/**
 * 主题模式 — 白天 / 晚上 / 本机
 */
:root, :root[data-theme="light"] {
  color-scheme: light;
  --header-bg: rgba(255, 255, 255, 0.95);
  --hero-bg: linear-gradient(135deg, #0f172a 0%, #1e3a5f 50%, #0f172a 100%);
  --input-bg: #ffffff;
  --nav-mobile-bg: #ffffff;
}
:root[data-theme="dark"] {
  color-scheme: dark;
  --color-text: #f1f5f9;
  --color-text-secondary: #94a3b8;
  --color-text-muted: #64748b;
  --color-bg: #0f172a;
  --color-bg-alt: #1e293b;
  --color-bg-dark: #020617;
  --color-border: #334155;
  --header-bg: rgba(15, 23, 42, 0.92);
  --hero-bg: linear-gradient(135deg, #020617 0%, #0f172a 50%, #020617 100%);
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.45);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.5);
  --input-bg: #1e293b;
  --nav-mobile-bg: #0f172a;
}
@media (prefers-color-scheme: dark) {
  :root[data-theme="system"] {
    color-scheme: dark;
    --color-text: #f1f5f9;
    --color-text-secondary: #94a3b8;
    --color-text-muted: #64748b;
    --color-bg: #0f172a;
    --color-bg-alt: #1e293b;
    --color-bg-dark: #020617;
    --color-border: #334155;
    --header-bg: rgba(15, 23, 42, 0.92);
    --hero-bg: linear-gradient(135deg, #020617 0%, #0f172a 50%, #020617 100%);
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.45);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.5);
    --input-bg: #1e293b;
    --nav-mobile-bg: #0f172a;
  }
}
@media (prefers-color-scheme: light) {
  :root[data-theme="system"] { color-scheme: light; }
}