:root {
  --bg: #f5f7fb;
  --card: #ffffff;
  --ink: #1a2233;
  --ink2: #5a6577;
  --accent: #2563eb;
  --accent-light: #dbeafe;
  --success: #16a34a;
  --success-light: #dcfce7;
  --danger: #dc2626;
  --danger-light: #fef2f2;
  --warn: #f59e0b;
  --border: #e2e8f0;
  --radius: 12px;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

body {
  font-family: "Noto Sans SC", "Noto Sans JP", "Microsoft YaHei", sans-serif;
  background: var(--bg);
  color: var(--ink);
  line-height: 1.6;
}

/* ===== Navigation ===== */
.nav {
  background: #fff;
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
}
.nav-inner {
  max-width: 960px;
  margin: 0 auto;
  padding: 0 16px;
  display: flex;
  align-items: center;
  height: 56px;
  gap: 32px;
}
.logo {
  font-size: 18px;
  font-weight: 700;
  color: var(--accent);
  text-decoration: none;
  white-space: nowrap;
}
.nav-links {
  display: flex;
  gap: 4px;
}
.nav-links a {
  padding: 8px 16px;
  border-radius: 8px;
  text-decoration: none;
  color: var(--ink2);
  font-size: 14px;
  font-weight: 500;
  transition: background .15s, color .15s;
}
.nav-links a:hover { background: var(--accent-light); color: var(--accent); }
.nav-links a.active { background: var(--accent); color: #fff; }

/* ===== Layout ===== */
.wrap { max-width: 960px; margin: 0 auto; padding: 24px 16px; }
.page { display: none; }
.page.active { display: block; }
.hidden { display: none !important; }

.page-header { margin-bottom: 24px; }
.page-header h2 { font-size: 24px; margin-bottom: 4px; }
.page-header p { color: var(--ink2); font-size: 14px; }

/* ===== Buttons ===== */
.btn {
  padding: 10px 20px;
  border-radius: 8px;
  border: none;
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  transition: all .15s;
}
.btn-primary { background: var(--accent); color: #fff; }
.btn-primary:hover { background: #1d4ed8; }
.btn-outline { background: #fff; color: var(--ink); border: 1px solid var(--border); }
.btn-outline:hover { background: var(--bg); }
.btn-sm { padding: 6px 12px; font-size: 13px; }

/* ===== Filter Bar ===== */
.filter-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  align-items: flex-end;
  margin-bottom: 24px;
  padding: 16px;
  background: #fff;
  border-radius: var(--radius);
  border: 1px solid var(--border);
}
.filter-group { display: flex; flex-direction: column; gap: 4px; }
.filter-group label { font-size: 12px; color: var(--ink2); font-weight: 600; }
.filter-group select {
  padding: 8px 12px;
  border-radius: 8px;
  border: 1px solid var(--border);
  font-size: 14px;
  background: #fff;
  min-width: 120px;
}
.filter-actions { display: flex; gap: 8px; margin-left: auto; }

/* ===== Card ===== */
.card {
  background: var(--card);
  padding: 24px;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  margin-bottom: 20px;
}
.card-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 16px;
}
.card-footer {
  display: flex;
  justify-content: flex-end;
  margin-top: 16px;
}
.meta-tag {
  font-size: 12px;
  padding: 4px 10px;
  background: var(--accent-light);
  color: var(--accent);
  border-radius: 20px;
  font-weight: 600;
}
.progress-tag {
  font-size: 14px;
  font-weight: 700;
  color: var(--ink2);
}

/* ===== Question ===== */
.question-text {
  font-size: 17px;
  line-height: 1.8;
  margin-bottom: 16px;
  white-space: pre-line;
  padding: 12px 16px;
  background: #f8fafc;
  border-radius: 8px;
  border-left: 4px solid var(--accent);
}

.options-list { display: flex; flex-direction: column; gap: 8px; }

.opt-btn {
  display: block;
  width: 100%;
  text-align: left;
  padding: 12px 16px;
  border: 2px solid var(--border);
  border-radius: 10px;
  background: #fff;
  font-size: 15px;
  cursor: pointer;
  transition: all .15s;
  line-height: 1.6;
}
.opt-btn:hover { border-color: var(--accent); background: var(--accent-light); }
.opt-btn.correct { border-color: var(--success); background: var(--success-light); }
.opt-btn.wrong { border-color: var(--danger); background: var(--danger-light); }
.opt-btn.disabled { pointer-events: none; opacity: 0.7; }
.opt-btn.highlight { border-color: var(--success); }

/* ===== Explanation ===== */
.explanation {
  margin-top: 16px;
  padding: 16px;
  background: #fffbeb;
  border-radius: 8px;
  border: 1px solid #fde68a;
  font-size: 14px;
  line-height: 1.8;
  white-space: pre-line;
}
.explanation strong { color: var(--accent); }

/* ===== Section Grid ===== */
.section-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 12px;
}
.section-card {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px;
  cursor: pointer;
  transition: all .15s;
}
.section-card:hover { border-color: var(--accent); transform: translateY(-2px); box-shadow: 0 4px 12px rgba(0,0,0,.08); }
.section-card .sec-num { font-size: 12px; color: var(--ink2); margin-bottom: 4px; }
.section-card .sec-name { font-size: 15px; font-weight: 700; margin-bottom: 4px; }
.section-card .sec-count { font-size: 13px; color: var(--ink2); }
.section-card .sec-bar { height: 4px; background: var(--border); border-radius: 2px; margin-top: 8px; overflow: hidden; }
.section-card .sec-bar-fill { height: 100%; background: var(--accent); border-radius: 2px; }
.section-cat { font-size: 11px; color: #fff; padding: 2px 8px; border-radius: 4px; display: inline-block; margin-bottom: 6px; }
.cat-文字語彙 { background: #6366f1; }
.cat-文法 { background: #f59e0b; }
.cat-読解 { background: #10b981; }

/* ===== Exam List ===== */
.exam-list { display: grid; grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); gap: 12px; }
.exam-card {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  cursor: pointer;
  transition: all .15s;
}
.exam-card:hover { border-color: var(--accent); }
.exam-card h3 { font-size: 16px; margin-bottom: 8px; }
.exam-card .exam-info { font-size: 13px; color: var(--ink2); }
.exam-card .exam-badge {
  display: inline-block;
  padding: 2px 8px;
  border-radius: 4px;
  font-size: 11px;
  font-weight: 600;
  margin-top: 8px;
}
.badge-full { background: var(--success-light); color: var(--success); }
.badge-partial { background: #fef3c7; color: #92400e; }

/* ===== Analysis Tabs ===== */
.analysis-tabs {
  display: flex;
  gap: 4px;
  margin-bottom: 20px;
  border-bottom: 2px solid var(--border);
  padding-bottom: 0;
}
.tab-btn {
  padding: 10px 20px;
  border: none;
  background: none;
  font-size: 14px;
  font-weight: 600;
  color: var(--ink2);
  cursor: pointer;
  border-bottom: 2px solid transparent;
  margin-bottom: -2px;
  transition: all .15s;
}
.tab-btn:hover { color: var(--accent); }
.tab-btn.active { color: var(--accent); border-bottom-color: var(--accent); }
.tab-content { display: none; }
.tab-content.active { display: block; }

/* ===== Grammar List ===== */
.grammar-list { display: flex; flex-direction: column; gap: 8px; }
.grammar-item {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 16px;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 8px;
}
.grammar-rank { font-size: 14px; font-weight: 700; color: var(--ink2); min-width: 28px; text-align: center; }
.grammar-pattern { font-size: 16px; font-weight: 700; color: var(--accent); min-width: 180px; }
.grammar-meaning { font-size: 14px; color: var(--ink2); flex: 1; }
.grammar-freq {
  font-size: 12px;
  padding: 4px 10px;
  background: var(--accent-light);
  color: var(--accent);
  border-radius: 20px;
  font-weight: 600;
  white-space: nowrap;
}

/* ===== Vocab List ===== */
.vocab-list { columns: 2; column-gap: 16px; }
.vocab-item {
  break-inside: avoid;
  padding: 8px 12px;
  margin-bottom: 8px;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 6px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.vocab-word { font-size: 15px; font-weight: 600; }
.vocab-freq { font-size: 12px; color: var(--ink2); }

/* ===== Stats ===== */
.stats-overview {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
  margin-bottom: 24px;
}
.stat-card {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  text-align: center;
}
.stat-num { font-size: 32px; font-weight: 800; color: var(--accent); }
.stat-label { font-size: 13px; color: var(--ink2); margin-top: 4px; }

.accuracy-bars { display: flex; flex-direction: column; gap: 8px; margin-bottom: 24px; }
.accuracy-row {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 8px 0;
}
.acc-label { font-size: 13px; min-width: 120px; font-weight: 600; }
.acc-bar { flex: 1; height: 20px; background: var(--border); border-radius: 10px; overflow: hidden; }
.acc-bar-fill { height: 100%; border-radius: 10px; transition: width .3s; }
.acc-bar-fill.good { background: var(--success); }
.acc-bar-fill.mid { background: var(--warn); }
.acc-bar-fill.bad { background: var(--danger); }
.acc-pct { font-size: 13px; font-weight: 700; min-width: 50px; text-align: right; }

.actions-row { display: flex; gap: 12px; }

/* ===== Audio Player ===== */
.audio-player {
  margin: 12px 0;
  padding: 12px 16px;
  background: #f0f4ff;
  border-radius: 10px;
  border: 1px solid #c7d2fe;
}
.audio-label {
  font-size: 13px;
  font-weight: 600;
  color: #4338ca;
  margin-bottom: 8px;
}

/* ===== Tag Chips ===== */
.tag-chips { display: flex; flex-wrap: wrap; gap: 6px; }
.tag-chip {
  display: inline-block;
  padding: 4px 10px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 6px;
  font-size: 13px;
}
.tag-chip small { color: var(--ink2); }

/* ===== Search Input ===== */
.search-input {
  padding: 8px 14px;
  border: 1px solid var(--border);
  border-radius: 8px;
  font-size: 14px;
  min-width: 250px;
  outline: none;
}
.search-input:focus { border-color: var(--accent); }

/* ===== Grammar Cards ===== */
.grammar-cards { display: flex; flex-direction: column; gap: 12px; }
.grammar-card {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px 20px;
  cursor: pointer;
  transition: all .15s;
}
.grammar-card:hover { border-color: var(--accent); }
.grammar-card.expanded { border-color: var(--accent); background: #f8faff; }
.gc-header { display: flex; align-items: center; gap: 12px; }
.gc-pattern { font-size: 23px; font-weight: 700; color: var(--accent); min-width: 180px; }
.gc-meaning { font-size: 18px; color: var(--ink); flex: 1; }
.gc-freq {
  font-size: 15px; padding: 4px 12px; border-radius: 20px;
  font-weight: 600; white-space: nowrap;
}
.gc-freq.hot { background: #fef3c7; color: #92400e; }
.gc-freq.warm { background: #dbeafe; color: #1e40af; }
.gc-freq.cold { background: var(--bg); color: var(--ink2); }
.gc-body { display: none; margin-top: 12px; padding-top: 12px; border-top: 1px solid var(--border); }
.grammar-card.expanded .gc-body { display: block; }
.gc-connection { font-size: 16px; color: var(--ink2); margin-bottom: 10px; }
.gc-connection strong { color: var(--ink); }
.gc-example {
  background: #f0f9ff; border-left: 3px solid var(--accent);
  padding: 12px 16px; margin: 8px 0; border-radius: 0 6px 6px 0;
  font-size: 17px; line-height: 1.9;
}
.gc-example .jp { font-size: 19px; }
.gc-exams { font-size: 15px; color: var(--ink2); margin-top: 10px; }
.gc-mark-btn {
  margin-top: 10px; padding: 6px 14px; border: 1px solid var(--accent);
  border-radius: 6px; background: #fff; color: var(--accent);
  font-size: 15px; cursor: pointer;
}
.gc-mark-btn.learned { background: var(--success-light); color: var(--success); border-color: var(--success); }

/* ===== Vocab Grid ===== */
.vocab-grid { display: flex; flex-direction: column; gap: 4px; }
.vocab-row {
  display: grid;
  grid-template-columns: 120px 120px 1fr;
  gap: 8px;
  padding: 8px 12px;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 6px;
  font-size: 14px;
  align-items: center;
}
.vocab-row:nth-child(even) { background: #fafbfc; }
.vr-word { font-weight: 700; font-size: 16px; }
.vr-reading { color: var(--accent); font-size: 13px; }
.vr-meaning { color: var(--ink2); }

/* ===== Result ===== */
.result-stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
  margin: 16px 0;
}

/* ===== Responsive ===== */
@media (max-width: 640px) {
  .nav-links a { padding: 6px 10px; font-size: 13px; }
  .filter-bar { flex-direction: column; }
  .filter-actions { margin-left: 0; }
  .stats-overview { grid-template-columns: 1fr; }
  .vocab-list { columns: 1; }
  .section-grid { grid-template-columns: 1fr 1fr; }
  .exam-list { grid-template-columns: 1fr; }
}