:root {
  --bg: #fbfaf7;
  --surface: #ffffff;
  --alt: #f3f1ec;
  --text: #1c1c1a;
  --text-2: #55554f;
  --text-3: #8a8a83;
  --line: #e4e1d9;
  --line-strong: #c9c5ba;
  --brand: #1d5c52;
  --brand-hover: #174a42;
  --on-brand: #ffffff;
  --radius: 14px;
  --sans: system-ui, -apple-system, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", sans-serif;
  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #15161a;
    --surface: #1d1f24;
    --alt: #1a1c21;
    --text: #eceae4;
    --text-2: #b3b1a9;
    --text-3: #7d7c76;
    --line: #2c2e35;
    --line-strong: #4a4d56;
    --brand: #5fb3a2;
    --brand-hover: #7cc5b5;
    --on-brand: #0f1714;
    color-scheme: dark;
  }
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--sans);
  font-size: 17px;
  line-height: 1.75;
  overflow-x: hidden;
}

a { color: inherit; }

.wrap {
  max-width: 1040px;
  margin-inline: auto;
  padding-inline: 24px;
}

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  background: var(--bg);
  border-bottom: 1px solid var(--line);
}
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 60px;
}
.brand {
  font-size: 20px;
  font-weight: 700;
  letter-spacing: 0.02em;
  text-decoration: none;
}
.brand span { color: var(--brand); }
.nav { display: flex; gap: 22px; font-size: 15px; }
.nav a { color: var(--text-2); text-decoration: none; }
.nav a:hover { color: var(--brand); }

/* Hero */
.hero { padding: 112px 0 96px; }
.eyebrow {
  margin: 0 0 16px;
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 0.08em;
  color: var(--brand);
}
h1 {
  margin: 0 0 20px;
  font-size: clamp(34px, 6vw, 56px);
  font-weight: 700;
  line-height: 1.2;
  letter-spacing: -0.01em;
}
.lead {
  max-width: 36em;
  margin: 0 0 36px;
  font-size: 19px;
  color: var(--text-2);
}

/* Buttons */
.actions { display: flex; flex-wrap: wrap; gap: 12px; }
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  height: 46px;
  padding: 0 22px;
  border: 1px solid transparent;
  border-radius: 999px;
  font: 500 16px var(--sans);
  text-decoration: none;
  cursor: pointer;
}
.btn-primary { background: var(--brand); color: var(--on-brand); }
.btn-primary:hover { background: var(--brand-hover); }
.btn-ghost { border-color: var(--line-strong); color: var(--text); }
.btn-ghost:hover { border-color: var(--brand); color: var(--brand); }
.btn-disabled {
  background: var(--alt);
  border-color: var(--line);
  color: var(--text-3);
  cursor: not-allowed;
}

/* Sections */
.section { padding: 88px 0; }
.section-alt { background: var(--alt); }
h2 {
  margin: 0 0 20px;
  font-size: 28px;
  font-weight: 700;
}
.section p { margin: 0 0 16px; }

/* About */
.about {
  display: grid;
  grid-template-columns: 200px 1fr;
  gap: 48px;
  align-items: start;
}
.avatar {
  width: 200px;
  height: 200px;
  display: grid;
  place-items: center;
  border-radius: var(--radius);
  background: var(--brand);
  color: var(--on-brand);
  font-size: 72px;
  font-weight: 700;
}
.facts {
  display: grid;
  gap: 10px;
  margin: 28px 0 0;
  padding: 0;
  list-style: none;
}
.facts li {
  padding: 14px 18px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}
.facts strong {
  margin-right: 6px;
  font-size: 20px;
  color: var(--brand);
}

/* Course card */
.card {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 20px;
  max-width: 620px;
  padding: 28px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}
.card p { margin: 0; }

/* Footer */
.site-footer {
  padding: 28px 0;
  border-top: 1px solid var(--line);
  font-size: 14px;
  color: var(--text-3);
}
.footer-inner {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 8px;
}

/* Phone */
@media (max-width: 760px) {
  .wrap { padding-inline: 16px; }
  .hero { padding: 72px 0 64px; }
  .section { padding: 64px 0; }
  .about { grid-template-columns: 1fr; gap: 28px; }
  .avatar { width: 120px; height: 120px; font-size: 48px; }
}