.sponsor-section {
    max-width: 1200px;
    margin: 0 auto;
    padding: 60px 40px;
}

.section-title {
    text-align: center;
    font-size: 32px;
    font-weight: 700;
    color: #333;
    margin-bottom: 50px;
    position: relative;
    padding-bottom: 20px;
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 80px;
    height: 4px;
    background: linear-gradient(90deg, #4a90e2, #67b8e3);
    border-radius: 2px;
}

.sponsor-category {
    margin-bottom: 60px;
}

.category-title {
    font-size: 24px;
    font-weight: 600;
    color: #2c3e50;
    margin-bottom: 30px;
    padding-left: 15px;
    border-left: 5px solid #4a90e2;
}

.sponsor-rank-group {
    margin-bottom: 50px;
    width: 100%;
}

.rank-group-title {
    font-size: 20px;
    font-weight: 600;
    color: #34495e;
    margin-bottom: 20px;
    padding-left: 12px;
    border-left: 4px solid #4a90e2;
}

/* プレミアムスポンサー */
.premium-sponsors {
    display: flex;
    flex-wrap: wrap;
    gap: 30px;
    margin-bottom: 50px;
}

.sponsor-card.premium {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 40px;
    border-radius: 12px;
    box-shadow: 0 8px 30px rgba(102, 126, 234, 0.3);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    flex: 1 1 calc(50% - 15px);
    min-width: 350px;
}

.sponsor-card.premium:hover {
    transform: translateY(-5px);
    box-shadow: 0 12px 40px rgba(102, 126, 234, 0.4);
}

.sponsor-card.premium .rank-badge {
    background: rgba(255, 255, 255, 0.3);
    color: white;
    padding: 8px 20px;
    border-radius: 20px;
    font-size: 14px;
    font-weight: 600;
    display: inline-block;
    margin-bottom: 15px;
}

.sponsor-card.premium .company-name {
    font-size: 28px;
    font-weight: 700;
    margin-bottom: 5px;
}

.sponsor-card.premium .individual-supporter {
    font-size: 16px;
    font-weight: 500;
    margin-bottom: 20px;
    opacity: 0.9;
}

.sponsor-card.premium .company-description {
    font-size: 15px;
    line-height: 1.8;
    opacity: 0.95;
}

/* ゴールドスポンサー */
.gold-sponsors {
    display: flex;
    flex-wrap: wrap;
    gap: 25px;
    margin-bottom: 50px;
}

.sponsor-card.gold {
    background: linear-gradient(135deg, #f7b733 0%, #fc4a1a 100%);
    color: white;
    padding: 35px;
    border-radius: 10px;
    box-shadow: 0 6px 25px rgba(247, 183, 51, 0.3);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    flex: 1 1 calc(33.333% - 17px);
    min-width: 300px;
}

.sponsor-card.gold:hover {
    transform: translateY(-4px);
    box-shadow: 0 10px 35px rgba(247, 183, 51, 0.4);
}

.sponsor-card.gold .rank-badge {
    background: rgba(255, 255, 255, 0.3);
    color: white;
    padding: 6px 18px;
    border-radius: 18px;
    font-size: 13px;
    font-weight: 600;
    display: inline-block;
    margin-bottom: 12px;
}

.sponsor-card.gold .company-name {
    font-size: 24px;
    font-weight: 700;
    margin-bottom: 5px;
}

.sponsor-card.gold .individual-supporter {
    font-size: 15px;
    font-weight: 500;
    margin-bottom: 18px;
    opacity: 0.9;
}

.sponsor-card.gold .company-description {
    font-size: 14px;
    line-height: 1.7;
    opacity: 0.95;
}

/* シルバースポンサー */
.silver-sponsors {
    display: flex;
    flex-wrap: wrap;
    gap: 20px;
    margin-bottom: 50px;
}

.sponsor-card.silver {
    background: linear-gradient(135deg, #a8a8a8 0%, #7f8c8d 100%);
    color: white;
    padding: 30px;
    border-radius: 8px;
    box-shadow: 0 4px 20px rgba(168, 168, 168, 0.3);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    flex: 1 1 calc(33.333% - 14px);
    min-width: 280px;
}

.sponsor-card.silver:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 30px rgba(168, 168, 168, 0.4);
}

.sponsor-card.silver .rank-badge {
    background: rgba(255, 255, 255, 0.3);
    color: white;
    padding: 5px 16px;
    border-radius: 16px;
    font-size: 12px;
    font-weight: 600;
    display: inline-block;
    margin-bottom: 10px;
}

.sponsor-card.silver .company-name {
    font-size: 20px;
    font-weight: 700;
    margin-bottom: 5px;
}

.sponsor-card.silver .individual-supporter {
    font-size: 14px;
    font-weight: 500;
    margin-bottom: 15px;
    opacity: 0.9;
}

.sponsor-card.silver .company-description {
    font-size: 13px;
    line-height: 1.6;
    opacity: 0.95;
}

/* サポーター（団体） */
.supporter-sponsors {
    display: flex;
    flex-wrap: wrap;
    gap: 15px;
    margin-bottom: 50px;
}

.sponsor-name-tag {
    background: white;
    border: 2px solid #4a90e2;
    color: #4a90e2;
    padding: 12px 24px;
    border-radius: 25px;
    font-weight: 600;
    font-size: 14px;
    transition: all 0.3s ease;
}

.sponsor-name-tag span {
    margin-left: 8px;
    font-weight: 500;
    font-size: 13px;
}

.sponsor-name-tag:hover {
    background: #4a90e2;
    color: white;
    transform: scale(1.05);
}

/* 個人協賛 */
.individual-sponsors {
    margin-top: 20px;
}

.individual-group {
    margin-bottom: 30px;
}

.individual-rank-title {
    font-size: 18px;
    font-weight: 600;
    color: #34495e;
    margin-bottom: 15px;
    padding-left: 12px;
    border-left: 3px solid #4a90e2;
}

.individual-names {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
}

.individual-name {
    background: #f8f9fa;
    color: #2c3e50;
    padding: 10px 20px;
    border-radius: 20px;
    font-size: 14px;
    font-weight: 500;
    border: 1px solid #e9ecef;
    transition: all 0.3s ease;
}

.individual-name:hover {
    background: #e9ecef;
    border-color: #4a90e2;
}

/* レスポンシブ対応 */
@media (max-width: 768px) {
    .sponsor-section {
        padding: 40px 20px;
    }
    
    .section-title {
        font-size: 24px;
    }
    
    .category-title {
        font-size: 20px;
    }
    
    .sponsor-card.premium,
    .sponsor-card.gold,
    .sponsor-card.silver {
        flex: 1 1 100%;
        min-width: 100%;
    }
    
    .sponsor-card.premium .company-name {
        font-size: 22px;
    }
    
    .sponsor-card.gold .company-name {
        font-size: 20px;
    }
    
    .sponsor-card.silver .company-name {
        font-size: 18px;
    }
}