/* Blue Helix TCG — Lessons. Static course theme. */
:root {
  --bg: #000000;
  --surface: #0d0d0d;
  --surface-2: #151515;
  --surface-3: #1c1c1c;
  --border: #272727;
  --border-2: #383838;
  --text: #e9e9e9;
  --text-strong: #ffffff;
  --muted: #8c8c8c;
  --muted-2: #6a6a6a;
  --gold: #D4A84B;
  --gold-600: #B8903A;
  --gold-300: #DCBF7F;
  --cream: #E8DCC4;
  --blue: #5B96D0;
  --blue-strong: #3D7DCA;
  --success: #22c55e;
  --warning: #f59e0b;
  --danger: #ef4444;
  --sidebar-w: 300px;
  --content-max: 820px;
  --radius: 12px;
  --shadow: 0 10px 30px rgba(0,0,0,.45);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  font-size: 17px;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}
img { max-width: 100%; }
a { color: var(--blue); text-decoration: none; }
a:hover { text-decoration: underline; }
::selection { background: rgba(212,168,75,.3); }

/* scroll progress */
.progress { position: fixed; top: 0; left: 0; height: 3px; width: 0%;
  background: linear-gradient(90deg, var(--gold-600), var(--gold), var(--gold-300));
  z-index: 100; transition: width .1s ease-out; }

/* ---------- layout ---------- */
.layout { display: flex; min-height: 100vh; }

.sidebar {
  width: var(--sidebar-w); flex: 0 0 var(--sidebar-w);
  position: sticky; top: 0; align-self: flex-start;
  height: 100vh; overflow-y: auto;
  background: linear-gradient(180deg, #0a0a0a, #060606);
  border-right: 1px solid var(--border);
  padding: 22px 16px 40px;
  scrollbar-width: thin; scrollbar-color: var(--border-2) transparent;
}
.sidebar::-webkit-scrollbar { width: 8px; }
.sidebar::-webkit-scrollbar-thumb { background: var(--border-2); border-radius: 8px; }

.brand { display: flex; align-items: center; gap: 11px; padding: 4px 8px 18px; }
.brand img { width: 38px; height: 38px; border-radius: 9px; }
.brand .b-name { font-weight: 800; color: var(--text-strong); letter-spacing: .2px; line-height: 1.1; }
.brand .b-sub { font-size: 11px; text-transform: uppercase; letter-spacing: 2px; color: var(--gold); font-weight: 600; }

.nav { display: flex; flex-direction: column; gap: 3px; }
.nav-section { margin: 16px 8px 6px; font-size: 10.5px; letter-spacing: 2px; text-transform: uppercase;
  color: var(--muted-2); font-weight: 700; }
.nav a {
  display: flex; align-items: baseline; gap: 10px;
  padding: 8px 12px; border-radius: 9px; color: var(--text);
  border-left: 2px solid transparent; font-size: 14.5px; line-height: 1.35;
}
.nav a:hover { background: var(--surface-2); text-decoration: none; }
.nav a .num { font-family: 'JetBrains Mono', monospace; font-size: 12px; color: var(--muted);
  min-width: 20px; font-weight: 600; }
.nav a.active { background: rgba(212,168,75,.08); border-left-color: var(--gold); color: var(--text-strong); font-weight: 600; }
.nav a.active .num { color: var(--gold); }
.nav a.home { color: var(--cream); }

/* ---------- topbar (mobile) ---------- */
.topbar { display: none; position: sticky; top: 0; z-index: 60;
  align-items: center; gap: 12px; padding: 11px 16px;
  background: rgba(8,8,8,.92); backdrop-filter: blur(10px); border-bottom: 1px solid var(--border); }
.topbar img { width: 28px; height: 28px; border-radius: 7px; }
.topbar .t-name { font-weight: 700; color: var(--text-strong); font-size: 15px; }
.hamburger { background: var(--surface-2); border: 1px solid var(--border-2); color: var(--text);
  width: 40px; height: 38px; border-radius: 9px; font-size: 18px; cursor: pointer; display: grid; place-items: center; }
.overlay { display: none; position: fixed; inset: 0; background: rgba(0,0,0,.6); z-index: 55; }

/* ---------- main / content ---------- */
.main { flex: 1 1 auto; min-width: 0; display: flex; flex-direction: column; }
.content { width: 100%; max-width: var(--content-max); margin: 0 auto; padding: 48px 32px 24px; flex: 1 0 auto; }

.kicker { font-family: 'JetBrains Mono', monospace; font-size: 12px; letter-spacing: 2.5px;
  text-transform: uppercase; color: var(--gold); font-weight: 600; margin-bottom: 10px; }
.kicker.opt { color: var(--blue); }

.content h1 { font-size: 2.3rem; line-height: 1.15; font-weight: 800; color: var(--text-strong);
  margin: 0 0 .5em; letter-spacing: -.5px; }
.content h2 { font-size: 1.5rem; font-weight: 700; color: var(--text-strong); margin: 2.2em 0 .7em;
  padding-bottom: .35em; border-bottom: 1px solid var(--border); }
.content h2::before { content: ""; }
.content h3 { font-size: 1.18rem; font-weight: 700; color: var(--cream); margin: 1.8em 0 .5em; }
.content h4 { font-size: 1rem; font-weight: 700; color: var(--gold-300); margin: 1.5em 0 .4em;
  text-transform: uppercase; letter-spacing: .5px; }
.content p { margin: 0 0 1.05em; }
.content strong { color: var(--cream); font-weight: 700; }
.content em { color: var(--text); }
.content ul, .content ol { margin: 0 0 1.15em; padding-left: 1.4em; }
.content li { margin: .38em 0; }
.content li::marker { color: var(--gold); }
.content ul ul, .content ol ol, .content ul ol, .content ol ul { margin: .3em 0 .4em; }
.content a { border-bottom: 1px solid rgba(91,150,208,.4); }
.content a:hover { border-bottom-color: var(--blue); text-decoration: none; }

.content hr { border: 0; border-top: 1px solid var(--border); margin: 2.4em 0; }

blockquote { margin: 1.4em 0; padding: 2px 20px; border-left: 3px solid var(--gold);
  background: var(--surface); border-radius: 0 10px 10px 0; color: var(--cream); }
blockquote p { margin: .8em 0; font-style: italic; }

code { font-family: 'JetBrains Mono', monospace; font-size: .86em; background: var(--surface-3);
  color: var(--gold-300); padding: .15em .42em; border-radius: 6px; border: 1px solid var(--border); }
pre { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 16px 18px; overflow-x: auto; margin: 0 0 1.3em; }
pre code { background: none; border: 0; color: var(--text); padding: 0; font-size: .85em; }

/* tables */
.table-wrap { overflow-x: auto; margin: 0 0 1.4em; border: 1px solid var(--border);
  border-radius: var(--radius); -webkit-overflow-scrolling: touch; }
table { width: 100%; border-collapse: collapse; font-size: 14.5px; min-width: 460px; }
thead th { background: linear-gradient(180deg, var(--gold), var(--gold-600)); color: #1a1306;
  text-align: left; padding: 11px 14px; font-weight: 700; white-space: nowrap; }
tbody td { padding: 10px 14px; border-top: 1px solid var(--border); vertical-align: top; }
tbody tr:nth-child(even) { background: rgba(255,255,255,.018); }
tbody tr:hover { background: rgba(212,168,75,.05); }
tbody td:first-child { color: var(--cream); font-weight: 600; }

/* ---------- pager ---------- */
.pager { display: flex; gap: 14px; max-width: var(--content-max); margin: 28px auto 0;
  padding: 26px 32px 0; width: 100%; border-top: 1px solid var(--border); }
.pager a { flex: 1 1 0; display: flex; flex-direction: column; gap: 3px; padding: 14px 16px;
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  color: var(--text); transition: border-color .15s, transform .15s; }
.pager a:hover { border-color: var(--gold-600); text-decoration: none; transform: translateY(-2px); }
.pager a.next { text-align: right; align-items: flex-end; }
.pager .dir { font-size: 11px; text-transform: uppercase; letter-spacing: 1.5px; color: var(--muted); }
.pager .ttl { font-weight: 600; color: var(--text-strong); font-size: 15px; }
.pager .spacer { flex: 1 1 0; }

/* ---------- footer ---------- */
.footer { max-width: var(--content-max); margin: 0 auto; width: 100%;
  padding: 40px 32px; color: var(--muted-2); font-size: 13px; line-height: 1.6; }
.footer .sep { color: var(--border-2); }

/* ---------- landing ---------- */
.hero { max-width: var(--content-max); margin: 0 auto; padding: 60px 32px 8px; }
.hero h1 { font-size: clamp(2.2rem, 5vw, 3.2rem); line-height: 1.08; font-weight: 800;
  color: var(--text-strong); margin: 8px 0 .35em; letter-spacing: -1px; }
.hero .tagline { font-size: 1.2rem; color: var(--cream); margin: 0 0 1.4em; max-width: 60ch; }
.promise { background: linear-gradient(135deg, rgba(212,168,75,.10), rgba(212,168,75,.02));
  border: 1px solid var(--border-2); border-left: 3px solid var(--gold); border-radius: var(--radius);
  padding: 16px 20px; margin: 0 0 1.8em; }
.promise b { color: var(--gold); }
.cta-row { display: flex; flex-wrap: wrap; gap: 12px; margin-bottom: 8px; }
.btn { display: inline-flex; align-items: center; gap: 8px; padding: 12px 22px; border-radius: 10px;
  font-weight: 700; font-size: 15px; cursor: pointer; border: 1px solid transparent; }
.btn-gold { background: linear-gradient(135deg, var(--gold), var(--gold-600)); color: #1a1306; }
.btn-gold:hover { text-decoration: none; filter: brightness(1.06); }
.btn-ghost { background: transparent; border-color: var(--border-2); color: var(--text); }
.btn-ghost:hover { text-decoration: none; border-color: var(--gold-600); }

.section-head { max-width: var(--content-max); margin: 38px auto 0; padding: 0 32px; }
.section-head h2 { font-size: 1.05rem; text-transform: uppercase; letter-spacing: 2px; color: var(--gold);
  font-weight: 700; margin: 0; }
.section-head p { color: var(--muted); margin: .3em 0 0; font-size: 15px; }

.howto { max-width: var(--content-max); margin: 14px auto 0; padding: 0 32px;
  display: grid; grid-template-columns: repeat(2, 1fr); gap: 12px; }
.howto .step { background: var(--surface); border: 1px solid var(--border); border-radius: 10px; padding: 14px 16px; font-size: 14.5px; }
.howto .step b { color: var(--cream); }

.grid { max-width: var(--content-max); margin: 16px auto 0; padding: 0 32px;
  display: grid; grid-template-columns: repeat(2, 1fr); gap: 14px; }
.card { display: flex; flex-direction: column; gap: 8px; padding: 18px 18px 20px;
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  transition: border-color .15s, transform .15s; }
.card:hover { border-color: var(--gold-600); text-decoration: none; transform: translateY(-3px); }
.card .c-top { display: flex; align-items: center; gap: 10px; }
.card .badge { font-family: 'JetBrains Mono', monospace; font-weight: 700; font-size: 13px;
  color: #1a1306; background: linear-gradient(135deg, var(--gold), var(--gold-600));
  width: 32px; height: 32px; border-radius: 8px; display: grid; place-items: center; flex: 0 0 auto; }
.card.opt .badge { background: linear-gradient(135deg, var(--blue), var(--blue-strong)); color: #051018; }
.card .c-title { font-weight: 700; color: var(--text-strong); font-size: 16px; line-height: 1.25; }
.card .c-sum { color: var(--muted); font-size: 14px; line-height: 1.55; }
.card .tag { align-self: flex-start; font-size: 10.5px; letter-spacing: 1.5px; text-transform: uppercase;
  color: var(--blue); border: 1px solid var(--border-2); border-radius: 999px; padding: 2px 9px; }

/* ---------- responsive ---------- */
@media (max-width: 900px) {
  body { font-size: 16px; }
  .topbar { display: flex; }
  .sidebar { position: fixed; top: 0; left: 0; z-index: 56; transform: translateX(-100%);
    transition: transform .22s ease; box-shadow: var(--shadow); }
  .sidebar.open { transform: translateX(0); }
  .overlay.show { display: block; }
  .content { padding: 30px 20px 16px; }
  .hero { padding: 36px 20px 8px; }
  .section-head, .howto, .grid { padding-left: 20px; padding-right: 20px; }
  .howto, .grid { grid-template-columns: 1fr; }
  .pager { padding: 22px 20px 0; }
  .footer { padding: 32px 20px; }
  .content h1 { font-size: 1.9rem; }
}
@media (max-width: 520px) {
  .pager { flex-direction: column; }
}

/* print */
@media print {
  .sidebar, .topbar, .pager, .progress, .overlay { display: none !important; }
  .content { max-width: none; }
  body { background: #fff; color: #000; }
}