/* HSK6級合格者による専門指導セクション */
.instructor-expertise-section {
    background: linear-gradient(135deg, #fff5f5 0%, #ffffff 50%, #fff5f5 100%);
    position: relative;
    overflow: hidden;
}

.instructor-expertise-section::before {
    content: "";
    position: absolute;
    top: -50%;
    right: -10%;
    width: 500px;
    height: 500px;
    background: radial-gradient(circle, rgba(230, 0, 18, 0.1) 0%, transparent 70%);
    border-radius: 50%;
    pointer-events: none;
}

.instructor-expertise-section::after {
    content: "";
    position: absolute;
    bottom: -50%;
    left: -10%;
    width: 600px;
    height: 600px;
    background: radial-gradient(circle, rgba(230, 0, 18, 0.08) 0%, transparent 70%);
    border-radius: 50%;
    pointer-events: none;
}

.expertise-content-wrapper {
    max-width: 80%;
    margin: 0 auto;
    position: relative;
    z-index: 1;
    margin-top: 3%;
}

.expertise-icon-circle {
    width: 100px;
    height: 100px;
    background: linear-gradient(135deg, #e60012 0%, #c40010 100%);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 2rem;
    box-shadow: 0 10px 30px rgba(230, 0, 18, 0.3);
    animation: pulse-icon 2s ease-in-out infinite;
}

@keyframes pulse-icon {

    0%,
    100% {
        transform: scale(1);
        box-shadow: 0 10px 30px rgba(230, 0, 18, 0.3);
    }

    50% {
        transform: scale(1.05);
        box-shadow: 0 15px 40px rgba(230, 0, 18, 0.4);
    }
}

.expertise-icon-circle i {
    font-size: 3rem;
    color: #ffffff;
}

.expertise-main-content {
    text-align: center;
}

.expertise-badge {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    background: linear-gradient(135deg, #e60012 0%, #ff4757 100%);
    color: #ffffff;
    padding: 0.75rem 1.5rem;
    border-radius: 50px;
    font-size: 0.95rem;
    font-weight: 700;
    margin-bottom: 1.5rem;
    box-shadow: 0 4px 15px rgba(230, 0, 18, 0.3);
}

.expertise-badge i {
    font-size: 1.1rem;
}

.expertise-title {
    font-size: 2rem;
    font-weight: 900;
    color: #1a1a1a;
    line-height: 1.4;
    margin-bottom: 2rem;
}

.expertise-highlight-box {
    background: #ffffff;
    border: 3px solid #e60012;
    border-radius: 20px;
    padding: 3rem 2.5rem;
    margin-bottom: 3rem;
    box-shadow: 0 10px 40px rgba(230, 0, 18, 0.15);
    display: flex;
    align-items: center;
    gap: 2rem;
}

.expertise-text {
    flex: 1;
}

.expertise-main-text {
    font-size: 1.3rem;
    line-height: 1.8;
    color: #2d2d2d;
}

.expertise-main-text strong {
    color: #e60012;
    font-weight: 900;
    font-size: 1.3rem;
}

.expertise-visual {
    flex-shrink: 0;
}

.certificate-badge {
    width: 120px;
    height: 120px;
    background: linear-gradient(135deg, #e60012 0%, #ff4757 100%);
    border-radius: 50%;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    box-shadow: 0 8px 25px rgba(230, 0, 18, 0.4);
    position: relative;
}

.certificate-badge::before {
    content: "";
    position: absolute;
    top: -5px;
    left: -5px;
    right: -5px;
    bottom: -5px;
    border: 2px dashed #e60012;
    border-radius: 50%;
    opacity: 0.5;
}

.certificate-badge i {
    font-size: 2.5rem;
    color: #ffffff;
    margin-bottom: 0.25rem;
}

.certificate-badge span {
    font-size: 0.85rem;
    font-weight: 700;
    color: #ffffff;
    text-align: center;
    line-height: 1.2;
}

.expertise-features-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 1.5rem;
    margin-bottom: 3rem;
    text-align: center;
}

.expertise-feature-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 1rem;
    background: #ffffff;
    padding: 0.3rem;
    border-radius: 15px;
    border-left: 4px solid #e60012;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.08);
    transition: all 0.3s ease;
}

.expertise-feature-item:hover {
    box-shadow: 0 6px 20px rgba(230, 0, 18, 0.15);
}

.feature-check-icon {
    flex-shrink: 0;
    width: 40px;
    height: 40px;
    background: linear-gradient(135deg, #e60012 0%, #ff4757 100%);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
}

.feature-check-icon i {
    font-size: 1.25rem;
    color: #ffffff;
}

.feature-content {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.feature-content h4 {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 1rem;
    font-size: 1.5rem;
    font-weight: 700;
    color: #e60012;
    margin-bottom: 0.5rem;
}

.feature-content p {
    font-size: 1.3rem;
    line-height: 1.6;
}

.expertise-cta-area {
    margin-top: 2rem;
}

.btn-expertise-cta {
    display: inline-flex;
    align-items: center;
    gap: 0.75rem;
    background: linear-gradient(135deg, #e60012 0%, #c40010 100%);
    color: #ffffff;
    padding: 1rem 2.5rem;
    border-radius: 50px;
    font-size: 1.1rem;
    font-weight: 700;
    text-decoration: none;
    box-shadow: 0 6px 20px rgba(230, 0, 18, 0.3);
    transition: all 0.3s ease;
}

.btn-expertise-cta:hover {
    transform: translateY(-3px);
    box-shadow: 0 10px 30px rgba(230, 0, 18, 0.4);
}

.btn-expertise-cta i {
    font-size: 1.25rem;
}

/* レスポンシブデザイン */
@media (max-width: 768px) {
    .expertise-icon-circle {
        width: 80px;
        height: 80px;
    }

    .expertise-icon-circle i {
        font-size: 2.5rem;
    }

    .expertise-title {
        font-size: 1.5rem;
    }

    .expertise-highlight-box {
        flex-direction: column;
        padding: 2rem 1.5rem;
        gap: 1.5rem;
    }

    .expertise-main-text {
        font-size: 1.1rem;
    }

    .expertise-main-text strong {
        font-size: 1rem;
    }

    .certificate-badge {
        width: 100px;
        height: 100px;
    }

    .certificate-badge i {
        font-size: 2rem;
    }

    .expertise-features-grid {
        gap: 1rem;
    }

    .expertise-feature-item {
        padding: 1.25rem;
    }

    .feature-content h4 {
        font-size: 1rem;
    }

    .feature-content p {
        font-size: 0.9rem;
    }

    .btn-expertise-cta {
        padding: 0.875rem 2rem;
        font-size: 1rem;
    }
}

@media (max-width: 480px) {
    .expertise-title {
        font-size: 1.25rem;
    }

    .expertise-main-text {
        font-size: 1rem;
    }

    .expertise-badge {
        font-size: 0.85rem;
        padding: 0.625rem 1.25rem;
    }
}