:root {
  /* 무채색 그라데이션 */
  --primary-gradient: linear-gradient(135deg, #1a1a1a 0%, #404040 100%);
  --secondary-gradient: linear-gradient(135deg, #2d2d2d 0%, #4a4a4a 100%);
  --accent-gradient: linear-gradient(135deg, #333333 0%, #5a5a5a 100%);
  --light-gradient: linear-gradient(135deg, #e8e8e8 0%, #f5f5f5 100%);
  
  /* 텍스트 컬러 */
  --text-dark: #1a1a1a;
  --text-medium: #333333;
  --text-light: #666666;
  --text-muted: #999999;
  --white: #ffffff;
  --light-bg: #f8f9fa;
  --medium-bg: #f0f0f0;
  
  --shadow-light: 0 5px 15px rgba(0, 0, 0, 0.08);
  --shadow-medium: 0 10px 40px rgba(0, 0, 0, 0.12);
  --shadow-heavy: 0 20px 60px rgba(0, 0, 0, 0.2);
  
  --border-radius: 12px;
  --transition: all 0.3s ease;
}

/* ===== timeline (fragment에 포함) ===== */
.timeline-year {
  font-size: 2rem;
  font-weight: 700;
  color: var(--text-medium);
  margin: 40px 0 25px 0;
  padding-bottom: 15px;
  border-bottom: 3px solid var(--medium-bg);
}
.timeline-year:first-child { margin-top: 0; }

/* ===== certification item (fragment: certItem) ===== */
.certification-item {
  background: var(--white);
  border: 2px solid var(--medium-bg);
  border-radius: var(--border-radius);
  padding: 35px;
  margin-bottom: 20px;
  transition: var(--transition);
  position: relative;
  display: flex;
  align-items: flex-start;
  gap: 25px;
}
.certification-item:hover {
  box-shadow: var(--shadow-medium);
  transform: translateY(-3px);
  border-color: var(--text-muted);
}

.certification-image {
  flex-shrink: 0;
  width: 120px;
  height: 160px;
  border-radius: 8px;
  overflow: hidden;
  border: 1px solid var(--medium-bg);
  cursor: pointer;
  transition: var(--transition);
}
.certification-image:hover { transform: scale(1.05); }
.certification-image img {
  width: 100%; height: 100%; object-fit: cover;
}

.certification-content { flex: 1; min-width: 0; }
.certification-date {
  color: var(--text-light); font-size: 1.1rem; font-weight: 600; margin-bottom: 12px;
}
.certification-title {
  font-size: 1.4rem; font-weight: 700; color: var(--text-medium);
  margin-bottom: 12px; line-height: 1.4;
}
.certification-organization {
  color: var(--text-light); font-size: 1.1rem; font-weight: 500; margin-bottom: 0;
}

.certification-category {
  position: absolute; top: -10px; right: 25px;
  background: var(--text-medium); color: var(--white); padding: 8px 16px;
  border-radius: 16px; font-size: .9rem; font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

/* 카테고리별 배지 색상 */
.certification-category.badge-cert {
  background: var(--primary-gradient);
  color: var(--white);
}

.certification-category.badge-patent {
  background: var(--secondary-gradient);
  color: var(--white);
}

/* ===== image modal (fragment: image-modal) ===== */
.modal-backdrop { background-color: rgba(0,0,0,.8); }

.modal-dialog { max-width: 90%; margin: 30px auto; }
.modal-content { border: none; border-radius: 12px; }
.modal-header { border-bottom: 1px solid var(--medium-bg); padding: 20px 25px; }
.modal-title { font-size: 1.2rem; font-weight: 700; color: var(--text-medium); }
.modal-body { padding: 25px; text-align: center; }
.modal-image {
  max-width: 100%; max-height: 70vh; border-radius: 8px;
  box-shadow: var(--shadow-light);
}

/* ===== responsive (컴포넌트 관련만 추림) ===== */
@media (max-width: 768px) {
  .timeline-year { font-size: 1.7rem; }

  .certification-item {
    padding: 25px 20px;
    flex-direction: column; align-items: center; text-align: center; gap: 20px;
  }
  .certification-image { width: 100px; height: 130px; }
  .certification-content { width: 100%; }

  .certification-title { font-size: 1.25rem; }
  .certification-date { font-size: 1rem; }
  .certification-organization { font-size: 1rem; }

  .certification-category {
    font-size: .85rem; padding: 6px 14px; top: -8px; right: 20px;
  }

  .modal-dialog { margin: 15px; max-width: calc(100% - 30px); }
  .modal-header, .modal-body { padding: 15px 20px; }
}