:root{--bg-gradient:linear-gradient(180deg, #e0f2fe 0%, #bae6fd 100%);--window-bg:#fff;--window-border:#cbd5e1;--text-main:#334155;--text-muted:#64748b;--titlebar-bg:#475569;--titlebar-text:#f8fafc;--nav-hover:#f1f5f9;--accent:#f59e0b}[data-theme=dark]{--bg-gradient:linear-gradient(180deg, #0f172a 0%, #172554 100%);--window-bg:#1e293b;--window-border:#334155;--text-main:#f8fafc;--text-muted:#94a3b8;--titlebar-bg:#0f172a;--titlebar-text:#e2e8f0;--nav-hover:#334155;--accent:#38bdf8}body{background:var(--bg-gradient);min-height:100vh;color:var(--text-main);margin:0;padding:0;font-family:Quicksand,sans-serif;transition:background .4s,color .4s}.os-window{background-color:var(--window-bg);border:1px solid var(--window-border);border-radius:12px;transition:background-color .4s,border-color .4s;overflow:hidden;box-shadow:0 10px 25px #00000014,0 4px 6px #0000000a}.os-titlebar{background-color:var(--titlebar-bg);color:var(--titlebar-text);align-items:center;gap:8px;padding:8px 16px;font-size:14px;font-weight:700;transition:background-color .4s,color .4s;display:flex}.os-dot{border-radius:50%;width:10px;height:10px;display:inline-block}.dot-red{background-color:#ff5f56}.dot-yellow{background-color:#ffbd2e}.dot-green{background-color:#27c93f}.nav-link{color:var(--text-main);border-radius:8px;padding:12px 16px;font-size:16px;font-weight:700;text-decoration:none;transition:background-color .2s,transform .1s;display:block}.nav-link:hover{background-color:var(--nav-hover);transform:translate(4px)}.os-input{border:1px solid var(--window-border);background-color:var(--window-bg);width:100%;color:var(--text-main);box-sizing:border-box;border-radius:6px;padding:10px 12px;font-family:Quicksand,sans-serif;font-size:15px;font-weight:600;transition:all .2s}.os-input:focus{border-color:var(--accent);outline:none;box-shadow:0 0 0 3px #38bdf833}