/* NOVA Research section — shared stylesheet */
:root {
    --bg: #0a0a0f;
    --card: #12121a;
    --accent: #8b5cf6;
    --accent2: #06b6d4;
    --text: #f0f0f0;
    --text-dim: #888;
    --glow: rgba(139, 92, 246, 0.3);
}

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

body {
    font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
    font-weight: 300;
    background: var(--bg);
    color: var(--text);
    min-height: 100vh;
    padding: 0 20px 40px;
    background-image:
        radial-gradient(ellipse at top, rgba(139, 92, 246, 0.1) 0%, transparent 50%),
        radial-gradient(ellipse at bottom, rgba(6, 182, 212, 0.1) 0%, transparent 50%);
}

/* Sticky Navigation */
.nav-header {
    position: sticky;
    top: 0;
    width: 100%;
    background: rgba(10, 10, 15, 0.9);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid rgba(255,255,255,0.05);
    padding: 16px 0;
    z-index: 1000;
    margin-bottom: 40px;
}

.nav-container {
    max-width: 800px;
    margin: 0 auto;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 20px;
}

.nav-brand {
    font-size: 1.3em;
    font-weight: 600;
    background: linear-gradient(135deg, var(--accent), var(--accent2));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    text-decoration: none;
}

.nav-links {
    display: flex;
    gap: 24px;
    align-items: center;
}

.nav-links a {
    color: var(--text);
    text-decoration: none;
    font-weight: 400;
    transition: all 0.3s ease;
}

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

.container {
    max-width: 800px;
    margin: 0 auto;
}

/* Index header */
.header {
    text-align: center;
    margin-bottom: 50px;
}

.header h1 {
    font-size: 3em;
    font-weight: 600;
    margin-bottom: 16px;
    background: linear-gradient(135deg, var(--accent), var(--accent2));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    text-shadow: 0 0 30px rgba(139, 92, 246, 0.4);
}

.header p {
    color: var(--text-dim);
    font-size: 1.1em;
    font-weight: 300;
}

.intro {
    background: var(--card);
    border-radius: 16px;
    padding: 30px;
    margin-bottom: 40px;
    line-height: 1.8;
    border: 1px solid rgba(255,255,255,0.05);
}

.intro p { margin-bottom: 15px; }
.intro p:last-child { margin-bottom: 0; }
.intro a { color: var(--accent); text-decoration: none; }
.intro a:hover { text-decoration: underline; }

/* Problem cards on index */
.problem-list {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.problem-card {
    background: var(--card);
    border-radius: 16px;
    padding: 28px;
    border: 1px solid rgba(255,255,255,0.05);
    text-decoration: none;
    color: var(--text);
    transition: all 0.3s ease;
    display: block;
}

.problem-card:hover {
    transform: translateY(-3px);
    border-color: var(--accent);
    box-shadow: 0 10px 40px rgba(139, 92, 246, 0.2);
}

.problem-card h2 {
    font-size: 1.35em;
    font-weight: 600;
    margin-bottom: 10px;
    color: var(--text);
}

.problem-card:hover h2 { color: var(--accent); }

.problem-card .desc {
    color: var(--text-dim);
    font-size: 0.95em;
    line-height: 1.6;
    margin-bottom: 14px;
}

/* Meta badges (shared: cards + problem pages) */
.meta-badges {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
    align-items: center;
}

.badge {
    background: rgba(139, 92, 246, 0.15);
    color: var(--accent);
    padding: 4px 12px;
    border-radius: 12px;
    font-size: 0.8em;
    border: 1px solid rgba(139, 92, 246, 0.3);
    font-weight: 400;
    white-space: nowrap;
}

.badge.difficulty {
    background: rgba(6, 182, 212, 0.12);
    color: var(--accent2);
    border-color: rgba(6, 182, 212, 0.3);
}

.badge.stat {
    background: rgba(255,255,255,0.04);
    color: var(--text-dim);
    border-color: rgba(255,255,255,0.1);
}

/* Problem page article */
article {
    background: var(--card);
    border: 1px solid rgba(255,255,255,0.08);
    border-radius: 16px;
    padding: 48px 40px;
}

.post-header {
    margin-bottom: 40px;
    text-align: center;
}

article h1 {
    font-size: 2.3em;
    font-weight: 600;
    background: linear-gradient(135deg, var(--accent), var(--accent2));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 20px;
    line-height: 1.2;
}

.post-header .meta-badges {
    justify-content: center;
}

.post-content {
    font-size: 1.05em;
    line-height: 1.8;
}

.post-content p { margin-bottom: 24px; }

.post-content h2 {
    font-size: 1.6em;
    font-weight: 600;
    margin: 48px 0 24px;
    color: var(--accent2);
}

.post-content h3 {
    font-size: 1.25em;
    font-weight: 600;
    margin: 36px 0 16px;
    color: var(--accent);
}

.post-content a {
    color: var(--accent);
    text-decoration: none;
    border-bottom: 1px solid rgba(139, 92, 246, 0.3);
    transition: all 0.3s ease;
}

.post-content a:hover {
    color: var(--accent2);
    border-bottom-color: var(--accent2);
}

.post-content code {
    background: rgba(139, 92, 246, 0.15);
    color: var(--accent2);
    padding: 2px 8px;
    border-radius: 4px;
    font-family: 'Fira Code', 'Consolas', 'Monaco', monospace;
    font-size: 0.9em;
    font-weight: 400;
}

.post-content blockquote {
    border-left: 3px solid var(--accent);
    padding-left: 24px;
    margin: 32px 0;
    color: var(--text-dim);
    font-style: italic;
}

.post-content em { color: var(--accent2); font-style: italic; }
.post-content strong { color: var(--accent); font-weight: 600; }

.post-content ul, .post-content ol {
    margin: 24px 0;
    padding-left: 24px;
}

.post-content li { margin-bottom: 12px; }

.post-content hr {
    border: none;
    border-top: 1px solid rgba(255,255,255,0.1);
    margin: 40px 0;
}

/* "My work" stats box */
.work-stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
    gap: 15px;
    margin: 24px 0;
}

.work-stat {
    padding: 14px;
    background: rgba(255,255,255,0.02);
    border: 1px solid rgba(255,255,255,0.06);
    border-radius: 8px;
    text-align: center;
}

.work-stat .label {
    font-size: 0.75em;
    font-weight: 400;
    color: var(--text-dim);
    text-transform: uppercase;
    letter-spacing: 1px;
}

.work-stat .value {
    font-size: 1.3em;
    font-weight: 600;
    margin-top: 4px;
    color: var(--accent2);
}

.page-updated {
    margin-top: 48px;
    padding-top: 24px;
    border-top: 1px solid rgba(255,255,255,0.1);
    color: var(--text-dim);
    font-size: 0.85em;
    text-align: center;
}

footer {
    margin-top: 60px;
    text-align: center;
    color: var(--text-dim);
    font-size: 0.9em;
    font-weight: 300;
}

footer a { color: var(--accent); text-decoration: none; }
footer a:hover { text-decoration: underline; }

@media (max-width: 600px) {
    article { padding: 32px 24px; }
    article h1 { font-size: 1.8em; }
    .header h1 { font-size: 2.2em; }
}