:root { color-scheme: light; --bg: #f5f6fa; --card: #fff; --text: #1d2433; --muted: #626a7b; --border: #e2e6ef; --accent: #285de0; --tint: #edf2ff; }
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) { color-scheme: dark; --bg: #111318; --card: #1c2029; --text: #f0f2f7; --muted: #adb5c6; --border: #343b4a; --accent: #91afff; --tint: #263353; }
}
:root[data-theme="dark"] { color-scheme: dark; --bg: #111318; --card: #1c2029; --text: #f0f2f7; --muted: #adb5c6; --border: #343b4a; --accent: #91afff; --tint: #263353; }
* { box-sizing: border-box; }
body { margin: 0; background: var(--bg); color: var(--text); font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", sans-serif; line-height: 1.6; }
main { max-width: 640px; margin: 0 auto; padding: 40px 22px max(32px, env(safe-area-inset-bottom)); }
h1 { margin: 0 0 8px; font-size: 28px; letter-spacing: -.5px; }
.intro { margin: 0 0 30px; color: var(--muted); font-size: 16px; }
nav { display: grid; gap: 18px; }
.tutorial { display: flex; align-items: center; gap: 16px; min-height: 144px; padding: 24px 20px; border: 1px solid var(--border); border-radius: 20px; background: var(--card); color: inherit; text-decoration: none; -webkit-tap-highlight-color: transparent; }
.tutorial:hover, .tutorial:active { border-color: var(--accent); }
.tutorial:focus-visible { outline: 3px solid var(--accent); outline-offset: 4px; }
.icon { display: grid; place-items: center; width: 52px; height: 52px; flex-shrink: 0; border-radius: 16px; color: var(--accent); background: var(--tint); }
svg { width: 27px; height: 27px; fill: none; stroke: currentColor; stroke-width: 1.8; stroke-linecap: round; stroke-linejoin: round; }
.copy { flex: 1; min-width: 0; }
strong { display: block; font-size: 19px; line-height: 1.45; }
.description { display: block; margin-top: 7px; color: var(--muted); font-size: 14px; }
.arrow { width: 18px; flex-shrink: 0; color: var(--muted); }
@media (max-width: 360px) { main { padding: 30px 16px; } .tutorial { padding: 22px 16px; gap: 12px; } .icon { width: 42px; height: 46px; } strong { font-size: 17px; } }
.version { font-size: 22px; font-weight: 700; }
.version-help { margin: 24px 0 0; color: var(--muted); font-size: 14px; }