:root {
    --bg-color: #0f172a;
    --text-color: #f1f5f9;
    --text-muted: #94a3b8;
    --primary-color: #38bdf8;
    --primary-glow: rgba(56, 189, 248, 0.5);
    --card-bg: rgba(30, 41, 59, 0.7);
    --card-border: rgba(255, 255, 255, 0.1);
    --glass-blur: blur(12px);
    --font-sans: 'Inter', system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}

@media (prefers-color-scheme: light) {
    :root {
        --bg-color: #f8fafc;
        --text-color: #0f172a;
        --text-muted: #64748b;
        --primary-color: #0284c7;
        --primary-glow: rgba(2, 132, 199, 0.3);
        --card-bg: rgba(255, 255, 255, 0.8);
        --card-border: rgba(0, 0, 0, 0.05);
    }
}

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

body {
    background-color: var(--bg-color);
    color: var(--text-color);
    font-family: var(--font-sans);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    transition: background-color 0.3s ease, color 0.3s ease;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    line-height: 1.2;
    font-weight: 700;
    margin-bottom: 1rem;
    letter-spacing: -0.025em;
}

a {
    color: var(--primary-color);
    text-decoration: none;
    transition: color 0.2s ease, text-shadow 0.2s ease;
}

a:hover {
    text-shadow: 0 0 8px var(--primary-glow);
}

/* Layout */
.app-container {
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

.main-content {
    flex: 1;
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem;
    padding-top: 6rem; /* Account for fixed navbar */
}

/* Navbar */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: 70px;
    background: var(--card-bg);
    backdrop-filter: var(--glass-blur);
    -webkit-backdrop-filter: var(--glass-blur);
    border-bottom: 1px solid var(--card-border);
    z-index: 100;
    display: flex;
    justify-content: center;
}

.nav-content {
    width: 100%;
    max-width: 1200px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 2rem;
}

.logo {
    font-size: 1.25rem;
    font-weight: 700;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--text-color);
}

.logo-icon {
    font-size: 1.5rem;
}

.nav-links {
    display: flex;
    gap: 2rem;
}

.nav-links a {
    color: var(--text-color);
    font-weight: 500;
    opacity: 0.8;
}

.nav-links a:hover {
    opacity: 1;
    color: var(--primary-color);
}

/* Hero Section */
.hero-section {
    text-align: center;
    padding: 4rem 0;
    animation: fadeInDown 0.8s ease-out;
}

.hero-title {
    font-size: 3.5rem;
    margin-bottom: 1rem;
}

.gradient-text {
    background: linear-gradient(135deg, var(--primary-color), #818cf8);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    text-shadow: 0 0 30px var(--primary-glow);
}

.hero-subtitle {
    font-size: 1.25rem;
    color: var(--text-muted);
    max-width: 600px;
    margin: 0 auto;
}

/* Grid Layout */
.articles-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 2rem;
    padding: 2rem 0;
}

/* Premium Card */
.article-card {
    background: var(--card-bg);
    backdrop-filter: var(--glass-blur);
    -webkit-backdrop-filter: var(--glass-blur);
    border: 1px solid var(--card-border);
    border-radius: 16px;
    overflow: hidden;
    color: var(--text-color);
    transition: transform 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275), box-shadow 0.3s ease;
    display: flex;
    flex-direction: column;
}

.article-card:hover {
    transform: translateY(-8px);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.2), 0 0 20px var(--primary-glow);
    border-color: rgba(255, 255, 255, 0.2);
}

.card-content {
    padding: 1.5rem;
    display: flex;
    flex-direction: column;
    flex: 1;
}

.card-tags {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 1rem;
}

.card-tag {
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    font-weight: 600;
    color: var(--primary-color);
    background: rgba(56, 189, 248, 0.1);
    padding: 0.25rem 0.5rem;
    border-radius: 4px;
}

.card-title {
    font-size: 1.25rem;
    margin-bottom: 0.75rem;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.card-excerpt {
    color: var(--text-muted);
    font-size: 0.95rem;
    margin-bottom: 1.5rem;
    flex: 1;
}

.card-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-top: 1px solid var(--card-border);
    padding-top: 1rem;
    font-size: 0.875rem;
}

.card-date {
    color: var(--text-muted);
}

.read-more {
    font-weight: 600;
    color: var(--primary-color);
}

/* Article Reading View */
.article-container {
    max-width: 800px;
    margin: 0 auto;
    background: var(--card-bg);
    backdrop-filter: var(--glass-blur);
    -webkit-backdrop-filter: var(--glass-blur);
    border: 1px solid var(--card-border);
    border-radius: 24px;
    padding: 3rem;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    animation: fadeIn 0.5s ease-out;
}

.article-header {
    text-align: center;
    margin-bottom: 3rem;
    padding-bottom: 2rem;
    border-bottom: 1px solid var(--card-border);
}

.article-meta-tags {
    display: flex;
    justify-content: center;
    gap: 0.5rem;
    margin-bottom: 1.5rem;
    flex-wrap: wrap;
}

.badge {
    background: var(--primary-color);
    color: #fff;
    padding: 0.25rem 0.75rem;
    border-radius: 9999px;
    font-size: 0.875rem;
    font-weight: 600;
}

.article-title {
    font-size: 2.5rem;
    margin-bottom: 1.5rem;
}

.article-meta {
    display: flex;
    justify-content: center;
    gap: 2rem;
    color: var(--text-muted);
    font-size: 0.95rem;
    flex-wrap: wrap;
}

.meta-item {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.source-link {
    display: inline-flex;
    align-items: center;
    gap: 0.25rem;
    font-weight: 600;
}

/* Markdown Content Styling */
.markdown-content {
    font-size: 1.1rem;
    line-height: 1.8;
}

.markdown-content h1, .markdown-content h2, .markdown-content h3 {
    margin-top: 2.5rem;
    margin-bottom: 1rem;
    color: var(--primary-color);
}

.markdown-content p {
    margin-bottom: 1.5rem;
}

.markdown-content img {
    max-width: 100%;
    height: auto;
    border-radius: 12px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.15);
    margin: 2rem auto;
    display: block;
    transition: transform 0.3s ease;
}

.markdown-content img:hover {
    transform: scale(1.02);
}

.markdown-content blockquote {
    border-left: 4px solid var(--primary-color);
    background: rgba(56, 189, 248, 0.05);
    padding: 1rem 1.5rem;
    border-radius: 0 8px 8px 0;
    margin: 1.5rem 0;
    font-style: italic;
    color: var(--text-muted);
}

.markdown-content ul, .markdown-content ol {
    margin-bottom: 1.5rem;
    padding-left: 2rem;
}

.markdown-content li {
    margin-bottom: 0.5rem;
}

.markdown-content code {
    background: rgba(255, 255, 255, 0.1);
    padding: 0.2em 0.4em;
    border-radius: 4px;
    font-family: monospace;
    font-size: 0.9em;
}

/* Footer */
.article-footer {
    margin-top: 3rem;
    padding-top: 2rem;
    border-top: 1px solid var(--card-border);
    text-align: center;
}

.footer-hash {
    font-size: 0.85rem;
    color: var(--text-muted);
    background: rgba(0, 0, 0, 0.2);
    padding: 0.75rem;
    border-radius: 8px;
    display: inline-block;
}

.hash-value {
    color: var(--primary-color);
    word-break: break-all;
}

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

.footer-sub {
    font-size: 0.85rem;
    margin-top: 0.5rem;
    opacity: 0.7;
}

/* Animations */
@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

@keyframes fadeInDown {
    from { opacity: 0; transform: translateY(-20px); }
    to { opacity: 1; transform: translateY(0); }
}

@media (max-width: 768px) {
    .article-container {
        padding: 1.5rem;
    }
    .article-title {
        font-size: 2rem;
    }
    .hero-title {
        font-size: 2.5rem;
    }
    .nav-links {
        display: none; /* simple mobile fallback */
    }
}

/* Search & Filters */
.search-container {
    max-width: 600px;
    margin: 2rem auto 1rem;
    padding: 0 1rem;
}
.search-input {
    width: 100%;
    padding: 1rem 1.5rem;
    border-radius: 9999px;
    border: 1px solid var(--card-border);
    background: var(--card-bg);
    color: var(--text-color);
    font-size: 1.1rem;
    outline: none;
    backdrop-filter: var(--glass-blur);
    -webkit-backdrop-filter: var(--glass-blur);
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.05);
    transition: box-shadow 0.3s ease, border-color 0.3s ease;
}
.search-input:focus {
    box-shadow: 0 0 0 2px var(--primary-glow);
    border-color: var(--primary-color);
}
.filter-container {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 0.75rem;
    margin-bottom: 3rem;
    padding: 0 1rem;
}
.filter-btn {
    padding: 0.5rem 1.25rem;
    border-radius: 9999px;
    border: 1px solid var(--card-border);
    background: var(--card-bg);
    color: var(--text-muted);
    font-weight: 500;
    cursor: pointer;
    backdrop-filter: var(--glass-blur);
    -webkit-backdrop-filter: var(--glass-blur);
    transition: all 0.2s ease;
}
.filter-btn:hover {
    color: var(--text-color);
    border-color: var(--primary-glow);
}
.filter-btn.active {
    background: var(--primary-color);
    color: #fff;
    border-color: var(--primary-color);
    box-shadow: 0 4px 15px var(--primary-glow);
}