/* ===== Reset & Base ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --primary: #0891b2;
  --primary-dark: #0e7490;
  --primary-light: #e0f7fa;
  --success: #16a34a;
  --success-light: #dcfce7;
  --danger: #dc2626;
  --danger-light: #fee2e2;
  --warning: #d97706;
  --warning-light: #fef3c7;
  --bg: #f0f9ff;
  --surface: #ffffff;
  --surface2: #f8fafc;
  --border: #e2e8f0;
  --text: #0f172a;
  --text-muted: #64748b;
  --radius: 12px;
  --shadow: 0 2px 12px rgba(8,145,178,0.10);
  --shadow-lg: 0 8px 32px rgba(8,145,178,0.18);
}

body {
  font-family: 'Segoe UI', 'Hiragino Sans', 'Meiryo', sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
}

/* ===== Header ===== */
header {
  background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
  color: #fff;
  padding: 24px 0 20px;
  text-align: center;
  box-shadow: 0 2px 16px rgba(8,145,178,0.25);
}
.header-inner h1 { font-size: 2rem; font-weight: 700; letter-spacing: 0.05em; }
.header-inner .subtitle { font-size: 0.95rem; opacity: 0.82; margin-top: 4px; }

/* ===== Tabs ===== */
.tabs {
  display: flex;
  justify-content: center;
  gap: 0;
  background: var(--surface);
  border-bottom: 2px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: 0 2px 8px rgba(0,0,0,0.06);
}
.tab-btn {
  flex: 1;
  max-width: 180px;
  padding: 14px 8px;
  border: none;
  background: none;
  cursor: pointer;
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--text-muted);
  border-bottom: 3px solid transparent;
  transition: color 0.2s, border-color 0.2s, background 0.2s;
}
.tab-btn:hover { background: var(--primary-light); color: var(--primary); }
.tab-btn.active { color: var(--primary); border-bottom-color: var(--primary); font-weight: 700; }

/* ===== Tab Content ===== */
.tab-content { display: none; max-width: 960px; margin: 0 auto; padding: 28px 16px 48px; }
.tab-content.active { display: block; }

/* ===== Buttons ===== */
button { cursor: pointer; border: none; border-radius: 8px; font-size: 0.9rem; font-weight: 600; transition: background 0.18s, transform 0.1s, box-shadow 0.18s; }
button:active { transform: scale(0.97); }

.btn-primary { background: var(--primary); color: #fff; padding: 9px 20px; }
.btn-primary:hover { background: var(--primary-dark); box-shadow: 0 2px 8px rgba(8,145,178,0.3); }

.btn-secondary { background: var(--surface); color: var(--text); padding: 9px 20px; border: 1.5px solid var(--border); }
.btn-secondary:hover { background: var(--surface2); }

.btn-success { background: var(--success); color: #fff; padding: 9px 20px; }
.btn-success:hover { background: #15803d; box-shadow: 0 2px 8px rgba(22,163,74,0.3); }

.btn-danger { background: var(--danger); color: #fff; padding: 9px 20px; }
.btn-danger:hover { background: #b91c1c; box-shadow: 0 2px 8px rgba(220,38,38,0.3); }

.btn-icon { background: none; border: none; padding: 4px 8px; border-radius: 6px; font-size: 1rem; }
.btn-icon:hover { background: var(--surface2); }

.btn-lg { padding: 13px 36px; font-size: 1.05rem; border-radius: 10px; }

/* ===== 単語帳 ===== */
.toolbar {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  align-items: center;
  margin-bottom: 18px;
}
.toolbar input[type="text"] {
  flex: 1;
  min-width: 180px;
  padding: 9px 14px;
  border: 1.5px solid var(--border);
  border-radius: 8px;
  font-size: 0.9rem;
  outline: none;
  transition: border-color 0.2s;
}
.toolbar input[type="text"]:focus { border-color: var(--primary); }
.toolbar select {
  padding: 9px 12px;
  border: 1.5px solid var(--border);
  border-radius: 8px;
  font-size: 0.9rem;
  outline: none;
  background: var(--surface);
  cursor: pointer;
}
.toolbar select:focus { border-color: var(--primary); }

.table-wrap {
  background: var(--surface);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  overflow: hidden;
}
table { width: 100%; border-collapse: collapse; }
thead th {
  background: var(--primary);
  color: #fff;
  padding: 12px 14px;
  text-align: left;
  font-size: 0.88rem;
  font-weight: 600;
  white-space: nowrap;
}
tbody tr { border-bottom: 1px solid var(--border); transition: background 0.15s; }
tbody tr:last-child { border-bottom: none; }
tbody tr:hover { background: var(--primary-light); }
tbody td { padding: 11px 14px; font-size: 0.9rem; vertical-align: middle; }

.mastered-badge {
  display: inline-block;
  background: var(--success-light);
  color: var(--success);
  border-radius: 20px;
  padding: 2px 10px;
  font-size: 0.78rem;
  font-weight: 700;
}
.unmastered-badge {
  display: inline-block;
  background: var(--border);
  color: var(--text-muted);
  border-radius: 20px;
  padding: 2px 10px;
  font-size: 0.78rem;
}
.action-btns { display: flex; gap: 6px; }
.btn-edit { background: var(--warning-light); color: var(--warning); border-radius: 6px; padding: 5px 10px; font-size: 0.82rem; }
.btn-edit:hover { background: #fde68a; }
.btn-del { background: var(--danger-light); color: var(--danger); border-radius: 6px; padding: 5px 10px; font-size: 0.82rem; }
.btn-del:hover { background: #fca5a5; }
.text-ellipsis { max-width: 180px; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.empty-msg { text-align: center; color: var(--text-muted); padding: 32px 16px; font-size: 0.95rem; }

/* ===== フラッシュカード ===== */
.fc-controls {
  display: flex;
  align-items: center;
  gap: 18px;
  flex-wrap: wrap;
  margin-bottom: 14px;
}
.fc-controls label { display: flex; align-items: center; gap: 6px; cursor: pointer; font-size: 0.95rem; }
.fc-controls input[type="radio"] { accent-color: var(--primary); }

.fc-progress-wrap { text-align: center; font-size: 0.92rem; color: var(--text-muted); margin-bottom: 10px; }

#fc-area {
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 280px;
  margin: 0 auto;
  max-width: 560px;
}

/* CSS 3D Flip */
.card {
  perspective: 1000px;
  width: 100%;
  height: 260px;
  cursor: pointer;
  user-select: none;
}
.card-inner {
  position: relative;
  width: 100%;
  height: 100%;
  transition: transform 0.6s cubic-bezier(.4,0,.2,1);
  transform-style: preserve-3d;
}
.card-inner.flipped { transform: rotateY(180deg); }
.card-front, .card-back {
  backface-visibility: hidden;
  position: absolute;
  width: 100%;
  height: 100%;
  border-radius: var(--radius);
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  padding: 28px;
  box-shadow: var(--shadow-lg);
  text-align: center;
}
.card-front {
  background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
  color: #fff;
}
.card-back {
  transform: rotateY(180deg);
  background: var(--surface);
  border: 2px solid var(--primary-light);
  color: var(--text);
}
.card-hint {
  font-size: 0.78rem;
  opacity: 0.72;
  margin-bottom: 12px;
  letter-spacing: 0.04em;
}
.card-word {
  font-size: 2.4rem;
  font-weight: 700;
  letter-spacing: 0.03em;
  line-height: 1.2;
}
.card-back .card-word { color: var(--primary-dark); font-size: 2rem; }
.card-example {
  margin-top: 12px;
  font-size: 0.82rem;
  color: var(--text-muted);
  font-style: italic;
  max-width: 100%;
}
.card-note { font-size: 0.8rem; color: var(--text-muted); margin-top: 6px; }

.fc-actions {
  display: flex;
  justify-content: center;
  gap: 16px;
  margin-top: 22px;
  flex-wrap: wrap;
}
.fc-nav {
  display: flex;
  justify-content: center;
  gap: 16px;
  margin-top: 14px;
}

/* ===== クイズ ===== */
.quiz-screen { max-width: 600px; margin: 0 auto; }

#quiz-start-screen { text-align: center; padding: 32px 16px; }
#quiz-start-screen h2 { font-size: 1.7rem; color: var(--primary-dark); margin-bottom: 10px; }
#quiz-start-screen p { color: var(--text-muted); margin-bottom: 24px; }
.quiz-setting { margin-bottom: 28px; font-size: 0.95rem; }
.quiz-setting select { margin-left: 8px; padding: 6px 10px; border: 1.5px solid var(--border); border-radius: 8px; font-size: 0.95rem; }

.quiz-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  background: var(--surface);
  border-radius: 10px;
  padding: 10px 18px;
  margin-bottom: 20px;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-muted);
  box-shadow: var(--shadow);
}
.quiz-question-box {
  background: var(--surface);
  border-radius: var(--radius);
  padding: 28px 24px 20px;
  box-shadow: var(--shadow);
  text-align: center;
  margin-bottom: 20px;
}
.quiz-label { font-size: 0.82rem; color: var(--text-muted); margin-bottom: 8px; letter-spacing: 0.04em; }
.quiz-word { font-size: 2.6rem; font-weight: 700; color: var(--primary-dark); margin-bottom: 8px; }
.quiz-example-hint { font-size: 0.82rem; color: var(--text-muted); font-style: italic; }

.quiz-options {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  margin-bottom: 14px;
}
.quiz-option {
  background: var(--surface);
  border: 2px solid var(--border);
  border-radius: 10px;
  padding: 16px 14px;
  font-size: 1.05rem;
  font-weight: 600;
  text-align: center;
  cursor: pointer;
  transition: background 0.18s, border-color 0.18s, transform 0.12s;
}
.quiz-option:hover:not(:disabled) { background: var(--primary-light); border-color: var(--primary); }
.quiz-option.correct { background: var(--success-light); border-color: var(--success); color: var(--success); }
.quiz-option.wrong { background: var(--danger-light); border-color: var(--danger); color: var(--danger); }
.quiz-option:disabled { cursor: default; }

.quiz-feedback {
  text-align: center;
  padding: 10px;
  border-radius: 8px;
  font-weight: 700;
  font-size: 1rem;
  margin-bottom: 4px;
}
.quiz-feedback.correct { background: var(--success-light); color: var(--success); }
.quiz-feedback.wrong { background: var(--danger-light); color: var(--danger); }

#quiz-result-screen { text-align: center; padding: 32px 16px; }
#quiz-result-screen h2 { font-size: 1.7rem; color: var(--primary-dark); margin-bottom: 24px; }
.result-score-box {
  background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
  color: #fff;
  border-radius: 50%;
  width: 150px;
  height: 150px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  margin: 0 auto 24px;
  box-shadow: var(--shadow-lg);
}
.result-score-num { font-size: 2.4rem; font-weight: 700; }
.result-score-label { font-size: 0.88rem; opacity: 0.85; }
.result-details { color: var(--text-muted); font-size: 0.95rem; margin-bottom: 28px; }
#quiz-result-screen .btn-primary, #quiz-result-screen .btn-secondary { margin: 0 6px; }

/* ===== 統計 ===== */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  gap: 14px;
  margin-bottom: 28px;
}
.stat-card {
  background: var(--surface);
  border-radius: var(--radius);
  padding: 22px 16px;
  text-align: center;
  box-shadow: var(--shadow);
  border-top: 4px solid var(--primary);
}
.stat-num { font-size: 2rem; font-weight: 700; color: var(--primary-dark); }
.stat-label { font-size: 0.82rem; color: var(--text-muted); margin-top: 4px; }

.stats-chart-section, .stats-history-section {
  background: var(--surface);
  border-radius: var(--radius);
  padding: 22px 24px;
  margin-bottom: 18px;
  box-shadow: var(--shadow);
}
.stats-chart-section h3, .stats-history-section h3 {
  font-size: 1rem;
  font-weight: 700;
  color: var(--primary-dark);
  margin-bottom: 18px;
}

/* Donut Chart (pure CSS) */
.donut-wrap { display: flex; align-items: center; gap: 32px; flex-wrap: wrap; }
.donut {
  width: 140px;
  height: 140px;
  border-radius: 50%;
  background: conic-gradient(var(--primary) 0% 0%, var(--border) 0% 100%);
  position: relative;
  flex-shrink: 0;
}
.donut::after {
  content: '';
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%,-50%);
  width: 72px;
  height: 72px;
  background: var(--surface);
  border-radius: 50%;
}
.donut-legend { font-size: 0.9rem; color: var(--text-muted); }
.legend-dot {
  display: inline-block;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  margin-right: 6px;
  vertical-align: middle;
}
.mastered-dot { background: var(--primary); }
.unmastered-dot { background: var(--border); }
.donut-legend span + span { margin-left: 16px; }

.history-list { list-style: none; }
.history-list li {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 10px 0;
  border-bottom: 1px solid var(--border);
  font-size: 0.9rem;
}
.history-list li:last-child { border-bottom: none; }
.history-score { font-weight: 700; color: var(--primary-dark); }
.history-date { color: var(--text-muted); font-size: 0.82rem; }

/* ===== Modal ===== */
.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(15,23,42,0.45);
  z-index: 1000;
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 16px;
  animation: fadeIn 0.15s ease;
}
@keyframes fadeIn { from { opacity: 0; } to { opacity: 1; } }

.modal-box {
  background: var(--surface);
  border-radius: 16px;
  padding: 32px 28px;
  width: 100%;
  max-width: 480px;
  box-shadow: 0 20px 60px rgba(0,0,0,0.2);
  animation: slideUp 0.2s ease;
}
.modal-sm { max-width: 360px; }
@keyframes slideUp { from { transform: translateY(24px); opacity: 0; } to { transform: translateY(0); opacity: 1; } }

.modal-box h2 { font-size: 1.2rem; font-weight: 700; color: var(--primary-dark); margin-bottom: 20px; }
.form-group { margin-bottom: 14px; }
.form-group label { display: block; font-size: 0.85rem; font-weight: 600; margin-bottom: 5px; color: var(--text-muted); }
.form-group input[type="text"] {
  width: 100%;
  padding: 9px 12px;
  border: 1.5px solid var(--border);
  border-radius: 8px;
  font-size: 0.95rem;
  outline: none;
  transition: border-color 0.2s;
}
.form-group input[type="text"]:focus { border-color: var(--primary); }
.checkbox-group label { display: flex; align-items: center; gap: 8px; font-size: 0.92rem; color: var(--text); cursor: pointer; }
.checkbox-group input[type="checkbox"] { accent-color: var(--primary); width: 16px; height: 16px; }
.required { color: var(--danger); }
.optional { color: var(--text-muted); font-weight: 400; }
.form-actions { display: flex; gap: 10px; margin-top: 20px; }
.form-actions button { flex: 1; }
.delete-word-label { font-size: 1.1rem; font-weight: 700; color: var(--danger); text-align: center; margin-bottom: 20px; }

/* ===== 単語集インポート ===== */
.btn-set {
  padding: 8px 16px;
  background: #fef3c7;
  color: #92400e;
  border: 1.5px solid #fcd34d;
  border-radius: var(--radius-sm);
  font-size: 0.88rem;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.15s;
  white-space: nowrap;
}
.btn-set:hover { background: #fde68a; }

.modal-import { max-width: 680px; width: 95vw; max-height: 90vh; overflow-y: auto; }

.import-desc { color: var(--text-muted); margin-bottom: 20px; }

.level-cards {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
  margin-bottom: 16px;
}
.level-card {
  border: 2px solid var(--border);
  border-radius: var(--radius);
  padding: 16px 12px;
  cursor: pointer;
  text-align: center;
  transition: border-color 0.15s, box-shadow 0.15s;
}
.level-card:hover { border-color: #94a3b8; box-shadow: 0 2px 8px rgba(0,0,0,0.08); }
.level-card.selected { border-color: var(--primary); box-shadow: 0 0 0 3px rgba(8,145,178,0.15); }
.level-badge {
  display: inline-block;
  color: white;
  font-size: 12px;
  font-weight: 700;
  padding: 2px 10px;
  border-radius: 20px;
  margin-bottom: 8px;
}
.level-title { font-size: 0.95rem; font-weight: 700; margin-bottom: 6px; }
.level-info { font-size: 0.78rem; color: var(--text-muted); line-height: 1.6; margin-bottom: 6px; }
.level-count { font-size: 0.85rem; font-weight: 700; color: var(--primary); }

.import-mode-row {
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 10px 14px;
  background: #f8fafc;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
  margin-bottom: 14px;
  flex-wrap: wrap;
}
.import-mode-label { font-size: 0.85rem; font-weight: 600; color: var(--text-muted); white-space: nowrap; }
.radio-label-import {
  display: flex;
  align-items: center;
  gap: 5px;
  font-size: 0.88rem;
  cursor: pointer;
}

.import-preview { border: 1px solid var(--border); border-radius: var(--radius-sm); overflow: hidden; margin-bottom: 4px; }
.import-preview-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 8px 12px;
  background: #f1f5f9;
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--text-muted);
}
.import-preview-list { max-height: 200px; overflow-y: auto; }
.preview-word-row {
  display: flex;
  gap: 10px;
  padding: 6px 12px;
  border-bottom: 1px solid #f1f5f9;
  font-size: 0.85rem;
  align-items: center;
}
.preview-word-row:last-child { border-bottom: none; }
.preview-en { font-weight: 700; min-width: 110px; color: var(--text); }
.preview-jp { min-width: 120px; color: #1e40af; }
.preview-note { font-size: 0.78rem; color: var(--text-muted); }
.preview-more { padding: 8px 12px; font-size: 0.82rem; color: var(--text-muted); font-style: italic; }

/* ===== Responsive ===== */
@media (max-width: 600px) {
  .header-inner h1 { font-size: 1.4rem; }
  .tab-btn { font-size: 0.8rem; padding: 12px 4px; }
  .quiz-options { grid-template-columns: 1fr; }
  .card-word { font-size: 1.8rem; }
  .card-back .card-word { font-size: 1.5rem; }
  thead th:nth-child(3), tbody td:nth-child(3),
  thead th:nth-child(4), tbody td:nth-child(4) { display: none; }
}

/* ===== 関連ツールセクション ===== */
.related-tools {
  margin: 3rem auto;
  padding: 1.5rem;
  max-width: 900px;
  background: var(--surface);
  border-radius: 12px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.08);
  text-align: center;
}
.related-tools h2 { font-size: 1.4rem; margin-bottom: 0.8rem; color: var(--primary); }
.related-tools p { color: var(--text-muted); margin-bottom: 1rem; }
.tool-links { display: flex; flex-wrap: wrap; justify-content: center; gap: 1rem; margin-bottom: 1rem; }
.tool-card {
  display: inline-block; padding: 0.8rem 1.2rem;
  background: var(--primary-light); border: 1px solid var(--primary);
  border-radius: 10px; text-decoration: none; color: var(--primary);
  font-weight: 500; transition: all 0.2s;
}
.tool-card:hover { background: var(--primary); color: #fff; transform: translateY(-2px); }
.more-tools a { color: var(--primary); text-decoration: none; }
.more-tools a:hover { text-decoration: underline; }
footer {
  text-align: center; padding: 1.5rem 0;
  background-color: #f1f5f9; color: #555;
  font-size: 0.9rem; border-top: 1px solid #e2e8f0; margin-top: 2rem;
}
.footer-nav a { color: var(--primary); text-decoration: none; margin: 0 0.5rem; }
.footer-nav a:hover { text-decoration: underline; }