body {
    font-family: 'Arial', sans-serif;
    background: linear-gradient(135deg, #f4f4f4 0%, #e8e8e8 100%);
    color: #333;
    margin: 0;
    padding: 20px;
    line-height: 1.6;
    display: flex;
    justify-content: center;
    align-items: center;
    flex-direction: column;
    min-height: 100vh;
    transform: scale(0.9);
}

.container {
    text-align: center;
    max-width: 900px;
    width: 100%;
    background-color: #fff;
    padding: 50px 40px;
    border-radius: 20px;
    box-shadow: 0 15px 35px rgba(0, 0, 0, 0.1);
    backdrop-filter: blur(10px);
}

h1 {
    font-size: 2.8rem;
    color: #007ACC;
    text-align: center;
    margin: 0 0 40px 0;
    position: relative;
    font-weight: 700;
}

h1::after {
    content: '';
    position: absolute;
    bottom: -15px;
    left: 50%;
    transform: translateX(-50%);
    width: 80px;
    height: 4px;
    background: linear-gradient(90deg, #007ACC, #005B99);
    border-radius: 2px;
}

.grade-section {
    margin-bottom: 50px;
}

h2 {
    font-size: 2rem;
    color: #005B99;
    text-align: center;
    margin: 40px 0 30px 0;
    position: relative;
    font-weight: 600;
}

h2::before {
    content: '📚';
    margin-right: 10px;
    font-size: 1.5rem;
}

.notice-box {
    display: flex;
    align-items: flex-start;
    background: linear-gradient(135deg, #fff3cd, #ffeaa7);
    border: 2px solid #007ACC;
    border-radius: 15px;
    padding: 20px;
    margin: 30px 0;
    box-shadow: 0 5px 15px rgba(0, 122, 204, 0.1);
    position: relative;
    overflow: hidden;
}

.notice-box::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 5px;
    height: 100%;
    background: linear-gradient(180deg, #007ACC, #005B99);
}

.notice-icon {
    font-size: 1.5rem;
    margin-right: 15px;
    flex-shrink: 0;
}

.notice-text {
    color: #333;
    font-size: 1rem;
    line-height: 1.6;
    text-align: left;
}

.lesson-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 25px;
    margin-top: 30px;
}

.lesson-card {
    background: linear-gradient(135deg, #007ACC 0%, #005B99 100%);
    border-radius: 20px;
    overflow: hidden;
    box-shadow: 0 10px 30px rgba(0, 122, 204, 0.3);
    transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    position: relative;
    transform-style: preserve-3d;
}

.lesson-card:hover {
    transform: translateY(-10px) rotateX(5deg);
    box-shadow: 0 20px 40px rgba(0, 122, 204, 0.4);
}

.lesson-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,0.3), transparent);
    transition: left 0.6s ease;
    z-index: 1;
}

.lesson-card:hover::before {
    left: 100%;
}

.lesson-card a {
    display: block;
    text-decoration: none;
    color: white;
    padding: 35px 25px;
    position: relative;
    z-index: 2;
    height: 100%;
    box-sizing: border-box;
}

.lesson-icon {
    position: absolute;
    top: 20px;
    right: 25px;
    font-size: 2.5rem;
    opacity: 0.3;
    transition: all 0.3s ease;
}

.lesson-card:hover .lesson-icon {
    opacity: 0.6;
    transform: rotate(10deg) scale(1.1);
}

.lesson-number {
    font-size: 0.85rem;
    opacity: 0.9;
    margin-bottom: 12px;
    font-weight: 300;
    letter-spacing: 1px;
    text-transform: uppercase;
}

.lesson-title {
    font-size: 1.4rem;
    font-weight: 700;
    margin: 0 0 15px 0;
    line-height: 1.3;
}

.lesson-description {
    font-size: 0.9rem;
    opacity: 0.8;
    font-weight: 300;
    letter-spacing: 0.5px;
}

/* コメントアウトされたアイテム用のスタイル */
.lesson-card.disabled {
    opacity: 0.5;
    pointer-events: none;
    background: linear-gradient(135deg, #ccc, #999);
}

@media (max-width: 768px) {
    .container {
        padding: 30px 25px;
        margin: 10px;
    }
    
    h1 {
        font-size: 2.2rem;
    }

    h2 {
        font-size: 1.6rem;
    }

    .lesson-grid {
        grid-template-columns: 1fr;
        gap: 20px;
    }

    .lesson-card a {
        padding: 25px 20px;
    }

    .lesson-title {
        font-size: 1.2rem;
    }

    .lesson-description {
        font-size: 0.9rem;
    }

    .notice-box {
        flex-direction: column;
        text-align: left;
    }

    .notice-icon {
        margin-bottom: 10px;
        margin-right: 0;
    }

    .notice-text {
        font-size: 0.9rem;
    }
}

/* お知らせページ用の追加スタイル */
.notice {
    color: #333;
    font-size: 1.3rem;
    margin-bottom: 30px;
    line-height: 1.8;
    padding: 30px;
    background: linear-gradient(135deg, #f8f9fa 0%, #e9ecef 100%);
    border-radius: 15px;
    border: 2px solid #007ACC;
    position: relative;
    overflow: hidden;
    box-shadow: 0 8px 25px rgba(0, 122, 204, 0.1);
}

.notice::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 6px;
    height: 100%;
    background: linear-gradient(180deg, #007ACC, #005B99);
}

.notice::after {
    content: '📋';
    position: absolute;
    top: 20px;
    right: 25px;
    font-size: 2rem;
    opacity: 0.3;
}

.status-badge {
    display: inline-block;
    color: #fff;
    background: linear-gradient(135deg, #007ACC 0%, #005B99 100%);
    padding: 15px 30px;
    border-radius: 25px;
    font-weight: bold;
    text-align: center;
    margin: 30px 0;
    transition: all 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    text-transform: uppercase;
    letter-spacing: 1px;
    font-size: 0.95rem;
    box-shadow: 0 8px 20px rgba(0, 122, 204, 0.3);
    position: relative;
    overflow: hidden;
}

.status-badge::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,0.3), transparent);
    transition: left 0.5s ease;
}

.status-badge:hover {
    background: linear-gradient(135deg, #005B99 0%, #003d7a 100%);
    transform: translateY(-3px);
    box-shadow: 0 12px 25px rgba(0, 122, 204, 0.4);
}

.status-badge:hover::before {
    left: 100%;
}

.status-badge:active {
    transform: translateY(-1px);
}

.footer {
    color: #555;
    font-size: 1.1rem;
    margin-top: 40px;
    line-height: 1.6;
    font-style: italic;
    opacity: 0.8;
    position: relative;
}

.footer::before {
    content: '';
    position: absolute;
    top: -20px;
    left: 50%;
    transform: translateX(-50%);
    width: 50px;
    height: 2px;
    background: linear-gradient(90deg, transparent, #007ACC, transparent);
}

/* アニメーション追加 */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.notice {
    animation: fadeInUp 0.6s ease-out;
}

.status-badge {
    animation: fadeInUp 0.8s ease-out;
}

.footer {
    animation: fadeInUp 1s ease-out;
}

@media (max-width: 600px) {
    .notice {
        font-size: 1.1rem;
        padding: 25px 20px;
        margin-bottom: 25px;
    }

    .notice::after {
        font-size: 1.5rem;
        top: 15px;
        right: 20px;
    }

    .status-badge {
        padding: 12px 24px;
        font-size: 0.85rem;
        margin: 25px 0;
    }

    .footer {
        font-size: 0.95rem;
        margin-top: 30px;
    }
}

@media (max-width: 480px) {
    .lesson-grid {
        grid-template-columns: 1fr;
    }
    
    .lesson-card {
        border-radius: 15px;
    }
    
    .lesson-card:hover {
        transform: translateY(-5px);
    }

    .notice {
        font-size: 1rem;
        padding: 20px 15px;
    }

    .status-badge {
        padding: 10px 20px;
        font-size: 0.8rem;
    }
}