:root {
    --primary: #5e6ad2;
    --primary-hover: #828fff;
    --ink: #f7f8f8;
    --ink-muted: #d0d6e0;
    --ink-subtle: #8a8f98;
    --canvas: #010102;
    --surface-1: #0f1011;
    --surface-2: #141516;
    --hairline: #23252a;
    --hairline-strong: #34343a;
    --radius-md: 8px;
    --radius-lg: 12px;
    --radius-xl: 16px;
}

* { box-sizing: border-box; }

body {
    background: var(--canvas);
    color: var(--ink);
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    font-size: 16px;
    line-height: 1.5;
    letter-spacing: -0.05px;
}

a { color: var(--primary); text-decoration: none; }
a:hover { color: var(--primary-hover); }

h1, h2, h3, h4 {
    font-weight: 600;
    letter-spacing: -0.6px;
    color: var(--ink);
}

.site-header {
    background: var(--canvas);
    border-bottom: 1px solid var(--hairline);
    position: sticky;
    top: 0;
    z-index: 100;
}

.navbar { height: 64px; padding: 0; }
.navbar-brand { color: var(--ink) !important; font-weight: 700; font-size: 20px; }
.navbar-brand span { color: var(--primary); }
.nav-link { color: var(--ink-subtle) !important; font-size: 14px; font-weight: 500; padding: 8px 16px !important; }
.nav-link:hover { color: var(--ink) !important; }
.navbar-toggler { border-color: var(--hairline); }

.hero {
    padding: 96px 0 64px;
    border-bottom: 1px solid var(--hairline);
}
.hero .eyebrow {
    color: var(--primary);
    font-size: 13px;
    font-weight: 500;
    letter-spacing: 0.4px;
    text-transform: uppercase;
}
.hero h1 {
    font-size: 48px;
    line-height: 1.15;
    letter-spacing: -1.5px;
    margin: 16px 0 24px;
    max-width: 800px;
}
.hero p.lead {
    color: var(--ink-muted);
    font-size: 18px;
    max-width: 640px;
}

.section { padding: 64px 0; }
.section-heading {
    font-size: 32px;
    margin-bottom: 32px;
}

.card-topic {
    background: var(--surface-1);
    border: 1px solid var(--hairline);
    border-radius: var(--radius-lg);
    padding: 24px;
    height: 100%;
    display: block;
    color: var(--ink);
    transition: border-color .2s ease;
}
.card-topic:hover { border-color: var(--hairline-strong); color: var(--ink); }
.card-topic .category-tag {
    display: inline-block;
    background: var(--surface-2);
    color: var(--ink-muted);
    font-size: 12px;
    padding: 2px 10px;
    border-radius: 9999px;
    margin-bottom: 12px;
}
.card-topic h3 { font-size: 20px; margin-bottom: 8px; }
.card-topic p { color: var(--ink-subtle); font-size: 14px; margin: 0; }

.breadcrumb-nav {
    background: var(--surface-1);
    border-bottom: 1px solid var(--hairline);
    padding: 12px 0;
}
.breadcrumb { margin: 0; font-size: 13px; }
.breadcrumb-item, .breadcrumb-item a { color: var(--ink-subtle); }
.breadcrumb-item.active { color: var(--ink); }
.breadcrumb-item + .breadcrumb-item::before { color: var(--ink-subtle); }

.article-layout { padding: 48px 0; }
.article-content h2 {
    font-size: 26px;
    margin-top: 40px;
    margin-bottom: 16px;
    padding-top: 8px;
}
.article-content p {
    color: var(--ink-muted);
    margin-bottom: 16px;
}
.article-header h1 { font-size: 36px; margin-bottom: 12px; }
.article-meta { color: var(--ink-subtle); font-size: 14px; margin-bottom: 32px; }

.toc-box {
    background: var(--surface-1);
    border: 1px solid var(--hairline);
    border-radius: var(--radius-lg);
    padding: 20px;
    position: sticky;
    top: 88px;
}
.toc-title { font-size: 14px; text-transform: uppercase; letter-spacing: 0.4px; color: var(--ink-subtle); margin-bottom: 12px; }
.toc-list { list-style: none; padding: 0; margin: 0; }
.toc-list li { margin-bottom: 8px; }
.toc-list a { color: var(--ink-muted); font-size: 14px; }
.toc-list a:hover { color: var(--primary); }

.related-content { padding: 48px 0; border-top: 1px solid var(--hairline); }
.related-heading { font-size: 24px; margin-bottom: 24px; }
.related-card {
    display: block;
    background: var(--surface-1);
    border: 1px solid var(--hairline);
    border-radius: var(--radius-lg);
    padding: 20px;
    height: 100%;
    color: var(--ink);
}
.related-card:hover { border-color: var(--hairline-strong); color: var(--ink); }
.related-category { color: var(--primary); font-size: 12px; text-transform: uppercase; letter-spacing: 0.4px; }
.related-card h3 { font-size: 16px; margin: 8px 0; }
.related-card p { color: var(--ink-subtle); font-size: 13px; margin: 0; }

.faq-item {
    background: var(--surface-1);
    border: 1px solid var(--hairline);
    border-radius: var(--radius-md);
    padding: 16px 20px;
    margin-bottom: 12px;
}
.faq-item summary {
    cursor: pointer;
    font-weight: 500;
    color: var(--ink);
    list-style: none;
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::before { content: '+'; color: var(--primary); margin-right: 10px; font-weight: 700; }
.faq-item[open] summary::before { content: '−'; }
.faq-item p { color: var(--ink-muted); margin: 12px 0 0; }

.btn-primary-custom {
    background: var(--primary);
    color: #fff;
    border: none;
    border-radius: var(--radius-md);
    padding: 10px 20px;
    font-weight: 500;
    font-size: 14px;
}
.btn-primary-custom:hover { background: var(--primary-hover); color: #fff; }

.form-control {
    background: var(--surface-1);
    border: 1px solid var(--hairline);
    color: var(--ink);
    border-radius: var(--radius-md);
}
.form-control:focus {
    background: var(--surface-1);
    color: var(--ink);
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(94,106,210,0.3);
}
.form-label { color: var(--ink-muted); font-size: 14px; }

.site-footer {
    background: var(--canvas);
    border-top: 1px solid var(--hairline);
    padding: 64px 0 32px;
    color: var(--ink-subtle);
    font-size: 14px;
}
.footer-brand { color: var(--ink); font-size: 18px; margin-bottom: 12px; }
.footer-text { color: var(--ink-subtle); font-size: 13px; }
.footer-heading { color: var(--ink); font-size: 13px; text-transform: uppercase; letter-spacing: 0.4px; margin-bottom: 16px; }
.footer-list { list-style: none; padding: 0; }
.footer-list li { margin-bottom: 8px; }
.footer-list a { color: var(--ink-subtle); font-size: 14px; }
.footer-list a:hover { color: var(--primary); }
.footer-divider { border-color: var(--hairline); margin: 32px 0 16px; }
.footer-disclaimer { font-size: 12px; color: var(--ink-subtle); max-width: 800px; }
.footer-copy { font-size: 12px; color: var(--ink-subtle); margin-top: 8px; }

.cookie-banner {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    background: var(--surface-1);
    border-top: 1px solid var(--hairline-strong);
    padding: 20px;
    z-index: 999;
    display: none;
}
.cookie-banner.show { display: block; }
.cookie-banner p { color: var(--ink-muted); font-size: 14px; margin: 0 0 12px; }
.cookie-banner .btn { margin-right: 8px; }

.img-fluid-frame {
    border-radius: var(--radius-xl);
    border: 1px solid var(--hairline);
    overflow: hidden;
    margin-bottom: 24px;
}
.img-fluid-frame img { width: 100%; display: block; }

.category-index-card {
    background: var(--surface-1);
    border: 1px solid var(--hairline);
    border-radius: var(--radius-lg);
    padding: 20px;
    margin-bottom: 16px;
}

.form-status {
    margin-top: 16px;
    padding: 12px 16px;
    border-radius: var(--radius-md);
    background: rgba(39, 166, 68, 0.15);
    color: #6de088;
    display: none;
}
.form-status.show { display: block; }

@media (max-width: 768px) {
    .hero h1 { font-size: 32px; }
    .hero { padding: 64px 0 40px; }
    .toc-box { position: static; margin-bottom: 24px; }
}