:root[data-theme="light"] {
    --bg-color: #f8fafc;
    --text-color: #334155;
    --header-bg: rgba(255, 255, 255, 0.8);
    --card-bg: #ffffff;
    --card-content-bg: #f1f5f9;
    --hover-bg: #e2e8f0;
    --active-bg: #3b82f6;
    --active-text: #ffffff;
    --border-color: #e2e8f0;
    --heading-color: #1e293b;
    --subheading-color: #334155;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --footer-bg: #ffffff;
    --footer-text: #64748b;
    --footer-link: #3b82f6;
    --footer-border: #f1f5f9;
    --logo-color: #1e293b;
    --product-table-th: #99ccff;
    --product-table-tr: #d9ecff;
}

:root[data-theme="dark"] {
    --bg-color: #0f172a;
    --text-color: #e2e8f0;
    --header-bg: rgba(15, 23, 42, 0.8);
    --card-bg: #1e293b;
    --card-content-bg: #334155;
    --hover-bg: #334155;
    --active-bg: #3b82f6;
    --active-text: #ffffff;
    --border-color: #334155;
    --heading-color: #f8fafc;
    --subheading-color: #e2e8f0;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.2), 0 2px 4px -1px rgba(0, 0, 0, 0.1);
    --footer-bg: #1e293b;
    --footer-text: #94a3b8;
    --footer-link: #60a5fa;
    --footer-border: #334155;
    --logo-color: #f8fafc;
    --product-table-th: #3D5A80;
    --product-table-tr: #62b0ff;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--bg-color);
    transition: background-color 0.3s ease, color 0.3s ease;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

header {
    background-color: var(--header-bg);
    backdrop-filter: blur(8px);
    box-shadow: var(--shadow);
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 1000;
    transition: transform 0.3s ease;
}

    header.scroll-down {
        transform: translateY(-100%);
    }

nav {
    max-width: 1200px;
    margin: 0 auto;
    padding: 1rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--heading-color);
    flex: 1;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    transition: transform 0.3s ease;
    cursor: pointer;
}

    .logo:hover {
        transform: scale(1.05);
    }

.logo-img {
    width: 32px;
    height: 32px;
    color: var(--logo-color);
}

.search-box {
    display: flex;
    gap: 0.5rem;
    justify-content: center;
    flex: 2;
}

    .search-box input {
        padding: 0.75rem 1rem;
        border: 1px solid var(--border-color);
        border-radius: 8px;
        width: 300px;
        background-color: var(--card-bg);
        color: var(--text-color);
        transition: all 0.3s ease;
    }

        .search-box input:focus {
            outline: none;
            border-color: var(--active-bg);
            box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.2);
        }

    .search-box button {
        padding: 0.75rem 1.5rem;
        background-color: var(--active-bg);
        color: var(--active-text);
        border: none;
        border-radius: 8px;
        cursor: pointer;
        transition: all 0.3s ease;
        font-weight: 500;
    }

        .search-box button:hover {
            transform: translateY(-1px);
            box-shadow: 0 4px 6px rgba(59, 130, 246, 0.2);
        }

.theme-toggle {
    flex: 1;
    display: flex;
    justify-content: flex-end;
}

    .theme-toggle button {
        background: none;
        border: none;
        cursor: pointer;
        font-size: 1.5rem;
        padding: 0.5rem;
        border-radius: 50%;
        transition: all 0.3s ease;
    }

        .theme-toggle button:hover {
            background-color: var(--hover-bg);
            transform: rotate(360deg);
        }

main {
    display: flex;
    max-width: 1200px;
    margin: 80px auto 0;
    padding: 1rem;
    gap: 2rem;
    flex: 1;
}

.sidebar {
    width: 280px;
    background: var(--card-bg);
    border-radius: 12px;
    padding: 1.5rem;
    box-shadow: var(--shadow);
}

.category-group {
    margin-bottom: 2rem;
    opacity: 0;
    transform: translateX(-20px);
    animation: slideIn 0.5s ease forwards;
}

    .category-group h3 {
        color: var(--heading-color);
        font-size: 1.1rem;
        margin-bottom: 1rem;
        padding-bottom: 0.5rem;
        border-bottom: 2px solid var(--border-color);
    }

.categories li {
    padding: 0.75rem 1rem;
    cursor: pointer;
    border-radius: 8px;
    margin-bottom: 0.5rem;
    transition: all 0.3s ease;
    list-style: none;
    color: var(--text-color);
    position: relative;
    overflow: hidden;
}

    .categories li::before {
        content: '';
        position: absolute;
        left: 0;
        top: 0;
        width: 4px;
        height: 100%;
        background-color: var(--active-bg);
        transform: scaleY(0);
        transition: transform 0.3s ease;
    }

    .categories li:hover::before {
        transform: scaleY(1);
    }

    .categories li:hover {
        background-color: var(--hover-bg);
        padding-left: 1.5rem;
    }

    .categories li.active {
        background-color: var(--active-bg);
        color: var(--active-text);
        transform: translateX(0.5rem);
    }

.submenu {
    display: none;
    margin: 0.5rem 0 0.5rem 1rem;
    padding-left: 1rem;
    border-left: 2px solid var(--border-color);
}

    .submenu li {
        padding: 0.5rem 1rem;
        font-size: 0.9rem;
        opacity: 0;
        transform: translateX(-10px);
        transition: all 0.3s ease;
    }

.has-submenu.expanded .submenu li {
    opacity: 1;
    transform: translateX(0);
}

.toggle-submenu {
    position: absolute;
    right: 1rem;
    top: 50%;
    transform: translateY(-50%);
    transition: transform 0.3s ease;
}

    .toggle-submenu.rotated {
        transform: translateY(-50%) rotate(180deg);
    }

.content {
    flex: 1;
    background: var(--card-bg);
    border-radius: 12px;
    padding: 2rem;
    box-shadow: var(--shadow);
    opacity: 0;
    transform: translateY(20px);
    animation: fadeIn 0.5s ease forwards;
    width: 1000px;
}

.category-content {
    display: none;
}

    .category-content.active {
        display: block;
        animation: fadeIn 0.3s ease;
    }

.help-card {
    background: var(--card-content-bg);
    border-radius: 12px;
    padding: 1.5rem;
    margin-top: 1rem;
    transition: all 0.3s ease;
}

    .help-card:hover {
        transform: translateY(-2px);
        box-shadow: var(--shadow);
    }

h1 {
    color: var(--heading-color);
    margin-bottom: 1.5rem;
    font-size: 2rem;
}

h2 {
    color: var(--subheading-color);
    margin-bottom: 1rem;
}

footer {
    background-color: var(--footer-bg);
    color: var(--footer-text);
    padding: 3rem 0;
    margin-top: 2rem;
    border-top: 1px solid var(--footer-border);
}

.footer-content {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    justify-content: space-around;
    padding: 0 2rem;
}

.footer-section {
    flex: 1;
    max-width: 300px;
    opacity: 0;
    transform: translateY(20px);
    animation: fadeIn 0.5s ease forwards;
}

    .footer-section h3 {
        color: var(--heading-color);
        margin-bottom: 1rem;
        font-size: 1.2rem;
    }

.footer-categories {
    list-style: none;
}

    .footer-categories li {
        margin-bottom: 0.75rem;
    }

    .footer-categories a {
        color: var(--footer-link);
        text-decoration: none;
        transition: all 0.3s ease;
        position: relative;
    }

        .footer-categories a::after {
            content: '';
            position: absolute;
            width: 100%;
            height: 2px;
            bottom: -2px;
            left: 0;
            background-color: var(--footer-link);
            transform: scaleX(0);
            transition: transform 0.3s ease;
        }

        .footer-categories a:hover::after {
            transform: scaleX(1);
        }

.footer-bottom {
    text-align: center;
    margin-top: 2rem;
    padding-top: 1rem;
    border-top: 1px solid var(--footer-border);
}

mark {
    background-color: rgba(255, 215, 0, 0.3);
    color: var(--text-color);
    padding: 0.2rem 0.4rem;
    border-radius: 4px;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateX(-20px);
    }

    to {
        opacity: 1;
        transform: translateX(0);
    }
}

/* @media (max-width: 768px) { */
@media (max-width: 1150px) {
    main {
        flex-direction: column;
    }

    .sidebar {
        width: 100%;
    }

    .search-box input {
        width: 200px;
    }

    .footer-content {
        flex-direction: column;
        align-items: center;
        gap: 2rem;
    }

    .footer-section {
        text-align: center;
    }
}

.product-table {
    width: 100%;
    border-collapse: collapse;
    background-color: #e6f7ff;
    font-family: Arial, sans-serif;
    margin: 20px 0;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
}

    .product-table th, .product-table td {
        padding: 12px 15px;
        text-align: center;
        border: 1px solid #b3d9ff;
    }

    .product-table th {
        background-color: var(--product-table-th);
        color: var(--text-color);
        font-weight: bold;
    }

    .product-table tr:nth-child(even) {
        background-color: var(--product-table-tr);
        color: var(--text-color);
    }