:root {
    --primary: #121212;
    --secondary: #1E1E1E;
    --accent-blue: #0D98BA;
    --accent-purple: #BB86FC;
    --accent-teal: #03DAC6;
    --text-primary: #FFFFFF;
    --text-secondary: #BDBDBD;
}

body {
    font-family: 'Roboto', sans-serif;
    background-color: var(--primary);
    color: var(--text-primary);
    line-height: 1.6;
    margin: 0;
    padding: 0;
    overflow-x: hidden;
}

.header {
    background: linear-gradient(135deg, var(--primary), #1A1A2E);
    padding: 2rem 0;
    text-align: center;
    position: relative;
    overflow: hidden;
}

.header::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: url('https://images.gptkong.com/demo/sample3.png') center/cover no-repeat;
    opacity: 0.1;
    z-index: 0;
}

.header-content {
    position: relative;
    z-index: 1;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
}

.notice {
    background-color: var(--accent-blue);
    color: white;
    padding: 1rem;
    text-align: center;
    font-weight: bold;
    margin-bottom: 2rem;
    border-radius: 5px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
}

.main-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem;
}

.article-container {
    background-color: var(--secondary);
    border-radius: 15px;
    padding: 2rem;
    box-shadow: 0 10px 30px rgba(0,0,0,0.3);
    margin-bottom: 3rem;
}

h1, h2, h3, h4 {
    color: var(--text-primary);
    margin-top: 2rem;
    position: relative;
}

h2 {
    font-size: 2rem;
    padding-bottom: 0.5rem;
    border-bottom: 2px solid var(--accent-blue);
}

h3 {
    font-size: 1.5rem;
    color: var(--accent-teal);
}

p {
    margin-bottom: 1.5rem;
    font-size: 1.1rem;
}

.code-container {
    background-color: #1A1A1A;
    border-radius: 10px;
    padding: 1.5rem;
    margin: 2rem 0;
    overflow: auto;
    border-left: 4px solid var(--accent-purple);
}

pre {
    margin: 0;
    font-family: 'Courier New', monospace;
    white-space: pre-wrap;
}

code {
    color: var(--accent-teal);
    font-family: 'Courier New', monospace;
}

.image-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 2rem;
    margin: 3rem 0;
}

.image-card {
    background-color: var(--secondary);
    border-radius: 15px;
    overflow: hidden;
    box-shadow: 0 5px 15px rgba(0,0,0,0.2);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.image-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 15px 30px rgba(0,0,0,0.3);
}

.image-card img {
    width: 100%;
    height: auto;
    display: block;
    border-radius: 15px 15px 0 0;
}

.image-caption {
    padding: 1rem;
    background-color: #2C2C2C;
    border-radius: 0 0 15px 15px;
}

.nav-tabs {
    display: flex;
    flex-wrap: wrap;
    margin: 2rem 0;
    border-bottom: 1px solid var(--accent-blue);
}

.nav-tab {
    padding: 1rem 2rem;
    background-color: transparent;
    color: var(--text-primary);
    border: none;
    cursor: pointer;
    font-weight: bold;
    position: relative;
    transition: all 0.3s ease;
}

.nav-tab:hover {
    color: var(--accent-teal);
}

.nav-tab.active {
    color: var(--accent-blue);
}

.nav-tab.active::after {
    content: '';
    position: absolute;
    bottom: -1px;
    left: 0;
    width: 100%;
    height: 3px;
    background-color: var(--accent-blue);
}

.tab-content {
    display: none;
    animation: fadeIn 0.5s ease;
}

.tab-content.active {
    display: block;
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

.footer {
    background-color: var(--secondary);
    padding: 2rem;
    text-align: center;
    margin-top: 3rem;
    border-radius: 15px 15px 0 0;
}

@media (max-width: 768px) {
    .header-content, .main-container {
        padding: 1rem;
    }
    
    h2 {
        font-size: 1.5rem;
    }
    
    h3 {
        font-size: 1.3rem;
    }
    
    .image-grid {
        grid-template-columns: 1fr;
    }
}

/* Animation classes */
.pulse {
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0% { transform: scale(1); }
    50% { transform: scale(1.05); }
    100% { transform: scale(1); }
}

.float {
    animation: float 6s ease-in-out infinite;
}

@keyframes float {
    0% { transform: translateY(0px); }
    50% { transform: translateY(-20px); }
    100% { transform: translateY(0px); }
}