:root{--page-bg: #f4f6fb;--text-primary: #0f172a;--text-muted: #5f6b7a;--card-bg: linear-gradient(145deg, #ffffff, #f3f6ff);--card-border: #e5e9f2;--card-shadow: 0 16px 28px -18px rgba(31, 41, 55, .35), 0 8px 14px -10px rgba(31, 41, 55, .18);--button-bg: #3b82f6;--button-bg-hover: #1d4ed8;--button-text: #ffffff}body.theme-dark{--page-bg: #0b1220;--text-primary: #e2e8f0;--text-muted: #94a3b8;--card-bg: linear-gradient(160deg, #0f172a, #111827);--card-border: #1f2937;--card-shadow: 0 18px 30px -18px rgba(0, 0, 0, .65), 0 10px 16px -12px rgba(0, 0, 0, .45);--button-bg: #2563eb;--button-bg-hover: #1d4ed8;--button-text: #e0f2fe}*{box-sizing:border-box}body{margin:0;min-height:100vh;background:var(--page-bg);color:var(--text-primary);font-family:Segoe UI,system-ui,-apple-system,sans-serif;transition:background .3s ease,color .3s ease}