*{box-sizing:border-box;margin:0;padding:0}:root{--primary:#4f8cff;--primary-light:#e8f0ff;--success:#34c759;--success-light:#e8f9ee;--success-bg:#e8f9ee;--warning:#ff9500;--bg:#f5f5f7;--card-bg:#fff;--text:#1a1a1a;--text-secondary:#666;--border:#e5e5e5;--radius:12px}body{background:var(--bg);color:var(--text);-webkit-font-smoothing:antialiased;font-family:-apple-system,BlinkMacSystemFont,Segoe UI,sans-serif}.app{flex-direction:column;max-width:480px;min-height:100vh;margin:0 auto;display:flex}.app-header{background:var(--primary);color:#fff;text-align:center;padding:16px 20px}.app-header h1{font-size:18px;font-weight:600}.app-main{flex:1;padding:16px 16px 80px;overflow-y:auto}.card{background:var(--card-bg);border-radius:var(--radius);margin-bottom:12px;padding:16px;box-shadow:0 1px 3px #0000000f}.card-title{margin-bottom:12px;font-size:16px;font-weight:600}.btn{cursor:pointer;border:none;border-radius:8px;justify-content:center;align-items:center;padding:8px 16px;font-size:14px;font-weight:500;transition:all .2s;display:inline-flex}.btn-primary{background:var(--primary);color:#fff}.btn-success{background:var(--success);color:#fff}.btn-outline{border:1px solid var(--border);color:var(--text);background:0 0}.btn-sm{padding:6px 12px;font-size:13px}.btn:disabled{opacity:.5;cursor:not-allowed}.tag{background:var(--primary-light);color:var(--primary);border-radius:4px;padding:2px 8px;font-size:12px;display:inline-block}.tag-success{background:var(--success-light);color:var(--success)}.bottom-nav{background:var(--card-bg);border-top:1px solid var(--border);width:100%;max-width:480px;padding:8px 0;padding-bottom:env(safe-area-inset-bottom,8px);display:flex;position:fixed;bottom:0;left:50%;transform:translate(-50%)}.nav-item{color:var(--text-secondary);cursor:pointer;background:0 0;border:none;flex-direction:column;flex:1;align-items:center;padding:4px;font-size:11px;display:flex}.nav-item.active{color:var(--primary)}.nav-icon{margin-bottom:2px;font-size:20px}.vocab-item{border-bottom:1px solid var(--border);align-items:center;padding:8px 0;display:flex}.vocab-item:last-child{border-bottom:none}.vocab-word{color:var(--primary);min-width:80px;font-weight:600}.vocab-meaning{color:var(--text-secondary);font-size:14px}.sentence-item{border-bottom:1px solid var(--border);padding:8px 0}.sentence-item:last-child{border-bottom:none}.sentence-en{margin-bottom:2px;font-weight:500}.sentence-zh{color:var(--text-secondary);font-size:14px}