.professors-section {
    padding: 2rem 0 4rem;
    background-color: var(--color-bg);
    min-height: calc(100vh - 80px);
}

.professors-section h1 {
    text-align: center;
    font-size: 2.5rem;
    color: #2d3748;
    margin-bottom: 0.5rem;
}

.section-subtitle {
    text-align: center;
    font-size: 1.2rem;
    color: #64748b;
    margin-bottom: 3rem;
}

.field-category {
    padding: 2rem;
    background-color: #fff;
    border-radius: 20px;
    box-shadow: 0 4px 14px rgba(0,0,0,0.05);
    border: 1px solid #e5e7eb;
    margin-bottom: 2rem;
    position: relative;
    cursor: pointer;
    transition: box-shadow 0.2s ease, transform 0.15s ease;
    scroll-margin-top: 175px; /* ensure space for main nav + sub-nav */
    overflow: hidden; /* clip top accent bar within rounded corners */
}

/* Centered, slightly shorter accent bar */
.field-category::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    width: 100%;
    transform: none;
    background: var(--color-light-grey);
}

/* Slight grow on hover like category cards */
.field-category:hover::before {
    height: 6px;
}

.field-category:hover {
    box-shadow: 0 6px 20px rgba(0,0,0,0.08);
    transform: translateY(-2px);
}

.cat-title {
    font-size: 1.6rem;
    font-weight: 600;
    color: var(--color-text-primary);
    margin: 0;
}

.cat-toggle {
    display: flex;
    align-items: center;
    gap: 0.4rem;
    margin-left: auto;
}

.field-category .toggle-icon {
    transform: rotate(90deg); /* expanded */
}

.field-category.collapsed .toggle-icon {
    transform: rotate(0deg); /* collapsed right */
}

.hint {
    font-size: 0.88rem;
    color: var(--color-text-secondary);
}

.professors-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 1.5rem;
}

.professor-card {
    background: #ffffff;
    border-radius: 12px;
    padding: 1.5rem;
    box-shadow: 0 2px 8px rgba(0,0,0,0.08);
    border: 1px solid #e2e8f0;
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

/* Remove accent bar from each professor card for cleaner design */
.professor-card::before {
    content: none;
}

.professor-card:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 25px rgba(0,0,0,0.15);
}

.professor-image {
    text-align: center;
    margin-bottom: 1rem;
}

.professor-image img {
    width: 110px;
    height: 110px;
    border-radius: 50%;
    object-fit: cover;
    border: 4px solid #e2e8f0;
}

.professor-info h3 {
    font-size: 1.3rem;
    color: #2d3748;
    margin-bottom: 0.5rem;
    text-align: center;
}

.professor-info .affiliation {
    color: #4f46e5;
    font-weight: 600;
    text-align: center;
    margin-bottom: 0.8rem;
}

.professor-info .research-area {
    color: #64748b;
    margin-bottom: 0.5rem;
    line-height: 1.5;
}

.professor-info .email {
    color: #059669;
    font-size: 0.9rem;
    margin-bottom: 1rem;
}

.research-interests {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    justify-content: center;
}

.tag {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 0.3rem 0.8rem;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 500;
}

/* User Info */
.user-info {
    color: white;
    font-weight: 500;
    margin-right: 1rem;
}

/* 반응형 디자인 */
@media (max-width: 768px) {
    .professors-grid {
        grid-template-columns: 1fr;
    }
    
    .field-category {
        margin: 0 1rem 2rem;
        padding: 1.5rem;
    }
    
    .professors-section h1 {
        font-size: 2rem;
    }
    
    .field-category h2 {
        font-size: 1.5rem;
    }

    .nav-buttons {
        flex-direction: column;
        gap: 5px;
        align-items: flex-end;
    }

    .user-info {
        margin-right: 0;
        margin-bottom: 0.5rem;
        font-size: 0.9rem;
    }

    /* no offsets needed thanks to overflow clipping */
}

@media (max-width: 480px) {
    .professor-card {
        padding: 1rem;
    }
    
    .research-interests {
        justify-content: flex-start;
    }
    
    .tag {
        font-size: 0.75rem;
        padding: 0.25rem 0.6rem;
    }
}

.professor-card .research-tags .badge {
    font-weight: 500;
    padding: 0.4em 0.7em;
}

/* Category Section Styling */
.field-category {
    padding: 2rem;
    background-color: #fff;
    border-radius: 20px;
    box-shadow: 0 4px 14px rgba(0,0,0,0.05);
    border: 1px solid #e5e7eb;
    margin-bottom: 2rem;
}

.field-category::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 4px;
    background: var(--color-light-grey);
    border-top-left-radius: 20px;
    border-top-right-radius: 20px;
}

.field-category.digital-ai-sw::before,
.field-category.drug-design-discovery::before,
.field-category.drug-delivery::before {
    background: var(--color-accent);
    opacity: 0.6;
}

/* Match gradient style */
.field-category.digital-ai-sw::before {background:linear-gradient(90deg,#3b82f6,#1d4ed8);}/* blue */
.field-category.drug-design-discovery::before {background:linear-gradient(90deg,#10b981,#059669);}/* green */
.field-category.drug-delivery::before {background:linear-gradient(90deg,#f59e0b,#d97706);}/* orange */

.cat-emoji {
    font-size:1.75rem;
    margin-right:0.5rem;
}

/* --- custom overrides added 2025-06-14 --- */
.contact-buttons .btn {
    font-size: 0.8rem;
    padding: 0.25rem 0.75rem;
}
.btn-outline-secondary {
    color: #0d6efd;
    border-color: #0d6efd;
}
.btn-outline-secondary:hover {
    color: #fff;
    background-color: #0d6efd;
}
.career-list {
    max-height: 220px;
    overflow-y: auto;
}
.career-list li {
    font-size: 0.85rem;
    margin-bottom: 0.25rem;
    color: #334155;
}

.mentoring-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.4rem 0.5rem;
}

.mentoring-tags .badge {
    font-weight: 500;
    white-space: normal;
    line-height: 1.35;
}

.cat-count {
    background-color: #d1d1d6;
    color: var(--color-text-primary);
    padding: 0.35rem 0.75rem;
    border-radius: 6px;
    font-weight: 600;
    font-size: 0.9rem;
    margin-left: 0.75rem;
    display: inline-block;
}

/* === Category Layout === */
.cat-header {
    display: flex;
    align-items: center;
    gap: 0.4rem;
    cursor: pointer;
}
.cat-header .hint {
    margin-left: auto;
    font-size: 0.9rem;
    color: var(--color-text-secondary);
}
.cat-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-top: 1px solid #e3e5e7;
    padding-top: 0.75rem;
    margin-top: 0.75rem;
}
.cat-desc {
    font-size: 1rem;
    color: var(--color-text-secondary);
}
.cat-meta .cat-count {
    background-color: #d1d1d6;
    color: var(--color-text-primary);
    padding: 0.35rem 0.75rem;
    border-radius: 6px;
    font-weight: 600;
}