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

:root {
    --bg-primary: #0a0a0a;
    --bg-secondary: #1a1a1a;
    --bg-header: #000;
    --text-primary: #ffffff;
    --text-secondary: #cccccc;
    --text-muted: #888;
    --border-color: #333;
    --accent-color: #4f46e5;
    --accent-hover: #3730a3;
    --hero-gradient-start: #0a0a0a;
    --hero-gradient-end: #1a1a1a;
    --hero-text-gradient-start: #ffffff;
    --hero-text-gradient-end: #cccccc;
}

[data-theme="light"] {
    --bg-primary: #ffffff;
    --bg-secondary: #f8f9fa;
    --bg-header: #ffffff;
    --text-primary: #1a1a1a;
    --text-secondary: #4a5568;
    --text-muted: #718096;
    --border-color: #e2e8f0;
    --accent-color: #4f46e5;
    --accent-hover: #3730a3;
    --hero-gradient-start: #ffffff;
    --hero-gradient-end: #f7fafc;
    --hero-text-gradient-start: #1a1a1a;
    --hero-text-gradient-end: #4a5568;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', sans-serif;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    transition: background-color 0.3s ease, color 0.3s ease;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

header {
    background-color: var(--bg-header);
    padding: 1rem 0;
    border-bottom: 1px solid var(--border-color);
    transition: background-color 0.3s ease, border-color 0.3s ease;
}

nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.8rem;
    font-weight: 700;
    color: var(--text-primary);
    text-decoration: none;
    transition: color 0.3s ease;
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 2rem;
    align-items: center;
}

.nav-links a {
    color: var(--text-secondary);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s ease;
}

.nav-links a:hover {
    color: var(--text-primary);
}

.theme-switcher {
    background: none;
    border: 1px solid var(--border-color);
    color: var(--text-secondary);
    padding: 0.5rem;
    cursor: pointer;
    font-size: 1.2rem;
    transition: all 0.3s ease;
    border-radius: 4px;
    margin-left: 1rem;
}

.theme-switcher:hover {
    background-color: var(--bg-secondary);
    color: var(--text-primary);
    border-color: var(--accent-color);
}

.beontrack-link {
    background-color: var(--accent-color);
    color: white !important;
    padding: 0.75rem 1.5rem;
    border-radius: 0;
    text-decoration: none;
    font-weight: 600;
    transition: background-color 0.3s ease;
    font-size: 1rem;
}

.beontrack-link:hover {
    background-color: var(--accent-hover);
}

main {
    padding: 3rem 0;
    min-height: calc(100vh - 200px);
}

.hero {
    text-align: center;
    padding: 4rem 0;
    background: linear-gradient(135deg, var(--hero-gradient-start) 0%, var(--hero-gradient-end) 100%);
    transition: background 0.3s ease;
}

.hero h1 {
    font-size: 3.5rem;
    font-weight: 800;
    margin-bottom: 1rem;
    background: linear-gradient(135deg, var(--hero-text-gradient-start) 0%, var(--hero-text-gradient-end) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero p {
    font-size: 1.2rem;
    color: var(--text-secondary);
    max-width: 600px;
    margin: 0 auto 2rem;
    transition: color 0.3s ease;
}

.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 2rem;
    text-align: center;
}

.grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 2rem;
    margin-bottom: 3rem;
}

.card {
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 0;
    padding: 0;
    transition: all 0.3s ease;
    overflow: hidden;
}

.card-image {
    width: 100%;
    height: 200px;
    overflow: hidden;
}

.card-featured-image {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.3s ease;
}

.card:hover .card-featured-image {
    transform: scale(1.05);
}

.card-content {
    padding: 2rem;
    text-align: center;
}

.card:not(.card:has(.card-image)) {
    padding: 2rem;
}

.card:hover {
    border-color: var(--accent-color);
    transform: translateY(-2px);
    box-shadow: 0 8px 32px rgba(79, 70, 229, 0.1);
}

.card h3 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-primary);
    transition: color 0.3s ease;
}

.card p {
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
    transition: color 0.3s ease;
}

.card-meta {
    color: var(--text-muted);
    font-size: 0.9rem;
    margin-bottom: 1rem;
    transition: color 0.3s ease;
}

.btn {
    display: inline-block;
    background-color: var(--accent-color);
    color: white;
    padding: 0.75rem 1.5rem;
    text-decoration: none;
    font-weight: 600;
    border-radius: 0;
    border: none;
    cursor: pointer;
    transition: all 0.3s ease;
    font-size: 1rem;
}

.btn:hover {
    background-color: var(--accent-hover);
    transform: translateY(-1px);
}

.btn-secondary {
    background-color: transparent;
    border: 2px solid var(--accent-color);
    color: var(--accent-color);
}

.btn-secondary:hover {
    background-color: var(--accent-color);
    color: white;
}

.article-content {
    max-width: 800px;
    margin: 0 auto;
    padding: 2rem 0;
}

.article-content h1 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.featured-image-container {
    margin: 2rem auto;
    width: 100%;
    overflow: hidden;
    border-radius: 8px;
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.1);
    transition: box-shadow 0.3s ease;
    text-align: center;
}

[data-theme="light"] .featured-image-container {
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.08);
}

.featured-image {
    width: 100%;
    height: auto;
    min-height: 300px;
    max-height: 500px;
    object-fit: cover;
    display: block;
    transition: transform 0.3s ease;
}

.featured-image:hover {
    transform: scale(1.02);
}

.article-body {
    margin: 2rem 0;
}

.article-navigation {
    margin-top: 3rem;
    padding-top: 2rem;
    border-top: 1px solid var(--border-color);
    transition: border-color 0.3s ease;
}

.article-content h2 {
    font-size: 2rem;
    margin: 2rem 0 1rem;
    color: var(--text-primary);
    transition: color 0.3s ease;
}

.article-content h3 {
    font-size: 1.5rem;
    margin: 1.5rem 0 1rem;
    color: var(--text-primary);
    transition: color 0.3s ease;
}

.article-content p {
    margin-bottom: 1.5rem;
    color: var(--text-secondary);
    font-size: 1.1rem;
    transition: color 0.3s ease;
}

.article-content pre {
    background-color: var(--bg-secondary);
    padding: 1.5rem;
    border-left: 4px solid var(--accent-color);
    overflow-x: auto;
    margin: 1.5rem 0;
    transition: background-color 0.3s ease;
}

.article-content code {
    background-color: var(--bg-secondary);
    padding: 0.2rem 0.4rem;
    border-radius: 3px;
    font-family: 'Monaco', 'Menlo', 'Ubuntu Mono', monospace;
    transition: background-color 0.3s ease;
}

.webtool-interface {
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    padding: 2rem;
    margin: 2rem 0;
    border-radius: 0;
    transition: all 0.3s ease;
}

.webtool-icon {
    font-size: 3rem;
    text-align: center;
    margin-bottom: 1rem;
}

.webtool-featured-image {
    width: 80px;
    height: 80px;
    object-fit: cover;
    border-radius: 8px;
    margin: 0 auto 1rem;
    display: block;
    transition: transform 0.3s ease;
}

.webtool-featured-image:hover {
    transform: scale(1.05);
}

.card-link {
    text-decoration: none;
    color: inherit;
    display: block;
    transition: transform 0.3s ease;
}

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

.card-link .card {
    height: 100%;
    cursor: pointer;
}

.card-link .card:hover {
    transform: none;
}

footer {
    background-color: var(--bg-header);
    padding: 2rem 0;
    border-top: 1px solid var(--border-color);
    text-align: center;
    color: var(--text-muted);
    transition: all 0.3s ease;
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 1rem;
}

@media (max-width: 768px) {
    .hero h1 {
        font-size: 2.5rem;
    }
    
    /* Center all H1 and H2 headings on mobile */
    h1, h2 {
        text-align: center;
    }
    
    nav {
        justify-content: center;
    }
    
    .nav-links {
        display: none;
    }
    
    .logo {
        font-size: 1.5rem;
    }
    
    /* Center Back to Tools button on mobile */
    .article-content > div:last-child {
        text-align: center;
    }
    
    /* Stack markdown reader buttons vertically on mobile */
    .webtool-interface div[style*="display: flex"] {
        flex-direction: column !important;
        gap: 1rem !important;
    }
    
    .webtool-interface div[style*="display: flex"] .btn {
        width: 100% !important;
        flex: none !important;
    }
    
    /* Stack QR code generator vertically on mobile */
    .webtool-interface div[style*="display: grid"] {
        grid-template-columns: 1fr !important;
        gap: 2rem !important;
    }
    
    /* Fix fullscreen markdown reader padding on mobile */
    #fullscreenOverlay div[style*="padding: 2rem 4rem"] {
        padding: 1rem !important;
    }
    
    .grid {
        grid-template-columns: 1fr;
    }
    
    .footer-content {
        flex-direction: column-reverse;
        text-align: center;
    }
    
    /* Hide copyright text on mobile, show only "All rights reserved" */
    .footer-content div:first-child p {
        display: none;
    }
    
    .footer-content div:first-child::after {
        content: "All rights reserved";
        display: block;
        color: var(--text-secondary);
    }
    
    .article-content {
        padding: 1rem 0;
    }
    
    .article-content h1 {
        font-size: 2rem;
    }
    
    .featured-image-container {
        margin: 1.5rem auto;
        border-radius: 0;
    }
    
    .featured-image {
        min-height: 200px;
        max-height: 300px;
    }
}