:root{--bg-primary:#000;--bg-secondary:#0a0a0a;--bg-card:#121212;--border-color:#222;--text-main:#fff;--text-muted:#a0a0a0;--accent-green:#1db954;--accent-hover:#1ed760;--border-radius-md:12px;--border-radius-lg:20px;--transition-speed:.3s ease}[data-theme=light]{--bg-primary:#f5f5f7;--bg-secondary:#fff;--bg-card:#fff;--border-color:#e5e5ea;--text-main:#1d1d1f;--text-muted:#86868b}*{box-sizing:border-box;margin:0;padding:0}body{background-color:var(--bg-primary);color:var(--text-main);-webkit-font-smoothing:antialiased;min-height:100vh;transition:background-color var(--transition-speed), color var(--transition-speed);font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,sans-serif}.app-container{max-width:800px;margin:0 auto;padding:2rem}.top-bar{justify-content:space-between;align-items:center;margin-bottom:2.5rem;display:flex}.theme-toggle{background:var(--bg-card);border:1px solid var(--border-color);color:var(--text-main);cursor:pointer;transition:all var(--transition-speed);border-radius:20px;padding:.5rem 1rem;font-weight:600}.theme-toggle:hover{border-color:var(--text-muted)}.nav-tabs{border-bottom:1px solid var(--border-color);gap:1rem;margin-bottom:2rem;padding-bottom:1rem;display:flex}.nav-tab{color:var(--text-muted);cursor:pointer;transition:color var(--transition-speed);background:0 0;border:none;padding:.5rem 0;font-size:1.1rem;font-weight:600}.nav-tab.active{color:var(--text-main);border-bottom:2px solid var(--accent-green)}