:root {
  --bg: #f7f8fb;
  --surface: #ffffff;
  --surface-2: #eef0f6;
  --text: #1a1d29;
  --text-dim: #5b6072;
  --border: #e2e4ec;
  --accent: #4f46e5;
  --accent-2: #0ea5a4;
  --accent-soft: #eef0ff;
  --radius: 14px;
  --maxw: 1120px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f1117;
    --surface: #161925;
    --surface-2: #1f2333;
    --text: #eef0f6;
    --text-dim: #9aa0b4;
    --border: #2a2e40;
    --accent: #818cf8;
    --accent-2: #2dd4bf;
    --accent-soft: #23264a;
  }
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  background: var(--bg);
  color: var(--text);
  font-family: "Inter", -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }
.wrap { max-width: var(--maxw); margin: 0 auto; padding: 0 20px; }

/* Top bar */
.topbar { border-bottom: 1px solid var(--border); background: var(--surface); position: sticky; top: 0; z-index: 20; }
.topbar .wrap { display: flex; align-items: center; justify-content: space-between; height: 64px; }
.brand { font-weight: 800; font-size: 1.1rem; letter-spacing: -0.02em; }
.brand .dot { color: var(--accent); }
.topbar nav a { color: var(--text-dim); font-size: 0.88rem; margin-left: 18px; }
.topbar nav a:hover { color: var(--text); text-decoration: none; }

/* Hero */
.hero { padding: 70px 0 30px; text-align: center; }
.hero .eyebrow { color: var(--accent); font-weight: 700; font-size: 0.8rem; letter-spacing: 0.14em; text-transform: uppercase; }
.hero h1 { font-size: clamp(2.2rem, 5vw, 3.4rem); line-height: 1.05; letter-spacing: -0.03em; margin: 14px auto 18px; max-width: 900px; }
.hero h1 .grad { background: linear-gradient(100deg, var(--accent), var(--accent-2)); -webkit-background-clip: text; background-clip: text; -webkit-text-fill-color: transparent; }
.hero .lead { color: var(--text-dim); font-size: 1.12rem; max-width: 680px; margin: 0 auto; }
.hero .stats { display: flex; justify-content: center; gap: 34px; margin: 32px 0 8px; flex-wrap: wrap; }
.hero .stats .n { font-size: 1.6rem; font-weight: 800; color: var(--text); letter-spacing: -0.02em; }
.hero .stats .l { font-size: 0.78rem; color: var(--text-dim); text-transform: uppercase; letter-spacing: 0.05em; }
.hero .cta { margin-top: 26px; }
.btn-primary { display: inline-block; background: var(--accent); color: #fff; font-weight: 600; font-size: 0.95rem; padding: 12px 26px; border-radius: 999px; }
.btn-primary:hover { text-decoration: none; opacity: 0.92; }

/* Section heading */
.section { padding: 46px 0 10px; }
.section-head { text-align: center; max-width: 640px; margin: 0 auto 30px; }
.section-head h2 { font-size: 1.7rem; letter-spacing: -0.02em; margin: 0 0 8px; }
.section-head p { color: var(--text-dim); margin: 0; }

/* Learning path */
.path { display: flex; align-items: stretch; gap: 0; overflow-x: auto; padding: 6px 0 20px; }
.path-step { flex: 1 0 auto; min-width: 130px; text-align: center; position: relative; padding: 0 8px; }
.path-step:not(:last-child)::after { content: ""; position: absolute; top: 20px; right: -6px; width: 12px; height: 2px; background: var(--border); }
.path-step .pill { display: inline-flex; align-items: center; justify-content: center; width: 40px; height: 40px; border-radius: 12px; background: var(--accent-soft); color: var(--accent); font-weight: 800; margin-bottom: 8px; }
.path-step .nm { font-size: 0.82rem; color: var(--text); font-weight: 600; line-height: 1.3; }
.path-step .ph { font-size: 0.72rem; color: var(--text-dim); }

/* Subject cards */
.subjects { display: grid; grid-template-columns: repeat(auto-fill, minmax(330px, 1fr)); gap: 18px; margin: 10px 0 60px; }
.subject {
  position: relative; background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 22px 22px 20px; display: flex; flex-direction: column;
  transition: border-color 0.15s ease, transform 0.15s ease;
}
.subject.live:hover { border-color: var(--accent); transform: translateY(-2px); }
.subject .top { display: flex; align-items: center; gap: 13px; margin-bottom: 12px; }
.subject .icon { width: 44px; height: 44px; border-radius: 11px; display: flex; align-items: center; justify-content: center; font-size: 1.35rem; flex-shrink: 0; background: var(--accent-soft); }
.subject .num { font-size: 0.72rem; font-weight: 700; letter-spacing: 0.08em; color: var(--text-dim); text-transform: uppercase; }
.subject h3 { font-size: 1.16rem; margin: 2px 0 0; letter-spacing: -0.01em; }
.subject .desc { color: var(--text-dim); font-size: 0.92rem; flex: 1; margin: 0 0 14px; }
.subject .meta { display: flex; align-items: center; gap: 10px; font-size: 0.8rem; color: var(--text-dim); margin-bottom: 14px; flex-wrap: wrap; }
.subject .meta .chip { background: var(--surface-2); border-radius: 999px; padding: 3px 10px; }
.subject .foot { display: flex; align-items: center; justify-content: space-between; margin-top: auto; }
.subject .go { font-weight: 600; font-size: 0.9rem; color: var(--accent); }
.subject.soon { opacity: 0.85; }
.subject.soon .icon { background: var(--surface-2); filter: grayscale(0.3); }
.badge { font-size: 0.68rem; font-weight: 700; text-transform: uppercase; letter-spacing: 0.06em; padding: 3px 9px; border-radius: 999px; }
.badge.live { background: color-mix(in srgb, var(--accent-2) 18%, transparent); color: var(--accent-2); }
.badge.soon { background: var(--surface-2); color: var(--text-dim); }
.card-link { position: absolute; inset: 0; border-radius: var(--radius); }

/* progress bar on live card */
.progress-line { height: 6px; background: var(--surface-2); border-radius: 4px; overflow: hidden; margin-bottom: 14px; }
.progress-line > div { height: 100%; background: linear-gradient(90deg, var(--accent), var(--accent-2)); width: 0; }

/* Philosophy strip */
.philo { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 30px 30px; margin: 20px 0 50px; }
.philo h2 { font-size: 1.4rem; margin: 0 0 14px; letter-spacing: -0.01em; }
.philo p { color: var(--text-dim); margin: 0 0 12px; max-width: 760px; }
.philo .grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 16px; margin-top: 22px; }
.philo .grid .it b { display: block; color: var(--text); font-size: 0.95rem; margin-bottom: 3px; }
.philo .grid .it span { color: var(--text-dim); font-size: 0.87rem; }

footer { border-top: 1px solid var(--border); padding: 30px 0; color: var(--text-dim); font-size: 0.85rem; text-align: center; }
footer a { color: var(--text-dim); }

@media (max-width: 560px) {
  .hero { padding: 46px 0 20px; }
  .subjects { grid-template-columns: 1fr; }
}