body {
        font-family: sans-serif;
        margin: 0;
        background-color: #f9f9f9;
        color: #333;
    }

    header.masthead {
        display: flex;
        justify-content: space-between;
        align-items: center;
        padding: 1rem 2rem;
        background-color: #212121;
    }

    .logo {
        text-align: right;
    }

    .logo img {
        max-width: 300px; /* slightly bigger */
        height: auto;
    }

    .logo-text {
        font-size: 0.85rem;
        color: #ccc;
        margin-top: 0.3rem;
    }

    main {
        background-color: #f9f9f9;
        color: #333;
        text-align: center;
        padding: 4rem 2rem;
        min-height: 90vh;
    }

    #container {
        display: flex;
        flex-direction: row;
        width: 100%;
        height: 100vh;
    }

    canvas {
        display: block;
        margin: 2rem auto;
        padding: 1rem;
        background: white;
        border: 1px solid #ccc;
        box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
        border-radius: 6px;
        width: auto;
        max-width: 95vw; /* Never exceed viewport */
        height: auto;
    }

    .page-label {
        text-align: center;
        font-size: 0.85rem;
        color: #777;
        margin-top: -1rem;
        margin-bottom: 2rem;
    }

    #pdfViewerContainer {
        flex-grow: 1;
        padding: 0; /* Remove default padding */
        overflow-y: auto;
        height: 100vh;
        display: flex;
        flex-direction: column;
        align-items: center;
        justify-content: flex-start;
        box-sizing: border-box;
    }

    #pdfViewerContainer.with-padding {
        padding: 2rem;
    }

    #pdf-canvas-container canvas {
        opacity: 0;
        transform: translateY(20px);
        transition: opacity 0.4s ease, transform 0.4s ease;
    }

    #pdf-canvas-container canvas.visible {
        opacity: 1;
        transform: translateY(0);
    }

    #backButton {
        position: absolute;
        top: 1.5rem;
        left: 1.5rem;
        background-color: #007bff;
        color: white;
        border: none;
        border-radius: 6px;
        padding: 0.5rem 1rem;
        cursor: pointer;
        font-size: 1rem;
        box-shadow: 0 2px 6px rgba(0,0,0,0.1);
        transition: background-color 0.2s ease;
        display: none;
    }

    #backButton:hover {
        background-color: #0056b3;
    }

    #defaultTitle {
        max-width: 900px;
        width: 100%;
        text-align: center;
        margin: 3rem 0 2rem 0;
        color: #333;
    }

    #sidebar {
        width: 25%;
        min-width: 250px;
        max-width: 300px;
        background-color: #f4f4f4;
        overflow-y: auto;
        border-right: 1px solid #ccc;
        padding: 1rem;
        transition: transform 0.4s ease, opacity 0.4s ease;
    }

    #sidebar.hiding {
        transform: translateX(-100%);
        opacity: 0;
    }

    #sidebar.hidden {
        display: none;
    }

    h1 {
        font-size: 2.5rem;
        margin-bottom: 2rem;
    }

    .nav-links a {
        display: block;
        font-size: 1.5rem;
        margin: 1rem auto;
        text-decoration: none;
        color: #007bff;
        padding: 1rem;
        border: 1px solid #ccc;
        max-width: 400px;
        background: white;
        border-radius: 8px;
        transition: 0.2s;
        text-align: center;
    }

    .nav-links a:hover {
        background-color: #e6f0ff;
    }

    .back-link {
        margin-top: 2rem;
        display: inline-block;
        color: #555;
        text-decoration: none;
        border-bottom: 1px dashed #555;
    }

    .portfolio-list a {
        display: block;
        margin: 0.5rem 0;
        padding: 0.5rem;
        background: #fff;
        border: 1px solid #ccc;
        border-radius: 6px;
        color: #007bff;
        text-decoration: none;
        transition: background 0.2s ease;
    }

    .portfolio-list a:hover {
        background: #e6f0ff;
    }

    @media (min-width: 480px) {
        .logo {
            margin: 10px 10px 10px 15px;
        }
    }

    @media (min-width: 768px) {
        .logo img {
            max-width: 260px;
        }
    }

    @media (max-width: 767px) {
        .logo img {
            max-width: 180px;
        }
    }