:root {
  --bg: #0b1020;
  --surface: rgba(255, 255, 255, 0.06);
  --border: rgba(255, 255, 255, 0.12);
  --text: rgba(255, 255, 255, 0.9);
  --muted: rgba(255, 255, 255, 0.72);
  --accent: #7c5cff;
  --accent-2: #2ee59d;
  --shadow: 0 24px 60px rgba(0, 0, 0, 0.45);
  --radius: 18px;
}

@media (prefers-color-scheme: light) {
  :root {
    --bg: #f6f7fb;
    --surface: rgba(255, 255, 255, 0.8);
    --border: rgba(10, 20, 40, 0.12);
    --text: rgba(10, 20, 40, 0.92);
    --muted: rgba(10, 20, 40, 0.7);
    --shadow: 0 18px 45px rgba(10, 20, 40, 0.12);
  }
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  color-scheme: light dark;
}

body {
  margin: 0;
  min-height: 100svh;
  font-family:
    ui-sans-serif,
    system-ui,
    -apple-system,
    "Segoe UI",
    "Hiragino Sans",
    "Noto Sans JP",
    "Yu Gothic",
    sans-serif;
  line-height: 1.7;
  letter-spacing: 0.01em;
  color: var(--text);
  background:
    radial-gradient(1200px 700px at 15% 10%, rgba(124, 92, 255, 0.35), transparent 60%),
    radial-gradient(900px 600px at 80% 20%, rgba(46, 229, 157, 0.22), transparent 55%),
    radial-gradient(900px 600px at 50% 90%, rgba(124, 92, 255, 0.18), transparent 60%),
    var(--bg);
  padding: clamp(20px, 4vw, 44px);
}

.container {
  max-width: 860px;
  margin: 0 auto;
  padding: clamp(18px, 3vw, 28px);
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  backdrop-filter: blur(10px);
}

h1,
h2 {
  line-height: 1.2;
  margin: 0 0 0.6em;
  letter-spacing: -0.01em;
}

h1 {
  font-size: clamp(28px, 3.2vw, 40px);
  position: relative;
  padding-bottom: 0.55em;
}

h1::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: min(220px, 60%);
  height: 3px;
  border-radius: 999px;
  background: linear-gradient(90deg, var(--accent), var(--accent-2));
  opacity: 0.95;
}

h2 {
  font-size: clamp(18px, 2.1vw, 24px);
  color: var(--muted);
  margin-top: 1.2em;
}

p {
  margin: 0.6em 0 1.1em;
  color: var(--text);
}

ul,
ol {
  margin: 0.6em 0 1.1em;
  padding-left: 1.2em;
}

li {
  margin: 0.35em 0;
}

ul > li::marker {
  color: var(--accent-2);
}

ol > li::marker {
  color: var(--accent);
  font-variant-numeric: tabular-nums;
}

:focus-visible {
  outline: 3px solid color-mix(in oklab, var(--accent) 75%, white 25%);
  outline-offset: 3px;
  border-radius: 10px;
}