:root{--color-bg: #0f0f0f;--color-surface: #1a1a1a;--color-surface-2: #252525;--color-text: #ffffff;--color-text-muted: #888888;--color-accent: #00d4aa;--color-accent-hover: #00b894;--color-danger: #ff4757;--radius: 12px;--spacing: 1rem}*{margin:0;padding:0;box-sizing:border-box}body{font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,sans-serif;background:var(--color-bg);color:var(--color-text);line-height:1.5}.container{max-width:800px;margin:0 auto;padding:var(--spacing)}.card{background:var(--color-surface);border-radius:var(--radius);padding:calc(var(--spacing) * 1.5);margin-bottom:var(--spacing)}.card-title{font-size:1.25rem;font-weight:600;margin-bottom:.5rem}.btn{display:inline-flex;align-items:center;gap:.5rem;padding:.75rem 1.25rem;border:none;border-radius:var(--radius);background:var(--color-accent);color:#000;font-weight:600;cursor:pointer;transition:all .2s}.btn:hover{background:var(--color-accent-hover)}.btn-secondary{background:var(--color-surface-2);color:var(--color-text)}.btn-secondary:hover{background:#333}.nav{display:flex;gap:1rem;padding:var(--spacing) 0;border-bottom:1px solid var(--color-surface-2);margin-bottom:var(--spacing)}.nav a{color:var(--color-text-muted);text-decoration:none;font-weight:500;padding:.5rem 0;border-bottom:2px solid transparent;transition:all .2s}.nav a:hover,.nav a.active{color:var(--color-accent);border-bottom-color:var(--color-accent)}.word-card{display:flex;align-items:center;gap:1rem;padding:1rem;background:var(--color-surface-2);border-radius:var(--radius);margin-bottom:.5rem}.word-hanzi{font-size:2rem;font-weight:700}.word-meta{flex:1}.word-pinyin{color:var(--color-accent);font-size:.875rem}.word-meaning{color:var(--color-text-muted);font-size:.875rem}.level-badge{display:inline-block;padding:.25rem .5rem;border-radius:4px;font-size:.75rem;font-weight:600;background:var(--color-surface)}.level-1{color:#888}.level-2{color:#4a9eff}.level-3{color:#ffd93d}.level-4{color:#ff9f43}.level-5{color:#ff4757}.stats-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(120px,1fr));gap:1rem;margin-bottom:var(--spacing)}.stat-card{background:var(--color-surface-2);padding:1rem;border-radius:var(--radius);text-align:center}.stat-value{font-size:1.75rem;font-weight:700;color:var(--color-accent)}.stat-label{font-size:.75rem;color:var(--color-text-muted);text-transform:uppercase;letter-spacing:.05em}