/* === 博士研究计划 === */
.research-proposal {
    margin-top: 2rem;
}

.proposal-card {
    background: var(--color-background);
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius-lg);
    padding: 2rem;
    box-shadow: var(--color-card-shadow);
    transition: var(--transition);
}

.proposal-card:hover {
    box-shadow: var(--color-card-shadow-hover);
    transform: translateY(-2px);
}

.proposal-card h4 {
    color: var(--color-primary);
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.proposal-title {
    font-size: 1.125rem;
    font-weight: 700;
    color: var(--color-heading);
    margin: 0.5rem 0 1rem 0;
    line-height: 1.5;
}

.proposal-desc {
    color: var(--color-text);
    line-height: 1.7;
    margin-bottom: 1.5rem;
}

.proposal-highlights {
    background: rgba(0, 120, 212, 0.03);
    border-left: 3px solid var(--color-primary);
    padding: 1.25rem;
    border-radius: 6px;
    margin: 1.5rem 0;
}

.highlight-row {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 0.875rem;
    line-height: 1.6;
}

.highlight-row:last-child {
    margin-bottom: 0;
}

.highlight-label {
    flex-shrink: 0;
    font-weight: 700;
    color: var(--color-primary);
    min-width: 100px;
}

.proposal-download {
    margin-top: 1.5rem;
    text-align: center;
}

.proposal-download .btn {
    padding: 0.75rem 1.5rem;
}

/* === 研究成果卡片链接按钮 === */
.card-link-btn {
    display: inline-block;
    margin-top: 1rem;
    padding: 0.5rem 1rem;
    background: var(--color-primary);
    color: white;
    text-decoration: none;
    border-radius: 6px;
    font-size: 0.875rem;
    font-weight: 600;
    transition: var(--transition);
}

.card-link-btn:hover {
    background: var(--color-primary-hover);
    transform: translateX(4px);
}

/* === 5列网格布局 === */
.grid-5 {
    grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
}

/* === 统计行单行布局 === */
.stats-row {
    display: flex;
    justify-content: space-around;
    align-items: center;
    gap: 2rem;
    flex-wrap: nowrap;
}

.stats-row .stat-item {
    flex: 1;
    min-width: 0;
}

@media (max-width: 768px) {
    .stats-row {
        flex-wrap: wrap;
        gap: 1rem;
    }
    
    .stats-row .stat-item {
        flex: 1 1 calc(50% - 0.5rem);
        min-width: 120px;
    }
}