:root {
    --bg-color: #052066;
    --card-bg: #060f20;
    --text-color: #f3f4f6;
    --text-muted: #9ca3af;
    --accent-color: #1a6cef;
    --accent-hover: #004ff9;
    --border-color: #061932;
    --error-color: #dc4444;
    --max-width: 1100px;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

body {
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
    padding-bottom: 60px;
}

header {
    background-color: rgba(19, 26, 38, 0.95);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 100;
    backdrop-filter: blur(8px);
}

.app-container {
    width: 100%;
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}

.logo a {
    font-size: 1.5rem;
    font-weight: 800;
    color: #ffffff;
    text-decoration: none;
    letter-spacing: -0.5px;
}

#nav-menu ul {
    display: flex;
    list-style: none;
    gap: 24px;
}

#nav-menu a {
    color: var(--text-muted);
    text-decoration: none;
    font-size: 0.95rem;
    font-weight: 500;
    transition: color 0.2s ease;
}

#nav-menu a:hover,
#nav-menu a.active {
    color: var(--accent-color);
}

main {
    max-width: var(--max-width);
    margin: 40px auto 0 auto;
    padding: 0 20px;
}

main h1 {
    font-size: 2.5rem;
    font-weight: 800;
    letter-spacing: -1px;
    margin-bottom: 8px;
    color: #ffffff;
}

main > p {
    color: var(--text-muted);
    font-size: 1.1rem;
    margin-bottom: 40px;
}

.article-list {
    display: grid;
    grid-template-columns: 1fr;
    gap: 24px;
}

.database-article-item {
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 30px;
    transition: transform 0.2s ease, border-color 0.2s ease, box-shadow 0.2s ease;
}

.database-article-item:hover {
    transform: translateY(-2px);
    border-color: #374151;
    box-shadow: 0 10px 25px -5px rgba(0, 0, 0, 0.3);
}

.article-tag {
    display: inline-block;
    background-color: rgba(59, 130, 246, 0.1);
    color: var(--accent-color) !important;
    padding: 4px 10px;
    border-radius: 6px;
    font-size: 0.75rem !important;
    letter-spacing: 0.5px;
}

.article-item-title {
    font-size: 1.75rem;
    font-weight: 700;
    color: #ffffff;
    line-height: 1.3;
}

.article-item-content {
    font-size: 1.05rem;
    color: #d1d5db !important;
    margin-top: 10px;
}

.read-more-link {
    display: inline-flex;
    align-items: center;
    color: var(--accent-color) !important;
    transition: color 0.2s ease, transform 0.2s ease;
}

.read-more-link:hover {
    color: var(--accent-hover) !important;
    transform: translateX(4px);
}

.error-msg, 
.no-data-msg {
    text-align: center;
    padding: 40px;
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    font-weight: 500;
}

.error-msg {
    color: var(--error-color) !important;
    border-color: rgba(239, 68, 68, 0.2);
    background-color: rgba(239, 68, 68, 0.05);
}

@media (max-width: 768px) {
    header {
        position: relative;
    }
    
    .app-container {
        flex-direction: column;
        height: auto;
        padding: 20px;
        gap: 15px;
    }

    #nav-menu ul {
        flex-wrap: wrap;
        justify-content: center;
        gap: 15px;
    }

    main h1 {
        font-size: 2rem;
    }
    
    .database-article-item {
        padding: 20px;
    }

    .article-item-title {
        font-size: 1.4rem;
    }
}