:root {
  color-scheme: light;
  --bg: #f5f6f8;
  --panel: #fff;
  --panel-strong: #fff;
  --soft: #f0f2f5;
  --text: #1b2029;
  --secondary: #444d5c;
  --muted: #606a79;
  --line: #dde1e7;
  --primary: #215dbd;
  --primary-hover: #174c9f;
  --primary-soft: #eaf1fe;
  --on-primary: #fff;
  --success: #18704d;
  --warning: #88510e;
  --danger: #a93343;
  --radius: 12px;
  --control-radius: 8px;
  --mono: ui-monospace, "SFMono-Regular", Consolas, monospace;
  --ease: cubic-bezier(.2, .7, .3, 1);
  font-family: system-ui, "PingFang SC", "Microsoft YaHei", sans-serif;
  font-size: 14px;
}

:root[data-theme="dark"] {
  color-scheme: dark;
  --bg: #13151a;
  --panel: #1a1d24;
  --panel-strong: #1f232c;
  --soft: #232731;
  --text: #edf0f6;
  --secondary: #c1c8d5;
  --muted: #a0aab9;
  --line: #323743;
  --primary: #98bcff;
  --primary-hover: #b2ceff;
  --primary-soft: #23334d;
  --on-primary: #132541;
  --success: #87cea9;
  --warning: #edbd83;
  --danger: #fa9aa8;
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }

body {
  margin: 0;
  min-height: 100vh;
  background: var(--bg);
  color: var(--text);
  line-height: 1.5;
  font-variant-numeric: tabular-nums;
}

button, input, select, textarea { font: inherit; }
button { cursor: pointer; }
button:disabled { cursor: not-allowed; opacity: .55; }
:focus-visible { outline: 2px solid var(--primary); outline-offset: 2px; }
a { color: var(--primary); }
strong, b, h1, h2, h3 { font-weight: 600; }
h2 { font-size: 20px; line-height: 1.3; }
h3 { font-size: 16px; line-height: 1.4; }

.shell {
  width: min(100%, 1328px);
  min-width: 0;
  margin: 0 auto;
  padding: 32px clamp(20px, 3vw, 48px) 56px;
}

.hero {
  display: flex;
  justify-content: space-between;
  align-items: flex-end;
  gap: 20px;
  margin-bottom: 24px;
}

.eyebrow, .step-label {
  margin: 0;
  color: var(--muted);
  font-size: 12px;
  font-weight: 500;
}

.back-link {
  display: inline-block;
  margin-bottom: 12px;
  color: var(--muted);
  font-size: 13px;
  text-decoration: none;
}
.back-link:hover { color: var(--primary); }

h1 {
  margin: 4px 0 8px;
  font-size: clamp(28px, 3vw, 40px);
  line-height: 1.2;
  letter-spacing: -.025em;
  overflow-wrap: anywhere;
}

.subtitle {
  max-width: 60ch;
  margin: 0;
  color: var(--muted);
  font-size: 14px;
  line-height: 1.65;
}

.header-actions { display: flex; align-items: center; flex-wrap: wrap; gap: 8px; }
.header-actions .primary-button { width: auto; margin: 0; }

@media (max-width: 620px) {
  .shell { padding: 24px 16px 40px; }
  .hero { flex-direction: column; align-items: flex-start; gap: 12px; margin-bottom: 16px; }
}