/* Reset and base styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --bg-color: #fafafa;
    --text-color: #2a2a2a;
    --nav-bg: #f0f0f0;
    --nav-hover: #e0e0e0;
    --link-color: #4a4a4a;
    --border-color: #d0d0d0;
    --heading-color: #1a1a1a;
}

/* Auto dark theme based on system preference */
@media (prefers-color-scheme: dark) {
    :root:not([data-theme="light"]) {
        --bg-color: #1a1a1a;
        --text-color: #d0d0d0;
        --nav-bg: #252525;
        --nav-hover: #303030;
        --link-color: #b0b0b0;
        --border-color: #404040;
        --heading-color: #e0e0e0;
    }
}

/* Manual dark theme override */
:root[data-theme="dark"] {
    --bg-color: #1a1a1a;
    --text-color: #d0d0d0;
    --nav-bg: #252525;
    --nav-hover: #303030;
    --link-color: #b0b0b0;
    --border-color: #404040;
    --heading-color: #e0e0e0;
}

/* Manual light theme override */
:root[data-theme="light"] {
    --bg-color: #fafafa;
    --text-color: #2a2a2a;
    --nav-bg: #f0f0f0;
    --nav-hover: #e0e0e0;
    --link-color: #4a4a4a;
    --border-color: #d0d0d0;
    --heading-color: #1a1a1a;
}

body {
    font-family: 'Courier New', Courier, monospace;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
    min-height: 100vh;
}

/* Navigation */
nav {
    background-color: var(--nav-bg);
    padding: 1rem 2rem;
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 100;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

nav ul {
    list-style: none;
    display: flex;
    gap: 2rem;
    flex-wrap: wrap;
}

nav a {
    color: var(--link-color);
    text-decoration: none;
    font-weight: bold;
    transition: background-color 0.2s;
    padding: 0.5rem 1rem;
    display: block;
}

nav a:hover {
    background-color: var(--nav-hover);
}

nav a.active {
    text-decoration: underline;
}

/* Theme toggle */
.theme-toggle {
    background-color: var(--nav-hover);
    border: 1px solid var(--border-color);
    color: var(--text-color);
    padding: 0.5rem 1rem;
    font-family: 'Courier New', Courier, monospace;
    font-size: 0.9rem;
    cursor: pointer;
    transition: background-color 0.2s;
    white-space: nowrap;
}

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

.theme-toggle:focus {
    outline: 2px solid var(--link-color);
    outline-offset: 2px;
}

/* Main content */
main {
    max-width: 900px;
    margin: 0 auto;
    padding: 2rem;
}

h1 {
    color: var(--heading-color);
    font-size: 2rem;
    margin-bottom: 1.5rem;
    border-bottom: 2px solid var(--border-color);
    padding-bottom: 0.5rem;
}

h2 {
    color: var(--heading-color);
    font-size: 1.5rem;
    margin-top: 2rem;
    margin-bottom: 1rem;
}

h3 {
    color: var(--heading-color);
    font-size: 1.2rem;
    margin-top: 1.5rem;
    margin-bottom: 0.5rem;
}

p {
    margin-bottom: 1rem;
}

a {
    color: var(--link-color);
}

/* Product cards on home page */
.product-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}

.product-card {
    border: 1px solid var(--border-color);
    padding: 1.5rem;
    background-color: var(--nav-bg);
    transition: transform 0.2s;
}

.product-card:hover {
    transform: translateY(-2px);
}

.product-card h3 {
    margin-top: 0;
}

.product-card a {
    display: inline-block;
    margin-top: 1rem;
    padding: 0.5rem 1rem;
    background-color: var(--nav-hover);
    text-decoration: none;
    transition: background-color 0.2s;
}

.product-card a:hover {
    background-color: var(--border-color);
}

/* Specifications list */
.specs {
    background-color: var(--nav-bg);
    padding: 1.5rem;
    margin: 1.5rem 0;
    border-left: 3px solid var(--border-color);
}

.specs ul {
    list-style-position: inside;
    margin-left: 1rem;
}

.specs li {
    margin-bottom: 0.5rem;
}

/* Notice box */
.notice {
    background-color: var(--nav-bg);
    border: 2px solid var(--border-color);
    padding: 1rem;
    margin: 2rem 0;
    font-style: italic;
}

/* Footer */
footer {
    text-align: center;
    padding: 2rem;
    margin-top: 4rem;
    border-top: 1px solid var(--border-color);
    font-size: 0.9rem;
}

/* Responsive design */
@media (max-width: 600px) {
    nav {
        flex-direction: column;
        gap: 1rem;
        align-items: stretch;
    }

    nav ul {
        flex-direction: column;
        gap: 0;
    }

    .theme-toggle {
        width: 100%;
        text-align: center;
    }

    main {
        padding: 1rem;
    }

    .product-grid {
        grid-template-columns: 1fr;
    }
}