/* CTF section */
  .ctf-locked-preview {
    padding: 20px 24px;
    background: var(--bg-elev);
    border: 1px dashed var(--border);
    border-radius: var(--radius);
    text-align: center;
  }
  .ctf-locked-title {
    font-family: var(--font-display);
    font-size: 15px;
    color: var(--text-secondary);
    margin-bottom: 6px;
    letter-spacing: -0.01em;
  }
  .ctf-locked-sub {
    font-size: 12px;
    color: var(--text-muted);
    line-height: 1.6;
    margin-bottom: 10px;
  }
  .ctf-locked-progress {
    font-family: var(--font-mono);
    font-size: 11px;
    color: var(--text-muted);
    letter-spacing: 0.04em;
  }
  .section-title-line {
    display: flex;
    justify-content: space-between;
    align-items: baseline;
    margin-bottom: 8px;
  }
  .section-title-main {
    font-family: var(--font-display);
    font-size: 16px;
    color: var(--text-primary);
    letter-spacing: -0.01em;
  }
  .section-title-sub {
    font-size: 11px;
    color: var(--text-muted);
    font-family: var(--font-mono);
  }
  .ctf-tip {
    padding: 12px 14px;
    background: rgba(163, 217, 192, 0.05);
    border-left: 3px solid var(--success);
    border-radius: 4px;
    font-size: 12px;
    line-height: 1.6;
    color: var(--text-secondary);
    margin: 12px 0 16px;
  }
  .ctf-tip strong { color: var(--text-primary); }
  .ctf-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 12px;
  }
  .ctf-card {
    display: block;
    padding: 16px 18px;
    background: var(--bg-elev);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    text-decoration: none;
    color: var(--text-primary);
    transition: all 0.15s;
  }
  .ctf-card:hover {
    border-color: var(--accent);
    transform: translateY(-1px);
  }
  .ctf-card-header {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 8px;
  }
  .ctf-card-icon {
    font-size: 20px;
    flex-shrink: 0;
  }
  .ctf-card-title {
    font-family: var(--font-display);
    font-size: 14px;
    color: var(--text-primary);
    letter-spacing: -0.01em;
  }
  .ctf-card-level {
    font-family: var(--font-mono);
    font-size: 10px;
    color: var(--text-muted);
    letter-spacing: 0.04em;
    margin-top: 2px;
  }
  .ctf-card-badge {
    margin-left: auto;
    padding: 2px 8px;
    background: rgba(163, 217, 192, 0.12);
    color: var(--success);
    border-radius: 3px;
    font-size: 10px;
    font-family: var(--font-mono);
    letter-spacing: 0.03em;
  }
  .ctf-card-desc {
    font-size: 12px;
    color: var(--text-secondary);
    line-height: 1.55;
  }

  /* Flashcards & Review System */
  .review-card {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 16px 20px;
    background: linear-gradient(135deg, rgba(163, 217, 192, 0.06), rgba(163, 217, 192, 0.02));
    border: 1px solid rgba(163, 217, 192, 0.25);
    border-radius: var(--radius);
    margin-bottom: 20px;
    cursor: pointer;
    transition: all 0.15s;
  }
  .review-card:hover {
    border-color: var(--success);
    transform: translateY(-1px);
  }
  .review-card-info { display: flex; align-items: center; gap: 14px; }
  .review-card-icon { font-size: 24px; }
  .review-card-title {
    font-family: var(--font-display);
    font-size: 15px;
    color: var(--text-primary);
    letter-spacing: -0.01em;
  }
  .review-card-sub {
    font-size: 11px;
    color: var(--text-muted);
    font-family: var(--font-mono);
    margin-top: 2px;
  }
  .review-card-count {
    padding: 6px 14px;
    background: var(--success);
    color: var(--bg);
    border-radius: 4px;
    font-family: var(--font-mono);
    font-size: 12px;
    font-weight: 500;
  }
  /* Flashcard modal */
  .flashcard-body {
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 40px 20px;
    min-height: 400px;
  }
  .flashcard-progress {
    font-family: var(--font-mono);
    font-size: 11px;
    color: var(--text-muted);
    letter-spacing: 0.04em;
    margin-bottom: 24px;
  }
  .flashcard-progress-bar {
    width: 100%;
    max-width: 500px;
    height: 3px;
    background: var(--border);
    border-radius: 2px;
    overflow: hidden;
    margin-bottom: 32px;
  }
  .flashcard-progress-fill {
    height: 100%;
    background: var(--accent);
    transition: width 0.3s ease;
  }
  .flashcard {
    width: 100%;
    max-width: 640px;
    padding: 36px 32px;
    background: var(--bg-elev);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    text-align: center;
    margin-bottom: 24px;
    min-height: 200px;
    display: flex;
    flex-direction: column;
    justify-content: center;
  }
  .flashcard-question {
    font-size: 20px;
    line-height: 1.5;
    color: var(--text-primary);
    font-weight: 400;
  }
  .flashcard-answer {
    font-size: 18px;
    line-height: 1.55;
    color: var(--accent);
    font-weight: 400;
    margin-top: 20px;
    padding-top: 20px;
    border-top: 1px solid var(--border);
  }
  .flashcard-hint {
    font-family: var(--font-mono);
    font-size: 11px;
    color: var(--text-muted);
    margin-top: 24px;
    letter-spacing: 0.04em;
  }
  .flashcard-rating {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 8px;
    width: 100%;
    max-width: 640px;
  }
  .flashcard-rating-btn {
    padding: 12px 16px;
    background: transparent;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    color: var(--text-primary);
    font-family: var(--font-display);
    font-size: 13px;
    cursor: pointer;
    transition: all 0.15s;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 4px;
  }
  .flashcard-rating-btn:hover { transform: translateY(-1px); }
  .flashcard-rating-btn .interval {
    font-family: var(--font-mono);
    font-size: 10px;
    color: var(--text-muted);
    letter-spacing: 0.04em;
  }
  .flashcard-rating-btn.again { border-color: var(--danger); color: var(--danger); }
  .flashcard-rating-btn.hard { border-color: var(--warning); color: var(--warning); }
  .flashcard-rating-btn.good { border-color: var(--accent); color: var(--accent); }
  .flashcard-rating-btn.easy { border-color: var(--success); color: var(--success); }
  .flashcard-empty {
    text-align: center;
    padding: 60px 20px;
    color: var(--text-muted);
  }
  .flashcard-empty h3 {
    color: var(--text-primary);
    font-family: var(--font-display);
    font-size: 18px;
    margin-bottom: 12px;
  }
  /* Morning review */
  /* 저장 실패 · 파일 캐시 불일치 경고 (2026-08-02)
     학습 기록이 안 남는 상황이라 눈에 띄어야 한다. 닫기 버튼을 두지 않는다. */
  .save-error {
    padding: 16px 20px;
    background: rgba(217, 163, 163, 0.07);
    border: 1px solid rgba(217, 163, 163, 0.4);
    border-radius: var(--radius);
    margin-bottom: 20px;
  }
  .save-error-title {
    font-family: var(--font-display);
    font-size: 14px;
    color: var(--danger);
    margin-bottom: 6px;
  }
  .save-error-text {
    font-size: 12.5px;
    line-height: 1.65;
    color: var(--text-primary);
  }
  .save-error-detail {
    font-family: var(--font-mono);
    font-size: 11px;
    color: var(--text-muted);
  }
  .save-error-actions { margin-top: 12px; }

  /* 첫 실행 안내 배너 · 차단형 confirm 대체 (2026-08-02) */
  .setup-banner {
    padding: 18px 22px;
    background: rgba(163, 217, 192, 0.04);
    border: 1px solid rgba(163, 217, 192, 0.22);
    border-radius: var(--radius);
    margin-bottom: 20px;
    position: relative;
  }
  .setup-banner-close {
    position: absolute;
    top: 10px;
    right: 12px;
    background: transparent;
    border: none;
    color: var(--text-muted);
    font-size: 14px;
    cursor: pointer;
    padding: 4px 8px;
    line-height: 1;
  }
  .setup-banner-close:hover { color: var(--text-primary); }
  .setup-banner-title {
    font-family: var(--font-display);
    font-size: 14px;
    color: var(--success);
    letter-spacing: -0.01em;
    margin-bottom: 6px;
    padding-right: 28px;
  }
  .setup-banner-text {
    font-size: 12.5px;
    line-height: 1.6;
    color: var(--text-secondary);
    margin-bottom: 14px;
  }
  .setup-banner-actions {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
  }

  .morning-review {
    padding: 20px 24px;
    background: linear-gradient(135deg, rgba(255, 220, 130, 0.06), rgba(255, 220, 130, 0.02));
    border: 1px solid rgba(212, 183, 107, 0.25);
    border-radius: var(--radius);
    margin-bottom: 20px;
    position: relative;
  }
  .morning-review-close {
    position: absolute;
    top: 12px;
    right: 12px;
    background: transparent;
    border: none;
    color: var(--text-muted);
    font-size: 18px;
    cursor: pointer;
    padding: 4px 8px;
  }
  .morning-review-title {
    font-family: var(--font-display);
    font-size: 15px;
    color: var(--warning);
    letter-spacing: -0.01em;
    margin-bottom: 8px;
  }
  .morning-review-day {
    font-family: var(--font-mono);
    font-size: 11px;
    color: var(--text-muted);
    letter-spacing: 0.04em;
    margin-bottom: 12px;
  }
  .morning-review-content {
    font-size: 13px;
    line-height: 1.65;
    color: var(--text-primary);
  }
  .morning-review-content code {
    font-family: var(--font-mono);
    font-size: 11px;
    background: var(--bg);
    padding: 1px 6px;
    border-radius: 3px;
    color: var(--accent);
  }
  /* Quiz modal */
  .quiz-question-block {
    padding: 20px 22px;
    background: var(--bg-elev);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    margin-bottom: 16px;
  }
  .quiz-question-num {
    font-family: var(--font-mono);
    font-size: 10px;
    color: var(--text-muted);
    letter-spacing: 0.06em;
    margin-bottom: 6px;
  }
  .quiz-question-text {
    font-size: 14px;
    line-height: 1.6;
    color: var(--text-primary);
    margin-bottom: 12px;
  }
  .quiz-options { display: flex; flex-direction: column; gap: 6px; }
  .quiz-option {
    padding: 10px 14px;
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: 6px;
    cursor: pointer;
    font-size: 13px;
    transition: all 0.15s;
    text-align: left;
    color: var(--text-primary);
    font-family: inherit;
  }
  .quiz-option:hover { border-color: var(--accent); }
  .quiz-option.selected { border-color: var(--accent); background: rgba(163, 217, 192, 0.05); }
  .quiz-option.correct { border-color: var(--success); background: rgba(163, 217, 192, 0.1); color: var(--success); }
  .quiz-option.incorrect { border-color: var(--danger); background: rgba(217, 163, 163, 0.05); color: var(--danger); }
  .quiz-explanation {
    margin-top: 10px;
    padding: 10px 12px;
    background: var(--bg);
    border-left: 3px solid var(--accent);
    border-radius: 4px;
    font-size: 12px;
    color: var(--text-secondary);
    line-height: 1.6;
  }
  .quiz-result-summary {
    padding: 20px 24px;
    background: var(--bg-elev);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    text-align: center;
    margin-bottom: 16px;
  }
  .quiz-result-score {
    font-family: var(--font-display);
    font-size: 28px;
    color: var(--text-primary);
    letter-spacing: -0.02em;
    margin-bottom: 6px;
  }
  .quiz-result-message {
    font-size: 13px;
    color: var(--text-secondary);
  }