:root {
  --bg: #f6f4ef;
  --bg-2: #ece8df;
  --ink: #1a1a1a;
  --muted: #6a6a6a;
  --accent: #c8362f;
  --accent-2: #1a4d8c;
  --ok: #2b8a3e;
  --warn: #d97706;
  --bad: #b91c1c;
  --card: #ffffff;
  --shadow: 0 1px 2px rgba(0,0,0,.04), 0 4px 16px rgba(0,0,0,.06);
}
* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  font-family: -apple-system, "Segoe UI", "Hiragino Sans", "Yu Gothic", sans-serif;
  background: var(--bg);
  color: var(--ink);
  line-height: 1.5;
}
header {
  background: var(--card);
  border-bottom: 1px solid var(--bg-2);
  padding: 14px 24px 0;
  position: sticky; top: 0; z-index: 10;
  box-shadow: var(--shadow);
}
header h1 {
  margin: 0 0 8px;
  font-size: 22px;
  font-weight: 600;
  color: var(--accent);
}
header h1 .sub {
  font-size: 13px;
  font-weight: 400;
  color: var(--muted);
  margin-left: 12px;
}
nav { display: flex; gap: 2px; flex-wrap: wrap; }
nav button {
  background: transparent;
  border: none;
  padding: 10px 16px;
  font-size: 14px;
  font-weight: 500;
  color: var(--muted);
  cursor: pointer;
  border-bottom: 2px solid transparent;
  transition: all .15s;
}
nav button:hover { color: var(--ink); }
nav button.active {
  color: var(--accent);
  border-bottom-color: var(--accent);
}

main {
  max-width: 1100px;
  margin: 24px auto;
  padding: 0 24px 80px;
}
.tab { display: none; }
.tab.active { display: block; }

.card {
  background: var(--card);
  border-radius: 10px;
  padding: 20px 22px;
  margin-bottom: 18px;
  box-shadow: var(--shadow);
}
.card h2 { margin: 0 0 12px; font-size: 17px; font-weight: 600; }
.card p { margin: 6px 0; }
.big { font-size: 36px; font-weight: 700; color: var(--accent); margin: 4px 0 8px; }
.hint { color: var(--muted); font-size: 13px; }
.plan li { margin: 4px 0; }

.toolbar {
  display: flex;
  gap: 14px;
  align-items: center;
  flex-wrap: wrap;
  background: var(--card);
  padding: 12px 16px;
  border-radius: 10px;
  box-shadow: var(--shadow);
  margin-bottom: 16px;
}
.toolbar label {
  font-size: 13px;
  color: var(--muted);
  display: flex;
  gap: 6px;
  align-items: center;
}
.toolbar select, .toolbar input[type="checkbox"] {
  font-size: 13px;
}
.toolbar select {
  border: 1px solid var(--bg-2);
  padding: 4px 8px;
  border-radius: 6px;
  background: white;
}
.counter { margin-left: auto; color: var(--muted); font-size: 13px; }

.flashcard {
  background: var(--card);
  border-radius: 12px;
  padding: 60px 30px;
  min-height: 280px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow);
  margin-bottom: 12px;
  cursor: pointer;
  user-select: none;
}
.flashcard .front {
  font-size: 48px;
  font-weight: 500;
  text-align: center;
}
.flashcard .back {
  margin-top: 24px;
  border-top: 1px dashed var(--bg-2);
  padding-top: 24px;
  font-size: 18px;
  text-align: center;
  max-width: 700px;
}
.flashcard.kanji-card .front { font-size: 120px; line-height: 1; font-family: "Yu Mincho", "MS Mincho", serif; }
.flashcard .back .row { margin: 4px 0; }
.flashcard .back .label { color: var(--muted); font-size: 12px; text-transform: uppercase; margin-right: 6px; }
.flashcard .back .reading-on { color: var(--accent-2); font-weight: 500; }
.flashcard .back .reading-kun { color: var(--accent); font-weight: 500; }
.flashcard .back .examples { margin-top: 12px; font-size: 14px; color: var(--muted); }
.flashcard .back .example { margin: 3px 0; }
.hidden { display: none !important; }

.controls {
  display: flex;
  gap: 10px;
  justify-content: center;
  margin-bottom: 18px;
}
.controls button {
  padding: 10px 18px;
  border: none;
  border-radius: 8px;
  font-size: 14px;
  font-weight: 500;
  cursor: pointer;
  background: var(--ink);
  color: white;
}
.controls .grade { display: flex; gap: 8px; }
.controls .grade button.bad { background: var(--bad); }
.controls .grade button.ok { background: var(--warn); }
.controls .grade button.good { background: var(--ok); }
.controls .grade button.great { background: var(--accent-2); }
button.danger { background: var(--bad); color: white; border: none; padding: 8px 14px; border-radius: 6px; cursor: pointer; }

.sync-status { font-size: 12px; font-weight: 400; margin-left: 10px; color: var(--muted); }
.sync-status.ok { color: var(--ok); }
.sync-status.pending { color: var(--warn); }
.sync-status.bad { color: var(--bad); }

.state-chip {
  display: inline-block;
  padding: 2px 8px;
  border-radius: 10px;
  font-size: 11px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: .03em;
  background: var(--bg-2);
  color: var(--muted);
}
.state-chip.new   { background: #e9eef6; color: #5a6b8a; }
.state-chip.bad   { background: #fbe1e1; color: var(--bad); }
.state-chip.warn  { background: #fdebd3; color: var(--warn); }
.state-chip.ok    { background: #def0e1; color: var(--ok); }
.state-chip.great { background: #dde7f6; color: var(--accent-2); }
.state-meta { font-size: 11px; color: var(--muted); margin-left: 6px; white-space: nowrap; }

.list-toggle { margin-top: 16px; background: var(--card); border-radius: 8px; padding: 12px 16px; box-shadow: var(--shadow); }
.list-toggle summary { cursor: pointer; font-weight: 500; }

table.data {
  width: 100%;
  border-collapse: collapse;
  background: var(--card);
  border-radius: 8px;
  overflow: hidden;
  font-size: 14px;
  margin-top: 8px;
}
table.data th, table.data td {
  padding: 8px 12px;
  text-align: left;
  border-bottom: 1px solid var(--bg-2);
  vertical-align: top;
}
table.data th { background: var(--bg-2); font-weight: 600; }
table.data tr:last-child td { border-bottom: none; }
table.data tr:hover { background: var(--bg); }
table.data .kanji-cell { font-size: 22px; font-family: "Yu Mincho", "MS Mincho", serif; }
table.data .group-row td {
  background: #eaf2fb;
  font-weight: 600;
  color: var(--accent-2);
  font-size: 13px;
}

#grammar-content .grammar-item {
  background: var(--card);
  border-radius: 10px;
  padding: 18px 22px;
  margin-bottom: 14px;
  box-shadow: var(--shadow);
}
#grammar-content .grammar-item h3 {
  margin: 0 0 6px;
  font-size: 17px;
  color: var(--accent);
}
#grammar-content .grammar-item .meta {
  font-size: 12px;
  color: var(--muted);
  margin-bottom: 10px;
}
#grammar-content .grammar-item .form {
  background: var(--bg-2);
  padding: 8px 14px;
  border-radius: 6px;
  font-family: ui-monospace, "Cascadia Code", monospace;
  font-size: 14px;
  display: inline-block;
  margin: 6px 0;
}
#grammar-content .grammar-item .example {
  margin: 6px 0;
  padding-left: 12px;
  border-left: 3px solid var(--bg-2);
}
#grammar-content .grammar-item .example .jp { font-size: 16px; }
#grammar-content .grammar-item .example .en { font-size: 13px; color: var(--muted); }
#grammar-content .exercise {
  margin-top: 12px;
  background: var(--bg);
  border-radius: 6px;
  padding: 12px 14px;
}
#grammar-content .exercise summary { cursor: pointer; font-weight: 500; color: var(--accent-2); }
#grammar-content .exercise ol { margin: 8px 0 0; padding-left: 22px; }

#oral-questions details {
  margin: 8px 0;
  background: var(--bg);
  padding: 10px 14px;
  border-radius: 6px;
}
#oral-questions details summary { cursor: pointer; font-weight: 500; }
#oral-questions details .answer { margin-top: 8px; font-size: 14px; color: var(--muted); padding-left: 12px; border-left: 3px solid var(--accent); }

#mock-test .q { margin: 10px 0; padding: 10px; background: var(--bg); border-radius: 6px; }
#mock-test input[type="text"] {
  border: 1px solid var(--bg-2);
  padding: 4px 8px;
  border-radius: 4px;
  font-size: 14px;
  font-family: inherit;
  min-width: 200px;
}
#mock-test .result { margin-left: 8px; font-weight: 600; font-size: 13px; }
#mock-test .result.ok { color: var(--ok); }
#mock-test .result.bad { color: var(--bad); }
#mock-check {
  background: var(--accent-2); color: white; border: none;
  padding: 10px 18px; border-radius: 8px; font-size: 14px;
  font-weight: 500; cursor: pointer;
}
#mock-score { font-weight: 600; margin-top: 12px; }

#progress-bars .bar-group { margin: 8px 0; }
#progress-bars .label-row { display: flex; justify-content: space-between; font-size: 13px; margin-bottom: 3px; }
#progress-bars .bar { background: var(--bg-2); height: 8px; border-radius: 4px; overflow: hidden; }
#progress-bars .bar > div { background: var(--ok); height: 100%; transition: width .3s; }

#cheatsheet table { font-size: 13px; }
#cheatsheet h4 { color: var(--accent); margin: 14px 0 6px; }

@media (max-width: 640px) {
  main { padding: 0 12px 60px; }
  header { padding: 10px 12px 0; }
  .flashcard { padding: 40px 20px; min-height: 220px; }
  .flashcard .front { font-size: 36px; }
  .flashcard.kanji-card .front { font-size: 90px; }
  table.data { font-size: 12px; }
  table.data th, table.data td { padding: 6px 8px; }
}