:root {
    --bg:           #0A0D13;
    --bg-2:         #101722;
    --card:         #141C2A;
    --border:       rgba(120, 140, 170, 0.14);
    --border-strong:rgba(120, 140, 170, 0.30);
    --accent:       #4EE6D5;
    --accent-2:     #1787FF;
    --text:         #F8FBFF;
    --text-muted:   #93A1B5;
    --text-dim:     #64748B;
    --ease:         cubic-bezier(0.22, 1, 0.36, 1);
    --prose:        680px;
    --toc-w:        220px;
}

* { margin: 0; padding: 0; box-sizing: border-box; }
*::selection { background: var(--accent); color: var(--bg); }

html { scroll-behavior: smooth; scroll-padding-top: 80px; }

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    min-height: 100vh;
}

body::before {
    content: '';
    position: fixed; inset: 0;
    background:
        radial-gradient(60% 50% at 25% 5%, rgba(78,230,213,0.10) 0%, transparent 55%),
        radial-gradient(55% 45% at 78% 15%, rgba(255,107,53,0.08) 0%, transparent 55%);
    pointer-events: none; z-index: 0;
}

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

.wrap { max-width: 1080px; margin: 0 auto; padding: 0 24px; position: relative; z-index: 1; }
.wrap-narrow { max-width: 720px; }

/* ---------- Header ---------- */
.site-header {
    position: sticky; top: 0; z-index: 50;
    background: rgba(10, 13, 19, 0.78);
    backdrop-filter: blur(14px);
    border-bottom: 1px solid var(--border);
}
.nav {
    max-width: 1080px; margin: 0 auto; padding: 16px 24px;
    display: flex; align-items: center; justify-content: space-between; gap: 16px;
}
.brand {
    display: inline-flex; align-items: center; gap: 10px;
    font-size: 17px; font-weight: 800; letter-spacing: -0.01em;
    text-decoration: none; color: var(--text);
}
.brand:hover { text-decoration: none; }
.brand-mark {
    width: 26px; height: 26px; border-radius: 7px;
    background: linear-gradient(135deg, #4EE6D5 0%, #1787FF 50%, #FF6B35 100%);
    flex-shrink: 0;
}
.nav-links { display: flex; align-items: center; gap: 20px; }
.nav-links a {
    color: var(--text-muted); font-size: 0.92rem; font-weight: 500;
    text-decoration: none;
}
.nav-links a:hover { color: var(--text); }

/* ---------- Listing ---------- */
.list-hero { padding: 64px 0 40px; }
.list-hero h1 {
    font-size: clamp(2rem, 5vw, 3rem);
    font-weight: 900; letter-spacing: -0.03em; line-height: 1.1;
    margin-bottom: 12px;
}
.list-hero p { color: var(--text-muted); font-size: 1.1rem; max-width: 36ch; }

.post-list { list-style: none; padding: 0 0 80px; display: flex; flex-direction: column; gap: 0; }
.post-list li { border-top: 1px solid var(--border); }
.post-list li:last-child { border-bottom: 1px solid var(--border); }
.post-list a {
    display: block; padding: 28px 0;
    text-decoration: none; color: inherit;
    transition: opacity 0.2s var(--ease);
}
.post-list a:hover { opacity: 0.85; text-decoration: none; }
.post-list .post-date {
    font-size: 0.82rem; font-weight: 600;
    color: var(--text-dim); letter-spacing: 0.02em;
    margin-bottom: 8px;
}
.post-list h2 {
    font-size: 1.35rem; font-weight: 800; letter-spacing: -0.02em;
    margin-bottom: 8px; color: var(--text);
}
.post-list .post-desc { color: var(--text-muted); font-size: 0.98rem; max-width: 52ch; }

.empty { color: var(--text-muted); padding: 40px 0 80px; }

/* ---------- Article layout ---------- */
.article-wrap { padding: 40px 0 80px; }

.article-layout {
    display: grid;
    grid-template-columns: minmax(0, 1fr) var(--toc-w);
    gap: 48px;
    align-items: start;
}

.article-header { margin-bottom: 36px; }
.article-header .meta {
    display: flex; flex-wrap: wrap; align-items: center; gap: 10px;
    font-size: 0.85rem; color: var(--text-dim); margin-bottom: 16px;
}
.article-header .meta .dot {
    width: 3px; height: 3px; border-radius: 50%; background: var(--text-dim);
}
.article-header h1 {
    font-size: clamp(1.85rem, 4.5vw, 2.6rem);
    font-weight: 900; letter-spacing: -0.03em; line-height: 1.15;
    margin-bottom: 14px;
}
.article-header .lede {
    font-size: 1.12rem; color: var(--text-muted); max-width: 40ch; line-height: 1.55;
}
.tags { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 18px; }
.tag {
    font-size: 11px; font-weight: 700; text-transform: uppercase; letter-spacing: 0.08em;
    padding: 5px 10px; border-radius: 6px;
    background: rgba(255,255,255,0.05); border: 1px solid var(--border);
    color: var(--text-muted);
}

/* ---------- TOC ---------- */
.toc {
    position: sticky; top: 88px;
    font-size: 0.82rem;
}
.toc-title {
    font-size: 11px; font-weight: 700; text-transform: uppercase;
    letter-spacing: 0.1em; color: var(--text-dim); margin-bottom: 12px;
}
.toc nav { border-left: 1px solid var(--border); }
.toc a {
    display: block; padding: 5px 0 5px 14px;
    color: var(--text-muted); text-decoration: none;
    border-left: 2px solid transparent; margin-left: -1px;
    transition: color 0.15s, border-color 0.15s;
    line-height: 1.4;
}
.toc a:hover { color: var(--text); text-decoration: none; }
.toc a.active { color: var(--accent); border-left-color: var(--accent); }
.toc a.toc-h3 { padding-left: 28px; font-size: 0.78rem; }

.toc-mobile {
    display: none;
    margin-bottom: 32px;
    border: 1px solid var(--border);
    border-radius: 12px;
    background: var(--card);
    overflow: hidden;
}
.toc-mobile summary {
    padding: 14px 16px;
    cursor: pointer; font-weight: 700; font-size: 0.9rem;
    color: var(--text-muted); list-style: none;
    display: flex; align-items: center; justify-content: space-between;
}
.toc-mobile summary::-webkit-details-marker { display: none; }
.toc-mobile summary::after { content: '+'; font-weight: 400; color: var(--text-dim); }
.toc-mobile[open] summary::after { content: '−'; }
.toc-mobile nav { padding: 0 8px 12px; border-left: none; }
.toc-mobile a { border-left: none; margin-left: 0; padding-left: 12px; }

/* ---------- Prose ---------- */
.prose {
    max-width: var(--prose);
    font-size: 1.05rem; line-height: 1.75; color: #c8d4e4;
}
.prose > *:first-child { margin-top: 0; }
.prose h2 {
    font-size: 1.45rem; font-weight: 800; letter-spacing: -0.02em;
    color: var(--text); margin: 2.4em 0 0.7em; line-height: 1.25;
}
.prose h3 {
    font-size: 1.15rem; font-weight: 700; letter-spacing: -0.015em;
    color: var(--text); margin: 1.8em 0 0.55em; line-height: 1.3;
}
.prose p { margin: 0 0 1.15em; }
.prose a { text-underline-offset: 3px; }
.prose strong { color: var(--text); font-weight: 700; }
.prose ul, .prose ol { margin: 0 0 1.15em; padding-left: 1.4em; }
.prose li { margin: 0.35em 0; }
.prose li::marker { color: var(--text-dim); }
.prose blockquote {
    margin: 1.4em 0; padding: 12px 18px;
    border-left: 3px solid var(--accent);
    background: rgba(78,230,213,0.06);
    color: var(--text-muted); border-radius: 0 10px 10px 0;
}
.prose hr {
    border: none; height: 1px; background: var(--border);
    margin: 2.5em 0;
}
.prose code {
    font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
    font-size: 0.88em;
    background: rgba(255,255,255,0.06);
    padding: 0.15em 0.4em; border-radius: 5px;
    color: #e8f0fa;
}
.prose pre {
    margin: 1.4em 0; padding: 18px 20px;
    background: var(--bg-2); border: 1px solid var(--border);
    border-radius: 12px; overflow-x: auto;
    font-size: 0.88rem; line-height: 1.55;
}
.prose pre code {
    background: none; padding: 0; font-size: inherit; color: #d4deeb;
}
.prose figure {
    margin: 1.6em 0;
}
.prose figure img,
.prose > p > img {
    display: block; width: 100%; height: auto;
    border-radius: 12px; border: 1px solid var(--border);
}
.prose figcaption {
    margin-top: 10px; font-size: 0.85rem;
    color: var(--text-dim); text-align: center;
}

.video-embed {
    position: relative; width: 100%;
    aspect-ratio: 16 / 9; margin: 1.6em 0;
    border-radius: 12px; overflow: hidden;
    border: 1px solid var(--border); background: #000;
}
.video-embed iframe {
    position: absolute; inset: 0; width: 100%; height: 100%; border: 0;
}

.prose .mermaid {
    margin: 1.6em 0; padding: 20px;
    background: var(--bg-2); border: 1px solid var(--border);
    border-radius: 12px; text-align: center; overflow-x: auto;
}

.article-footer {
    margin-top: 48px; padding-top: 28px;
    border-top: 1px solid var(--border);
    display: flex; justify-content: space-between; gap: 16px; flex-wrap: wrap;
    font-size: 0.9rem;
}
.article-footer a { color: var(--text-muted); font-weight: 600; }
.article-footer a:hover { color: var(--accent); text-decoration: none; }

/* ---------- Footer ---------- */
.site-footer { padding: 30px 0 50px; border-top: 1px solid var(--border); }
.foot {
    display: flex; justify-content: space-between; align-items: center;
    gap: 16px; flex-wrap: wrap; font-size: 13px; color: var(--text-dim);
}
.foot a { color: var(--text-muted); text-decoration: none; }
.foot a:hover { color: var(--text); }

/* ---------- Responsive ---------- */
@media (max-width: 900px) {
    .article-layout { grid-template-columns: 1fr; gap: 0; }
    .toc-desktop { display: none; }
    .toc-mobile { display: block; }
}

@media (prefers-reduced-motion: reduce) {
    html { scroll-behavior: auto; }
    * { transition: none !important; }
}