.8rem;
  border-bottom: 1px solid var(--border);
  cursor: pointer;
}
.chapter-list li:hover, .gp-list li:hover { background: var(--panel); }
.gp-list .section { color: var(--muted); margin-right: 0.5rem; font-size: 0.85rem; }
.gp-list .badge {
  font-size: 0.7rem;
  color: var(--muted);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 0 0.3rem;
  margin-left: 0.4rem;
}

.crumbs { color: var(--muted); font-size: 0.85rem; margin-bottom: 0.5rem; cursor: pointer; }
.crumbs span:hover { color: var(--accent); }

.pattern { font-size: 1.3rem; margin: 0 0 0.25rem; }
.meaning { color: var(--muted); margin: 0 0 0.5rem; }
.formality { display: inline-block; font-size: 0.75rem; background: var(--border); padding: 0.1rem 0.5rem; border-radius: 10px; margin-bottom: 0.6rem; }
.prose { white-space: pre-wrap; line-height: 1.5; }
.note { border-left: 3px solid var(--accent); padding-left: 0.7rem; margin-top: 0.6rem; color: var(--muted); }
.example-jp { font-size: 1.05rem; }
.example-en { color: var(--muted); font-size: 0.9rem; }
.vocab-row { display: flex; gap: 0.5rem; padding: 0.2rem 0; border-bottom: 1px solid var(--border); }
.vocab-row .term { min-width: 5rem; }
.vocab-row .reading { color: var(--muted); min-width: 6rem; }

.toggle-row { margin-bottom: 0.6rem; display: flex; gap: 1rem; align-items: center; font-size: 0.85rem; color: var(--muted); }

.flash {
  text-align: center;
  padding: 2.5rem 1rem;
  min-height: 180px;
  display: flex;
  flex-direction: column;
  justify-content: center;
}
.flash .front { font-size: 1.6rem; }
.flash .back { margin-top: 1rem; text-align: left; }
.rate-row { display: flex; gap: 0.5rem; justify-content: center; margin-top: 1.5rem; }
.rate-row button { flex: 1; max-width: 120px; padding: 0.6rem; border-radius: 6px; border: none; cursor: pointer; font-weight: 600; }
.rate-again { background: var(--bad); color: #fff; }
.rate-hard { background: #c98b3f; color: #fff; }
.rate-good { background: var(--good); color: #111; }
.rate-easy { background: var(--accent); color: #111; }

.quiz-prompt { font-size: 1.4rem; margin-bottom: 1rem; }
.quiz-options { display: flex; flex-direction: column; gap: 0.5rem; }
.quiz-options button { padding: 0.6rem; text-align: left; border-radius: 6px; border: 1px solid var(--border); background: var(--bg); color: var(--text); cursor: pointer; }
.quiz-options button:hover { border-color: var(--accent); }
.quiz-options button.correct { border-color: var(--good); background: rgba(95,201,122,0.15); }
.quiz-options button.wrong { border-color: var(--bad); background: rgba(224,98,95,0.15); }
input[type=text].quiz-input { font-size: 1.1rem; padding: 0.5rem; width: 100%; background: var(--bg); color: var(--text); border: 1px solid var(--border); border-radius: 6px; }
.quiz-footer { display: flex; justify-content: space-between; align-items: center; margin-top: 1rem; }

table.stats { width: 100%; border-collapse: collapse; }
table.stats th, table.stats td { text-align: left; padding: 0.4rem 0.6rem; border-bottom: 1px solid var(--border); }
table.stats th { color: var(--muted); font-size: 0.8rem; }

.muted { color: var(--muted); }
.empty { color: var(--muted); padding: 2rem; text-align: center; }
.actions-row { display: flex; gap: 0.5rem; margin-top: 1rem; flex-wrap: wrap; }
button.primary { background: var(--accent); color: #111; border: none; padding: 0.5rem 1rem; border-radius: 6px; cursor: pointer; font-weight: 600; }
button.secondary { background: transparent; color: var(--text); border: 1px solid var(--border); padding: 0.5rem 1rem; border-radius: 6px; cursor: pointer; }