:root {
  color-scheme: light;
  --bg: #f8fbff;
  --bg-soft: #edf5f7;
  --bg-elevated: rgba(255, 255, 255, 0.78);
  --text: #16202a;
  --muted: #5c6875;
  --line: rgba(56, 72, 87, 0.14);
  --brand: #5a5cf0;
  --brand-strong: #3538c9;
  --brand-cyan: #00a9c8;
  --accent: #1f9d7a;
  --warning: #b36b00;
  --shadow: 0 24px 60px rgba(29, 38, 64, 0.14);
  --radius: 8px;
  --header-height: 72px;
  --max-width: 1160px;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    color-scheme: dark;
    --bg: #10141d;
    --bg-soft: #151c28;
    --bg-elevated: rgba(23, 30, 43, 0.78);
    --text: #edf4ff;
    --muted: #a7b2c2;
    --line: rgba(209, 223, 241, 0.16);
    --brand: #9a9cff;
    --brand-strong: #c2c4ff;
    --brand-cyan: #55d9ef;
    --accent: #55d1a8;
    --warning: #ffc66b;
    --shadow: 0 24px 70px rgba(0, 0, 0, 0.36);
  }
}

:root[data-theme="dark"] {
  color-scheme: dark;
  --bg: #10141d;
  --bg-soft: #151c28;
  --bg-elevated: rgba(23, 30, 43, 0.78);
  --text: #edf4ff;
  --muted: #a7b2c2;
  --line: rgba(209, 223, 241, 0.16);
  --brand: #9a9cff;
  --brand-strong: #c2c4ff;
  --brand-cyan: #55d9ef;
  --accent: #55d1a8;
  --warning: #ffc66b;
  --shadow: 0 24px 70px rgba(0, 0, 0, 0.36);
}

:root[data-theme="light"] {
  color-scheme: light;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-width: 320px;
  background:
    linear-gradient(135deg, rgba(90, 92, 240, 0.08), transparent 28rem),
    linear-gradient(225deg, rgba(0, 169, 200, 0.08), transparent 26rem),
    var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  font-size: 16px;
  line-height: 1.7;
  text-rendering: optimizeLegibility;
}

body.nav-open {
  overflow: hidden;
}

img {
  display: block;
  max-width: 100%;
}

a {
  color: inherit;
  text-decoration: none;
}

p,
h1,
h2,
h3 {
  margin-top: 0;
}

p {
  color: var(--muted);
}

h1,
h2,
h3 {
  color: var(--text);
  line-height: 1.16;
}

h1 {
  font-size: 5.8rem;
  margin-bottom: 1rem;
}

h2 {
  font-size: 2.8rem;
  margin-bottom: 1rem;
}

h3 {
  font-size: 1.08rem;
  margin-bottom: 0.55rem;
}

button,
input,
textarea {
  font: inherit;
}

button {
  color: inherit;
}

:focus-visible {
  outline: 3px solid color-mix(in srgb, var(--brand-cyan) 72%, transparent);
  outline-offset: 3px;
}

.skip-link {
  position: fixed;
  left: 1rem;
  top: 1rem;
  z-index: 100;
  transform: translateY(-140%);
  border-radius: var(--radius);
  background: var(--text);
  color: var(--bg);
  padding: 0.6rem 0.8rem;
}

.skip-link:focus {
  transform: translateY(0);
}