*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
:root {
  --bg: #0a0c10; --surface: #111318; --card: #14171f;
  --border: #1e2330; --gold: #f0b429; --green: #22c55e;
  --red: #ef4444; --text: #e8eaf0; --muted: #6b7280;
  --accent: #8b5cf6;
}
body { background: var(--bg); color: var(--text); font-family: 'DM Sans', sans-serif; min-height: 100vh; }
.article-wrap { max-width: 800px; margin: 120px auto 80px; padding: 0 1.5rem; }
.back-link { display: inline-flex; align-items: center; gap: .5rem; color: var(--gold); text-decoration: none; font-size: .9rem; margin-bottom: 2rem; font-weight: 500; }
.back-link:hover { text-decoration: underline; }
.series-badge { display: inline-block; background: rgba(240,180,41,.12); border: 1px solid rgba(240,180,41,.35); color: var(--gold); font-size: .72rem; font-weight: 700; letter-spacing: .12em; text-transform: uppercase; padding: 4px 12px; border-radius: 20px; margin-bottom: 1rem; }
.day-label { color: var(--accent); font-size: .8rem; font-weight: 700; text-transform: uppercase; letter-spacing: .1em; margin-bottom: .4rem; }
h1 { font-family: 'Playfair Display', serif; font-size: clamp(1.8rem, 4vw, 2.6rem); line-height: 1.2; margin-bottom: .8rem; color: var(--text); }
.meta { color: var(--muted); font-size: .85rem; margin-bottom: 2rem; border-bottom: 1px solid var(--border); padding-bottom: 1.5rem; }
.hero-img { width: 100%; border-radius: 12px; aspect-ratio: 16/7; object-fit: cover; margin-bottom: 2.5rem; }
.body { font-size: 1.05rem; line-height: 1.85; color: #c9cdd9; }
.body h2 { font-family: 'Playfair Display', serif; color: var(--text); font-size: 1.4rem; margin: 2.2rem 0 .8rem; }
.body h3 { color: var(--gold); font-size: 1.05rem; font-weight: 600; margin: 1.5rem 0 .5rem; }
.body p { margin-bottom: 1.2rem; }
.body ul, .body ol { margin: 0 0 1.2rem 1.5rem; }
.body li { margin-bottom: .55rem; }
.body strong { color: var(--text); }
.body em { color: var(--gold); font-style: normal; font-weight: 600; }
.callout { background: #111318; border: 1px solid #1e2330; border-left: 4px solid var(--gold); border-radius: 8px; padding: 1.1rem 1.4rem; margin: 1.5rem 0; }
.callout-green { border-left-color: var(--green); }
.callout-red { border-left-color: var(--red); }
.callout-purple { border-left-color: var(--accent); }
.callout strong { color: var(--gold); display: block; margin-bottom: .3rem; font-size: .85rem; text-transform: uppercase; letter-spacing: .08em; }
.callout-green strong { color: var(--green); }
.callout-red strong { color: var(--red); }
.callout-purple strong { color: var(--accent); }
.code-block { background: #0d1117; border: 1px solid #1e2330; border-radius: 8px; padding: 1.2rem 1.4rem; margin: 1.5rem 0; font-family: 'Courier New', monospace; font-size: .88rem; color: #a5f3fc; overflow-x: auto; line-height: 1.7; }
.code-block .comment { color: #6b7280; }
.code-block .keyword { color: #c084fc; }
.code-block .string { color: #86efac; }
.code-block .number { color: #fbbf24; }
.formula-box { background: #0d1117; border: 1px solid var(--gold); border-radius: 8px; padding: 1rem 1.4rem; margin: 1.5rem 0; text-align: center; font-family: 'Courier New', monospace; color: var(--gold); font-size: 1rem; font-weight: 600; }
.key-concept { background: linear-gradient(135deg, rgba(139,92,246,.1), rgba(59,130,246,.05)); border: 1px solid rgba(139,92,246,.25); border-radius: 10px; padding: 1.2rem 1.4rem; margin: 1.5rem 0; }
.key-concept .label { color: var(--accent); font-size: .75rem; font-weight: 700; text-transform: uppercase; letter-spacing: .1em; margin-bottom: .5rem; }
.two-col { display: grid; grid-template-columns: 1fr 1fr; gap: 1rem; margin: 1.5rem 0; }
.col-card { background: #111318; border: 1px solid #1e2330; border-radius: 8px; padding: 1rem 1.2rem; }
.col-card .col-title { font-weight: 700; font-size: .9rem; margin-bottom: .5rem; }
.col-green .col-title { color: var(--green); }
.col-red .col-title { color: var(--red); }
.tag-list { display: flex; flex-wrap: wrap; gap: .5rem; margin-top: 2rem; }
.tag { background: #111318; border: 1px solid #1e2330; border-radius: 20px; padding: 4px 12px; font-size: .78rem; color: var(--muted); }
.nav-30 { background: #111318; border: 1px solid #1e2330; border-radius: 10px; padding: 1.2rem 1.5rem; margin-top: 3rem; display: flex; justify-content: space-between; align-items: center; }
.nav-30 a { color: var(--gold); text-decoration: none; font-size: .88rem; font-weight: 500; }
.nav-30 a:hover { text-decoration: underline; }
@media(max-width:600px) { .two-col { grid-template-columns: 1fr; } .article-wrap { margin-top: 90px; } }