:root {
    --background-dark: #1a1a1a;
    --background-light: #2c2c2c;
    --text-primary: #f0f0f0;
    --text-secondary: #a0a0a0;
    --accent-color: #BF00FF;
}

body {
    margin: 0;
    padding: 0;
    font-family: 'Poppins', sans-serif;
    background: var(--background-dark);
    color: var(--text-primary);
    height: 100vh;
    display: flex;
    flex-direction: column;
}

.header {
    background: var(--background-light);
    padding: 15px 20px;
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 20px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.2);
}

.header h1 {
    margin: 0;
    font-size: 1.4em;
    font-weight: 600;
}

.nav-buttons {
    display: flex;
    gap: 12px;
}

.nav-button {
    background: transparent;
    border: 1px solid var(--text-secondary);
    color: var(--text-secondary);
    padding: 10px 20px;
    border-radius: 6px;
    cursor: pointer;
    font-size: 14px;
    font-weight: 600;
    transition: all 0.3s ease;
}

.nav-button:hover {
    color: var(--accent-color);
    border-color: var(--accent-color);
    box-shadow: 0 0 10px rgba(191, 0, 255, 0.5);
}

.nav-button.active {
    color: #fff;
    background-color: var(--accent-color);
    border-color: var(--accent-color);
    box-shadow: 0 0 15px rgba(191, 0, 255, 0.7);
}

.content {
    flex: 1;
    background: var(--background-dark);
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 0;
    overflow: hidden;
}

.pdf-view {
    display: none;
    width: 100%;
    height: 100%;
    position: relative;
}

.pdf-view.active {
    display: flex;
    flex-direction: column;
}

.pdf-container {
    width: 100%;
    height: 100%;
    min-height: 600px;
    overflow: auto;
    -webkit-overflow-scrolling: touch;
    background: var(--background-dark);
    position: relative;
}

.pdf-canvas {
    display: block;
    margin: 0 auto;
}

.pdf-page {
    display: block;
    width: 100%;
    height: auto;
    margin-bottom: 2px;
}

.hidden {
    display: none;
}

@media (max-width: 768px) {
    .header {
        padding: 12px 15px;
        flex-direction: column;
        gap: 12px;
    }

    .header h1 {
        font-size: 1.2em;
        text-align: center;
    }

    .nav-buttons {
        justify-content: center;
        gap: 8px;
    }

    .nav-button {
        padding: 8px 16px;
        font-size: 13px;
    }

    .pdf-container {
        min-height: 500px;
    }

    .content {
        padding: 0;
    }
}