:root {
    --bg-gradient-start: #0f172a;
    --bg-gradient-end: #312e81;
    --card-bg: rgba(15, 23, 42, 0.75);
    --card-border: rgba(255, 255, 255, 0.14);
    --accent: #38bdf8;
    --text-primary: #f8fafc;
    --text-secondary: #cbd5f5;
    --tag-bg: rgba(59, 130, 246, 0.2);
}

body {
    font-family: 'Inter', 'Helvetica Neue', Arial, sans-serif;
    background: radial-gradient(circle at 20% 20%, #1d4ed8 0%, transparent 25%),
                radial-gradient(circle at 80% 0%, #a855f7 0%, transparent 30%),
                linear-gradient(135deg, var(--bg-gradient-start), var(--bg-gradient-end));
    min-height: 100vh;
    color: var(--text-primary);
    padding: 40px 20px;
}

.container {
    background: rgba(15, 23, 42, 0.6);
    border: 1px solid rgba(255, 255, 255, 0.08);
    box-shadow: 0 25px 80px rgba(15, 23, 42, 0.6);
    backdrop-filter: blur(18px);
}

header {
    background: transparent;
    border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

header h1 {
    font-size: 2.8em;
}

.header-nav a {
    border: 1px solid transparent;
}

.header-nav a:hover,
.header-nav a.active {
    border-color: rgba(255, 255, 255, 0.18);
    background: rgba(56, 189, 248, 0.1);
}

.search-filter {
    background: rgba(148, 163, 184, 0.08);
    border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

.search-box input,
.tag {
    background: rgba(15, 23, 42, 0.5);
    border: 1px solid rgba(255, 255, 255, 0.12);
    color: var(--text-primary);
}

.tag.active,
.tag:hover {
    background: var(--accent);
    border-color: var(--accent);
    color: #0f172a;
}

.papers-grid {
    background: transparent;
}

.paper-card {
    background: var(--card-bg);
    border-color: var(--card-border);
    box-shadow: inset 0 1px 0 rgba(255,255,255,0.05);
}

.paper-card:hover {
    border-color: var(--accent);
    box-shadow: 0 20px 50px rgba(56, 189, 248, 0.2);
}

.paper-title {
    color: var(--text-primary);
}

.paper-summary,
.paper-authors,
.paper-date,
.paper-category,
.paper-tag,
.page-info {
    color: var(--text-secondary);
}

.paper-category {
    background: rgba(56, 189, 248, 0.18);
    border: 1px solid rgba(56, 189, 248, 0.4);
    color: #e0f2fe;
}

.paper-tag {
    background: var(--tag-bg);
    border-color: rgba(56, 189, 248, 0.4);
}

.paper-link.primary {
    background: var(--accent);
    color: #0f172a;
    box-shadow: 0 10px 30px rgba(56, 189, 248, 0.25);
}

.paper-link.primary:hover {
    box-shadow: 0 20px 40px rgba(56, 189, 248, 0.35);
}

.paper-link.primary:focus-visible,
.paper-link.secondary:focus-visible {
    outline-color: rgba(56, 189, 248, 0.55);
}

.paper-link.secondary {
    color: var(--accent);
    border-color: rgba(56, 189, 248, 0.6);
    background: transparent;
    box-shadow: none;
}

.paper-link.secondary:hover {
    background: rgba(56, 189, 248, 0.2);
}

.about-content {
    color: var(--text-primary);
}

.about-section {
    background: rgba(15, 23, 42, 0.6);
    border: 1px solid rgba(255, 255, 255, 0.08);
    border-radius: 16px;
    padding: 24px;
    box-shadow: 0 12px 30px rgba(2, 6, 23, 0.45);
}

.about-section h2 {
    color: var(--text-primary);
}

.about-section p,
.about-section ul,
.about-section li {
    color: var(--text-secondary);
}

.about-section ul li::marker {
    color: var(--accent);
}

.pagination button,
.pagination .page-number {
    background: rgba(15, 23, 42, 0.5);
    border: 1px solid rgba(255, 255, 255, 0.12);
    color: var(--text-primary);
}

.pagination button:hover:not(:disabled),
.pagination .page-number.active {
    background: var(--accent);
    color: #0f172a;
}

footer {
    background: transparent;
    border-top: 1px solid rgba(255, 255, 255, 0.08);
}