:root {
    --primary-color: #007bff;
    --secondary-color: #f8f9fa;
    --text-color: #343a40;
    --light-text: #fff;
    --border-color: #dee2e6;
    --hover-color: #0056b3;
    --success-color: #28a745;
    --danger-color: #dc3545;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    margin: 0;
    background-color: var(--secondary-color);
    color: var(--text-color);
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

header {
    background-color: var(--light-text);
    border-bottom: 1px solid var(--border-color);
    padding: 1rem 2rem;
    position: sticky; /* Make header sticky */
    top: 0;
    z-index: 1001; /* Ensure header is above other content */
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 1200px;
    margin: 0 auto;
    flex-wrap: wrap; /* Allow wrapping on smaller screens */
}

.logo img {
    height: 40px; /* Adjust as needed */
    width: auto;
}

/* Modern, tab-based navigation */
#main-nav-tabs {
    display: flex;
    flex-wrap: wrap; /* Allow tabs to wrap on smaller screens */
    justify-content: center; /* Center tabs */
    list-style: none;
    padding: 0;
    margin: 1rem 0 0 0; /* Add some top margin */
    border-bottom: 2px solid var(--border-color);
}

#main-nav-tabs .nav-tab {
    padding: 1rem 1.5rem;
    text-decoration: none;
    color: var(--text-color);
    font-weight: 500;
    border: 2px solid transparent;
    border-bottom: none; /* Remove bottom border from tab */
    border-radius: 8px 8px 0 0; /* Rounded top corners */
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
}

#main-nav-tabs .nav-tab:hover {
    background-color: var(--secondary-color);
    border-color: var(--border-color);
}

#main-nav-tabs .nav-tab.active {
    color: var(--primary-color);
    background-color: var(--light-text);
    border-color: var(--border-color);
    border-bottom: 2px solid var(--light-text); /* Creates the tab effect */
    transform: translateY(2px); /* Lifts the active tab */
}

#main-nav-tabs .nav-tab i {
    margin-right: 0.5rem;
}

/* Hide hamburger menu and close button */
.hamburger-menu, .close-menu {
    display: none;
}

.language-switcher {
    margin-left: 1.5rem; /* Add margin to separate from nav */
}

.language-switcher select {
    padding: 0.5rem 1rem;
    border-radius: 8px; /* Rounded corners */
    border: 1px solid var(--border-color); /* Visible border */
    background-color: var(--secondary-color);
    color: var(--text-color);
    cursor: pointer;
    appearance: none; /* Remove default dropdown arrow */
    -webkit-appearance: none;
    -moz-appearance: none;
    background-image: url('data:image/svg+xml;charset=US-ASCII,%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20width%3D%22292.4%22%20height%3D%22292.4%22%20viewBox%3D%220%200%20292.4%20292.4%22%3E%3Cpath%20fill%3D%22%23007bff%22%20d%3D%22M287%20197.1L159.1%2069.2c-3.7-3.7-9.7-3.7-13.4%200L5.4%20197.1c-3.7%203.7-3.7%209.7%200%2013.4l13.4%2013.4c3.7%203.7%209.7%203.7%2013.4%200l114.9-114.9c3.7-3.7%209.7-3.7%2013.4%200l114.9%20114.9c3.7%203.7%209.7%203.7%2013.4%200l13.4-13.4c3.7-3.6%203.7-9.6%200-13.3z%22%2F%3E%3C%2Fsvg%3E');
    background-repeat: no-repeat;
    background-position: right 0.7em top 50%;
    background-size: 0.65em auto;
}

.language-switcher select:hover {
    border-color: var(--primary-color); /* Hover effect */
}

main {
    flex-grow: 1;
    padding: 2rem;
    max-width: 1200px;
    width: 100%;
    margin: 0 auto;
    box-sizing: border-box;
}

#converter-container {
    background: var(--light-text);
    padding: 3rem;
    border-radius: 10px;
    box-shadow: 0 4px 20px rgba(0,0,0,0.08);
    text-align: center;
}

.converter-ui h1 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.converter-ui p {
    font-size: 1.1rem;
    margin-bottom: 2rem;
    color: #6c757d;
}

#drop-zone {
    border: 3px dashed var(--border-color);
    border-radius: 10px;
    padding: 3rem;
    transition: border-color 0.3s, background-color 0.3s;
}

#drop-zone.dragover {
    border-color: var(--primary-color);
    background-color: #f0f8ff;
}

#upload-btn {
    background-color: var(--primary-color);
    color: var(--light-text);
    padding: 1rem 2rem;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    font-size: 1.2rem;
    font-weight: bold;
    transition: background-color 0.3s;
}

#upload-btn:hover {
    background-color: var(--hover-color);
}

#file-queue-container {
    margin-top: 2rem;
}

#file-list .file-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    background: var(--light-text);
    padding: 1rem;
    border-radius: 5px;
    margin-bottom: 1rem;
    box-shadow: 0 2px 5px rgba(0,0,0,0.05);
    flex-wrap: wrap; /* Allow file items to wrap */
}

.file-item .file-name {
    font-weight: 500;
    flex-basis: 60%; /* Give more space to file name */
    word-break: break-all; /* Break long file names */
}

.file-item .status {
    font-style: italic;
    color: #6c757d;
    flex-basis: 20%;
    text-align: right;
}

.file-item .download-btn {
    background-color: var(--success-color);
    color: var(--light-text);
    padding: 0.5rem 1rem;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    text-decoration: none;
    flex-basis: auto; /* Auto width for button */
    margin-top: 0.5rem; /* Add some top margin on wrap */
}

.file-item .remove-btn {
    background-color: var(--danger-color);
    color: var(--light-text);
    border: none;
    border-radius: 50%;
    width: 25px;
    height: 25px;
    font-size: 0.8rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-left: 0.5rem;
}

#download-all-btn,
#clear-all-btn {
    background-color: var(--success-color);
    color: var(--light-text);
    padding: 1rem 2rem;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    font-size: 1.2rem;
    font-weight: bold;
    display: block;
    margin: 2rem auto 0;
}

#clear-all-btn {
    background-color: var(--danger-color);
    margin-top: 1rem;
}

#download-all-btn.hidden,
#clear-all-btn.hidden {
    display: none;
}

/* New Info Sections */
.info-section {
    background: var(--light-text);
    padding: 2rem;
    border-radius: 10px;
    box-shadow: 0 4px 20px rgba(0,0,0,0.08);
    margin-top: 2rem;
    text-align: left;
}

.info-section h2 {
    color: var(--primary-color);
    font-size: 2rem;
    margin-bottom: 1.5rem;
    text-align: center;
}

.info-section p {
    font-size: 1.1rem;
    line-height: 1.8;
    margin-bottom: 1rem;
}

.how-it-works-steps {
    display: flex;
    justify-content: space-around;
    gap: 20px;
    margin-top: 2rem;
    flex-wrap: wrap;
}

.how-it-works-steps .step {
    flex: 1;
    min-width: 280px;
    background-color: var(--secondary-color);
    padding: 1.5rem;
    border-radius: 8px;
    text-align: center;
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
}

.step-icon {
    width: 80px;
    height: 80px;
    margin-bottom: 1rem;
}

.faq-item {
    margin-bottom: 1.5rem;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 1.5rem;
}

.faq-item:last-child {
    border-bottom: none;
    margin-bottom: 0;
    padding-bottom: 0;
}

.faq-item h3 {
    color: var(--text-color);
    font-size: 1.2rem;
    margin-bottom: 0.5rem;
}

footer {
    background-color: #343a40;
    color: var(--light-text);
    text-align: center;
    padding: 1.5rem;
    margin-top: auto;
}

footer ul {
    list-style: none;
    padding: 0;
    margin-top: 1rem;
}

footer ul li {
    display: inline;
    margin: 0 1rem;
}

footer ul li a {
    color: var(--light-text);
    text-decoration: none;
}

@media (max-width: 768px) {
    .header-content {
        flex-direction: row;
        justify-content: space-between; /* Keep logo left, hamburger right */
        align-items: center;
        position: relative;
    }

    .hamburger-menu {
        display: block; /* Show hamburger on mobile */
        position: absolute; /* Position absolutely within header-content */
        right: 1rem; /* Align to right corner */
        top: 50%;
        transform: translateY(-50%);
        z-index: 1002; /* Ensure it's above the menu when closed */
    }

    .logo {
        display: block; /* Ensure logo is always visible */
    }

    #main-nav-tabs {
        flex-direction: column;
        position: fixed; /* Make menu sticky */
        top: 0; /* Align to top */
        right: 0; /* Position at the right edge */
        width: 70%; /* Adjust width as needed */
        height: 100%; /* Full height */
        background-color: var(--light-text);
        box-shadow: -2px 0 5px rgba(0,0,0,0.2); /* Shadow for slide-in effect */
        transition: transform 0.3s ease-in-out; /* Smooth slide transition */
        z-index: 1000; /* Ensure it's below hamburger when closed, above content when open */
        overflow-y: auto; /* Enable scrolling for long menus */
        padding-top: 60px; /* Space for logo/close button at top */
        visibility: hidden;
        opacity: 0;
        pointer-events: none; /* Disable clicks when hidden */
    }

    #main-nav-tabs.open {
        right: 0; /* Slide in */
        visibility: visible;
        opacity: 1;
        pointer-events: auto; /* Enable clicks when visible */
        transition: right 0.3s ease-in-out, visibility 0s linear 0s, opacity 0.3s ease-in-out;
    }

    .close-menu {
        display: block; /* Show close button */
        position: absolute;
        top: 1rem;
        right: 1rem;
        background: none;
        border: none;
        font-size: 1.5rem;
        color: var(--text-color);
        cursor: pointer;
        z-index: 1001; /* Ensure it's above menu items */
    }

    #main-nav-tabs .nav-tab {
        display: block;
        padding: 1rem 1.5rem;
        border-bottom: 1px solid var(--border-color);
        text-align: left;
    }

    #main-nav-tabs .nav-tab.active {
        background-color: var(--primary-color);
        color: var(--light-text);
        transform: none; /* Reset transform for mobile */
    }

    .language-switcher {
        margin-top: 0;
        margin-left: 0;
        position: relative; /* Change to relative as it's inside the menu */
        padding: 1rem; /* Add padding for better spacing */
        border-top: 1px solid var(--border-color); /* Separator */
    }

    /* Rest of the mobile styles remain unchanged */
    main {
        padding: 1rem;
    }

    #converter-container {
        padding: 1.5rem;
    }

    .converter-ui h1 {
        font-size: 1.8rem;
    }

    .converter-ui p {
        font-size: 1rem;
    }

    #drop-zone {
        padding: 2rem 1rem;
    }

    #upload-btn {
        padding: 0.8rem 1.5rem;
        font-size: 1rem;
    }

    #file-list .file-item {
        flex-direction: column;
        align-items: flex-start;
    }

    .file-item .file-name,
    .file-item .status,
    .file-item .download-btn {
        flex-basis: 100%;
        text-align: left;
        margin-top: 0.5rem;
    }

    .file-item .download-btn {
        width: 100%;
        box-sizing: border-box;
    }

    #download-all-btn,
    #clear-all-btn {
        padding: 0.8rem 1.5rem;
        font-size: 1rem;
    }

    .info-section {
        padding: 1.5rem;
    }

    .info-section h2 {
        font-size: 1.5rem;
    }

    .info-section p {
        font-size: 0.95rem;
    }

    .how-it-works-steps .step {
        min-width: unset;
        width: 100%;
    }

    .faq-item h3 {
        font-size: 1.1rem;
    }

    footer ul li {
        margin: 0 0.5rem;
    }
}

/* Ensure hamburger menu is not displayed on larger screens */
@media (min-width: 769px) {
    .hamburger-menu, .close-menu {
        display: none !important;
    }

    #main-nav-tabs {
        display: flex !important; /* Ensure nav is always flex on desktop */
        flex-direction: row !important;
        position: static !important;
        transform: none !important;
        box-shadow: none !important;
        padding-top: 0 !important;
        width: auto !important;
        height: auto !important;
        overflow-y: visible !important;
    }

    .header-content .logo {
        margin-right: 20px; /* Add some space between logo and nav */
    }
}

/* Fix for potential layout issues on very small screens */
@media (max-width: 360px) {
    .header-content {
        padding: 0.5rem 1rem;
    }
}