@import url('https://fonts.googleapis.com/css2?family=Roboto:wght@300;400;700&family=Lora:wght@400;700&display=swap');

    :root {
        --primary-color: #1a5f7a;
        --secondary-color: #4caf50;
        --background-color: #183047;
        --card-background: #ffffff;
        --text-color: #333333;
        --hover-color: #e8f4f8;
    }

    body {
        font-family: 'Roboto', sans-serif;
        line-height: 1.6;
        color: var(--text-color);
        background-color: var(--background-color);
        margin: 0;
        padding: 0;
        transition: background-color 0.3s ease;
    }

    .container {
        max-width: 900px;
        margin: 40px auto;
        padding: 40px;
        background-color: var(--card-background);
        box-shadow: 0 10px 30px rgba(0,0,0,0.1);
        border-radius: 20px;
        transition: all 0.3s ease;
    }

    h1 {
        font-family: 'Lora', serif;
        color: var(--primary-color);
        text-align: center;
        margin-bottom: 40px;
        font-size: 2.8em;
        font-weight: 700;
        position: relative;
        padding-bottom: 15px;
    }

    h1::after {
        content: '';
        position: absolute;
        bottom: 0;
        left: 50%;
        transform: translateX(-50%);
        width: 100px;
        height: 4px;
        background-color: var(--primary-color);
        border-radius: 2px;
    }

    .chapter-list {
        list-style-type: none;
        padding: 0;
        display: grid;
        grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
        gap: 20px;
    }

    .chapter-item {
        background-color: var(--card-background);
        padding: 25px;
        border-radius: 15px;
        transition: all 0.3s ease;
        cursor: pointer;
        border: 2px solid var(--primary-color);
        display: flex;
        flex-direction: column;
        justify-content: space-between;
        height: 180px;
        position: relative;
        overflow: hidden;
    }

    .chapter-item::before {
        content: '';
        position: absolute;
        top: -2px;
        left: -2px;
        right: -2px;
        bottom: -2px;
        background: linear-gradient(45deg, var(--primary-color), var(--secondary-color));
        z-index: -1;
        filter: blur(10px);
        opacity: 0;
        transition: opacity 0.3s ease;
    }

    .chapter-item:hover::before {
        opacity: 1;
    }

    .chapter-item:hover {
        transform: translateY(-5px);
        box-shadow: 0 15px 30px rgba(26, 95, 122, 0.2);
    }

    .chapter-link {
        text-decoration: none;
        color: inherit;
        display: flex;
        flex-direction: column;
        height: 100%;
    }

    .chapter-number {
        font-family: 'Lora', serif;
        font-weight: bold;
        font-size: 1.2em;
        color: var(--primary-color);
        margin-bottom: 10px;
    }

    .chapter-title {
        font-weight: 500;
        margin-bottom: 15px;
        flex-grow: 1;
    }

    .progress-bar {
        background-color: #e0e0e0;
        height: 6px;
        width: 100%;
        border-radius: 3px;
        overflow: hidden;
        margin-top: auto;
    }

    .progress {
        width: 0;
        height: 100%;
        background-color: var(--secondary-color);
        transition: width 0.5s ease;
    }

    @keyframes pulse {
        0% { transform: scale(1); }
        50% { transform: scale(1.05); }
        100% { transform: scale(1); }
    }

    .pulse {
        animation: pulse 2s infinite;
    }

    .theme-toggle {
        position: fixed;
        top: 20px;
        right: 20px;
        background-color: var(--primary-color);
        color: white;
        border: none;
        padding: 10px 20px;
        border-radius: 20px;
        cursor: pointer;
        transition: all 0.3s ease;
    }

    .theme-toggle:hover {
        background-color: var(--secondary-color);
    }

    body.dark-mode {
        --background-color: #1a1a1a;
        --card-background: #2a2a2a;
        --text-color: #ffffff;
        --hover-color: #3a3a3a;
    }


    @import url('https://fonts.googleapis.com/css2?family=SF+Pro+Display:wght@300;400;500;600;700&display=swap');

:root {
    --primary-color: #0066CC;
    --secondary-color: #4caf50;
    --background-color: #f5f5f7;
    --card-background: #ffffff;
    --text-color: #1d1d1f;
    --hover-color: #f2f2f2;
}

body {
    font-family: 'SF Pro Display', -apple-system, BlinkMacSystemFont, sans-serif;
    line-height: 1.47059;
    letter-spacing: -0.022em;
    color: var(--text-color);
    background-color: var(--background-color);
    margin: 0;
    padding: 0;
    transition: background-color 0.3s ease;
}

.container {
    max-width: 1200px;
    margin: 40px auto;
    padding: 40px;
    background-color: var(--card-background);
    border-radius: 30px;
    transition: all 0.3s ease;
}

h1 {
    font-size: 48px;
    line-height: 1.08349;
    font-weight: 600;
    letter-spacing: -0.003em;
    color: var(--text-color);
    text-align: center;
    margin-bottom: 50px;
}

.chapter-list {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
    padding: 0;
    list-style: none;
}

.chapter-item {
    background-color: var(--card-background);
    border-radius: 18px;
    padding: 30px;
    transition: all 0.3s ease;
    cursor: pointer;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    border: none;
}

.chapter-item:hover {
    transform: scale(1.02);
    box-shadow: 0 8px 15px rgba(0, 0, 0, 0.1);
}

.chapter-link {
    text-decoration: none;
    color: inherit;
}

.chapter-number {
    color: var(--primary-color);
    font-size: 24px;
    margin-bottom: 15px;
    display: block;
}

.chapter-title h3 {
    font-size: 24px;
    line-height: 1.1;
    font-weight: 600;
    margin: 0 0 10px 0;
}

p {
    font-size: 17px;
    line-height: 1.47059;
    font-weight: 400;
    color: #86868b;
}

.progress-bar {
    height: 4px;
    background-color: #e8e8ed;
    border-radius: 2px;
    margin-top: 20px;
}

.progress {
    height: 100%;
    background-color: var(--primary-color);
    border-radius: 2px;
    transition: width 0.3s ease;
}

.theme-toggle {
    position: fixed;
    top: 20px;
    right: 20px;
    background-color: var(--primary-color);
    color: white;
    border: none;
    padding: 12px 24px;
    border-radius: 20px;
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s ease;
}

footer {
    background-color: var(--background-color);
    padding: 40px;
    text-align: center;
    font-size: 12px;
    color: #86868b;
    margin-top: 60px;
}

footer a {
    color: var(--primary-color);
    text-decoration: none;
}

body.dark-mode {
    --background-color: #000000;
    --card-background: #1c1c1e;
    --text-color: #ffffff;
    --hover-color: #2c2c2e;
}

@media (max-width: 768px) {
    .container {
        padding: 20px;
        margin: 20px;
    }

    h1 {
        font-size: 36px;
    }

    .chapter-item {
        padding: 20px;
    }
}