:root{--bg: #f6f8fb;--bg-elevated: #ffffff;--panel: #edf2f7;--text: #1f2937;--muted: #6b7280;--border: #dbe3ee;--accent: #2563eb;--accent-strong: #1d4ed8;--shadow: rgba(15, 23, 42, .12)}body,body.theme-bright{background:var(--bg);color:var(--text);transition:background-color .2s ease,color .2s ease}body.theme-dark{--bg: #0f172a;--bg-elevated: #111827;--panel: #1f2937;--text: #e5e7eb;--muted: #9ca3af;--border: #374151;--accent: #60a5fa;--accent-strong: #3b82f6;--shadow: rgba(2, 6, 23, .45)}body{margin:0;font-family:Arial,Helvetica,sans-serif;background:var(--bg);color:var(--text)}.app,.container,.card,.panel,section,main,aside{background:var(--bg-elevated);color:var(--text);border:1px solid var(--border);box-shadow:0 8px 24px var(--shadow)}button,input,select,textarea{background:var(--panel);color:var(--text);border:1px solid var(--border);border-radius:8px}button{background:var(--accent);color:#fff;border-color:transparent;cursor:pointer;transition:background-color .2s ease,transform .2s ease}button:hover{background:var(--accent-strong)}label,small,.caption,.subtitle{color:var(--muted)}hr{border-color:var(--border)}.theme-switcher{display:inline-flex;align-items:center;gap:.5rem;padding:.5rem .75rem;border-radius:999px;background:var(--panel);border:1px solid var(--border);color:var(--text)}